Saturn V fins?

On Apr 9, 3:24 pm, "Ken S. Tucker" wrote:
Hi behlin, I studied your post.

On Apr 8, 2:04 pm, wrote:



On Apr 8, 9:38 am, "Ken S. Tucker" wrote: Ackn
owledged this is an old debate, but fresh insight may surface,
opinions invited.
First let me say I have the highest respect for von Braun and
his team, so I think there is a rational reason, but even rocket
scientist's ask that question.

1) During the 1st stage boost an F-1 gimbal failurehttp://en.wikipedi
a.or

g/wiki/F-1_(rocket_engine)

The fins would maintain enough stability to give time for the
escape tower rockets to be a activated.

2) During 2nd stage separation, when the explosive bolts
fire, the 1st stage will have a positively predictable orientation.
If a bolt malfunctioned or was delayed, once again the escape
tower needs a decision if it is to be activated.

I think Braun et al thought alot about a manned rated booster
from the start, while the previously Atlas and Titan were nuke
throwers.
Regards
Ken S. Tucker

Neither are true

Then what is the reason for the fins?

#1 The fins would have no effect (velocity was too slow) during the
time the vehicle was vulnerable (near the LUT) to engine hard over.

Check this post, " Astro/Space Frequently Seen Acronyms"
didn't see LUT, but I think I know what you're talking about.
Fin effectiveness is proportional to velocity^2, so yes there
are a few seconds where they aren't effective, however
they rapidly effective.

Additionally, the EDS would activate based on attitude rates
regardless if the fins were there or not

The purpose of the fins is to reduce the attitude excursion
rate (in the event of a malfunction thrust vector control), to
one that will postpone the disassembly of the rocket,
especially where the joints between stages are.

#2, the staging occurred at too high of an attitude for the small fins
to have any effect on the stability of the first stage

And actually, the first stage is aft heavy after separation (unstable
configuration), which leads to the next item

Fin effectiveness is ~proportional to density*(velocity)^2.

at 200k ft, the density is negligible, which is why the stage does not
invert.

Additionally, no other vehicles require fins for staging





I'm certain we've all aware of launches where the Range
Officer destructs, do you think the fins buy some time?

No, because other vehicles didn't need them. They are just an
artifact of MSFC over conservatism.