Why does the shuttle throttle on ascent?

"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.

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tjd writes:

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

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

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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

"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

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.

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...

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.

"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
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Sed quis custodiet ipsos Custodes?

"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

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