Author Topic: Pegasus-Turbo  (Read 2158 times)

Offline Skyrocket

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Pegasus-Turbo
« on: 09/09/2013 03:13 PM »
I've just stumbled over an old Orbital press announcement concerning the "Pegasus Turbo", which apparently was a Pegasus-XL with two jettisonable turbojets.

Does anyone know, when and why the development was stopped?

Are there artist impressions of this rocket around?

Intro of the press release:
http://www.highbeam.com/doc/1G1-13037227.html

short report on the Space Digest newsletter:
http://cd.textfiles.com/spaceandast/TEXT/SPACEDIG/V16_0/V16NO075.TXT

Offline Robotbeat

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Re: Pegasus-Turbo
« Reply #1 on: 09/09/2013 03:34 PM »
Very interesting! And kind of makes sense... While for a ground-launched rocket, it makes more sense to just add more fuel and some extra solids or something, an air-launched rocket is very mass-constrained, so it pushes you toward high Isp solutions.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline JasonAW3

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Re: Pegasus-Turbo
« Reply #2 on: 09/09/2013 04:50 PM »
Ok,

     Crazy though here.

     Why not add throwaway solid fueled scram jets?  Placing the fuel behind the compression section should allow proper combustion while significantly boosting the delta-vee of the craft itself.
     As these would be literally Throw-away scram jets, they themselves would only have to have enough material strength and heat resistance to run until shortly after they burn out and are staged.  As the initial boost should take the Pegasus above the Mach number needed to ignite such an engine, this might be doable, if the added weight to thrust ratio would favor such a combo.  (And yes, I have heard that there were early tests with solid fuels for scramjets that the airforce did, and with some success).

Jason
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Offline Jim

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Re: Pegasus-Turbo
« Reply #3 on: 09/09/2013 05:04 PM »
 (And yes, I have heard that there were early tests with solid fuels for scramjets that the airforce did, and with some success).

Jason
[/quote]

The solid fuel was for boost to get it up to operational speed.  The scramjet still operated on liquid fuel for sustaining the flight.  It acted like a rocket until solid fuel burned out and then it acted like a scramjet.  So what is the benefit?

Offline JasonAW3

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Re: Pegasus-Turbo
« Reply #4 on: 09/09/2013 05:34 PM »
(And yes, I have heard that there were early tests with solid fuels for scramjets that the airforce did, and with some success).

Jason

The solid fuel was for boost to get it up to operational speed.  The scramjet still operated on liquid fuel for sustaining the flight.  It acted like a rocket until solid fuel burned out and then it acted like a scramjet.  So what is the benefit?
[/quote]

Ok,

     THAT (The solid fuel part) was NOT a point that was made entirely clear in the article.  Sorry about my misunderstanding.

     Liquid fueled scram jets could still be useful as you'd attain a MUCH higher velocity for the fuel load, once they were lit, than you would with turbojets.  That is essentially my point.

Jason
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Offline JasonAW3

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Re: Pegasus-Turbo
« Reply #5 on: 09/09/2013 05:33 PM »
(And yes, I have heard that there were early tests with solid fuels for scramjets that the airforce did, and with some success).

Jason

The solid fuel was for boost to get it up to operational speed.  The scramjet still operated on liquid fuel for sustaining the flight.  It acted like a rocket until solid fuel burned out and then it acted like a scramjet.  So what is the benefit?
[/quote]

Ok,

     THAT (The solid fuel part) was NOT a point that was made entirely clear in the article.  Sorry about my misunderstanding.

     Liquid fueled scram jets could still be useful as you'd attain a MUCH higher velocity for the fuel load, once they were lit, than you would with turbojets.  That is essentially my point.

Jason
My God!  It's full of universes!

Offline Robotbeat

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Re: Pegasus-Turbo
« Reply #6 on: 09/09/2013 05:47 PM »
This needs a separate thread for scramjet or whatever ideas.

This is about a specific, and interesting, proposal to put jet engines on Pegasus. I'd really like to see what happened to this specific idea.
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Offline baldusi

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Re: Pegasus-Turbo
« Reply #7 on: 09/09/2013 06:58 PM »
And please solve close your quotes.

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