Why does the shuttle throttle on ascent?

[Danny Deger]

Why does the shuttle throttle to 3 Gs on ascent?

Danny Deger

[Mxsmanic]

Danny Deger writes:

> Why does the shuttle throttle to 3 Gs on ascent?

The real Shuttle throttles back during ascent at a certain point in
order to reduce aerodynamic stresses as it rises through the
atmosphere.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Ron Natalie]

Danny Deger wrote:
> Why does the shuttle throttle to 3 Gs on ascent?
>
I don't know about G's but the shuttle adjust the engine thrust
up and down at various times in the launch based on the dynamic
pressures involved.

[John Doe]

Danny Deger wrote:
> Why does the shuttle throttle to 3 Gs on ascent?

As the fuel is burned/jettisoned the engines have a smaller vehicle mass
to accelerate. So to maintain an acceptable acceleration level, you
throttle back engines.

Also, as you leave the atmopsphere, there is less and less air resistance,
so you also need less power to maintain the desired acceleration level.

And early in the ascent, they throttle back to ensure the shuttle's air
speed isn't too great as it travels through the still dense atmosphere
since it would create too much aerodynamic drag.

[John T]

"Ron Natalie" > wrote in message
m
>
> I don't know about G's but the shuttle adjust the engine thrust
> up and down at various times in the launch based on the dynamic
> pressures involved.

"'Go' for throttle up."

My generation's equivalent of "Where were you when Kennedy got shot?"

--
John T
http://sage1solutions.com/blogs/TknoFlyer
Reduce spam. Use Sender Policy Framework: http://openspf.org
____________________

[Dudley Henriques]

"Danny Deger" > wrote in message
...
> Why does the shuttle throttle to 3 Gs on ascent?
>
> Danny Deger

As the shuttle ascends, the dynamic pressure (in slugs/sq.in) increases as
the square of the velocity. The shuttle is throttled back to 65% thrust to
avoid over stress at a speed computed under what is called critical q.
As the shuttle ascends, it is ascending into lower air density (which of
course transfers into a lowering dynamic pressure). The throttling back
takes the shuttle through a transition area during the ascent that ends as
the lowering air density meets the parameters that allow throttle up. This I
believe occurs at about 35 to 37K.
The point where lowering air density meets the ability to throttle up again
is the max q for the shuttle. (Max q meaning maximum dynamic pressure)
After reaching max q, the shuttle is go for throttle up as the increasing
velocity past max q will never exceed the structural limitations of the
shuttle due to it's entrance into lower air density that doesn't have the
ability to overstress the structure.
Hope this helps a bit.
Dudley Henriques

[Henry Spencer]

In article >,
Danny Deger > wrote:
>Why does the shuttle throttle to 3 Gs on ascent?

This is partly for the benefit of the passengers -- it's thought that a
healthy adult can be expected to take about 3G without testing -- and
partly to limit structural loads. (The Saturn V first stage shut down
its center engine early for the latter reason.)

There is also an earlier bit of throttle reduction, during the SRB burn,
done to keep speed down until the shuttle is out of the thickest air.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Dudley Henriques]

On the way;

DH

"Richard Riley" > wrote in message
...
> On Sat, 6 Jan 2007 22:10:34 -0500, "Dudley Henriques"
> > wrote:
>
>>
>>Hope this helps a bit.
>>Dudley Henriques
>
> Dudley, would you email me off list? (not on this topic)
>
> Richard at riley dot net

[David Kazdan]

Dudley:

Isn't dynamic pressure expressed in pressure units, pounds per
square inch (or SI, Pascals: newtons/sq. meter)? Mass density, which
you mention later, is in slugs/cu.in or cu.ft (or SI, Kg/cu.meter).

Thanks for all your good posts, I've learned a lot from them over
the years.

David

Dudley Henriques wrote:
> "Danny Deger" > wrote in message
> ...
>> Why does the shuttle throttle to 3 Gs on ascent?
>>
>> Danny Deger
>
> As the shuttle ascends, the dynamic pressure (in slugs/sq.in) increases as
> the square of the velocity. The shuttle is throttled back to 65% thrust to
> avoid over stress at a speed computed under what is called critical q.
> As the shuttle ascends, it is ascending into lower air density (which of
> course transfers into a lowering dynamic pressure). The throttling back
> takes the shuttle through a transition area during the ascent that ends as
> the lowering air density meets the parameters that allow throttle up. This I
> believe occurs at about 35 to 37K.
> The point where lowering air density meets the ability to throttle up again
> is the max q for the shuttle. (Max q meaning maximum dynamic pressure)
> After reaching max q, the shuttle is go for throttle up as the increasing
> velocity past max q will never exceed the structural limitations of the
> shuttle due to it's entrance into lower air density that doesn't have the
> ability to overstress the structure.
> Hope this helps a bit.
> Dudley Henriques
>
>

[Danny Deger]

"Danny Deger" > wrote in message
...
> Why does the shuttle throttle to 3 Gs on ascent?
>

The answer is:

So Navy Fighter pilots can fly the shuttle :-)

Danny Deger

P.S. I was an Air Force figher pilot.

[Dudley Henriques]

Bear with me David. I've been away from this stuff for a long while :-))


Rho for SSL is 0.002378 slugs/cu ft. Mass in slugs is the weight in
lbs/32.2
For high performance flight test dealing with uncompressible airflow; for
density (slugs ft3) for mass airflow (slugs/sec)


"David Kazdan" > wrote in message
t...
> Dudley:
>
> Isn't dynamic pressure expressed in pressure units, pounds per square
> inch (or SI, Pascals: newtons/sq. meter)? Mass density, which you mention
> later, is in slugs/cu.in or cu.ft (or SI, Kg/cu.meter).
>
> Thanks for all your good posts, I've learned a lot from them over the
> years.
>
> David
>
> Dudley Henriques wrote:
>> "Danny Deger" > wrote in message
>> ...
>>> Why does the shuttle throttle to 3 Gs on ascent?
>>>
>>> Danny Deger
>>
>> As the shuttle ascends, the dynamic pressure (in slugs/sq.in) increases
>> as the square of the velocity. The shuttle is throttled back to 65%
>> thrust to avoid over stress at a speed computed under what is called
>> critical q.
>> As the shuttle ascends, it is ascending into lower air density (which of
>> course transfers into a lowering dynamic pressure). The throttling back
>> takes the shuttle through a transition area during the ascent that ends
>> as the lowering air density meets the parameters that allow throttle up.
>> This I believe occurs at about 35 to 37K.
>> The point where lowering air density meets the ability to throttle up
>> again is the max q for the shuttle. (Max q meaning maximum dynamic
>> pressure)
>> After reaching max q, the shuttle is go for throttle up as the increasing
>> velocity past max q will never exceed the structural limitations of the
>> shuttle due to it's entrance into lower air density that doesn't have the
>> ability to overstress the structure.
>> Hope this helps a bit.
>> Dudley Henriques

[[email protected]]

Danny Deger wrote:
> Why does the shuttle throttle to 3 Gs on ascent?
>
> Danny Deger

Because structurally the shuttle vehicle is only stressed for 3 g's. If
they didn't throttle back in the late stages of the ascent when the
fuel is almost gone and the vehicle is light, it would exceed this
level of acceleration. Since the engines are liquid fueled, they can
hold full thrust until the fuel is gone.

Bud

[Greg D. Moore \(Strider\)]

"Danny Deger" > wrote in message
...
>
> "Danny Deger" > wrote in message
> ...
>> Why does the shuttle throttle to 3 Gs on ascent?
>>
>
> The answer is:
>
> So Navy Fighter pilots can fly the shuttle :-)

Ah, is this so that they can let the AF pilots catch up?
>
> Danny Deger
>
> P.S. I was an Air Force figher pilot.

I was wondering why you of all people was asking this. :-)



>
>
>

[Morgans[_2_]]

"Henry Spencer" > wrote

> This is partly for the benefit of the passengers -- it's thought that a
> healthy adult can be expected to take about 3G without testing -- and
> partly to limit structural loads. (The Saturn V first stage shut down
> its center engine early for the latter reason.)

The center engine shutting down is a fact that I had never heard, before
now.

Amazing what you can learn, hanging out here, if you take the time to listen
to ones with information to give. (unlike some we know)
--
Jim in NC

[Pat Flannery]

John T wrote:
> "'Go' for throttle up."
>
> My generation's equivalent of "Where were you when Kennedy got shot?"
>

I'm old enough to answer both those questions.

Pat

[Jim[_12_]]

BTW "go at throttle up" is, as I understood, is simply a radio call to
confirm communication with the vehicle, same as the "roll program" call. Is
that correct?
Jim
"Morgans" > wrote in message
...
>
> "Henry Spencer" > wrote
>
>> This is partly for the benefit of the passengers -- it's thought that a
>> healthy adult can be expected to take about 3G without testing -- and
>> partly to limit structural loads. (The Saturn V first stage shut down
>> its center engine early for the latter reason.)
>
> The center engine shutting down is a fact that I had never heard, before
> now.
>
> Amazing what you can learn, hanging out here, if you take the time to
> listen to ones with information to give. (unlike some we know)
> --
> Jim in NC
>

[Jim[_12_]]

Thanks Danny, I had a good belly laugh from that one.
Jim
> wrote in message
ps.com...
>
> Danny Deger wrote:
>> Why does the shuttle throttle to 3 Gs on ascent?
>>
>> Danny Deger
>
> Because structurally the shuttle vehicle is only stressed for 3 g's. If
> they didn't throttle back in the late stages of the ascent when the
> fuel is almost gone and the vehicle is light, it would exceed this
> level of acceleration. Since the engines are liquid fueled, they can
> hold full thrust until the fuel is gone.
>
> Bud
>

[Morgans[_2_]]

"Jim" > wrote

> BTW "go at throttle up" is, as I understood, is simply a radio call to
> confirm communication with the vehicle, same as the "roll program" call.
> Is that correct?

I'm no authority, but that is my understanding.

It is a confirmation to those along for the ride, that all functions are
within parameters, (thus the "go")as monitored from the ground, and no
action needs to be taken as the engines throttle back up.

It also probably serves as a reminder that the next jolt they feel is
expected, and to not be surprised at it. <g>

Kinda' like when you reduce power on final, and the passenger, if not told
to expect it, is rather "concerned" that they are about to crash. <g>
--
Jim in NC

[Jim[_12_]]

SSME's are "rated" at a certain thrust. However, the thrust rating has a
minimum, average and maximum. The "rated" thrust is the average. Therfore,
the engines can be run to an amount greater than "rated" thrust. I am not an
engineer or NASA personel, but I have read that during the nominal acent the
engines are throttled from 64% to 104% but can be throttled to 109% of
rated thrust if necessary.
Jim
"Richard Riley" > wrote in message
...
> On Sat, 6 Jan 2007 20:36:52 -0600, "Danny Deger"
> > wrote:
>
>>Why does the shuttle throttle to 3 Gs on ascent?
>>
>>Danny Deger
>>
>
> Heck, I still want to know how to go to 103% throttle.

[Morgans[_2_]]

"Richard Riley" > wrote in message
...
> On Sat, 6 Jan 2007 20:36:52 -0600, "Danny Deger"
> > wrote:
>
>>Why does the shuttle throttle to 3 Gs on ascent?
>>
>>Danny Deger
>>
>
> Heck, I still want to know how to go to 103% throttle.

Rather like the old prop jobs (DC-3 comes to mind as an example) that had a
wire across the throttle travel, which serves as a stop for full throttle
during normal operations. If it was needed for an emergency, like an engine
failure on takeoff, you can push through and past the wire for extra
emergency power. (100% plus power)

Of course, on some engines, that was grounds for grounding the aircraft to
inspect the engine, to see if it was damaged from exceeding 100% power.
--
Jim in NC

[Brian Gaff]

Yes, and it is also why the shedding foam can only do serious damage within
the lower atmosphere, as the drag cannot decelerate the chunks enough to
strike with enough force to do harm at that altitude.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Dudley Henriques" > wrote in message
...
>
> "Danny Deger" > wrote in message
> ...
>> Why does the shuttle throttle to 3 Gs on ascent?
>>
>> Danny Deger
>
> As the shuttle ascends, the dynamic pressure (in slugs/sq.in) increases as
> the square of the velocity. The shuttle is throttled back to 65% thrust to
> avoid over stress at a speed computed under what is called critical q.
> As the shuttle ascends, it is ascending into lower air density (which of
> course transfers into a lowering dynamic pressure). The throttling back
> takes the shuttle through a transition area during the ascent that ends as
> the lowering air density meets the parameters that allow throttle up. This
> I believe occurs at about 35 to 37K.
> The point where lowering air density meets the ability to throttle up
> again is the max q for the shuttle. (Max q meaning maximum dynamic
> pressure)
> After reaching max q, the shuttle is go for throttle up as the increasing
> velocity past max q will never exceed the structural limitations of the
> shuttle due to it's entrance into lower air density that doesn't have the
> ability to overstress the structure.
> Hope this helps a bit.
> Dudley Henriques
>

[Brian Gaff]

I don't think this is entirely true. I have some old stuff rattling around
in my mind from the 80s which put the rating at least twice this though of
course, only in the thrust direction. After all, the instantaneous
pressures on change can be rather less than subtle.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


> wrote in message
ps.com...
>
> Danny Deger wrote:
>> Why does the shuttle throttle to 3 Gs on ascent?
>>
>> Danny Deger
>
> Because structurally the shuttle vehicle is only stressed for 3 g's. If
> they didn't throttle back in the late stages of the ascent when the
> fuel is almost gone and the vehicle is light, it would exceed this
> level of acceleration. Since the engines are liquid fueled, they can
> hold full thrust until the fuel is gone.
>
> Bud
>

[Brian Gaff]

But the actual thrust abilities of the smes was increased over the life of
the Shuttle, I'm sure I read that.

Brian

--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email:
__________________________________________________ __________________________________________________ __________


"Morgans" > wrote in message
...
>
> "Richard Riley" > wrote in message
> ...
>> On Sat, 6 Jan 2007 20:36:52 -0600, "Danny Deger"
>> > wrote:
>>
>>>Why does the shuttle throttle to 3 Gs on ascent?
>>>
>>>Danny Deger
>>>
>>
>> Heck, I still want to know how to go to 103% throttle.
>
> Rather like the old prop jobs (DC-3 comes to mind as an example) that had
> a wire across the throttle travel, which serves as a stop for full
> throttle during normal operations. If it was needed for an emergency,
> like an engine failure on takeoff, you can push through and past the wire
> for extra emergency power. (100% plus power)
>
> Of course, on some engines, that was grounds for grounding the aircraft to
> inspect the engine, to see if it was damaged from exceeding 100% power.
> --
> Jim in NC
>

[Pat Flannery]

Richard Riley wrote:
> Heck, I still want to know how to go to 103% throttle.
>

Because the designers worked for "Spinal Tap".
Seriously, because of improvements in its abilities as it went from the
original design specifications to actual production, it now is capable
of exceeding its originally planned maximum thrust rating by a few percent.
Where the hell did my smileys go? My new Thunderbird mail program
seems to keep them hidden.

Pat

[Stubby]

Note. Slugs are a mass measurement whereas pounds are a force. There
is not a simple ratio because it depends on how strong gravity is. Of
course the shuttle has accelerations that are quite different than we
encounter on the face of the Earth!

There was a famous story of gold shippers that moved quantities of gold
from San Francisco to Anchorage in the 1800s. Of course they carefully
measured the gold before and after, presumably using a spring scale
rather than a balance. The bankers concluded a little bit of gold was
being lost from every shipment. After a lot of finger-pointing, they
identified the difference in gravity as the source of the difference.


Dudley Henriques wrote:
> Bear with me David. I've been away from this stuff for a long while :-))
>
>
> Rho for SSL is 0.002378 slugs/cu ft. Mass in slugs is the weight in
> lbs/32.2
> For high performance flight test dealing with uncompressible airflow; for
> density (slugs ft3) for mass airflow (slugs/sec)
>
>
> "David Kazdan" > wrote in message
> t...
>> Dudley:
>>
>> Isn't dynamic pressure expressed in pressure units, pounds per square
>> inch (or SI, Pascals: newtons/sq. meter)? Mass density, which you mention
>> later, is in slugs/cu.in or cu.ft (or SI, Kg/cu.meter).
>>
>> Thanks for all your good posts, I've learned a lot from them over the
>> years.
>>
>> David
>>
>> Dudley Henriques wrote:
>>> "Danny Deger" > wrote in message
>>> ...
>>>> Why does the shuttle throttle to 3 Gs on ascent?
>>>>
>>>> Danny Deger
>>> As the shuttle ascends, the dynamic pressure (in slugs/sq.in) increases
>>> as the square of the velocity. The shuttle is throttled back to 65%
>>> thrust to avoid over stress at a speed computed under what is called
>>> critical q.
>>> As the shuttle ascends, it is ascending into lower air density (which of
>>> course transfers into a lowering dynamic pressure). The throttling back
>>> takes the shuttle through a transition area during the ascent that ends
>>> as the lowering air density meets the parameters that allow throttle up.
>>> This I believe occurs at about 35 to 37K.
>>> The point where lowering air density meets the ability to throttle up
>>> again is the max q for the shuttle. (Max q meaning maximum dynamic
>>> pressure)
>>> After reaching max q, the shuttle is go for throttle up as the increasing
>>> velocity past max q will never exceed the structural limitations of the
>>> shuttle due to it's entrance into lower air density that doesn't have the
>>> ability to overstress the structure.
>>> Hope this helps a bit.
>>> Dudley Henriques
>
>

[Morgans[_2_]]

"Brian Gaff" > wrote

> Yes, and it is also why the shedding foam can only do serious damage
> within the lower atmosphere, as the drag cannot decelerate the chunks
> enough to strike with enough force to do harm at that altitude.

Sorry, but you got that one wrong.

The foam does the damage because of the high speed that it has when it hits
the shuttle.

If there was no drag, the foam would not hit with any force; it would be
going the same speed as the shuttle.

When a chunk of foam falls off, it is the drag of the stationary atmosphere
slowing the foam so effectively and rapidly, that causes the relative
closing speeds of the now nearly stationary foam hitting the speeding
shuttle.
--
Jim in NC

[Morgans[_2_]]

"Brian Gaff" > wrote in message
. uk...
>I don't think this is entirely true. I have some old stuff rattling around
>in my mind from the 80s which put the rating at least twice this though of
>course, only in the thrust direction. After all, the instantaneous
>pressures on change can be rather less than subtle.

