Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucsd!nosc!crash!pro-canaveral.cts.com!gandalf
From: gandalf@pro-canaveral.cts.com (Ken Hollis)
Newsgroups: sci.space.shuttle
Subject: Re : Re: Re : SSME Vs. F-1
Message-ID: <6303@crash.cts.com>
Date: 13 Dec 90 22:56:03 GMT
Sender: root@crash.cts.com
Lines: 32

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

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