"Proponent" wrote in message
ups.com...

Given that the S-IV project got started later and was larger and more
complex, how is it that it became operational before the Centaur?
We're there problems with the Centaur's manufacturer (Convair, or
whatever it was called then)? Was it lack of attention that from MSFC,
Centaur's original manager, that was the trouble?

Douglas's S-IVB worked well from its initial outing.

Then there's the S-II stage, which seems to have been the bottleneck in
the development of the Saturn V. Why was it so troublesome? Was it
incompetence at North American Aviation? The stage's mass structure
fraction was lower than that of the other H2 stages. Although that's
natural for a larger stage, does it indicate that the S-II design was
sailing closer to the wind? Was that a source of development problems?

NASA SP-4206 Stages of Saturn (yes, its on-line, if you don't want to read
the paper copy)

Table of Contents
http://history.nasa.gov/SP-4206/contents.htm

Have fun -- you will read how the weight issue was the real bottleneck --
and the S-II stage had to solve the problem.

gb