I agree. I recall that the dynamic air pressure on the shuttle is the
limiting factor, and that just happens to come out to the 3 G's that the
shuttle experiences.

Also, the attachment of the shuttle to the tank is a limiting factor.
--
Jim in NC

[Mxsmanic]

Morgans writes:

> "Brian Gaff" > wrote
>
> > Yes, and it is also why the shedding foam can only do serious damage
> > within the lower atmosphere, as the drag cannot decelerate the chunks
> > enough to strike with enough force to do harm at that altitude.
>
> Sorry, but you got that one wrong.
>
> The foam does the damage because of the high speed that it has when it hits
> the shuttle.
>
> If there was no drag, the foam would not hit with any force; it would be
> going the same speed as the shuttle.
>
> When a chunk of foam falls off, it is the drag of the stationary atmosphere
> slowing the foam so effectively and rapidly, that causes the relative
> closing speeds of the now nearly stationary foam hitting the speeding
> shuttle.

That's what he said.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[David Kazdan]

Stubby:

Right, that was my point...

David


Stubby wrote:
> Note. Slugs are a mass measurement whereas pounds are a force. There
> is not a simple ratio because it depends on how strong gravity is. Of
> course the shuttle has accelerations that are quite different than we
> encounter on the face of the Earth!
>
> There was a famous story of gold shippers that moved quantities of gold
> from San Francisco to Anchorage in the 1800s. Of course they carefully
> measured the gold before and after, presumably using a spring scale
> rather than a balance. The bankers concluded a little bit of gold was
> being lost from every shipment. After a lot of finger-pointing, they
> identified the difference in gravity as the source of the difference.
>
>
> Dudley Henriques wrote:
>> Bear with me David. I've been away from this stuff for a long while :-))
>>
>>
>> Rho for SSL is 0.002378 slugs/cu ft. Mass in slugs is the weight in
>> lbs/32.2
>> For high performance flight test dealing with uncompressible airflow;
>> for density (slugs ft3) for mass airflow (slugs/sec)
>>
>>
>> "David Kazdan" > wrote in message
>> t...
>>> Dudley:
>>>
>>> Isn't dynamic pressure expressed in pressure units, pounds per
>>> square inch (or SI, Pascals: newtons/sq. meter)? Mass density, which
>>> you mention later, is in slugs/cu.in or cu.ft (or SI, Kg/cu.meter).
>>>
>>> Thanks for all your good posts, I've learned a lot from them over
>>> the years.
>>>
>>> David
>>>
>>> Dudley Henriques wrote:
>>>> "Danny Deger" > wrote in message
>>>> ...
>>>>> Why does the shuttle throttle to 3 Gs on ascent?
>>>>>
>>>>> Danny Deger
>>>> As the shuttle ascends, the dynamic pressure (in slugs/sq.in)
>>>> increases as the square of the velocity. The shuttle is throttled
>>>> back to 65% thrust to avoid over stress at a speed computed under
>>>> what is called critical q.
>>>> As the shuttle ascends, it is ascending into lower air density
>>>> (which of course transfers into a lowering dynamic pressure). The
>>>> throttling back takes the shuttle through a transition area during
>>>> the ascent that ends as the lowering air density meets the
>>>> parameters that allow throttle up. This I believe occurs at about 35
>>>> to 37K.
>>>> The point where lowering air density meets the ability to throttle
>>>> up again is the max q for the shuttle. (Max q meaning maximum
>>>> dynamic pressure)
>>>> After reaching max q, the shuttle is go for throttle up as the
>>>> increasing velocity past max q will never exceed the structural
>>>> limitations of the shuttle due to it's entrance into lower air
>>>> density that doesn't have the ability to overstress the structure.
>>>> Hope this helps a bit.
>>>> Dudley Henriques
>>
>>

[Jose[_1_]]

> Yes, and it is also why the shedding foam can only do serious damage within
> the lower atmosphere, as the drag cannot decelerate the chunks enough to
> strike with enough force to do harm at that altitude.

Uh... even with no atmosphere, the rocket is accelerating wrt the
detached foam. I'm not convinced this is insignificant.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

[Tony]

Jose, if in space, the foam, when it detached, would be going the same
speed as the rocket, and the only incremental change in velocity would
be that cause by the rocket between the time it detached until it hit.
If the rocket was at say 3 Gs and the foam had 50 feet before it hit,
it would 'fall' for t = (2 * 50 / (3 * 32))^.5 or about a second.
Impact speed would be 100 feet a second or so or about 70 miles an
hour. It's light stuff, probably wouldn't hurt.

Because it's light stuff though, it probably had aerodyamic breaking to
about zero speed when it shed off in the atmosphere, and that would
mean a hypersonic impact. That would hurt -- and did.




On Jan 7, 10:35 am, Jose > wrote:
> > Yes, and it is also why the shedding foam can only do serious damage within
> > the lower atmosphere, as the drag cannot decelerate the chunks enough to
> > strike with enough force to do harm at that altitude.Uh... even with no atmosphere, the rocket is accelerating wrt the
> detached foam. I'm not convinced this is insignificant.
>
> Jose
> --
> He who laughs, lasts.
> for Email, make the obvious change in the address.

[Tony]

You airn't never been lost until you've been lost at Mach 3. I learned
that bit of wisdom from an air force jock. I can get lost at 150 kts.


On Jan 6, 11:31 pm, "Danny Deger" > wrote:
> "Danny Deger" > wrote in m...
>
> > Why does the shuttle throttle to 3 Gs on ascent?The answer is:
>
> So Navy Fighter pilots can fly the shuttle :-)
>
> Danny Deger
>
> P.S. I was an Air Force figher pilot.

[tjd]

If you've got a few hours to kill:

http://spaceflight.nasa.gov/shuttle/reference/shutref/events/

Sounds like essentially what Dudley said:

To keep the dynamic pressure on the vehicle below a specified level, on
the order of 580 pounds per square foot (max q), the main engines are
throttled down at approximately 26 seconds and throttled back up at
approximately 60 seconds. This also reduces heating on the vehicle.

[Danny Deger]

"Jim" > wrote in message
et...
> SSME's are "rated" at a certain thrust. However, the thrust rating has a
> minimum, average and maximum. The "rated" thrust is the average. Therfore,
> the engines can be run to an amount greater than "rated" thrust. I am not
> an engineer or NASA personel, but I have read that during the nominal
> acent the engines are throttled from 64% to 104% but can be throttled to
> 109% of rated thrust if necessary.

You are correct. For 2 engine out aborts, the last engine can be throttled
to 109%.

Danny Deger

[Danny Deger]

"Danny Deger" > wrote in message
...

> Why does the shuttle throttle to 3 Gs on ascent?
>

The 3 G throttling is done late in the flight (about 7:30)and has nothing to
do with dynamic pressure. It was designed in to allow "regular" people fly
the shuttle.

While in the atmosphere the main engines are throttled back to reduce the
maximum aerodynamic pressure. The grain in the SRB is also designed to have
them go through a period of reduced thrust at about the same time.

Danny Deger

[Danny Deger]

"Tony" > wrote in message
ps.com...
> You airn't never been lost until you've been lost at Mach 3. I learned
> that bit of wisdom from an air force jock. I can get lost at 150 kts.
>

I have never been lost in an airplane. Though, I have suffered from
temperary disorintation due to poorly designed maps :-)

Danny Deger

[Brian Thorn]

On Sun, 07 Jan 2007 07:42:46 GMT, "Jim" > wrote:

>BTW "go at throttle up" is, as I understood, is simply a radio call to
>confirm communication with the vehicle, same as the "roll program" call. Is
>that correct?

No, throttling high performance rocket engines is still somewhat
difficult and risky, despite the Shuttle making it look easy. NASA has
always worried that the Mains won't throttle back up as they are
intended, which would mean the crew would be going for a swim.
This risk is such that at one time, the now-cancelled Advanced Solid
Rocket Motor was going to eliminate the need for the early
throttle-down/up during SRB burn completely.

So the "Go at throttle-up" tells the crew that the engines did
throttle up as expected and the flight is "go" to proceed. One less
thing for the crew to worry about.

Brian

[Henry Spencer]

In article >,
Brian Gaff > wrote:
>But the actual thrust abilities of the smes was increased over the life of
>the Shuttle, I'm sure I read that.

Correct -- originally 100% was to be tops (surprise, surprise), but later
the engines were qualified for 104%, and at the time of Challenger there
were plans to qualify them for routine operation at 109%, and possibly
more. Those plans got scaled back in the post-Challenger safety rethink.

There is nothing particularly unusual about this; most rocket engines grow
in thrust as experience builds up and small improvements are made. It
attracted attention on the shuttle only because of how it was expressed:
numbers above 100% sound vaguely alarming to the ignorant. The RS-27A
first-stage engine on modern Delta IIs runs at 153% of its original thrust
rating. The H-1 first-stage engines on the Saturn IBs that launched ASTP
were running at 124% of the thrust of the first H-1s, and even those were
110% upgrades of the S-3D Thor/Jupiter engines, which were themselves
substantially more powerful than still-earlier versions. Had there been a
second production batch of Saturn Vs, almost certainly the first-stage
engines would have been F-1As, running at 120% of the original F-1 thrust.

That said, the SSMEs are cranky, marginal engines, and taking *them* up to
120% (as was once intended) is much more iffy than doing the same for
robust engines like the H-1 or F-1.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Tony]

You, like any other truthful person, talk about a temp disorientation
(because of badly designed maps? -- I like that!).

This is way off topic but it makes me smile and I hope it does that for
you, too.

A church was having a yard sale, and had big box of golf balls for
sale. The sign over the balls?

"I was lost, but now I'm found."

In that context, I'm still lost.




On Jan 7, 12:16 pm, "Danny Deger" > wrote:
> "Tony" > wrote in glegroups.com...
>
> > You airn't never been lost until you've been lost at Mach 3. I learned
> > that bit of wisdom from an air force jock. I can get lost at 150 kts.I have never been lost in an airplane. Though, I have suffered from
> temperary disorintation due to poorly designed maps :-)
>
> Danny Deger

[Scott Post]

In article m>,
Tony > wrote:
>You airn't never been lost until you've been lost at Mach 3. I learned
>that bit of wisdom from an air force jock. I can get lost at 150 kts.
>

The first time I took my wife for a ride in a J-3 Cub we had a stiff
headwind that had us making 37 knots across the ground. We were over
territory she's flown 100 times in faster planes but didn't recognize
any of it because we were going so slow. She was convinced we were
drifting into controlled airspace 50 miles away.

--
Scott Post

[Pat Flannery]

Morgans wrote:
>
> Of course, on some engines, that was grounds for grounding the aircraft to
> inspect the engine, to see if it was damaged from exceeding 100% power.
>
On the P-51 Mustang, this was called "War Emergency Power"; it would
give some extra zip, but would also destroy the engine in around ten
minutes after engaging it. :-)

Pat

[Pat Flannery]

Stubby wrote:
>
> There was a famous story of gold shippers that moved quantities of
> gold from San Francisco to Anchorage in the 1800s. Of course they
> carefully measured the gold before and after, presumably using a
> spring scale rather than a balance. The bankers concluded a little
> bit of gold was being lost from every shipment. After a lot of
> finger-pointing, they identified the difference in gravity as the
> source of the difference.
Shouldn't that be the other way around? the gold would weigh less as you
approached the equator due to the spinning of the Earth causing
centrifugal force on it.

Pat

[Pat Flannery]

Mxsmanic wrote:
>> The foam does the damage because of the high speed that it has when it hits
>> the shuttle.
>>
>> If there was no drag, the foam would not hit with any force; it would be
>> going the same speed as the shuttle.
>>
>> When a chunk of foam falls off, it is the drag of the stationary atmosphere
>> slowing the foam so effectively and rapidly, that causes the relative
>> closing speeds of the now nearly stationary foam hitting the speeding
>> shuttle.
>>
>
> That's what he said.
>
Actually, even with no atmosphere around the foam would still move
rearwards- because the Shuttle is still accelerating after it falls off.

Pat

[Rand Simberg]

On Sun, 07 Jan 2007 15:01:21 -0600, in a place far, far away, Pat
Flannery > made the phosphor on my monitor glow in
such a way as to indicate that:

>
>
>Stubby wrote:
>>
>> There was a famous story of gold shippers that moved quantities of
>> gold from San Francisco to Anchorage in the 1800s. Of course they
>> carefully measured the gold before and after, presumably using a
>> spring scale rather than a balance. The bankers concluded a little
>> bit of gold was being lost from every shipment. After a lot of
>> finger-pointing, they identified the difference in gravity as the
>> source of the difference.
>Shouldn't that be the other way around? the gold would weigh less as you
>approached the equator due to the spinning of the Earth causing
>centrifugal force on it.

Plus the surface is a little farther from the center, reducing the
apparent weight further. Maybe he means from Anchorage to San
Francisco, perhaps from the Klondike.

[Pat Flannery]

Jose wrote:
>> Yes, and it is also why the shedding foam can only do serious damage
>> within the lower atmosphere, as the drag cannot decelerate the chunks
>> enough to strike with enough force to do harm at that altitude.
>
> Uh... even with no atmosphere, the rocket is accelerating wrt the
> detached foam. I'm not convinced this is insignificant.
>
> Jose

You could figure this out; if there is no air around when the foam sheds
then its velocity in relation to the Shuttle is based on the distance it
covers and how many Gs the Shuttle is accelerating at.
From the bipod ramp to the place where it hit Columbia was about fifty
feet.
Say the Shuttle was accelerating at 3 G's. At one G acceleration is 32
ft. sec/per sec, so at 3 G's it's three times that, or around 100 ft.
per second, so the foam takes around around 1/2 second to reach the wing
after release (actually a little more than 1/2 second, as it's picking
up more velocity in relation to the shuttle in the last 1/2 second than
the first 1/2 second, so let's call it .7 seconds) So, it travels 50
feet in .7 seconds, or around 80 feet per second at impact. That works
out to around 55 mph at impact for that hypothetical case. IIRC, the
piece that hit Columbia was doing around 400 mph, so velocity is around
1/8 of that that damaged Columbia's wing. Every time you double the
velocity of a impactor, you quadruple its energy, so something going 55
mph isn't going to pose much of a threat at all, as if I'm doing my math
right it only has around 1.6% of the energy of the Columbia impact.

Pat

[Pat Flannery]

Brian Thorn wrote:
> No, throttling high performance rocket engines is still somewhat
> difficult and risky, despite the Shuttle making it look easy. NASA has
> always worried that the Mains won't throttle back up as they are
> intended, which would mean the crew would be going for a swim.
>


And considering what those ditching model tests looked like, this would
be a real good opportunity to use the parachutes. :-)

Pat

[Pat Flannery]

Rand Simberg wrote:
> Plus the surface is a little farther from the center, reducing the
> apparent weight further. Maybe he means from Anchorage to San
> Francisco, perhaps from the Klondike.
>

That's what I was thinking also; gold would be being shipped southwards
from Alaska, not to it.

Pat

[Morgans[_2_]]

"Pat Flannery" > wrote

> Shouldn't that be the other way around? the gold would weigh less as you
> approached the equator due to the spinning of the Earth causing
> centrifugal force on it.

Exactly what was intended. As it was weighed closer to the equator, it
would weigh less, thus making the people who owned the gold think that
someone had been taking some of it during shipment.
--
Jim in NC

[Mxsmanic]

Pat Flannery writes:

> On the P-51 Mustang, this was called "War Emergency Power"; it would
> give some extra zip, but would also destroy the engine in around ten
> minutes after engaging it. :-)

One wonders what sort of emergency would justify running the engine a
bit faster for just ten minutes, and then replacing the entire
aircraft.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Darkwing]

"Mxsmanic" > wrote in message
...
> Danny Deger writes:
>
>> Why does the shuttle throttle to 3 Gs on ascent?
>
> The real Shuttle <snip>

As opposed to your world of simulation.

-------------------------------------
DW

[tjd]

Mxsmanic wrote:
> One wonders what sort of emergency would justify running the engine a
> bit faster for just ten minutes, and then replacing the entire
> aircraft.

uh, you realize they were getting shot at and whatnot, right?

[Blueskies]

"Danny Deger" > wrote in message ...
:
: "Danny Deger" > wrote in message
: ...
:
: > Why does the shuttle throttle to 3 Gs on ascent?
: >
:
: The 3 G throttling is done late in the flight (about 7:30)and has nothing to
: do with dynamic pressure. It was designed in to allow "regular" people fly
: the shuttle.
:
:

Yes, the aerodynamic loads are highest early in the flight so the engines are throttled then back up. The shuttle rolls
over on its back to fake the occupants into feeling 3 gs when in fact the vehicle is pushing 4 gs....

[Tim Rogers]

"Blueskies" > wrote in message
. net...
>
> "Danny Deger" > wrote in message
> ...
> :
> : "Danny Deger" > wrote in message
> : ...
> :
> : > Why does the shuttle throttle to 3 Gs on ascent?
> : >
> :
> : The 3 G throttling is done late in the flight (about 7:30)and has
> nothing to
> : do with dynamic pressure. It was designed in to allow "regular" people
> fly
> : the shuttle.
> :
> :
>
> Yes, the aerodynamic loads are highest early in the flight so the engines
> are throttled then back up. The shuttle rolls
> over on its back to fake the occupants into feeling 3 gs when in fact the
> vehicle is pushing 4 gs....

No.
The 3 Gs is at the backs of the occupants (and along that same axis for the
vehicle.) This is the same if they are heads up or heads down.
If you lie with your back on the floor, you feel the same 1 G if your head
is facing north or south.

Tim

[Duncan (NZ)]

In article >,
says...
> Pat Flannery writes:
>
> > On the P-51 Mustang, this was called "War Emergency Power"; it would
> > give some extra zip, but would also destroy the engine in around ten
> > minutes after engaging it. :-)
>
> One wonders what sort of emergency would justify running the engine a
> bit faster for just ten minutes, and then replacing the entire
> aircraft.

saving yer bacon comes to mind.

