Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!ukma!gatech!ncar!noao!asuvax!enuxha!kluksdah
From: kluksdah@enuxha.UUCP (Norman C. Kluksdahl)
Newsgroups: sci.space.shuttle
Subject: Re: That SRB flame
Summary: Saturn V, shuttle plume
Keywords: Remember the Saturn V
Message-ID: <141@enuxha.UUCP>
Date: 3 Oct 88 21:44:33 GMT
References: <3447@ihuxz.ATT.COM>
Organization: Arizona State Univ, Tempe
Lines: 35

In article <3447@ihuxz.ATT.COM>, dwv@ihuxz.ATT.COM (Bazooka Joe) writes:
> 
> Since we all have been talking about this backflow theory on the SRBs,
> I was wondering if the same didn't happen on the Saturn V first stage.
> I seem to remember all the long camera shots looking like the last 30
> seconds of stage 1 burn was going up the sides of the bird? Anyone else
> remember this?
> 
(Disclaimer--I am quoting this from memory, without my sources in front
of me.  Although the essential facts are correct, there may be some small
error.  Please bear this in mind before flaming.)

IF memory serves me correctly, I seem to recall a few rather strange facts
relating to the development of the Saturn V.  There were a few designs, such
as the Saturn III and Saturn IV, which were to use 3 and 4 of the F-1 
engines respectively.  The Saturn IV was to have these engines arranged
in a square pattern at the base of the stage.  The reason this idea was
NOT carried through is that a SEVERE backflow of the exhaust gasses in the
center of the engines.  The effect was supposedly somewhat akin to blasting
the base of the stage with a very high powered torch, which was leading to
structural failure.  The solution was to strengthen the framework at the base
of the stage, and put a fifth engine in the center.  Exhaust from the fifth
engine would alleviate the backflow problem.  Voila, we have the Saturn V.

Now, this raises some interesting questions regarding the shuttle.  If the
backflow problem can be this severe, what is the effect of the backflow from
the SRB's and the three SSME's??  It seems to me that the critial area for
backflow would be at the base of the external tank.  If this is the case,
then I hope that the ET has very good insulation in that area.

Norman Kluksdahl         Arizona State University
                ..ncar!noao!asuvax!enuxha!kluksdah

This represents in no way, shape, or form the opinions of ASU (unless I have
made a mistake, in which they are the convenient scapegoat!!!!).