Vincent.Cate@SAM.CS.CMU.EDU (06/06/90)
From: Vincent.Cate@SAM.CS.CMU.EDU
It looks to me like it would be easy for Orbital Sciences Corp to add a
ramjet stage to its Pegasus rocket. Since it is launched from a B-52
it has the speed needed for a ramjet to operate. Since it has a wing
(unlike other launch vehicles) it should take little extra effort to
use a ramjet. I think this would cut the price per pound to orbit by a
factor of 2 to 4.
Does anyone know of any company that is selling ramjets today? Are
there any U.S. missiles that use ramjets? Any current experimental
ramjet planes? Any company that could easily make a ramjet from an old
but tested design? Are computer models good enough that there is
little risk in designing a new ramjet today?
I have only been able to find older ramjets so far. First there are at
least three old (60's) U.S. missiles - Bomarc, Talos, and Navajo.
There a couple of test planes (Lockheed X-7 and the French Vega).
The X-7 flew at up to mach 4.3. I am also told that the British
"Bloodhound" and the Soviet SA-4 "Ganef" and SA-6 are ramjet powered.
It seems like ramjets would be ideal for air-to-air missiles. They
should have much greater range than rocket powered missiles and maybe
even be able to go faster for missiles small enough to be launched from
a plane. Looks like a ramjet consumes around 2 lbs of fuel for every
lb-hour of thrust while a rocket uses over 10 lbs of fuel. If there
are not any current U.S. ramjet powered missiles, can anyone explain
why not?
What I would really like to know is how fast Orbital Sciences Corp
could buy a ramjet that could be used to power a Pegasus sized object
(about 40,000 lbs, so maybe 10,000 lbs thrust?) to Mach 5. Any time
estimates? Any cost estimates?
Thanks for any info,
-- Vince
vac@cs.cmu.edu
PS A Pegasus that used a ramjet first stage could be a great
test vehicle for scramjets.