--
Duncan

[Pat Flannery]

Mxsmanic wrote:
>
> One wonders what sort of emergency would justify running the engine a
> bit faster for just ten minutes, and then replacing the entire
> aircraft.
>

I think it probably had something to do with a FW-190D being around 400
feet behind you. :-)

Pat

[Newps]

Danny Deger wrote:

> "Danny Deger" > wrote in message
> ...
>
>>Why does the shuttle throttle to 3 Gs on ascent?
>>
>
>
> The answer is:
>
> So Navy Fighter pilots can fly the shuttle :-)
>
> Danny Deger
>
> P.S. I was an Air Force figher pilot.




Flare to land, squat to pee.

[Danny Deger]

"Blueskies" > wrote in message
. net...
>

snip

> Yes, the aerodynamic loads are highest early in the flight so the engines
> are throttled then back up. The shuttle rolls
> over on its back to fake the occupants into feeling 3 gs when in fact the
> vehicle is pushing 4 gs....
>
>

For some time now the shuttle rolls to heads up well before 3 G throttling.
This is done so the antennas can communicate with the TDRS satellites.

Danny Deger

[Dudley Henriques]

"Pat Flannery" > wrote in message
...
>
>
> Morgans wrote:
>>
>> Of course, on some engines, that was grounds for grounding the aircraft
>> to inspect the engine, to see if it was damaged from exceeding 100%
>> power.
>>
> On the P-51 Mustang, this was called "War Emergency Power"; it would give
> some extra zip, but would also destroy the engine in around ten minutes
> after engaging it. :-)
>
> Pat

Actually it's 5 minutes. WEP on my V1650-7 Merlin in the 51 could be
achieved by breaking the throttle gate . I never used it...actually never
needed it really. Under 5000 feet, normal max power at 61 inches gives you
all the power you need to exceed the operating limitations for the engine,
and at altitude on cross country, I was more concerned with saving a buck by
not stressing the engine anyway :-)
Also, if breaking the gate and using that extra 6" of MP, the Mustang should
be using 130 octane fuel and not the 100LL we poor folks have in the tanks
most of the time :-) 100LL limits the 51 to 55 inches anyway, so you can
forget using War Emergency Power for the general Mustang owner (Hoover might
be an exception since he has an expense account most of us envied :-)
I didn't fly the 51 in combat, which I guess is the gist of the discussion,
but in combat, if you used WEP, it was a 5 minute emergency only deal that
meant a complete engine breakdown and inspection within 5 hours. Needles to
say, the 51 drivers in combat didn't misuse their engines by using WEP
indiscriminately. Actually, if you had to go to WEP in combat, you were
almost always defensive against a hard turning opponent, and if you got to
that point, you were in deep do-do already!
Most of the guys flying the 51 in air to air tried to keep the temps down
(Coolant to 121 degrees was a doubtful trip home) For ACM in the 51, 61
inches and 3000RPM will give you a wide airspeed and energy envelope to
maneuver in all 3 dimensions. Going through the throttle gate was a sure
indication you had done something REAL wrong!!
Anyway, hope this helps a bit.
Dudley Henriques

[Pat Flannery]

Blueskies wrote:
> Yes, the aerodynamic loads are highest early in the flight so the engines are throttled then back up. The shuttle rolls
> over on its back to fake the occupants into feeling 3 gs when in fact the vehicle is pushing 4 gs....
>
>

That also lowers stress on the wings; the Bomarc ramjet missile used to
roll belly-up on the bearing to its target after liftoff, then turn
right-side up once in basically horizontal flight.

Pat

[Kyle Boatright]

"Henry Spencer" > wrote in message
...

<<<interesting stuff snipped>>>

> That said, the SSMEs are cranky, marginal engines, and taking *them* up to
> 120% (as was once intended) is much more iffy than doing the same for
> robust engines like the H-1 or F-1.
> --
> spsystems.net is temporarily off the air; | Henry Spencer
> mail to henry at zoo.utoronto.ca instead. |
>

Henry,

What makes the SS engines "cranky and marginal" vs the H-1 and/or F-1?

Thanks...

KB

[Mxsmanic]

"Darkwing" <theducksmail"AT"yahoo.com> writes:

> As opposed to your world of simulation.

I don't simulate the Shuttle, but I know that some people do.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Mxsmanic]

tjd writes:

> uh, you realize they were getting shot at and whatnot, right?

No, I don't. I've never flown in combat.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Pat Flannery]

Dudley Henriques wrote:
> Actually it's 5 minutes. WEP on my V1650-7 Merlin in the 51 could be
> achieved by breaking the throttle gate . I never used it...actually never
> needed it really. Under 5000 feet, normal max power at 61 inches gives you
> all the power you need to exceed the operating limitations for the engine,
> and at altitude on cross country, I was more concerned with saving a buck by
> not stressing the engine anyway :-)
>

What version did you fly? I've never had an opportunity to get a
first-hand account of what flying one was like.
Were they really as squirrelly on takeoff with the drop tanks as I've heard?
Thank God they decided to put the Merlin in it. That was a match made in
heaven.

Pat

[Dudley Henriques]

"Pat Flannery" > wrote in message
...
>
>
> Dudley Henriques wrote:
>> Actually it's 5 minutes. WEP on my V1650-7 Merlin in the 51 could be
>> achieved by breaking the throttle gate . I never used it...actually never
>> needed it really. Under 5000 feet, normal max power at 61 inches gives
>> you all the power you need to exceed the operating limitations for the
>> engine, and at altitude on cross country, I was more concerned with
>> saving a buck by not stressing the engine anyway :-)
>>
>
> What version did you fly? I've never had an opportunity to get a
> first-hand account of what flying one was like.
> Were they really as squirrelly on takeoff with the drop tanks as I've
> heard?
> Thank God they decided to put the Merlin in it. That was a match made in
> heaven.

I flew a D, as well as various other prop fighters as a civilian operator.
Never flew ours with external tanks. The airplane is stable on takeoff if
flown correctly and I wouldn't anticipate any specific issues with the
external tanks except the extended run. I believe the only caution on the
external tanks was for high speed buffet above 400 mph.
We had the fuselage tank removed and only flew the Mustang using the 2 mains
at 92 gallons each.(90 usable)
If you are interested in a pilot report on what it was like to fly the D, I
did one for the Warbirdalley site some years ago at the following ;
http://www.warbirdalley.com/articles/p51pr.htm#pirep1
Hope you find the report interesting.
Dudley Henriques

[Taylor[_1_]]

Danny Deger wrote:

> "Jim" > wrote in message
> et...
>
>>SSME's are "rated" at a certain thrust. However, the thrust rating has a
>>minimum, average and maximum. The "rated" thrust is the average. Therfore,
>>the engines can be run to an amount greater than "rated" thrust. I am not
>>an engineer or NASA personel, but I have read that during the nominal
>>acent the engines are throttled from 64% to 104% but can be throttled to
>>109% of rated thrust if necessary.
>
>
> You are correct. For 2 engine out aborts, the last engine can be throttled
> to 109%.

The engine builders worked for years to get the extra thrust out of the
engines reliably. There were a lot of problems with the engines at
settings over 104%. The reliability is now there up to 109%, although
it is now only reserved for emergencies, not a normal ascent profile.

[Taylor[_1_]]

Dudley Henriques wrote:

> "Pat Flannery" > wrote in message
> ...
>
>>
>>Morgans wrote:
>>
>>>Of course, on some engines, that was grounds for grounding the aircraft
>>>to inspect the engine, to see if it was damaged from exceeding 100%
>>>power.
>>>
>>
>>On the P-51 Mustang, this was called "War Emergency Power"; it would give
>>some extra zip, but would also destroy the engine in around ten minutes
>>after engaging it. :-)
>>
>>Pat
>
>
> Actually it's 5 minutes. WEP on my V1650-7 Merlin in the 51 could be
> achieved by breaking the throttle gate . I never used it...actually never
> needed it really. Under 5000 feet, normal max power at 61 inches gives you
> all the power you need to exceed the operating limitations for the engine,
> and at altitude on cross country, I was more concerned with saving a buck by
> not stressing the engine anyway :-)
> Also, if breaking the gate and using that extra 6" of MP, the Mustang should
> be using 130 octane fuel and not the 100LL we poor folks have in the tanks
> most of the time :-)

Does anyone still make the purple juice for the air races? I recall
that Phillips 66 used to...

[Taylor[_1_]]

Pat Flannery wrote:

>
>
> Mxsmanic wrote:
>
>>> The foam does the damage because of the high speed that it has when
>>> it hits the shuttle.
>>>
>>> If there was no drag, the foam would not hit with any force; it would
>>> be going the same speed as the shuttle.
>>>
>>> When a chunk of foam falls off, it is the drag of the stationary
>>> atmosphere slowing the foam so effectively and rapidly, that causes
>>> the relative closing speeds of the now nearly stationary foam hitting
>>> the speeding shuttle.
>>>
>>
>>
>> That's what he said.
>>
>
> Actually, even with no atmosphere around the foam would still move
> rearwards- because the Shuttle is still accelerating after it falls off.

The foam wouldn't move rearwords...the shuttle would move forwards.

[Skywise]

"John T" > wrote in news:45a06154$0$28077
:

> "Ron Natalie" > wrote in message
> m
>>
>> I don't know about G's but the shuttle adjust the engine thrust
>> up and down at various times in the launch based on the dynamic
>> pressures involved.
>
> "'Go' for throttle up."
>
> My generation's equivalent of "Where were you when Kennedy got shot?"

That, and now "Columbia, Houston. UHF comm check."

Got chills just typing that.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[Morgans[_2_]]

"Dudley Henriques" > wrote

> I flew a D, as well as various other prop fighters as a civilian operator.
> Never flew ours with external tanks. The airplane is stable on takeoff if
> flown correctly and I wouldn't anticipate any specific issues with the
> external tanks except the extended run. I believe the only caution on the
> external tanks was for high speed buffet above 400 mph.
> We had the fuselage tank removed and only flew the Mustang using the 2
> mains at 92 gallons each.(90 usable)

I had always heard that the fuselage tank was the source of the instability,
with it being so far behind the CG, to give it a dangerously aft CG. Today,
in peacetime, I don't suppose they would ever dream of putting that much
weight that far back, but it was war.

Comments?
--
Jim in NC

[Duncan (NZ)]

In article >,
says...
>
> "Brian Gaff" > wrote
>
> > Yes, and it is also why the shedding foam can only do serious damage
> > within the lower atmosphere, as the drag cannot decelerate the chunks
> > enough to strike with enough force to do harm at that altitude.
>
> Sorry, but you got that one wrong.
>
> The foam does the damage because of the high speed that it has when it hits
> the shuttle.
>
> If there was no drag, the foam would not hit with any force; it would be
> going the same speed as the shuttle.
>
> When a chunk of foam falls off, it is the drag of the stationary atmosphere
> slowing the foam so effectively and rapidly, that causes the relative
> closing speeds of the now nearly stationary foam hitting the speeding
> shuttle.

Isn't that exactly what he said?

--
Duncan

[MichaelJP]

"John T" > wrote in message
m...
> "Ron Natalie" > wrote in message
> m
>>
>> I don't know about G's but the shuttle adjust the engine thrust
>> up and down at various times in the launch based on the dynamic
>> pressures involved.
>
> "'Go' for throttle up."
>
> My generation's equivalent of "Where were you when Kennedy got shot?"

Even after many successful launches, always worry when I hear those words...

[John[_1_]]

Mxsmanic wrote:
> Pat Flannery writes:
>
> > On the P-51 Mustang, this was called "War Emergency Power"; it would
> > give some extra zip, but would also destroy the engine in around ten
> > minutes after engaging it. :-)
>
> One wonders what sort of emergency would justify running the engine a
> bit faster for just ten minutes, and then replacing the entire
> aircraft.
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

Ummm . . . a FW-190 (option: replace FW-190 with opponent on your six
.. . . really close . . . perhaps still there and shooting after after
what you have just finished what you used to think was your very best
move . . . in my book that rises to the level of an emergency. At that
point getting the pilot home was goal one.

Blue skies . . .

John

John

[Pat Flannery]

Dudley Henriques wrote:
> If you are interested in a pilot report on what it was like to fly the D, I
> did one for the Warbirdalley site some years ago at the following ;
> http://www.warbirdalley.com/articles/p51pr.htm#pirep1
> Hope you find the report interesting.
>
>

Thanks, I'll read that!

Pat

[Jim[_12_]]

Getting shot at is not so bad, its the whatnot that will make you have a bad
day.
Jim in Houston
"Mxsmanic" > wrote in message
...
> tjd writes:
>
>> uh, you realize they were getting shot at and whatnot, right?
>
> No, I don't. I've never flown in combat.
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

[Dylan Smith]

On 2007-01-07, Danny Deger > wrote:
>
> "Tony" > wrote in message
> ps.com...
>> You airn't never been lost until you've been lost at Mach 3. I learned
>> that bit of wisdom from an air force jock. I can get lost at 150 kts.
>>
>
> I have never been lost in an airplane. Though, I have suffered from
> temperary disorintation due to poorly designed maps :-)

I'm never lost - I'm always "here". The big question is of course where
"here" actuallyl is.

--
Yes, the Reply-To email address is valid.
Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de

[Dudley Henriques]

"Morgans" > wrote in message
...
>
> "Dudley Henriques" > wrote
>
>> I flew a D, as well as various other prop fighters as a civilian
>> operator. Never flew ours with external tanks. The airplane is stable on
>> takeoff if flown correctly and I wouldn't anticipate any specific issues
>> with the external tanks except the extended run. I believe the only
>> caution on the external tanks was for high speed buffet above 400 mph.
>> We had the fuselage tank removed and only flew the Mustang using the 2
>> mains at 92 gallons each.(90 usable)
>
> I had always heard that the fuselage tank was the source of the
> instability, with it being so far behind the CG, to give it a dangerously
> aft CG. Today, in peacetime, I don't suppose they would ever dream of
> putting that much weight that far back, but it was war.
>
> Comments?
> --
> Jim in NC

The fuselage tank held 85 gals of fuel and did indeed bring the cg back
causing a real change in flight characteristics. It really screwed around
with the pitch moments. It could be handled, but the general word was for
pilots to take the bird out with fuel in the tank and go upstairs and do
some "getting used to it" flying.
The danger point where it actually became a cg issue began at about 25 gals.
The flight characteristics got worse with more fuel in the tank over that 25
gals. At 40 gals in the tank, anything involving maneuvering flight was a
toss up for pitch control.
Dudley Henriques

[Dudley Henriques]

I believe the guys are getting their fuel from a specific source, but I'm
not sure who handles that now.
Dudley Henriques

"Taylor" > wrote in message
...
> Dudley Henriques wrote:
>
>> "Pat Flannery" > wrote in message
>> ...
>>
>>>
>>>Morgans wrote:
>>>
>>>>Of course, on some engines, that was grounds for grounding the aircraft
>>>>to inspect the engine, to see if it was damaged from exceeding 100%
>>>>power.
>>>>
>>>
>>>On the P-51 Mustang, this was called "War Emergency Power"; it would give
>>>some extra zip, but would also destroy the engine in around ten minutes
>>>after engaging it. :-)
>>>
>>>Pat
>>
>>
>> Actually it's 5 minutes. WEP on my V1650-7 Merlin in the 51 could be
>> achieved by breaking the throttle gate . I never used it...actually never
>> needed it really. Under 5000 feet, normal max power at 61 inches gives
>> you all the power you need to exceed the operating limitations for the
>> engine, and at altitude on cross country, I was more concerned with
>> saving a buck by not stressing the engine anyway :-)
>> Also, if breaking the gate and using that extra 6" of MP, the Mustang
>> should be using 130 octane fuel and not the 100LL we poor folks have in
>> the tanks most of the time :-)
>
> Does anyone still make the purple juice for the air races? I recall that
> Phillips 66 used to...

[Mxsmanic]

John writes:

> Ummm . . . a FW-190 (option: replace FW-190 with opponent on your six
> . . . really close . . . perhaps still there and shooting after after
> what you have just finished what you used to think was your very best
> move . . . in my book that rises to the level of an emergency. At that
> point getting the pilot home was goal one.

OK, but if you can only fly at emergency war power for five minutes,
and if it only offers a moderate advantage over normal maximum power,
it seems that there would be relatively few situations in which it
would make a difference. Either you'd be out of luck to begin with
and EWP wouldn't get you out of it, or you wouldn't be in danger and
so you wouldn't need EWP.

If EWP can give you an extra 50 kts, for example, at best you'd have
an advantage of five nautical miles when the engine disintegrates. If
the bad guys are only 30 knots slower, your advantage shrinks further.
And with a blown engine, you'll need to be completely out of danger
after five minutes, or all that effort wouldn't help.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Gig 601XL Builder]

Mxsmanic wrote:
> John writes:
>
>> Ummm . . . a FW-190 (option: replace FW-190 with opponent on your
>> six . . . really close . . . perhaps still there and shooting after
>> after what you have just finished what you used to think was your
>> very best move . . . in my book that rises to the level of an
>> emergency. At that point getting the pilot home was goal one.
>
> OK, but if you can only fly at emergency war power for five minutes,
> and if it only offers a moderate advantage over normal maximum power,
> it seems that there would be relatively few situations in which it
> would make a difference. Either you'd be out of luck to begin with
> and EWP wouldn't get you out of it, or you wouldn't be in danger and
> so you wouldn't need EWP.
>
> If EWP can give you an extra 50 kts, for example, at best you'd have
> an advantage of five nautical miles when the engine disintegrates. If
> the bad guys are only 30 knots slower, your advantage shrinks further.
> And with a blown engine, you'll need to be completely out of danger
> after five minutes, or all that effort wouldn't help.


You are absolutly right Anthony and all of the combat aircraft designers,
builders and pilots were silly for adding and using the feature. It is a sin
that you weren't around at the time to explain the them the error of their
ways.

[Pat Flannery]

Taylor wrote:
>
> The foam wouldn't move rearwords...the shuttle would move forwards.

Well, if you're going to split hairs, both the foam and the Shuttle
would still be moving forwards- it's just that the Shuttle would still
be gaining velocity and the foam traveling forwards at whatever velocity
it fell off at.

Pat

[Pat Flannery]

Skywise wrote:
> That, and now "Columbia, Houston. UHF comm check."
>
> Got chills just typing that.
>


Though it all happened so fast that it didn't sink in at the time, when
reading the transcripts the spooky part is when the temperature sensors
start climbing, then failing.

