gandalf@pro-canaveral.cts.com (Ken Hollis) (12/11/90)
Greetings and Salutations: From: francis@cs.ua.oz.au (Francis Vaughan) >Subject: Re: Re : SSME's (again...) + F-1s > >This discussion about redesign of parts of the SSMEs makes me >rather curious about a few things. So far we have seen a new engine . . . >Remember we have a proven overall design. We know that the F-1 >worked. In principle the old F-1 plus new turbopumps would fly, >same after a new combustion chamber etc. Suddenly we have a new >improved MANUFACTURABLE F-1. Yes, in theory, you could remanufacture the F-1 to take the place of the SRB's. In theory (and I have actually seen this in practice) you can use Lotus 1-2-3 for word processing also. The F-1's were one time, throw away engines. They also used LOX & RP-1 (essentially kerosene) for fuel. You also are looking for a "good" specific impulse, Is = F/W where "Is" is Specific Impulse, "F" is thrust, "W" is propellant consumption i.e. Steady Weight Flow Rate (lb/sec). Basically what it boils down to is that LH2 has a much better "W" than RP-1 because of the density of the fuels and the energy released. For the Atlas using RP-1 the Is = 290 seconds. For the Saturn V first stage using RP-1 the Is = 300 seconds. For the Saturn V second & third stage using LH2 the Is = 425 seconds, and for the SSME the Is = 455 seconds. If you are interested in the design of liquid rocket engines, I suggest "Design Of Liquid Propellant Rocket Engines" NASA Publication "NASA SP-125", 1971, Scientific and Technical Information Office, National Aeronautics and Space Administration, Washington D.C. I know the SRB's are bad enough about exhaust, but the way the environmentalists have been acting lately, they probably would scream if a "new generation" launch vehicle was made with complex carbons to kill the ozone even more (Of course I am not sure if they have started thinking about this angle yet...). Ken Hollis ProLine: gandalf@pro-canaveral Internet: gandalf@pro-canaveral.cts.com UUCP: crash!pro-canaveral!gandalf
henry@zoo.toronto.edu (Henry Spencer) (12/12/90)
In article <6241@crash.cts.com> gandalf@pro-canaveral.cts.com (Ken Hollis) writes: >... The F-1's were one time, throw away engines... "One time, throw away" engines that were designed to be fired 50 times, please note. There is really no such thing as a "throw away" engine with regenerative cooling; they are all reusable if they can be recovered. >... Basically what it boils down to is that LH2 has a much better >"W" than RP-1 because of the density of the fuels and the energy released. No, actually, the major advantage of LH2 is its low molecular weight. Its density is a major *dis*advantage, because it requires enormous tanks, to the point where studies for single-stage-to-orbit systems often conclude that a denser fuel is superior despite lower specific impulse. >If you are interested in the design of liquid rocket engines, I suggest >"Design Of Liquid Propellant Rocket Engines" NASA Publication "NASA SP-125", >1971... Actually, the Sutton book (Elements of Rocket Propulsion, I think -- my copy is at home) is a better place to start: it's in print, unlike SP-125, and gives a broader overall discussion with a gentler lead-in, and also a more current discussion of some issues. SP-125 is for hard-core techies. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry