Dear Dr. Strangewater

[pac plyer]

Hey Dr. Bad
> >
> >Twice now from my house over the last decade, we lucked out and
watched a rocket launch right at sunset out of Van. God it was
awesome! I live on a skypark and both times we were drinking beer
watching the sun go down in my back yard, which is about 400' from rwy
25 and then: what a show. We always stand out there, telling lies,
watching the amazing variety of bugsmashing machines try to negotiate
our desert runway; which as luck would have it, is immediately
following my 16 ft hangar that everybody hates (They don't blame me; I
didn't build it.) Great shows by legends in their own minds and
luckier than can be believed dweebs and students assures constant
entertainment every night. My legal (by four feet) hangar is the
great private pilot equalizer. But back to the topic!

The first shot the upper level wind took and distorted the contrail
for the following half hour or so: Twisted and spread the sucker like
a basket of snakes all over the sky. Man it was something. Then, a
few months ago the ICBM test went off towards the pacific. That one
was the best (zero wind.) We were all standing out there unaware again
(as airport drunks, er bums often are) and then all of a sudden, here
comes this asshole with a really bright landing light head-on against
the landing traffic! I told my buddy Ron, the skypark president, Oh
Oh watch this, Ron, this asshole's going to do a high-speed pass
opposing landing traffic! In the clear desert air, staring right into
the sunset it's tough to judge distances. Sun had just gone down, so
it made sense that moron here, who was going to scatter the traffic,
flipped his light on cuz he was coming from the west. But as seconds
went by, it became apparent as he got closer to us that he was really
packing a wallop! I thought: oh yeah! a green-eared test pilot that's
going to buzz the joint cuz his commander's away! (we get a show like
that every blue moon.) And then he started trailing smoke real bad
and then it hit all of us: a rocket out of Van. God it lumbered
slowly upward. All of us broke out into ****-eating grins while the
women gasped and shrieked. Then it bent over for the pacific (from
our persp.) and penetrated out of the atmosphere. A huge
neon-iridescent lavender umbrella opened up that looked kind of like
the first volcano image of Io. It sat there glowing for nearly an
hour and reminded me of the aurora borealis.

Now Dr. Strangewater, what the hell was that all about? Was it
propellant? Charged ion? What? Then tell us some rocket accounts
and use: "following is all fictional" preceding the story to quell any
jealous trolls/dweebs.

Your pal,

pacplyer

[John Ousterhout]

On Sun, 17 Aug 2003 15:11:41 GMT, (Badwater
Bill) wrote:

>On 15 Aug 2003 11:17:40 -0700, (pac plyer) wrote:

>>Hey Dr. Bad
>>> >
>>> >Twice now from my house over the last decade, we lucked out and
>>watched a rocket launch right at sunset out of Van.

>
>If you'd have been to our last Jean Fly in, you'd have witnessed a
>Vandenberg launch that evening too.


A few photos that I took of that spectacular rocket launch are near
the bottom of the page at: http://www.jouster.0catch.com/jean-99.html

- John Ousterhout -

[pac plyer]

John Ousterhout > wrote in message >...
> On Sun, 17 Aug 2003 15:11:41 GMT, (Badwater
> Bill) wrote:
>
> >On 15 Aug 2003 11:17:40 -0700, (pac plyer) wrote:
>
> >>Hey Dr. Bad
> >>> >
> >>> >Twice now from my house over the last decade, we lucked out and
> >>watched a rocket launch right at sunset out of Van.
>
> >
> >If you'd have been to our last Jean Fly in, you'd have witnessed a
> >Vandenberg launch that evening too.
>
>
> A few photos that I took of that spectacular rocket launch are near
> the bottom of the page at: http://www.jouster.0catch.com/jean-99.html
>
> - John Ousterhout -

Nice shots John, looks like you guys had fun. Let me know if you guys
have another reunion, need to sight in my mini-30.

Best regards,

pacplyer

[Badwater Bill]

On Sun, 17 Aug 2003 09:58:35 -0700, John Ousterhout
> wrote:

>On Sun, 17 Aug 2003 15:11:41 GMT, (Badwater
>Bill) wrote:
>
>>On 15 Aug 2003 11:17:40 -0700, (pac plyer) wrote:
>
>>>Hey Dr. Bad
>>>> >
>>>> >Twice now from my house over the last decade, we lucked out and
>>>watched a rocket launch right at sunset out of Van.
>
>>
>>If you'd have been to our last Jean Fly in, you'd have witnessed a
>>Vandenberg launch that evening too.
>
>
>A few photos that I took of that spectacular rocket launch are near
>the bottom of the page at: http://www.jouster.0catch.com/jean-99.html
>
>- John Ousterhout -


Thanks John for putting that up. You'll notice the effect I was
discussing about the gasses expanding once the rocket is virtually
outside of the atmosphere. What I find interesting is this happens
relatively quickly, like there is some kind of demarcation line of the
upper atmosphere where you are in it, then in a quantum jump you are
outside of it and the gasses begin expanding without bound. I've
watched these launches for years and they all are about the same.
Before I saw one of these 30 years ago I would have figured that the
demarcation of the upper atmosphere would have been more an analog
event than a digital jump as it seems to be.

In the second and third shots there you'll notice an effect of either
four nozzels or some kind of thrust director in the main nozzel
pushing the gasses symetrically out in 4 quadrants. I wonder what
this is? Anybody know what's going on?