Pat

[Pat Flannery]

Morgans wrote:
> I had always heard that the fuselage tank was the source of the instability,
> with it being so far behind the CG, to give it a dangerously aft CG. Today,
> in peacetime, I don't suppose they would ever dream of putting that much
> weight that far back, but it was war.
>
> Comments?
>
I'll take that any day of the week over the Bf-109, where you're main
fuselage tank goes under the pilot's seat, or the Me-163 where you're
sitting squeezed in between two tanks of hydrogen peroxide at your sides.
Another "brilliant" move was on the Sukhoi Su-7, where a cylindrical
fuselage fuel tank has a tunnel down its inside in which the jet engine
rests, so that bullets of shrapnel piercing the rear fuselage will
penetrate the fuel tank...and then the engine...letting superheated air
enter the fuel tank.
This led to some wonderful combat shots in the 1973 Yom Kippur war and
the wars between India and Pakistan of Su-7s plunging earthwards with
everything behind the wings ablaze and spraying fire all over the place
like a flamethrower.

Pat

[Pat Flannery]

John wrote:
>
>
> Ummm . . . a FW-190 (option: replace FW-190 with opponent on your six
> . . . really close . . . perhaps still there and shooting after after
> what you have just finished what you used to think was your very best
> move . . . in my book that rises to the level of an emergency. At that
> point getting the pilot home was goal one.
>
It's probably not going to help if the thing behind you has two
Junkers-Jumo 004 turbojets on it, and four MK-108 30 mm cannons pointing
toward you though. :-)

Pat

[The Rocket Scientist]

Danny Deger wrote:
> Why does the shuttle throttle to 3 Gs on ascent?
>
You would move like hell yourself if your ass was on fire.

Bill Sullivan

"What, me worry?" - Neuman

[Skywise]

Pat Flannery > wrote in news:12q559nm7crqq10
@corp.supernews.com:

>
>
> Skywise wrote:
>> That, and now "Columbia, Houston. UHF comm check."
>>
>> Got chills just typing that.
>>
>
>
> Though it all happened so fast that it didn't sink in at the time, when
> reading the transcripts the spooky part is when the temperature sensors
> start climbing, then failing.
>
> Pat

Although there was little chance of it, this was the first reentry
that I attempted to observe. If I could see it, it would have been
about 10 degrees off my northern horizon from here in the LA area.
Mountains and haze made it a long shot. But I got up anyway and had
NASA TV streaming to my computer.

I didn't see a thing so I just listened to the live feed. I wasn't
paying real close attention until I kept hearing that call for
comm check repeated. At first it didn't seem too serious. But when
I heard them ask when they expected tracking at Merritt Island
and they said "one minute ago" I got concerned. That's when I
turned on CNN.

Touchdown time came and went.

I'm thinkig, heck, maybe they had a problem and bailed out somewhere.
Maybe they had to use that new fangled escape chute thingy. Perhaps
they're in the Gulf of Mexico waiting for rescue. Or crash landed
somewhere else.

Then there was that first report of multiple trails seen over Texas
and I knew it was over, that there was no hope. That's when it really
hit me.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[Skywise]

Dylan Smith > wrote in
:

> On 2007-01-07, Danny Deger > wrote:
>>
>> "Tony" > wrote in message
>> ps.com...
>>> You airn't never been lost until you've been lost at Mach 3. I learned
>>> that bit of wisdom from an air force jock. I can get lost at 150 kts.
>>>
>>
>> I have never been lost in an airplane. Though, I have suffered from
>> temperary disorintation due to poorly designed maps :-)
>
> I'm never lost - I'm always "here". The big question is of course where
> "here" actuallyl is.

No matter where you go, there you are.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

[Pat Flannery]

Skywise wrote:
> Touchdown time came and went.
>
> I'm thinkig, heck, maybe they had a problem and bailed out somewhere.
> Maybe they had to use that new fangled escape chute thingy. Perhaps
> they're in the Gulf of Mexico waiting for rescue. Or crash landed
> somewhere else.
>
> Then there was that first report of multiple trails seen over Texas
> and I knew it was over, that there was no hope. That's when it really
> hit me.
>
> Brian
>

I of course managed to skip the launch of Challenger as by that time it
was getting old-hat, and I'd seen the other twenty-four launches.
My dad came upstairs and told me the space shuttle had exploded. I got
down those steps inside of around five seconds.
Then I skipped the landing of Columbia, as the whole mission had been
going so well.
My friend called up and told me the Columbia was missing. On went the TV
set inside of five seconds.
The topper was of course walking into the same friend's business on the
morning of September 11th, 2001 and after looking at the television set
to see some building on fire, asking him if there was a skyscraper on
fire somewhere. Just then the building collapsed.
If the Sun ever unexpectedly goes nova or WW III starts, I will of
course miss it till someone tells me or telephones me about it. :-[

Pat

[Anno v. Heimburg]

Mxsmanic wrote:
> No, I don't. I've never flown in combat.
Well, a lot of people have never flown in combat, but one could have deduced
from the fact that we were talking about the P-51 Mustang (a WWII fighter
plane) and the "war" part in "war emergency power" that the most likely
application of war emergency power was indeed, um, during wartime? War, as
in, combat?

[Pat Flannery]

I tried to reply to you personally, but the e-mail address doesn't work.


> I flew a D, as well as various other prop fighters as a civilian operator.
> Never flew ours with external tanks. The airplane is stable on takeoff if
> flown correctly and I wouldn't anticipate any specific issues with the
> external tanks except the extended run. I believe the only caution on the
> external tanks was for high speed buffet above 400 mph.
> We had the fuselage tank removed and only flew the Mustang using the 2 mains
> at 92 gallons each.(90 usable)
> If you are interested in a pilot report on what it was like to fly the D, I
> did one for the Warbirdalley site some years ago at the following ;
> http://www.warbirdalley.com/articles/p51pr.htm#pirep1
> Hope you find the report interesting.
> Dudley Henriques
>
Thanks for putting me on to that pilot report, that was very interesting
to read.
The overall feeling I got from it was of an aircraft that takes a lot of
effort to get fully attuned to and in sync with, but is capable of doing
outstanding things once you get enough hours in on it and understand how
it behaves.
I particularly liked your description of starting the Merlin up. :-D
You mentioned you had flown several types of prop driven fighters, what
other ones did you fly?
I once talked to a Navy pilot of a Grumman Bearcat who was very taken by
that aircraft.
About the most fascinating conversation I ever had with a pilot was
years ago after the Soviet Union had just fallen who flew a two-seater
TA-4J Skyhawk to the Minot N.D. airshow. He worked for Navy R&D and had
done three tours in Vietnam with the A-4.
His backseater was in awe of him, and like most really competent combat
pilots, he was one of the easiest-going down-to-earth guys you ever ran
into... no attitude, no mirrored sunglasses, no waxed mustache.
The reason he was there was that the Ukrainian Air Force had sent a pair
of MiG-29's on a U.S. tour, and the Navy wanted to see what they could
do aerobatically and try to get some insight into what they'd do if they
came up against a FA-18, so they had him and his inconspicuous Skyhawk
following them around the airshow circuit and observing them in action.
One thing we both noticed was the effortless way the Fulcrum could
ignite its afterburner stages; this is apparently nearly fully
automatic- the pilot merely advances the throttle, and the aircraft
senses airspeed, g forces, air density, and what type of maneuver is
going on and gives the amount of afterburner required. The MiG was going
in and out of various degrees of afterburner at several points during
even fairly simple aerobatic maneuvers.
He had been in on the abortive A-12 program, and his take on it was that
the Navy screwed over General Dynamics because it wanted to spend money
elsewhere after the end of the cold war; he described flying the
simulator and stated that he thought it was an excellent aircraft,
particularly complementing the pilot's view out of the cockpit, which he
said was truly outstanding.

Pat

[Mxsmanic]

Anno v. Heimburg writes:

> Well, a lot of people have never flown in combat, but one could have deduced
> from the fact that we were talking about the P-51 Mustang (a WWII fighter
> plane) and the "war" part in "war emergency power" that the most likely
> application of war emergency power was indeed, um, during wartime? War, as
> in, combat?

A lot of aircraft have flown in a lot of wartime, but they didn't do
it at emergency war power. Obviously, more than just wartime is
required to justify it.

--
Transpose mxsmanic and gmail to reach me by e-mail.

[Henry Spencer]

In article >,
Morgans > wrote:
>I had always heard that the fuselage tank was the source of the instability,
>with it being so far behind the CG, to give it a dangerously aft CG. Today,
>in peacetime, I don't suppose they would ever dream of putting that much
>weight that far back, but it was war.

Yep, lots of compromises in some of those wartime designs... Some of the
photo-recon versions of the Spitfire had a tail tank that compromised
stability even more drastically: the aircraft was outright aerodynamically
unstable with that tank full or nearly full. (Naturally, you emptied that
tank *first*... and didn't have much attention to spare for anything else
until it was empty.)
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Scott Hedrick]

"Mxsmanic" > wrote in message
...
> One wonders what sort of emergency would justify running the engine a
> bit faster for just ten minutes, and then replacing the entire
> aircraft.

Getting away from a bunch of someones shooting at me, for one. If I can't
get away within ten minutes, it's pretty obvious I'm not going to get away.

[Scott Hedrick]

"Dudley Henriques" > wrote in message
...
>At 40 gals in the tank, anything involving maneuvering flight was a toss up
>for pitch control.

"This is your wingman. You appear to be leaking oil."
"Negative, wingman. The CG just shifted and I **** my pants."

[Henry Spencer]

In article >,
Kyle Boatright > wrote:
>> That said, the SSMEs are cranky, marginal engines, and taking *them* up to
>> 120% (as was once intended) is much more iffy than doing the same for
>> robust engines like the H-1 or F-1.
>
>What makes the SS engines "cranky and marginal" vs the H-1 and/or F-1?

Mostly, they were too much of a leap into the technological unknown at the
time: NASA tried to pioneer bold new technology on what was supposed to
be a long-lived reusable engine, and unsurprisingly, this didn't work too
well. The H-1 and F-1 were much more conservative designs -- notably,
although the F-1 was a lot bigger than anything previously built, the
project tried hard to *avoid* pioneering in any other way -- and although
they did hit surprises and ended up breaking some new ground, they had
much more continuity with previous experience.

(For a while there was some feeling that the SSME's staged-combustion
cycle was just *inherently* troublesome, but that idea sort of collapsed
when it became clear that every major Russian rocket engine since about
1960 had been a staged-combustion design, typically including features
like oxidizer-rich preburners, which even NASA had deemed impractically
difficult...)

Three specific snags also aggravated this problem on the SSME:

(a) Most of the technology development on staged combustion had been done
by Pratt & Whitney, but oddly, the contract for the staged-combustion SSME
went to Rocketdyne instead. So the experienced people were shut out, and
the guys who were actually doing the work were having to come up to speed
on a technology that was new to them.

(b) The SSME program, like the shuttle in general, was starved for money
and opted to cut corners on subsystem testing in particular. The result
was an unusually long and painful development process, with subsystem
problems often not surfacing until whole-engine testing.

(c) Partly as a result of (a) and (b), it didn't become clear until too
late that the main LOX (I think it was) turbopump really needed one more
pump stage. Since a major redesign was politically and financially
impossible at that point, the result was a pump in which each stage was
pushed to the ragged edge of engineering practicality to meet a very
ambitious spec.

The combination of (b) and (c) was particularly nasty, because all too
often, a LOX-pump failure becomes a LOX-pump fire, which destroys the
evidence of what went wrong. Having this happen repeatedly to whole test
engines was just what an already-stressed development program didn't need.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Greg D. Moore \(Strider\)]

"Mxsmanic" > wrote in message
...
> John writes:
>
>> Ummm . . . a FW-190 (option: replace FW-190 with opponent on your six
>> . . . really close . . . perhaps still there and shooting after after
>> what you have just finished what you used to think was your very best
>> move . . . in my book that rises to the level of an emergency. At that
>> point getting the pilot home was goal one.
>
> OK, but if you can only fly at emergency war power for five minutes,
> and if it only offers a moderate advantage over normal maximum power,
> it seems that there would be relatively few situations in which it
> would make a difference. Either you'd be out of luck to begin with
> and EWP wouldn't get you out of it, or you wouldn't be in danger and
> so you wouldn't need EWP.
>
> If EWP can give you an extra 50 kts, for example, at best you'd have
> an advantage of five nautical miles when the engine disintegrates. If
> the bad guys are only 30 knots slower, your advantage shrinks further.
> And with a blown engine, you'll need to be completely out of danger
> after five minutes, or all that effort wouldn't help.

Yes, but that 5 nm may be enough to get out of their range, or get back to
friendly air-cover, etc.

The piont of it being emergency power is you can't always predict when or
how it'll be used.


>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

[muff528]

"Morgans" > wrote in message
...
>
> "Brian Gaff" > wrote
>
>> Yes, and it is also why the shedding foam can only do serious damage
>> within the lower atmosphere, as the drag cannot decelerate the chunks
>> enough to strike with enough force to do harm at that altitude.
>
> Sorry, but you got that one wrong.
>
> The foam does the damage because of the high speed that it has when it
> hits the shuttle.
>
> If there was no drag, the foam would not hit with any force; it would be
> going the same speed as the shuttle.
>
> When a chunk of foam falls off, it is the drag of the stationary
> atmosphere slowing the foam so effectively and rapidly, that causes the
> relative closing speeds of the now nearly stationary foam hitting the
> speeding shuttle.
> --
> Jim in NC
>

OK, now I'm trying to figure out how to insert a magical, imaginary conveyor
belt into this scenario. :-)

TP in FL (Go Gators!)

[Blueskies]

"Tim Rogers" > wrote in message ...
:
: "Blueskies" > wrote in message
: . net...
: >
: > "Danny Deger" > wrote in message
: > ...
: > :
: > : "Danny Deger" > wrote in message
: > : ...
: > :
: > : > Why does the shuttle throttle to 3 Gs on ascent?
: > : >
: > :
: > : The 3 G throttling is done late in the flight (about 7:30)and has
: > nothing to
: > : do with dynamic pressure. It was designed in to allow "regular" people
: > fly
: > : the shuttle.
: > :
: > :
: >
: > Yes, the aerodynamic loads are highest early in the flight so the engines
: > are throttled then back up. The shuttle rolls
: > over on its back to fake the occupants into feeling 3 gs when in fact the
: > vehicle is pushing 4 gs....
:
: No.
: The 3 Gs is at the backs of the occupants (and along that same axis for the
: vehicle.) This is the same if they are heads up or heads down.
: If you lie with your back on the floor, you feel the same 1 G if your head
: is facing north or south.
:
: Tim
:
:

Not talking about facing north or south, they're talking about hanging from your feet or standing upright...

[Dudley Henriques]

Glad you liked the report.
The Mustang is really very easy to fly. It does require constant attention
and doesn't suffer fools gladly however. Like any high performance airplane,
it has to be flown by the book and fooling around on the left side of the
envelope can get you killed in a hurry. Other than that....a piece of cake.
Dudley Henriques


"Pat Flannery" > wrote in message
...
>I tried to reply to you personally, but the e-mail address doesn't work.
>
>
>> I flew a D, as well as various other prop fighters as a civilian
>> operator. Never flew ours with external tanks. The airplane is stable on
>> takeoff if flown correctly and I wouldn't anticipate any specific issues
>> with the external tanks except the extended run. I believe the only
>> caution on the external tanks was for high speed buffet above 400 mph.
>> We had the fuselage tank removed and only flew the Mustang using the 2
>> mains at 92 gallons each.(90 usable)
>> If you are interested in a pilot report on what it was like to fly the D,
>> I did one for the Warbirdalley site some years ago at the following ;
>> http://www.warbirdalley.com/articles/p51pr.htm#pirep1
>> Hope you find the report interesting.
>> Dudley Henriques
>>
> Thanks for putting me on to that pilot report, that was very interesting
> to read.
> The overall feeling I got from it was of an aircraft that takes a lot of
> effort to get fully attuned to and in sync with, but is capable of doing
> outstanding things once you get enough hours in on it and understand how
> it behaves.
> I particularly liked your description of starting the Merlin up. :-D
> You mentioned you had flown several types of prop driven fighters, what
> other ones did you fly?
> I once talked to a Navy pilot of a Grumman Bearcat who was very taken by
> that aircraft.
> About the most fascinating conversation I ever had with a pilot was years
> ago after the Soviet Union had just fallen who flew a two-seater TA-4J
> Skyhawk to the Minot N.D. airshow. He worked for Navy R&D and had done
> three tours in Vietnam with the A-4.
> His backseater was in awe of him, and like most really competent combat
> pilots, he was one of the easiest-going down-to-earth guys you ever ran
> into... no attitude, no mirrored sunglasses, no waxed mustache.
> The reason he was there was that the Ukrainian Air Force had sent a pair
> of MiG-29's on a U.S. tour, and the Navy wanted to see what they could do
> aerobatically and try to get some insight into what they'd do if they came
> up against a FA-18, so they had him and his inconspicuous Skyhawk
> following them around the airshow circuit and observing them in action.
> One thing we both noticed was the effortless way the Fulcrum could ignite
> its afterburner stages; this is apparently nearly fully automatic- the
> pilot merely advances the throttle, and the aircraft senses airspeed, g
> forces, air density, and what type of maneuver is going on and gives the
> amount of afterburner required. The MiG was going in and out of various
> degrees of afterburner at several points during even fairly simple
> aerobatic maneuvers.
> He had been in on the abortive A-12 program, and his take on it was that
> the Navy screwed over General Dynamics because it wanted to spend money
> elsewhere after the end of the cold war; he described flying the simulator
> and stated that he thought it was an excellent aircraft, particularly
> complementing the pilot's view out of the cockpit, which he said was truly
> outstanding.
>
> Pat

[Greg D. Moore \(Strider\)]

"Blueskies" > wrote in message
et...
>
> "Tim Rogers" > wrote in message
> ...
> :
> : "Blueskies" > wrote in message
> : . net...
> : >
> : > "Danny Deger" > wrote in message
> : > ...
> : > :
> : > : "Danny Deger" > wrote in message
> : > : ...
> : > :
> : > : > Why does the shuttle throttle to 3 Gs on ascent?
> : > : >
> : > :
> : > : The 3 G throttling is done late in the flight (about 7:30)and has
> : > nothing to
> : > : do with dynamic pressure. It was designed in to allow "regular"
> people
> : > fly
> : > : the shuttle.
> : > :
> : > :
> : >
> : > Yes, the aerodynamic loads are highest early in the flight so the
> engines
> : > are throttled then back up. The shuttle rolls
> : > over on its back to fake the occupants into feeling 3 gs when in fact
> the
> : > vehicle is pushing 4 gs....
> :
> : No.
> : The 3 Gs is at the backs of the occupants (and along that same axis for
> the
> : vehicle.) This is the same if they are heads up or heads down.
> : If you lie with your back on the floor, you feel the same 1 G if your
> head
> : is facing north or south.
> :
> : Tim
> :
> :
>
> Not talking about facing north or south, they're talking about hanging
> from your feet or standing upright...

