gandalf@pro-canaveral.cts.com (Ken Hollis) (12/14/90)
Greetings and Salutations >From henry@zoo.toronto.edu (Henry Spencer) >>... The F-1's were one time, throw away engines... >"One time, throw away" engines that were designed to be fired 50 times, As they say, there is a reason why they call it "Rocket Tape". The basic attitude towards the Saturn-V was that they would never see that stage again, and to get it flying (one time) however they could. When you expect to see the vehicle back (as in the shuttle) then you are more careful how you design and test (and when broken) fix. I cannot speak up for the design of the F-1 (as to its life expectancy) but if it came from the same set of numbers that were computed for the SSME's...... >>"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 Right, I was attempting to say "Mass Flow Rate" for the major advantage of LH2 VS RP-1. The pure specific impulse is still better than RP-1, I didn't mean to imply there might not be trade-offs. The Ion engine has a fantastic specific impulse, but has a very low thrust. The SRB's have a specific impulse of 265.5 seconds, but has a thrust of 3,300,000 Lbs at sea level VS a specific impulse of 455 for the SSME's and a thrust of 375,000 Lbs at sea level. There is always a trade-off in the design, no matter what you are designing. Ken Hollis ProLine: gandalf@pro-canaveral Internet: gandalf@pro-canaveral.cts.com UUCP: crash!pro-canaveral!gandalf
henry@zoo.toronto.edu (Henry Spencer) (12/16/90)
In article <6303@crash.cts.com> gandalf@pro-canaveral.cts.com (Ken Hollis) writes: >... I cannot speak up for the design of the F-1 >(as to its life expectancy) but if it came from the same set of numbers that >were computed for the SSME's...... The SSME is infamous for short life expectancy and poor reliability. The F-1 was not. Remember that although the engines only *flew* once, they were generally ground-tested many times (which is why the engine for an expendable stage was specified for 50 firings). -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry
petej@phred.UUCP (Pete Jarvis) (12/18/90)
In article <1990Dec15.235958.10187@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >The SSME is infamous for short life expectancy and poor reliability. The F-1 >was not. The SSME is also quite a bit more complicated than the F-1 for good reasons. They needed a fast-start engine. The F-1 took 3 times longer to get up to thrust. Peter Jarvis.....