BWB

[Russell Kent]

Badwater Bill wrote:

> In the second and third shots there you'll notice an effect of either
> four nozzels or some kind of thrust director in the main nozzel
> pushing the gasses symetrically out in 4 quadrants. I wonder what
> this is? Anybody know what's going on?

What kind of launch vehicle was it? Perhaps it had fins (presumably 4) that
were causing a trailing vortex, and those votices were shaping the
propellant gases?

Russell Kent

[Corrie]

(Badwater Bill) wrote in message >...

> Thanks John for putting that up. You'll notice the effect I was
> discussing about the gasses expanding once the rocket is virtually
> outside of the atmosphere. What I find interesting is this happens
> relatively quickly, like there is some kind of demarcation line of the
> upper atmosphere where you are in it, then in a quantum jump you are
> outside of it and the gasses begin expanding without bound. I've
> watched these launches for years and they all are about the same.
> Before I saw one of these 30 years ago I would have figured that the
> demarcation of the upper atmosphere would have been more an analog
> event than a digital jump as it seems to be.


I suspect it appears to be a more dramatic change than it really is.
If I remember by college rocketry courses, the angle formed by the
exhaust is a function of Mach. At high altitudes, Mach drops off to
effectively zero, so the plume expands dramatically. This probably
appears more sudden than it really is due to the foreshortening effect
- like looking through a telephoto lens. The second stage may also
use a different type of fuel, with different plume characteristics.


> In the second and third shots there you'll notice an effect of either
> four nozzels or some kind of thrust director in the main nozzel
> pushing the gasses symetrically out in 4 quadrants. I wonder what
> this is? Anybody know what's going on?

Not knowing the particular vehicle, we can only speculate, but it's
fairly common to use verniers - nozzles mounted at an angle - for
steering and control. Fins don't do much at that altitude.

Corrie

[Bill Higdon]

Badwater Bill wrote:
> On 18 Aug 2003 09:33:47 -0700, (Corrie) wrote:
>
>
(Badwater Bill) wrote in message >...
>>
>>
>>>Thanks John for putting that up. You'll notice the effect I was
>>>discussing about the gasses expanding once the rocket is virtually
>>>outside of the atmosphere. What I find interesting is this happens
>>>relatively quickly, like there is some kind of demarcation line of the
>>>upper atmosphere where you are in it, then in a quantum jump you are
>>>outside of it and the gasses begin expanding without bound. I've
>>>watched these launches for years and they all are about the same.
>>>Before I saw one of these 30 years ago I would have figured that the
>>>demarcation of the upper atmosphere would have been more an analog
>>>event than a digital jump as it seems to be.
>>
>>
>>I suspect it appears to be a more dramatic change than it really is.
>>If I remember by college rocketry courses, the angle formed by the
>>exhaust is a function of Mach. At high altitudes, Mach drops off to
>>effectively zero, so the plume expands dramatically. This probably
>>appears more sudden than it really is due to the foreshortening effect
>>- like looking through a telephoto lens. The second stage may also
>>use a different type of fuel, with different plume characteristics.
>>
>>
>>
>>>In the second and third shots there you'll notice an effect of either
>>>four nozzels or some kind of thrust director in the main nozzel
>>>pushing the gasses symetrically out in 4 quadrants. I wonder what
>>>this is? Anybody know what's going on?
>>
>>Not knowing the particular vehicle, we can only speculate, but it's
>>fairly common to use verniers - nozzles mounted at an angle - for
>>steering and control. Fins don't do much at that altitude.
>>
>>Corrie
>
>
> That's what I was thinking. It was a minuteman rocket. Does the
> Minuteman have four nozzels?
>
> Bill
>

IIRC,
yes the 2nd and 3rd stages are multi nozzle design with 4 nozzles.
Bill Higdon

[Corrie]

(Badwater Bill) wrote in message >...
> >Not knowing the particular vehicle, we can only speculate, but it's
> >fairly common to use verniers - nozzles mounted at an angle - for
> >steering and control. Fins don't do much at that altitude.
>
> That's what I was thinking. It was a minuteman rocket. Does the
> Minuteman have four nozzels?

Not according to this:
http://www.wpafb.af.mil/museum/engines/eng66.htm

Other launch photos:
http://pirlwww.lpl.arizona.edu/~jscotti/rocket.html
http://home.earthlink.net/~kd6nrp/msls-ift-3-3.htm shows the X-shaped
plume

According to this: http://www.designation-systems.net/dusrm/m-30.html
the Minuteman has a single engine in each stage.

That's all I can find. The photo at earthlink confirms the X-shaped
exhaust, but I can't find a reason for it.

But hey - this is interesting (adding 'steering' to the google
search-term list) http://groups.yahoo.com/group/space-modelers/message/32302
:

""The Rocket" by David Baker say Nitrogen Tetroxide ... is injected
into
the SRB nozzle to change the shockwave pattern and therefore the
exhaust
plume to give a limited thrust-vectoring for steering. "

So maybe that's it!

[Badwater Bill]

>""The Rocket" by David Baker say Nitrogen Tetroxide ... is injected
>into
>the SRB nozzle to change the shockwave pattern and therefore the
>exhaust
>plume to give a limited thrust-vectoring for steering. "
>
>So maybe that's it!

Maybe that's it. If you look at an old Redstone rocket you see those
two metal-plate (and movable) thrust deflectors placed directly in the
exhaust at 90 degree angles from one another. That separates the
exhaust into four quadrants and would cause this effect of the "X"
shaped exhaust I'm guessing.

What do you other rocket guys think?

Bill