Considering the velocity vector is forward, it still doesn't really matter
which way they are.


>
>

[Greg D. Moore \(Strider\)]

"Henry Spencer" > wrote in message
...
> Three specific snags also aggravated this problem on the SSME:
>
> (a) Most of the technology development on staged combustion had been done
> by Pratt & Whitney, but oddly, the contract for the staged-combustion SSME
> went to Rocketdyne instead. So the experienced people were shut out, and
> the guys who were actually doing the work were having to come up to speed
> on a technology that was new to them.
>
> (b) The SSME program, like the shuttle in general, was starved for money
> and opted to cut corners on subsystem testing in particular. The result
> was an unusually long and painful development process, with subsystem
> problems often not surfacing until whole-engine testing.
>
> (c) Partly as a result of (a) and (b), it didn't become clear until too
> late that the main LOX (I think it was) turbopump really needed one more
> pump stage. Since a major redesign was politically and financially
> impossible at that point, the result was a pump in which each stage was
> pushed to the ragged edge of engineering practicality to meet a very
> ambitious spec.
>
> The combination of (b) and (c) was particularly nasty, because all too
> often, a LOX-pump failure becomes a LOX-pump fire, which destroys the
> evidence of what went wrong. Having this happen repeatedly to whole test
> engines was just what an already-stressed development program didn't need.

To be fair, the engine has improved greatly since the first ones were built.

The current Block IIs appear to have incorporated several major changes
improving them, prolonging their cycles between tear-downs and over-all
making them far better than the originals.

(and much of the work was done by Pratt & Whitney.)

(of course I still think some people continue to hold old biases against the
SSME :-)

> --
> spsystems.net is temporarily off the air; | Henry Spencer
> mail to henry at zoo.utoronto.ca instead. |
>

[Pat Flannery]

Henry Spencer wrote:
> Yep, lots of compromises in some of those wartime designs... Some of the
> photo-recon versions of the Spitfire had a tail tank that compromised
> stability even more drastically
>
_Tail tank_?! Oh, I've got to see a cutaway of this! :-)
Apparently, some Soviet jets used fuel tanks in the vertical fin.
The Monogram (now it's Revell after the two companies merged)
transparent model of the P-51D has the fuselage fuel tank in it:
http://www.hobbylinc.com/htm/rvl/rvl04726.htm
The really amazing model was the transparent Monogram 1/24th scale Bell
UH-1 "Huey" helicopter.
It took forever to spin up to full speed, but God help you if that main
rotor ever hit you at full RPM. :-D

Pat

[Greg D. Moore \(Strider\)]

"muff528" > wrote in message
news:z4Coh.2414$%Q4.1156@trnddc06...
>
> "Morgans" > wrote in message
> ...
>>
>> "Brian Gaff" > wrote
>>
>>> Yes, and it is also why the shedding foam can only do serious damage
>>> within the lower atmosphere, as the drag cannot decelerate the chunks
>>> enough to strike with enough force to do harm at that altitude.
>>
>> Sorry, but you got that one wrong.
>>
>> The foam does the damage because of the high speed that it has when it
>> hits the shuttle.
>>
>> If there was no drag, the foam would not hit with any force; it would be
>> going the same speed as the shuttle.
>>
>> When a chunk of foam falls off, it is the drag of the stationary
>> atmosphere slowing the foam so effectively and rapidly, that causes the
>> relative closing speeds of the now nearly stationary foam hitting the
>> speeding shuttle.
>> --
>> Jim in NC
>>
>
> OK, now I'm trying to figure out how to insert a magical, imaginary
> conveyor
> belt into this scenario. :-)

Please tell me you're not referring to that silly Straight Dope thing on a
plane on a conveyor belt.


>
> TP in FL (Go Gators!)
>

[Tim Rogers]

"Greg D. Moore (Strider)" > wrote in message
ink.net...
>
> "Blueskies" > wrote in message
> et...
>>
>> "Tim Rogers" > wrote in message
>> ...
>> :
>> : "Blueskies" > wrote in message
>> : . net...
>> : >
>> : > "Danny Deger" > wrote in message
>> : > ...
>> : > :
>> : > : "Danny Deger" > wrote in message
>> : > : ...
>> : > :
>> : > : > Why does the shuttle throttle to 3 Gs on ascent?
>> : > : >
>> : > :
>> : > : The 3 G throttling is done late in the flight (about 7:30)and has
>> : > nothing to
>> : > : do with dynamic pressure. It was designed in to allow "regular"
>> people
>> : > fly
>> : > : the shuttle.
>> : > :
>> : > :
>> : >
>> : > Yes, the aerodynamic loads are highest early in the flight so the
>> engines
>> : > are throttled then back up. The shuttle rolls
>> : > over on its back to fake the occupants into feeling 3 gs when in fact
>> the
>> : > vehicle is pushing 4 gs....
>> :
>> : No.
>> : The 3 Gs is at the backs of the occupants (and along that same axis for
>> the
>> : vehicle.) This is the same if they are heads up or heads down.
>> : If you lie with your back on the floor, you feel the same 1 G if your
>> head
>> : is facing north or south.
>> :
>> : Tim
>> :
>> :
>>
>> Not talking about facing north or south, they're talking about hanging
>> from your feet or standing upright...
>
> Considering the velocity vector is forward, it still doesn't really matter
> which way they are.

That was my point exactly.
Thanks for the clarification, Greg.

Tim

[muff528]

"Greg D. Moore (Strider)" > wrote in message
ink.net...
>
> "muff528" > wrote in message
> news:z4Coh.2414$%Q4.1156@trnddc06...
>>
>> "Morgans" > wrote in message
>> ...
>>>
>>> "Brian Gaff" > wrote
>>>
>>>> Yes, and it is also why the shedding foam can only do serious damage
>>>> within the lower atmosphere, as the drag cannot decelerate the chunks
>>>> enough to strike with enough force to do harm at that altitude.
>>>
>>> Sorry, but you got that one wrong.
>>>
>>> The foam does the damage because of the high speed that it has when it
>>> hits the shuttle.
>>>
>>> If there was no drag, the foam would not hit with any force; it would be
>>> going the same speed as the shuttle.
>>>
>>> When a chunk of foam falls off, it is the drag of the stationary
>>> atmosphere slowing the foam so effectively and rapidly, that causes the
>>> relative closing speeds of the now nearly stationary foam hitting the
>>> speeding shuttle.
>>> --
>>> Jim in NC
>>>
>>
>> OK, now I'm trying to figure out how to insert a magical, imaginary
>> conveyor
>> belt into this scenario. :-)
>
> Please tell me you're not referring to that silly Straight Dope thing on a
> plane on a conveyor belt.
>
>
I don't know what you're talking about :)

[Henry Spencer]

In article >,
Pat Flannery > wrote:
>> Yep, lots of compromises in some of those wartime designs... Some of the
>> photo-recon versions of the Spitfire had a tail tank that compromised
>> stability even more drastically
>>
>_Tail tank_?! Oh, I've got to see a cutaway of this! :-)

Not literally in the tail, if (dim) memory serves, but it was called that
because it was in the aft fuselage.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Henry Spencer]

In article >,
Blueskies > wrote:
>: The 3 Gs is at the backs of the occupants (and along that same axis for the
>: vehicle.) This is the same if they are heads up or heads down.
>: If you lie with your back on the floor, you feel the same 1 G if your head
>: is facing north or south.
>
>Not talking about facing north or south, they're talking about hanging
>from your feet or standing upright...

When all the forces (engine thrust and air drag) are from your back to
your chest or vice versa, being head-up or head-down is precisely the same
as being head-northward or head-southward while lying on your back on
Earth, i.e. it makes not the slightest difference in what you feel.

The shuttle in ascent is in free fall except for thrust and drag. The
ascent path, and the shuttle's orientation during ascent, are carefully
chosen to *avoid* having the wings generate lift. The wings are not
strong enough to provide any useful amount of lift during ascent, and
the dominant concern is to avoid tearing them off by overloading them.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Paul A. Suhler]

Henry Spencer > wrote:
>Three specific snags also aggravated this problem on the SSME:

[...]

In his book "Advanced Engine Development at Pratt & Whitney," Dick
Mulready devoted a chapter to the competition to develop the space
shuttle engine. By the time of selection, P&W's XLR129 had over 251
seconds of operation, versus 0.461 for Rocketdyne's engine.

During a visit, Dick Bissell, a consultant for United Aircraft and
formerly of the CIA and progenitor of the U-2 and Blackbird, said,
"I am sorry, but you cannot win. It was already decided in advance.
The only reason for the competition was to transfer your technolody
to them."

Does anyone have any opinion on the relative merits of the P&W and
Rocketdyne designs? On the politics?

Thanks,

Paul

[[email protected]]

Absolutely correct!

Bud



On Jan 8, 6:00 pm, "Greg D. Moore \(Strider\)"
> wrote:
> "Blueskies" > wrote in odigy.net...
>
>
>
>
>
>
>
> > "Tim Rogers" > wrote in message
> ...
> > :
> > : "Blueskies" > wrote in message
> > .net...
> > : >
> > : > "Danny Deger" > wrote in message
> > : ...
> > : > :
> > : > : "Danny Deger" > wrote in message
> > : > ...
> > : > :
> > : > : > Why does the shuttle throttle to 3 Gs on ascent?
> > : > : >
> > : > :
> > : > : The 3 G throttling is done late in the flight (about 7:30)and has
> > : > nothing to
> > : > : do with dynamic pressure. It was designed in to allow "regular"
> > people
> > : > fly
> > : > : the shuttle.
> > : > :
> > : > :
> > : >
> > : > Yes, the aerodynamic loads are highest early in the flight so the
> > engines
> > : > are throttled then back up. The shuttle rolls
> > : > over on its back to fake the occupants into feeling 3 gs when in fact
> > the
> > : > vehicle is pushing 4 gs....
> > :
> > : No.
> > : The 3 Gs is at the backs of the occupants (and along that same axis for
> > the
> > : vehicle.) This is the same if they are heads up or heads down.
> > : If you lie with your back on the floor, you feel the same 1 G if your
> > head
> > : is facing north or south.
> > :
> > : Tim
> > :
> > :
>
> > Not talking about facing north or south, they're talking about hanging
> > from your feet or standing upright...Considering the velocity vector is forward, it still doesn't really matter
> which way they are.
>
>
>
> - Hide quoted text -- Show quoted text -- Hide quoted text -- Show quoted text -

[Jeff Findley]

"Pat Flannery" > wrote in message
...
>
> The really amazing model was the transparent Monogram 1/24th scale Bell
> UH-1 "Huey" helicopter.
> It took forever to spin up to full speed, but God help you if that main
> rotor ever hit you at full RPM. :-D

I didn't have a transparent UH-1, but the one I did their regular UH-1 model
(at least I think it was a Monogram). I modified so that it would spin the
top rotor via an electric motor and a couple of LEGO gears. Luckily on this
model the fuselage cover easily slid on and off, so everything was hidden.
Boy that thing would spin that main rotor *fast*. ;-)

Unfortunately, my painting skills weren't that great at the time, so the
overall appearance was rather shabby and like almost all of my (poorly
built) models from that era, it was likely destroyed by fire crackers.

Jeff
--
"They that can give up essential liberty to obtain a
little temporary safety deserve neither liberty nor
safety"
- B. Franklin, Bartlett's Familiar Quotations (1919)

[Gig 601XL Builder]

Mxsmanic wrote:
> Anno v. Heimburg writes:
>
>> Well, a lot of people have never flown in combat, but one could have
>> deduced from the fact that we were talking about the P-51 Mustang (a
>> WWII fighter plane) and the "war" part in "war emergency power" that
>> the most likely application of war emergency power was indeed, um,
>> during wartime? War, as in, combat?
>
> A lot of aircraft have flown in a lot of wartime, but they didn't do
> it at emergency war power. Obviously, more than just wartime is
> required to justify it.

Look Anthony, the engine is designed to fly at X power setting without doing
undue harm to itself so the plane can land and fight another day. In combat,
X might not be enough at some moment to get the pilot out of harms way. So
the aircraft is capable of providing X+ which while it will give the pilot
some added power and maybe the chance of saving both himself and the
airframe it will cause the engine to be replaced.

It is very much like the parachute that Cirrus is using today. If they are
used something is going to break but the a pilot has a chance to survive
that they might not have otherwise had.

[Herb Schaltegger]

On Tue, 9 Jan 2007 08:44:27 -0600, Jeff Findley wrote
(in article >):

> and like almost all of my (poorly built) models from that era, it was likely
> destroyed by fire crackers.

We loaded pellets into our Crossman airguns, but the principle was the
same. :-)

--
Herb Schaltegger
"You can run on for a long time . . . sooner or later, God'll cut you
down." - Johnny Cash
<http://www.angryherb.net>

[Pat Flannery]

Jeff Findley wrote:
> I didn't have a transparent UH-1, but the one I did their regular UH-1 model
> (at least I think it was a Monogram). I modified so that it would spin the
> top rotor via an electric motor and a couple of LEGO gears. Luckily on this
> model the fuselage cover easily slid on and off, so everything was hidden.
> Boy that thing would spin that main rotor *fast*. ;-)
>
Yes, they also did a non-transparent version, minus some of the inner
framework parts.
> Unfortunately, my painting skills weren't that great at the time, so the
> overall appearance was rather shabby and like almost all of my (poorly
> built) models from that era, it was likely destroyed by fire crackers.
>
I've seen some pretty shabby looking real ones over the years.
Monogram also did a 1/48 scale Huey and Huey Cobra.
Revell did a 1/32 scale Huey ( in fact they did at least two versions of
it) in 1/32 scale, and also did a 1/32 scale Cobra.
These all were around at the time of the Vietnam War, so Hueys were well
known.
Want to see my favorite Vietnam-era weapon?
The farm tractor company, Allis-Chalmers, goes to war in a big way in a
tiny tank:
http://en.wikipedia.org/wiki/Ontos_tank

Pat

> Jeff
>

[mike flugennock]

Jeff Findley wrote:
> "Pat Flannery" > wrote in message
> ...
>
>>The really amazing model was the transparent Monogram 1/24th scale Bell
>>UH-1 "Huey" helicopter.
>>It took forever to spin up to full speed, but God help you if that main
>>rotor ever hit you at full RPM. :-D

Iirc, this was the 'copter with what my Dad called the "Jesus Nut", that
one nut that allegedly held the whole craft together and, when hit by
enemy fire, gave all aboard just enough time to yell "Oh, JESUS!".



--

..

"Though I could not caution all, I yet may warn a few:
Don't lend your hand to raise no flag atop no ship of fools!"

--grateful dead.
__________________________________________________ _____________
Mike Flugennock, flugennock at sinkers dot org
"Mikey'zine": dubya dubya dubya dot sinkers dot org

[MichaelJP]

"Dudley Henriques" > wrote in message
...
>
> Glad you liked the report.
> The Mustang is really very easy to fly. It does require constant attention
> and doesn't suffer fools gladly however. Like any high performance
> airplane, it has to be flown by the book and fooling around on the left
> side of the envelope can get you killed in a hurry. Other than that....a
> piece of cake.
> Dudley Henriques
>

Always interested in reading warbird flying reports.

It always strikes me how amazing it must have felt in WW2 to be a fresh
young pilot entrusted with such a high performance machine, especially
relative to other transport in the 40's.

I wonder how many found it too much and came to grief - were there any
trainer versions of the P51D or was the first flight always the first solo
as well?

[MichaelJP]

"Henry Spencer" > wrote in message
...
> In article >,
> Blueskies > wrote:
>>: The 3 Gs is at the backs of the occupants (and along that same axis for
>>the
>>: vehicle.) This is the same if they are heads up or heads down.
>>: If you lie with your back on the floor, you feel the same 1 G if your
>>head
>>: is facing north or south.
>>
>>Not talking about facing north or south, they're talking about hanging
>>from your feet or standing upright...
>
> When all the forces (engine thrust and air drag) are from your back to
> your chest or vice versa, being head-up or head-down is precisely the same
> as being head-northward or head-southward while lying on your back on
> Earth, i.e. it makes not the slightest difference in what you feel.
>
> The shuttle in ascent is in free fall except for thrust and drag. The
> ascent path, and the shuttle's orientation during ascent, are carefully
> chosen to *avoid* having the wings generate lift. The wings are not
> strong enough to provide any useful amount of lift during ascent, and
> the dominant concern is to avoid tearing them off by overloading them.
> --
> spsystems.net is temporarily off the air; | Henry Spencer
> mail to henry at zoo.utoronto.ca instead. |
>

That's interesting, I'd wondered about that.

Is it also the case that the zero-lift trajectory you describe is very
similar to the optimum flight path for orbital insertion? Or is a lot more
fuel used because of it?

[Pat Flannery]

MichaelJP wrote:
> I wonder how many found it too much and came to grief - were there any
> trainer versions of the P51D or was the first flight always the first solo
> as well?
>

I don't think I've ever seen a trainer P-51, in fact most U.S. WW II
fighter didn't have a trainer version.
I assume that after you had done enough hours in a Texan trainer they
assumed you were ready to take on a Mustang, although I have heard of
some pilots training stateside in P-39s before moving up to P-47s or
P-51s overseas.
(Chuck Yeager for instance)

Pat

[Scott Hedrick]

"Herb Schaltegger" > wrote in
message .com...
> We loaded pellets into our Crossman airguns, but the principle was the
> same. :-)

My brother and I used to sink battleship models that way. Once surfaced and
dried out again, a piece of paper coated with glue made it seaworthy again.
We had many models that started with styrene and ended with paper mache.

[Herb Schaltegger]

On Wed, 10 Jan 2007 18:58:43 -0600, Scott Hedrick wrote
(in article >):

>
> "Herb Schaltegger" > wrote in
> message .com...
>> We loaded pellets into our Crossman airguns, but the principle was the
>> same. :-)
>
> My brother and I used to sink battleship models that way. Once surfaced and
> dried out again, a piece of paper coated with glue made it seaworthy again.
> We had many models that started with styrene and ended with paper mache.
>
>

We also used to use bags full of those green plastic army men as BB
targets. I will never forget my favorite lucky shot. You remember
that guy who was standing up, arm hauled back with grenade in hand
ready to throw? I once managed to hit one of those guys dead-center in
the head, causing the plastic to extrude into a perfectly circular ring
around the guy's brand-new copper face. :-D


--
Herb Schaltegger
"You can run on for a long time . . . sooner or later, God'll cut you
down." - Johnny Cash
<http://www.angryherb.net>

[Pat Flannery]

Scott Hedrick wrote:
>
> My brother and I used to sink battleship models that way. Once surfaced and
> dried out again, a piece of paper coated with glue made it seaworthy again.
> We had many models that started with styrene and ended with paper mache.
>

There is a group of ship modelers who build radio controlled warships
out of balsa wood, plywood, and Silkspan fabric that are themselves
equipped with remote control BB guns and go out sailing around sinking
each other.
The radio gear is kept in a BB protected waterproof container so that
it doesn't get damaged when the ship goes down.
http://www.modelwarshipcombat.com/
This must be a _lot_ of fun! :-)

Pat

[Henry Spencer]

In article >,
MichaelJP > wrote:
>> chosen to *avoid* having the wings generate lift. The wings are not
>> strong enough to provide any useful amount of lift during ascent, and
>> the dominant concern is to avoid tearing them off by overloading them.
>
>Is it also the case that the zero-lift trajectory you describe is very
>similar to the optimum flight path for orbital insertion? Or is a lot more
>fuel used because of it?

Yes and no. :-)

If memory serves, the ascent trajectory is pretty close to what a wingless
rocket with similar mass and propulsion characteristics would fly. Flying
even slightly sideways at supersonic speeds is very hard on lightweight
structures; even jet fighters, built for violent maneuvering, can handle
only a very little bit of this. Rockets normally take considerable pains
to fly pretty much(*) straight "into the wind" until clear of most of the
atmosphere. The shuttle trajectory isn't *exactly* what a wingless rocket
would use, because the trajectory that minimizes loads on the orbiter
wings isn't exactly the trajectory that would minimize structural loads in
general -- the wings have priority. But the penalty for this is small.

(* There are minor exceptions, in which lift can be of some use after the
air thins out, plus some complications for air-launched rockets like
Pegasus. But this is still basically correct. )

*However*, there is a more general caveat: even the wingless-rocket
trajectory actually isn't optimal. For one thing, an optimal ascent would
tip over toward the horizontal much more quickly. On Earth, the early
ascent has to be close to vertical, to get the rocket up out of the
atmosphere before the speed builds up too much. For another thing, even
disregarding that, the straight-into-the-wind trajectory isn't exactly
optimal, although it's not too far off.

The only rocket ascent that was ever able to use a truly optimized
trajectory was the Apollo LM ascent stage's departure from the Moon. On
Earth, you inevitably pay some price for the necessities of getting clear
of the atmosphere quickly and pointing straight into the wind while you
do. It's not huge, but it's significant. This is one of the two big
technical advantages of air launch -- starting from even 30,000ft means
you're dealing with considerably thinner air, reducing the price tag
noticeably. (The other is also related to thinner air: rocket engines
are more efficient with less back pressure. The forward speed of the
aircraft is a relatively minor gain by comparison, unless it's a pretty
unusual aircraft.)
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[MichaelJP]

"Henry Spencer" > wrote in message
...
> In article >,
> MichaelJP > wrote:
>>> chosen to *avoid* having the wings generate lift. The wings are not
>>> strong enough to provide any useful amount of lift during ascent, and
>>> the dominant concern is to avoid tearing them off by overloading them.
>>
>>Is it also the case that the zero-lift trajectory you describe is very
>>similar to the optimum flight path for orbital insertion? Or is a lot more
>>fuel used because of it?
>
> Yes and no. :-)
>
> If memory serves, the ascent trajectory is pretty close to what a wingless
> rocket with similar mass and propulsion characteristics would fly. Flying
> even slightly sideways at supersonic speeds is very hard on lightweight
> structures; even jet fighters, built for violent maneuvering, can handle
> only a very little bit of this. Rockets normally take considerable pains
> to fly pretty much(*) straight "into the wind" until clear of most of the
> atmosphere. The shuttle trajectory isn't *exactly* what a wingless rocket
> would use, because the trajectory that minimizes loads on the orbiter
> wings isn't exactly the trajectory that would minimize structural loads in
> general -- the wings have priority. But the penalty for this is small.
>
> (* There are minor exceptions, in which lift can be of some use after the
> air thins out, plus some complications for air-launched rockets like
> Pegasus. But this is still basically correct. )
>
> *However*, there is a more general caveat: even the wingless-rocket
> trajectory actually isn't optimal. For one thing, an optimal ascent would
> tip over toward the horizontal much more quickly. On Earth, the early
> ascent has to be close to vertical, to get the rocket up out of the
> atmosphere before the speed builds up too much. For another thing, even
> disregarding that, the straight-into-the-wind trajectory isn't exactly
> optimal, although it's not too far off.
>
> The only rocket ascent that was ever able to use a truly optimized
> trajectory was the Apollo LM ascent stage's departure from the Moon. On
> Earth, you inevitably pay some price for the necessities of getting clear
> of the atmosphere quickly and pointing straight into the wind while you
> do. It's not huge, but it's significant. This is one of the two big
> technical advantages of air launch -- starting from even 30,000ft means
> you're dealing with considerably thinner air, reducing the price tag
> noticeably. (The other is also related to thinner air: rocket engines
> are more efficient with less back pressure. The forward speed of the
> aircraft is a relatively minor gain by comparison, unless it's a pretty
> unusual aircraft.)
> --
> spsystems.net is temporarily off the air; | Henry Spencer
> mail to henry at zoo.utoronto.ca instead. |
>

Thanks for the extra detail!

[John[_1_]]

Henry Spencer wrote:
> In article >,
> MichaelJP > wrote:
> >> chosen to *avoid* having the wings generate lift. The wings are not
> >> strong enough to provide any useful amount of lift during ascent, and
> >> the dominant concern is to avoid tearing them off by overloading them.
> >
> >Is it also the case that the zero-lift trajectory you describe is very
> >similar to the optimum flight path for orbital insertion? Or is a lot more
> >fuel used because of it?
>
> Yes and no. :-)
>
> If memory serves, the ascent trajectory is pretty close to what a wingless
> rocket with similar mass and propulsion characteristics would fly. Flying
> even slightly sideways at supersonic speeds is very hard on lightweight
> structures; even jet fighters, built for violent maneuvering, can handle
> only a very little bit of this. Rockets normally take considerable pains
> to fly pretty much(*) straight "into the wind" until clear of most of the
> atmosphere. The shuttle trajectory isn't *exactly* what a wingless rocket
> would use, because the trajectory that minimizes loads on the orbiter
> wings isn't exactly the trajectory that would minimize structural loads in
> general -- the wings have priority. But the penalty for this is small.
>
> (* There are minor exceptions, in which lift can be of some use after the
> air thins out, plus some complications for air-launched rockets like
> Pegasus. But this is still basically correct. )
>
> *However*, there is a more general caveat: even the wingless-rocket
> trajectory actually isn't optimal. For one thing, an optimal ascent would
> tip over toward the horizontal much more quickly. On Earth, the early
> ascent has to be close to vertical, to get the rocket up out of the
> atmosphere before the speed builds up too much. For another thing, even
> disregarding that, the straight-into-the-wind trajectory isn't exactly
> optimal, although it's not too far off.
>
> The only rocket ascent that was ever able to use a truly optimized
> trajectory was the Apollo LM ascent stage's departure from the Moon. On
> Earth, you inevitably pay some price for the necessities of getting clear
> of the atmosphere quickly and pointing straight into the wind while you
> do. It's not huge, but it's significant. This is one of the two big
> technical advantages of air launch -- starting from even 30,000ft means
> you're dealing with considerably thinner air, reducing the price tag
> noticeably. (The other is also related to thinner air: rocket engines
> are more efficient with less back pressure. The forward speed of the
> aircraft is a relatively minor gain by comparison, unless it's a pretty
> unusual aircraft.)
> --
> spsystems.net is temporarily off the air; | Henry Spencer
> mail to henry at zoo.utoronto.ca instead. |

Henry,

During the few test shots of Trident missles that I have seen, I always
thought that the angle at which the vehicle flew was remarkable; like
nothing I had ever seen, save for the occassional errant Estes rocket.
The angle seemed close to 45 degrees, although I had no way of really
knowing, almost immediately after emerging from the water and ignition.

I wonder about the considerations that went into choosing the approach
of dispensing of the climb above the densest portion of the atmosphere
before beginning the trip downrange.

Take care all

John

[MichaelJP]

"Pat Flannery" > wrote in message
...
>
>
> Morgans wrote:
>> I had always heard that the fuselage tank was the source of the
>> instability, with it being so far behind the CG, to give it a dangerously
>> aft CG. Today, in peacetime, I don't suppose they would ever dream of
>> putting that much weight that far back, but it was war.
>>
>> Comments?
>>
> I'll take that any day of the week over the Bf-109, where you're main
> fuselage tank goes under the pilot's seat, or the Me-163 where you're
> sitting squeezed in between two tanks of hydrogen peroxide at your sides.

I always think flying an Me-163 in combat must have been one of the most
crazy experiences in wartime aviation, firstly you have all the explosive
fuel around you, secondly you are shortly to be boosted at tremendous climb
rates into the middle of a heavily armed B-17 formation, thirdly if you
survive all that and manage to get a shot in before the couple of minutes
before the motor dies, you have to glide back like a brick to a tiny
airfield and land on a skid!

[Herb Schaltegger]

On Wed, 10 Jan 2007 19:45:06 -0600, Henry Spencer wrote
(in article >):

> (The other is also related to thinner air: rocket engines are more efficient

> with less back pressure.

My undergraduate propulsion prof would be gagging at your use of the
term "back pressure" Henry. He used to almost spit and fume when
someone let it slip. :-p

--
Herb Schaltegger
"You can run on for a long time . . . sooner or later, God'll cut you
down." - Johnny Cash
<http://www.angryherb.net>

[Pat Flannery]

MichaelJP wrote:
>> This is one of the two big
>> technical advantages of air launch -- starting from even 30,000ft means
>> you're dealing with considerably thinner air, reducing the price tag
>> noticeably. (The other is also related to thinner air: rocket engines
>> are more efficient with less back pressure. The forward speed of the
>> aircraft is a relatively minor gain by comparison, unless it's a pretty
>> unusual aircraft.)
>>
> Thanks for the extra detail!
>


There's another advantage if you're using cryogenic propellants. The
propellants can be kept in insulated tankage within the carrier until
altitude is reached and the transferred into the LV. Since the
temperature is well subzero at altitude, there isn't water vapor around
to form ice on the tankage, so the weight and complexity of insulation
can be done away with.
Assuming you are using a Shuttle-style jettisonable ET, that a built-in
performance boost, as well as a cost savings on the ETs themselves.
Although a completely rreusable LV will have a TPS to take reentry
heating, and therefore will already have exterior insulation, the drop
tank solution makes for far easier design as far as vehicle weight goes.

Pat

[Pat Flannery]

John wrote:
>
> During the few test shots of Trident missles that I have seen, I always
> thought that the angle at which the vehicle flew was remarkable; like
> nothing I had ever seen, save for the occassional errant Estes rocket.
> The angle seemed close to 45 degrees, although I had no way of really
> knowing, almost immediately after emerging from the water and ignition.
>

Here's a photo of one doing that right after launch:
http://encyclopedia.quickseek.com/images/Trident_missile_image.jpg
One thing Trident has is a extensible nose aerospike that sets up a
shockwave ahead of it for drag reduction during ascent.
I wonder if that influenced the ascent trajectory?

Pat

[Pat Flannery]

MichaelJP wrote:
> I always think flying an Me-163 in combat must have been one of the most
> crazy experiences in wartime aviation, firstly you have all the explosive
> fuel around you, secondly you are shortly to be boosted at tremendous climb
> rates into the middle of a heavily armed B-17 formation, thirdly if you
> survive all that and manage to get a shot in before the couple of minutes
> before the motor dies, you have to glide back like a brick to a tiny
> airfield and land on a skid!
>

As a glider it was superb, thanks to Lippisch's background as a glider
designer.
Although the pilots tended to dive away at high speed to escape enemy
fighters once their fuel was gone (and to get back to base ASAP for the
same reason), it had a really good gliding performance, and the pilots
who flew it said its handling qualities were superior to any other
German aircraft.
It's only drawback in gliding flight was that it was _too_ good at it -
once it got down in ground effect near landing, it had a tendency to
just float along above the ground till speed bled off and it would
settle down. Even the addition of underwing extensible spoilers didn't
completely solve the problem, and a lot of pilots were injured or killed
by the aircraft remaining stubbornly airborne down the whole length of
the landing field (they landed on grass generally) and not touching down
till it arrived on the rough ground outside the field's boundaries.

Pat

[Henry Spencer]

In article >,
Herb Schaltegger > wrote:
>> (also related to thinner air: rocket engines are more efficient
>> with less back pressure.
>
>My undergraduate propulsion prof would be gagging at your use of the
>term "back pressure" Henry...

This is the difference between someone whose idea of an unsophisticated
audience is upper-year engineering students, and someone who's actually
had practice writing for, and talking to, non-captive audiences. :-)

Is "back pressure" strictly correct? Arguably not, although the issue is
more complicated than it looks (for one thing, ambient pressure at the
nozzle exit isn't necessarily the same as ambient pressure elsewhere on
the engine, which in turn isn't necessarily the same as ambient pressure
on the vehicle -- rocket exhausts can be powerful ejector pumps). But it
*is* what you say if you want to give the right general impression to an
audience that doesn't care to hear the rigorous details.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Henry Spencer]

In article >,
Pat Flannery > wrote:
>>> This is one of the two big technical advantages of air launch...
>
>There's another advantage if you're using cryogenic propellants. The
>propellants can be kept in insulated tankage within the carrier until
>altitude is reached and the transferred into the LV. Since the
>temperature is well subzero at altitude, there isn't water vapor around
>to form ice on the tankage, so the weight and complexity of insulation
>can be done away with.

You don't really need insulation against ice anyway, unless you've been
stupid enough to put something fragile downstream of the tank surfaces.
Just let it fall off after engine ignition, as the Saturn V did.

The big reason why you might need tank insulation is if the tank holds
LH2, in which case you need to insulate to prevent liquid air from
condensing... and that'll happen even at subzero temperatures, so you
can't get away with leaving it off.

>Although a completely rreusable LV will have a TPS to take reentry
>heating, and therefore will already have exterior insulation, the drop
>tank solution makes for far easier design as far as vehicle weight goes.

The gain is actually rather questionable, after you consider reentry --
the drop tank leaves behind a heavy, dense vehicle that makes a severe
reentry. At reentry time, it's *good* if lots of the volume inside the
TPS is empty tanks. The drop tank does make for far easier design if you
can "throw the TPS problem over the fence" to the materials team...
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Henry Spencer]

In article om>,
John > wrote:
>During the few test shots of Trident missles that I have seen, I always
>thought that the angle at which the vehicle flew was remarkable; like
>nothing I had ever seen, save for the occassional errant Estes rocket.
>The angle seemed close to 45 degrees, although I had no way of really
>knowing, almost immediately after emerging from the water and ignition.

I wonder, though, if it actually ascends in that direction, or if that's
just a transient error -- perhaps something to do with the dynamics of
breaking the surface -- that the guidance system sorts out a second or
two later.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[MichaelJP]

"Pat Flannery" > wrote in message
...
>
>
> MichaelJP wrote:
>> I always think flying an Me-163 in combat must have been one of the most
>> crazy experiences in wartime aviation, firstly you have all the explosive
>> fuel around you, secondly you are shortly to be boosted at tremendous
>> climb rates into the middle of a heavily armed B-17 formation, thirdly if
>> you survive all that and manage to get a shot in before the couple of
>> minutes before the motor dies, you have to glide back like a brick to a
>> tiny airfield and land on a skid!
>>
>
> As a glider it was superb, thanks to Lippisch's background as a glider
> designer.
> Although the pilots tended to dive away at high speed to escape enemy
> fighters once their fuel was gone (and to get back to base ASAP for the
> same reason), it had a really good gliding performance, and the pilots who
> flew it said its handling qualities were superior to any other German
> aircraft.
> It's only drawback in gliding flight was that it was _too_ good at it -
> once it got down in ground effect near landing, it had a tendency to just
> float along above the ground till speed bled off and it would settle down.
> Even the addition of underwing extensible spoilers didn't completely solve
> the problem, and a lot of pilots were injured or killed by the aircraft
> remaining stubbornly airborne down the whole length of the landing field
> (they landed on grass generally) and not touching down till it arrived on
> the rough ground outside the field's boundaries.
>
> Pat

Thanks Pat - the ME-163 is modelled in the superb combat flight sim IL-2,
trying it last night they must have modelled this aircraft quite nicely as I
found it very difficult to bleed off enough speed in the hold-off, exactly
as you said above. Landing on the grass the skid dug in and certainly a real
aircraft would have been destroyed.

Difference is I could reset for another go:)

Doing some other testing I found it impossible to recover from a spin
entered from a slow-speed stall. Wonder if that's correct?

[MichaelJP]

"Henry Spencer" > wrote in message
...
> In article >,
> Herb Schaltegger > wrote:
>>> (also related to thinner air: rocket engines are more efficient
>>> with less back pressure.
>>
>>My undergraduate propulsion prof would be gagging at your use of the
>>term "back pressure" Henry...
>
> This is the difference between someone whose idea of an unsophisticated
> audience is upper-year engineering students, and someone who's actually
> had practice writing for, and talking to, non-captive audiences. :-)
>
> Is "back pressure" strictly correct? Arguably not, although the issue is
> more complicated than it looks (for one thing, ambient pressure at the
> nozzle exit isn't necessarily the same as ambient pressure elsewhere on
> the engine, which in turn isn't necessarily the same as ambient pressure
> on the vehicle -- rocket exhausts can be powerful ejector pumps). But it
> *is* what you say if you want to give the right general impression to an
> audience that doesn't care to hear the rigorous details.
> --
> spsystems.net is temporarily off the air; | Henry Spencer
> mail to henry at zoo.utoronto.ca instead. |
>

In a similar way that the term "centrifugal force" is generally despised by
experts, but for most people it's quite a good way to describe the
sensations they experience.

[Herb Schaltegger]

On Thu, 11 Jan 2007 21:37:33 -0600, Henry Spencer wrote
(in article >):

> In article >,
> Herb Schaltegger > wrote:
>>> (also related to thinner air: rocket engines are more efficient
>>> with less back pressure.
>>
>> My undergraduate propulsion prof would be gagging at your use of the
>> term "back pressure" Henry...
>
> This is the difference between someone whose idea of an unsophisticated
> audience is upper-year engineering students, and someone who's actually
> had practice writing for, and talking to, non-captive audiences. :-)
>
> Is "back pressure" strictly correct? Arguably not, although the issue is
> more complicated than it looks (for one thing, ambient pressure at the
> nozzle exit isn't necessarily the same as ambient pressure elsewhere on
> the engine, which in turn isn't necessarily the same as ambient pressure
> on the vehicle -- rocket exhausts can be powerful ejector pumps). But it
> *is* what you say if you want to give the right general impression to an
> audience that doesn't care to hear the rigorous details.
>

I know what you're saying Henry. It's just that every time I hear
"back pressure" in terms of rocket or gas turbing engines, I still to
this day have the mental image of Prof. Wilkerson standing at the
blackboard, closing his eyes as if in pain and squeezing his hand so
hard the chalk snaps . . . ;-)

--
Herb Schaltegger
"You can run on for a long time . . . sooner or later, God'll cut you
down." - Johnny Cash
<http://www.angryherb.net>

[Greg D. Moore \(Strider\)]

"Herb Schaltegger" > wrote in
message .com...
>
> I know what you're saying Henry. It's just that every time I hear
> "back pressure" in terms of rocket or gas turbing engines, I still to
> this day have the mental image of Prof. Wilkerson standing at the
> blackboard, closing his eyes as if in pain and squeezing his hand so
> hard the chalk snaps . . . ;-)

He only snapped chalk? You're lucky.

I had a Latin teacher that would throw it... very quickly... at the
blackboard behind your head.

THAT got your attention.


>
> --
> Herb Schaltegger
> "You can run on for a long time . . . sooner or later, God'll cut you
> down." - Johnny Cash
> <http://www.angryherb.net>
>

[Steve Foley]

"Greg D. Moore (Strider)" > wrote in message
news:TeMph.13533
> "Herb Schaltegger" > wrote in

>> I know what you're saying Henry. It's just that every time I hear
>> "back pressure" in terms of rocket or gas turbing engines, I still to
>> this day have the mental image of Prof. Wilkerson standing at the
>> blackboard, closing his eyes as if in pain and squeezing his hand so
>> hard the chalk snaps . . . ;-)
>
> He only snapped chalk? You're lucky.
>
> I had a Latin teacher that would throw it... very quickly... at the
> blackboard behind your head.

Why would your Latin get upset when you mentioned "back pressure"? <g>

[Greg D. Moore \(Strider\)]

"Steve Foley" > wrote in message
news:8mMph.7617$GL.3332@trndny06...
> "Greg D. Moore (Strider)" > wrote in
> message news:TeMph.13533
>> "Herb Schaltegger" > wrote in
>
>>> I know what you're saying Henry. It's just that every time I hear
>>> "back pressure" in terms of rocket or gas turbing engines, I still to
>>> this day have the mental image of Prof. Wilkerson standing at the
>>> blackboard, closing his eyes as if in pain and squeezing his hand so
>>> hard the chalk snaps . . . ;-)
>>
>> He only snapped chalk? You're lucky.
>>
>> I had a Latin teacher that would throw it... very quickly... at the
>> blackboard behind your head.
>
> Why would your Latin get upset when you mentioned "back pressure"? <g>

Because we were conjugating it properly. Geesh :-)


>
>

[Derek Lyons]

(Henry Spencer) wrote:

>In article om>,
>John > wrote:
>>During the few test shots of Trident missles that I have seen, I always
>>thought that the angle at which the vehicle flew was remarkable; like
>>nothing I had ever seen, save for the occassional errant Estes rocket.
>>The angle seemed close to 45 degrees, although I had no way of really
>>knowing, almost immediately after emerging from the water and ignition.
>
>I wonder, though, if it actually ascends in that direction, or if that's
>just a transient error -- perhaps something to do with the dynamics of
>breaking the surface -- that the guidance system sorts out a second or
>two later.

There can be attitude transients caused by hydrodynamic effects of the
passage through the water as well as the effects of breaking the
surface. ('Tail slap' as the missile exits is of particular concern.)
Polaris was acutely sensitive to this because of their need to perform
a roll maneuver immediately upon ignition.

In the early days they even tested a set of flow velocity sensors
mounted on the SSBN to attempt to predict wave action and the
calculate the best moment for launch!

They do tend to fly a steeper trajectory than is usual as well.
Partly to encourage seperation between birds (which are being salvoed
at short intervals) and partly as a safety measure to the get the bird
away from the boat as soon as possible.

Also, SLBM launches are typically filmed at much shorter ranges than
is usual for NASA launches - which messes with your ability to
estimate flight angle.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

[Pat Flannery]

Henry Spencer wrote:
>
> The big reason why you might need tank insulation is if the tank holds
> LH2, in which case you need to insulate to prevent liquid air from
> condensing... and that'll happen even at subzero temperatures, so you
> can't get away with leaving it off.
>

In the case of a carrier aircraft, the airstream should carry away any
liquid air on the tank.

>
>> Although a completely rreusable LV will have a TPS to take reentry
>> heating, and therefore will already have exterior insulation, the drop
>> tank solution makes for far easier design as far as vehicle weight goes.
>>
>
> The gain is actually rather questionable, after you consider reentry --
> the drop tank leaves behind a heavy, dense vehicle that makes a severe
> reentry. At reentry time, it's *good* if lots of the volume inside the
> TPS is empty tanks. The drop tank does make for far easier design if you
> can "throw the TPS problem over the fence" to the materials team...

I'm really surprised that the small air-launched orbiter with giant drop
tank concept didn't get anywhere- both we and the Russians thought the
idea had enough merit to do designs of the concept:
http://www.buran.ru/htm/busfact.htm#maks-op
http://www.abo.fi/~mlindroo/SpaceLVs/Slides/sld053.htm

Pat

[Pat Flannery]

Henry Spencer wrote:
> I wonder, though, if it actually ascends in that direction, or if that's
> just a transient error -- perhaps something to do with the dynamics of
> breaking the surface -- that the guidance system sorts out a second or
> two later.
>

No, I've seen films of the launch; it comes out of the water straight,
then immediately pitches over and climbs at a steep angle;
There's a video of a launch here:
https://wrc.navair-rdte.navy.mil/warfighter_enc/movies/Subs/trident.mpg

Pat

[Derek Lyons]

Pat Flannery > wrote:

>
>
>Henry Spencer wrote:
>> I wonder, though, if it actually ascends in that direction, or if that's
>> just a transient error -- perhaps something to do with the dynamics of
>> breaking the surface -- that the guidance system sorts out a second or
>> two later.
>>
>
>No, I've seen films of the launch; it comes out of the water straight,
>then immediately pitches over and climbs at a steep angle;
>There's a video of a launch here:
>https://wrc.navair-rdte.navy.mil/warfighter_enc/movies/Subs/trident.mpg

That's one launch out of many Pat. I've seen pictures of a Polaris
coming out at about 30 degrees from vertical.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

[Pat Flannery]

MichaelJP wrote:
> Thanks Pat - the ME-163 is modelled in the superb combat flight sim IL-2,
> trying it last night they must have modelled this aircraft quite nicely as I
> found it very difficult to bleed off enough speed in the hold-off, exactly
> as you said above. Landing on the grass the skid dug in and certainly a real
> aircraft would have been destroyed.
>
Obviously somebody did their research when writing the program for it.
It might have something to do with the fact tat the ailerons also serve
as its elevators.
Does the simulator have the spoilers on it?
The controls for them are located just to the left of the control stick.
There's a manual pump mechanism handle with a ball top, and to the rear
of it the actual flap control lever.
On the actual aircraft you turn the control handle 180 degrees, then
pump the pump handle six times to put the flaps fully down.
> Difference is I could reset for another go:)
>
> Doing some other testing I found it impossible to recover from a spin
> entered from a slow-speed stall. Wonder if that's correct?
>
It's supposed to have a very abrupt and severe stall according to Eric
Brown's flight notes; he states it goes into a steep spiraling dive, but
you can recover from it in a "straightforward" manner. I don't know it
that means you turn into the spin and convert it into a dive or what.
BTW, he was able to get the one he was flying up to 440 mph in _gliding_
flight in a dive, which gives you some idea of just how aerodynamic this
little thing was.
He wrecked his Komet by doing progressively faster and faster ballasted
landings as tests for a British high speed research aircraft that the
RAF was planning, till the skid finally came through the floorboard of
the cockpit after a landing at 158 mph.

Pat

[Pat Flannery]

Greg D. Moore (Strider) wrote:
>
> He only snapped chalk? You're lucky.
>
> I had a Latin teacher that would throw it... very quickly... at the
> blackboard behind your head.
>
> THAT got your attention.
>
>

The nuns were fond of throwing erasers _at_ your head, and some of them
were made partially of wood.

Pat

[Rand Simberg]

On Fri, 12 Jan 2007 22:12:42 -0600, in a place far, far away, Pat
Flannery > made the phosphor on my monitor glow in
such a way as to indicate that:

>
>
>Greg D. Moore (Strider) wrote:
>>
>> He only snapped chalk? You're lucky.
>>
>> I had a Latin teacher that would throw it... very quickly... at the
>> blackboard behind your head.
>>
>> THAT got your attention.
>>
>>
>
>The nuns were fond of throwing erasers _at_ your head, and some of them
>were made partially of wood.

Was your head one of those? It would explain much.

[Henry Spencer]

In article >,
Pat Flannery > wrote:
>> The big reason why you might need tank insulation is if the tank holds
>> LH2, in which case you need to insulate to prevent liquid air from
>> condensing...
>
>In the case of a carrier aircraft, the airstream should carry away any
>liquid air on the tank.

With any luck, assuming it doesn't go somewhere it shouldn't... but the
condensation will still produce a massive heat flux into the LH2 tank, and
it doesn't take much to boil LH2.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Pat Flannery]

Derek Lyons wrote:
>
> There can be attitude transients caused by hydrodynamic effects of the
> passage through the water as well as the effects of breaking the
> surface. ('Tail slap' as the missile exits is of particular concern.)
> Polaris was acutely sensitive to this because of their need to perform
> a roll maneuver immediately upon ignition.
>

I noticed when I went looking for Polaris launch photos that they seem
to exit the water at angles in quite a few cases.
The first Trident test at Cape Kennedy took off a quite an angle:
http://commons.wikimedia.org/wiki/Image:Trident_C4_first_launch.jpg

> In the early days they even tested a set of flow velocity sensors
> mounted on the SSBN to attempt to predict wave action and the
> calculate the best moment for launch!
>
> They do tend to fly a steeper trajectory than is usual as well.
> Partly to encourage seperation between birds (which are being salvoed
> at short intervals) and partly as a safety measure to the get the bird
> away from the boat as soon as possible.
>
I would have loved to have been there when the crew of sub saw film of
this for the first time:
http://hometown.aol.com/sdrcgeru/images/pic%20-%20d5_cartwheel.jpg :-)

Pat

[Pat Flannery]

Derek Lyons wrote:
> That's one launch out of many Pat. I've seen pictures of a Polaris
> coming out at about 30 degrees from vertical.
>

Actually if you watch that, it's a salvo launch of two missiles.
And yes, I've seen photos of Polaris coming out of the water at an
angle, then strightning out after motor igniton; in this case the
Trident comes out straight, then pivots over on motor ignition, as it
sets itself on its ascent trajectory at only a few hundred feet in the air.


Pat

[John[_1_]]

Pat Flannery wrote:
> Derek Lyons wrote:
> >
> > There can be attitude transients caused by hydrodynamic effects of the
> > passage through the water as well as the effects of breaking the
> > surface. ('Tail slap' as the missile exits is of particular concern.)
> > Polaris was acutely sensitive to this because of their need to perform
> > a roll maneuver immediately upon ignition.
> >
>
> I noticed when I went looking for Polaris launch photos that they seem
> to exit the water at angles in quite a few cases.
> The first Trident test at Cape Kennedy took off a quite an angle:
> http://commons.wikimedia.org/wiki/Image:Trident_C4_first_launch.jpg
>
That pictures seems to show a land launch from Launch Complex 25 at
Cape Canaveral Air Force Station, which might . . . I emphasize might
.. . . suggest that the initial non vertical climb is how the vehicle
is designed to perform . . . interesting *S*

Blue skies

John

[John[_1_]]

> I would have loved to have been there when the crew of sub saw film of
> this for the first time:
> http://hometown.aol.com/sdrcgeru/images/pic%20-%20d5_cartwheel.jpg :-)
>
> Pat

Imagine the orders given . . . IF . . . the CO of that boat had any
idea of what going on above their heads . . .

perhaps the phrases "ahead," "flank" and "screw the telemetry mast"
figured into the conversation.

Blue skies

John

[Derek Lyons]

Pat Flannery > wrote:
>
>Derek Lyons wrote:
>
>> They do tend to fly a steeper trajectory than is usual as well.
>> Partly to encourage seperation between birds (which are being salvoed
>> at short intervals) and partly as a safety measure to the get the bird
>> away from the boat as soon as possible.
>>
>I would have loved to have been there when the crew of sub saw film of
>this for the first time:
>http://hometown.aol.com/sdrcgeru/images/pic%20-%20d5_cartwheel.jpg :-)

Knew a guy who was there - they had just enough time (after launch) to
start to congratulate themselves when *boom*. The self destruct shook
the boat.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

[Brian Thorn]

On Fri, 12 Jan 2007 19:55:43 GMT, (Derek Lyons)
wrote:

>There can be attitude transients caused by hydrodynamic effects of the
>passage through the water as well as the effects of breaking the
>surface. ('Tail slap' as the missile exits is of particular concern.)
>Polaris was acutely sensitive to this because of their need to perform
>a roll maneuver immediately upon ignition.

Coincidentally, History Channel this morning ran a show about the ICBM
Race and included Polaris launch footage. That roll was damned
impressive!

Brian

[Pat Flannery]

John wrote:

> That pictures seems to show a land launch from Launch Complex 25 at
> Cape Canaveral Air Force Station, which might . . . I emphasize might
> . . . suggest that the initial non vertical climb is how the vehicle
> is designed to perform . . . interesting *S*
>
> Blue skies
>
>
>

That's what I thought also.
This photo of another land launch, shows the same antenna in the
background, although this time the missile is ascending vertically:
http://www.bomb-shelter.net/images/stories/trident_sub_missile.jpg
You really want to see one starting at a angle, check this photo:
http://www.spacegatewaysupport.com/images/trident4sm.jpg
This one, on the other hand, seems to be going more vertical as it
climbs: http://www.sciprods.com/images/trident_ll_02m.jpg
I think I know what's going on here; If you are attacking a target
that's well under the missile's maximum range, you don't have to worry
about getting the optimal trajectory for low air drag, but can fire it
on a depressed trajectory so that it stays fairly low in altitude and
can get nearer its target before detection by enemy radar, making any
attempt to intercept it more difficult.
That's probably what the inclined launches are testing; they're trading
altitude and range for speed, and operating more like a field gun than a
howitzer.

Pat

[Jason A. Ciastko]

> That's what I thought also.
> This photo of another land launch, shows the same antenna in the
> background, although this time the missile is ascending vertically:
> http://www.bomb-shelter.net/images/stories/trident_sub_missile.jpg
> You really want to see one starting at a angle, check this photo:
> http://www.spacegatewaysupport.com/images/trident4sm.jpg
> This one, on the other hand, seems to be going more vertical as it climbs:
> http://www.sciprods.com/images/trident_ll_02m.jpg
> I think I know what's going on here; If you are attacking a target that's
> well under the missile's maximum range, you don't have to worry about
> getting the optimal trajectory for low air drag, but can fire it on a
> depressed trajectory so that it stays fairly low in altitude and can get
> nearer its target before detection by enemy radar, making any attempt to
> intercept it more difficult.
> That's probably what the inclined launches are testing; they're trading
> altitude and range for speed, and operating more like a field gun than a
> howitzer.
>
> Pat

IIRC (I'll check with my co-worker that was on boomers), but I believe the
vertical launch tubes the hold the ICBMs are "tilted" slightly outboard and
are not truly vertical. I believe this was done so if the rocket motor did
not light, it would not come back down onto the boat.

Jason C

[John[_1_]]

Pat Flannery wrote:
> John wrote:
>
> > That pictures seems to show a land launch from Launch Complex 25 at
> > Cape Canaveral Air Force Station, which might . . . I emphasize might
> > . . . suggest that the initial non vertical climb is how the vehicle
> > is designed to perform . . . interesting *S*
> >
> > Blue skies
> >
> >
> >
>
> That's what I thought also.
> This photo of another land launch, shows the same antenna in the
> background, although this time the missile is ascending vertically:
> http://www.bomb-shelter.net/images/stories/trident_sub_missile.jpg
> You really want to see one starting at a angle, check this photo:
> http://www.spacegatewaysupport.com/images/trident4sm.jpg
> This one, on the other hand, seems to be going more vertical as it
> climbs: http://www.sciprods.com/images/trident_ll_02m.jpg
> I think I know what's going on here; If you are attacking a target
> that's well under the missile's maximum range, you don't have to worry
> about getting the optimal trajectory for low air drag, but can fire it
> on a depressed trajectory so that it stays fairly low in altitude and
> can get nearer its target before detection by enemy radar, making any
> attempt to intercept it more difficult.
> That's probably what the inclined launches are testing; they're trading
> altitude and range for speed, and operating more like a field gun than a
> howitzer.
>
> Pat
\
Pat,

The second pic seems to support Henry's thought that what we have been
seeing is a transient and that as the missle climbs it pitchs to a more
typical vertical ascent. I saw one or two of these from a long way off
.. . . and more importantly . . . a very long time ago . . . and to be
honest and I simply cannot remember what they looked like.

Now STS-1 . . . that I will always remember . . . after a steady diet
of Titan II's and Saturn V's, I remember being amazed at how fast the
shuttle left the pad (in a comparative sense)

Take care . . .

John

[Henry Spencer]

In article >,
Pat Flannery > wrote:
>No, I've seen films of the launch; it comes out of the water straight,
>then immediately pitches over and climbs at a steep angle;
>There's a video of a launch here:
>https://wrc.navair-rdte.navy.mil/warfighter_enc/movies/Subs/trident.mpg

Actually, on that video it looks like it does *both*: comes out of the
water more or less straight, pitches over fairly steeply, and then
gradually straightens out as it climbs -- not all the way to vertical, but
to a considerably less dramatic tilt than the initial pitchover produced.

Could be an engine-startup transient that the guidance system then sorted
out (in particular, transient flow separation during startup is not at all
rare, and can briefly produce large unwanted thrust vectoring), some sort
of guidance/control-startup transient, or a deliberate "get a bit of
horizontal distance from the sub immediately" maneuver.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Henry Spencer]

In article >,
Pat Flannery > wrote:
>I would have loved to have been there when the crew of sub saw film of
>this for the first time:
>http://hometown.aol.com/sdrcgeru/images/pic%20-%20d5_cartwheel.jpg :-)

Of course, the crew that *really* didn't want to hear/see anything like
that were the folks aboard the Ethan Allen in May 1962, when she did the
only US SLBM test ever with a live warhead...
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Mary Pegg]

Pat Flannery wrote:

> http://www.abo.fi/~mlindroo/SpaceLVs/Slides/sld053.htm

A 747 with an SSME in the tail...

[Note to r.a.p. - that's a Space Shuttle Main Engine]

[Pat Flannery]

Brian Thorn wrote:
> Coincidentally, History Channel this morning ran a show about the ICBM
> Race and included Polaris launch footage. That roll was damned
> impressive!
>
Is this the show that has the footage of the solid-fueled Minuteman
launch identified as a Titan II?

Pat

[Pat Flannery]

Mary Pegg wrote:
> A 747 with an SSME in the tail...
The _New_ Boeing SST proposal! ;-)
It makes sense though... since you're storing LOX and LH2 on the 747
anyway for pumping into the ET at altitude, you might get some use out
of them to up its maximum release altitude at the same time.

Pat

[Henry Spencer]

In article >,
Pat Flannery > wrote:
>I'm really surprised that the small air-launched orbiter with giant drop
>tank concept didn't get anywhere- both we and the Russians thought the
>idea had enough merit to do designs of the concept...

Or without drop tank. Grumman's proposal to the SDIO SSTO competition
(won by McDD with DC-X) was a no-drop-tank orbiter, air launched from a
747, that used existing engines and quite ordinary structures.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Pat Flannery]

Henry Spencer wrote:
>
> Of course, the crew that *really* didn't want to hear/see anything like
> that were the folks aboard the Ethan Allen in May 1962, when she did the
> only US SLBM test ever with a live warhead...
>

Frigate Bird! Hardly anyone knows we ever did that one:
http://www.navy.mil/navydata/cno/n87/usw/issue_24/frigate_bird.htm
Where I'd have been a little queasy about being is on the Carbonero or
Medregal at twenty-five miles from the aim point, and thinking to
yourself "I sure hope that thing's guidance system works right." :-)

Pat

[Brian Thorn]

On Sat, 13 Jan 2007 16:28:30 -0600, Pat Flannery >
wrote:

>> Coincidentally, History Channel this morning ran a show about the ICBM
>> Race and included Polaris launch footage. That roll was damned
>> impressive!
>>
>Is this the show that has the footage of the solid-fueled Minuteman
>launch identified as a Titan II?

Yep. They show nearly identical footage a moment later and correctly
identify the Minuteman II.

Brian

[Derek Lyons]

"Jason A. Ciastko" > wrote:

>IIRC (I'll check with my co-worker that was on boomers), but I believe the
>vertical launch tubes the hold the ICBMs are "tilted" slightly outboard and
>are not truly vertical.

Nope.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

[Derek Lyons]

(Henry Spencer) wrote:

>Could be an engine-startup transient that the guidance system then sorted
>out (in particular, transient flow separation during startup is not at all
>rare, and can briefly produce large unwanted thrust vectoring), some sort
>of guidance/control-startup transient, or a deliberate "get a bit of
>horizontal distance from the sub immediately" maneuver.

Possibly, no, somewhat.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

[Henry Spencer]

In article >,
Pat Flannery > wrote:
>> A 747 with an SSME in the tail...
>
>...It makes sense though... since you're storing LOX and LH2 on the 747
>anyway for pumping into the ET at altitude, you might get some use out
>of them to up its maximum release altitude at the same time.

If memory serves, Boeing eventually concluded that this wasn't a good way
to do it -- too much structural strengthening needed? They looked instead
at injecting fuel into the bypass ducts of the turbofans (!), and
concluded that they could get a very large thrust increase that way, and
that it wouldn't hurt the engines if you kept the duration short.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. |

[Jason A. Ciastko]

"Derek Lyons" > wrote in message > "Jason A. Ciastko"
> wrote:
>
>>IIRC (I'll check with my co-worker that was on boomers), but I believe the
>>vertical launch tubes the hold the ICBMs are "tilted" slightly outboard
>>and
>>are not truly vertical.
>
> Nope.
>
> D.

Getting old is h*ll...

Thanks Derek. I'll stay with my swing wings now....


--
Jason A. Ciastko
Referee's are the only guys who can rob you
and then get a police escort out of the stadium.

[Pat Flannery]

Brian Thorn wrote:
>
> Yep. They show nearly identical footage a moment later and correctly
> identify the Minuteman II.
>

Then, right at the end of the show, they had footage of a Titan II
taking off.
Editors should know more about their subject.
My all-time favorite in this regard is still the Discovery Wings episode
on the B-17, where we learn that it's armed with ten _50 mm_ machine
guns. How would you like to be in a FW-190 coming into a squadron of
those? On the way home from a mission they could descend to low altitude
and engage in tank busting.
Still if nothing else it did have some interesting footage of Soviet
missiles, including that loopy Scud launcher that rises up to the top of
the submarine's conning tower.

Pat

[Pat Flannery]

Henry Spencer wrote:
> If memory serves, Boeing eventually concluded that this wasn't a good way
> to do it -- too much structural strengthening needed? They looked instead
> at injecting fuel into the bypass ducts of the turbofans (!), and
> concluded that they could get a very large thrust increase that way, and
> that it wouldn't hurt the engines if you kept the duration short.
>
Somewhat similar to the way NASA looked into upping their SR-71's
performance via H2O2 injection into the afterburners.
But in that case the improvement in performance was pretty marginal.
Borrowing a page from the D-21/M-12 program, I wonder if you could use
the mini-shuttle's engines for the final climb, while constantly topping
the ET up from the internal tankage till release.

Pat

[Jim Davis]

Pat Flannery wrote:

> My all-time favorite in this regard is still the Discovery Wings
> episode on the B-17, where we learn that it's armed with ten _50
> mm_ machine guns.

Surely you (or Discovery Wings) meant ten 12.7 mm (0.5") machine
guns?

Jim Davis

[Pat Flannery]

Jim Davis wrote:
>
> Surely you (or Discovery Wings) meant ten 12.7 mm (0.5") machine
> guns?
>
>

That's what they obviously meant, but the narrator called them "50 mm
machine guns".
How would you like to be a waist gunner with one of those.... that would
be empowerment, wouldn't it?
The Germans did take after bombers with Me-410s armed with a single 50
mm cannon though.
They also shoehorned one of those into a prototype Me-262 jet's nose:
http://www.warbirdsresourcegroup.org/LRG/images/lrg0208.jpg

Pat

[[email protected]]

The shuttle actually throttles back twice during ascent. The first time
is at max Q. This is not a 3 G situation for the vehicle. After the
solids are dropped, the shuttle again throttles back in the last 30
seconds or so before main engine cut-off, so as to not exceed 3 G's of
forward acceleration when the fuel is almost gone. Whether this is due
to a structural or other reason, I'm not sure. But structural makes the
most sense for several reasons, weight being the primary one.

Bud


Jim wrote:
> Thanks Danny, I had a good belly laugh from that one.
> Jim
> > wrote in message
> ps.com...
> >
> > Danny Deger wrote:
> >> Why does the shuttle throttle to 3 Gs on ascent?
> >>
> >> Danny Deger
> >
> > Because structurally the shuttle vehicle is only stressed for 3 g's. If
> > they didn't throttle back in the late stages of the ascent when the
> > fuel is almost gone and the vehicle is light, it would exceed this
> > level of acceleration. Since the engines are liquid fueled, they can
> > hold full thrust until the fuel is gone.
> >
> > Bud
> >

[MichaelJP]

> MichaelJP wrote:
>> Thanks Pat - the ME-163 is modelled in the superb combat flight sim IL-2,
>> trying it last night they must have modelled this aircraft quite nicely
>> as I found it very difficult to bleed off enough speed in the hold-off,
>> exactly as you said above. Landing on the grass the skid dug in and
>> certainly a real aircraft would have been destroyed.
>>
> Obviously somebody did their research when writing the program for it.
> It might have something to do with the fact tat the ailerons also serve as
> its elevators.
> Does the simulator have the spoilers on it?
> The controls for them are located just to the left of the control stick.
> There's a manual pump mechanism handle with a ball top, and to the rear of
> it the actual flap control lever.
> On the actual aircraft you turn the control handle 180 degrees, then pump
> the pump handle six times to put the flaps fully down.

Don't think so, but it does have landing flaps. IL-2 is pretty good as a
simulator but it models 100's of different aircraft and variants so it has
to make compromises and not all the subtleties are there. Amazing value
though for the price.

>> Difference is I could reset for another go:)
>>
>> Doing some other testing I found it impossible to recover from a spin
>> entered from a slow-speed stall. Wonder if that's correct?
>>
> It's supposed to have a very abrupt and severe stall according to Eric
> Brown's flight notes; he states it goes into a steep spiraling dive, but
> you can recover from it in a "straightforward" manner. I don't know it
> that means you turn into the spin and convert it into a dive or what.
> BTW, he was able to get the one he was flying up to 440 mph in _gliding_
> flight in a dive, which gives you some idea of just how aerodynamic this
> little thing was.
> He wrecked his Komet by doing progressively faster and faster ballasted
> landings as tests for a British high speed research aircraft that the RAF
> was planning, till the skid finally came through the floorboard of the
> cockpit after a landing at 158 mph.
>
> Pat

Interesting, what's your source for the Eric Brown story, I'd like to read
more.

[Pat Flannery]

MichaelJP wrote:
>
> Interesting, what's your source for the Eric Brown story, I'd like to read
> more.
>

Eric Brown wrote a series books about the 487 types of planes he flew
in his career as a test pilot.
The one I have is "Wings of The Luftwaffe"(all the titles have "Wings"
in them).
Each aircraft type has both a cutaway of the whole aircraft, and a
detailed drawing of the cockpit from the pilot's perspective with
everything labeled.
He gives an overview of all the handling characteristics of each type:
http://www.amazon.com/Wings-Luftwaffe-Flying-German-aircraft/dp/0385135211
In another book, "Wings of the Weird and Wonderful" he actually flew one
of these: http://www.warbirdsresourcegroup.org/LRG/bv141.html

Pat

[Danny Deger]

> wrote in message
oups.com...
> The shuttle actually throttles back twice during ascent. The first time
> is at max Q. This is not a 3 G situation for the vehicle. After the
> solids are dropped, the shuttle again throttles back in the last 30
> seconds or so before main engine cut-off, so as to not exceed 3 G's of
> forward acceleration when the fuel is almost gone. Whether this is due
> to a structural or other reason, I'm not sure. But structural makes the
> most sense for several reasons, weight being the primary one.
>
> Bud

The answer is:
So Navy fighter pilots can fly the shuttle :-)

Danny Deger

snip

[[email protected]]

Danny Deger wrote:
> > wrote in message
> oups.com...
> > The shuttle actually throttles back twice during ascent. The first time
> > is at max Q. This is not a 3 G situation for the vehicle. After the
> > solids are dropped, the shuttle again throttles back in the last 30
> > seconds or so before main engine cut-off, so as to not exceed 3 G's of
> > forward acceleration when the fuel is almost gone. Whether this is due
> > to a structural or other reason, I'm not sure. But structural makes the
> > most sense for several reasons, weight being the primary one.
> >
> > Bud
>
> The answer is:
> So Navy fighter pilots can fly the shuttle :-)
>
> Danny Deger
>
> snip

[[email protected]]

I read that. Nice double meaning. However I think Navy pilots get to 9
G's like AF Raptor pilots do. I was just explaining to the ones that
thought the max Q issue was 3 G's, which it is not.

Bud


Danny Deger wrote:
> > wrote in message
> oups.com...
> > The shuttle actually throttles back twice during ascent. The first time
> > is at max Q. This is not a 3 G situation for the vehicle. After the
> > solids are dropped, the shuttle again throttles back in the last 30
> > seconds or so before main engine cut-off, so as to not exceed 3 G's of
> > forward acceleration when the fuel is almost gone. Whether this is due
> > to a structural or other reason, I'm not sure. But structural makes the
> > most sense for several reasons, weight being the primary one.
> >
> > Bud
>
> The answer is:
> So Navy fighter pilots can fly the shuttle :-)
>
> Danny Deger
>
> snip

[Danny Deger]

> wrote in message
ups.com...
>I read that. Nice double meaning. However I think Navy pilots get to 9
> G's like AF Raptor pilots do. I was just explaining to the ones that
> thought the max Q issue was 3 G's, which it is not.
>

This is true. Two different times to throttle on ascent for 2 different
reasons.

Danny Deger

[Greg D. Moore \(Strider\)]

"Pat Flannery" > wrote in message
...
>
>
> Henry Spencer wrote:
>>
>> Of course, the crew that *really* didn't want to hear/see anything like
>> that were the folks aboard the Ethan Allen in May 1962, when she did the
>> only US SLBM test ever with a live warhead...
>
> Frigate Bird! Hardly anyone knows we ever did that one:
> http://www.navy.mil/navydata/cno/n87/usw/issue_24/frigate_bird.htm
> Where I'd have been a little queasy about being is on the Carbonero or
> Medregal at twenty-five miles from the aim point, and thinking to yourself
> "I sure hope that thing's guidance system works right." :-)

I only read about it since someone asked if we had ever done that and I
figured I'd look it up.


>
> Pat

[Hilton]

Danny Deger wrote:
>
> While in the atmosphere the main engines are throttled back to reduce the
> maximum aerodynamic pressure. The grain in the SRB is also designed to
> have them go through a period of reduced thrust at about the same time.

Not sure what you mean by "grain in the SRB", but the physical propellant
shape is designed the reduce the thrust by approximately a third 50 seconds
after lift-off to prevent overstressing the vehicle during maximum dynamic
pressure.

Hilton

[Peter Stickney]

Pat Flannery wrote:

>
>
> MichaelJP wrote:
>> I wonder how many found it too much and came to grief - were there any
>> trainer versions of the P51D or was the first flight always the first
>> solo as well?
>>
>
> I don't think I've ever seen a trainer P-51, in fact most U.S. WW II
> fighter didn't have a trainer version.
> I assume that after you had done enough hours in a Texan trainer they
> assumed you were ready to take on a Mustang, although I have heard of
> some pilots training stateside in P-39s before moving up to P-47s or
> P-51s overseas.
> (Chuck Yeager for instance)

During the war there weren't any 2 chair P-51s (Except a few one-offs like
the 2-seat P-51B that was used by Eisenhower for direct recon of Normandy.)

There were some TF-51Ds put together after the war by Temco - They can be
spotted by their having the bigger F-51H fin & rudder, and a canopy shape
that gives a bit more rear headroom. Cavalier made some, as well -
including a couple delivered to the U.S. Army in the 1960s for use as chase
planes for the AH-56 Cheyenne Compound Helicopter.

But, backduring the War, the usual procedure before transitioning to a singe
seat fighter was to demonstrate proficiency in landing an AT-6 from the
read seat.
This gave the same lousy over-the-nose visibility, and the T-6's much
snarkier behavior on landing and rollout meant that if you could handle
that, you could pretty much handle anything.

Figher training (More of less what we'd call LIFT (Lead-In Fighter Training
these days) was typically performed in war-weary P-39s or P-40s. It was
considered part of the Advanced Single Engine syllabus.

The U.S. Aviation Training Programs, both Army and Navy, were some of the
most amazing miracles of WW 2. A lot of study went into syllabus and
methods - And the result was Pilots coming out of training in with 250-300
hours who could not only fly a fighter, but fly it on instruments, navigate
their way from England to Prague and back, and fight the Luftwaffe (or the
IJN) to a standstill when they got there.
Well, and the U.S. Aviation Industry, that could build fighters that could
not only fly from England to Prague, but take on the short-ranged
interceptors when it got there, and, if necessary, run them out of gas, and
fly home.
(The only German fighter pilots who got instrument training were the
NachtJagd. This was a factor in choosing bomber pilots to fly the early
jets - they could make instrument let-down in the usual crappy German
weather. An Me 262 didn't have the fuel on board to stooge around looking
for a hole in the clouds to descend through, or a VFR airfield.

Pete Stickney
Without data, all you have is an opinion

[Pat Flannery]

Peter Stickney wrote:
> (The only German fighter pilots who got instrument training were the
> NachtJagd.
>

How would you like to be the pilot of one of those single seat radar
equipped FW-190 night fighters?
That must have kept one mighty busy.
See if you can figure this out BTW; it's a Ba-349 "Natter" control
panel:
http://www.fantasyofflight.com/Images/aircraft/natter/Natter_Cockpit.jpg
That thing in the middle with the crosshairs on it has to have something
to do with the semi-automated way it was vectored by ground control to
the incoming bombers... but how does it work? I don't think the nose was
recoverable after being jettisoned, so it has to be cheap, but it looks
pretty sophisticated, like something that might have a gyro or cathode
ray tube in it.

Pat