Saturn V fins?

Acknowledged 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 failure
http://en.wikipedia.org/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

On Apr 8, 9:38 am, "Ken S. Tucker" wrote:
Acknowledged 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.wikipedia.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

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

#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

man rating is not a big deal, mostly smoke and mirrors for the
uninformed. After all, Atlas and Titan were "man rated" after the
fact

wrote:

#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.

The fins resistance to attitude change is dependent of the rate of
attitude change, not vehicle velocity. The fins effect on attitude
stability changes with vehicle velocity.

Two subtly different things, don't confuse them.

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

Of course the EDS activates on attitude rates regardless of fin
presence, because the EDS was designed to activate on attitude rates.

man rating is not a big deal, mostly smoke and mirrors for the
uninformed. After all, Atlas and Titan were "man rated" after the
fact

Yeah, the hundreds of thousands of engineering man hours invested in
man rating the Atlas and Titan, not to mention the extensive system
changes, and also not to mention the increased QA during production...
all smoke and mirrors.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

On Apr 8, 3:50 pm, (Derek Lyons) wrote:
wrote:

This guy "behlin" did not provide any information,
about why, that's my posted question.

#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.

The fins resistance to attitude change is dependent of the rate of
attitude change, not vehicle velocity. The fins effect on attitude
stability changes with vehicle velocity.

Two subtly different things, don't confuse them.

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

Of course the EDS activates on attitude rates regardless of fin
presence, because the EDS was designed to activate on attitude rates.

man rating is not a big deal, mostly smoke and mirrors for the
uninformed. After all, Atlas and Titan were "man rated" after the
fact

Yeah, the hundreds of thousands of engineering man hours invested in
man rating the Atlas and Titan, not to mention the extensive system
changes, and also not to mention the increased QA during production...
all smoke and mirrors.
D.

A famous astronaut informed me he did NOT know why
the Saturn V had wings, and went on to humorously
suggest von Braun liked putting wings on all his rockets.

You can see in this diagram,
http://en.wikipedia.org/wiki/Jupiter...specifications
the Jupiter didn't have fins, but it was monkey rated.
The Redstone did and was used successfully in the
Mercury program.

I read (perhaps rumor), when John Glenn was on top of
an Atlas, he recalled 1 out of 4 exploded.

Also read the next batch of Saturn V's (never ordered)
were to lose the wings because the 1st batch proved
to work so well, suggesting they were a safety.
Ken

On Apr 8, 6:50 pm, (Derek Lyons) wrote:
wrote:
#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.

The fins resistance to attitude change is dependent of the rate of
attitude change, not vehicle velocity.

Incorrect. Attitude rate has no bearing on the fins effectiveness,
which is dependent on the angle of attack (not the attitude rate) and
the velocity. The vehicle could have a large attitude rate, but
with a zero angle of attack, the fin is not doing anything
additionally your comment has no bearing on my statement. While the
vehicle is near the tower, the fins are not effective.

"Ken S. Tucker" wrote:

A famous astronaut informed me he did NOT know why
the Saturn V had wings, and went on to humorously
suggest von Braun liked putting wings on all his rockets.

The Saturn V had fins, not wings. But famous or not, that doesn't
mean the astronaut was an expert on booster design.

You can see in this diagram,
http://en.wikipedia.org/wiki/Jupiter...specifications
the Jupiter didn't have fins, but it was monkey rated.
The Redstone did and was used successfully in the
Mercury program.

Different design generations - the earlier Redstone was essentially an
A4, while the Jupiter builds on the experience gained in the MX-774
tests.

Also read the next batch of Saturn V's (never ordered)
were to lose the wings because the 1st batch proved
to work so well, suggesting they were a safety.

The Saturn V future developments shown at the Encyclpedia Astronuatica
(http://www.astronautix.com/lvs/saturnv.htm) show the fins as being
retained.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

wrote:

On Apr 8, 6:50 pm, (Derek Lyons) wrote:
wrote:
#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.

The fins resistance to attitude change is dependent of the rate of
attitude change, not vehicle velocity.

Incorrect. Attitude rate has no bearing on the fins effectiveness,
which is dependent on the angle of attack (not the attitude rate) and
the velocity.

Wrong. Try holding a piece of cardboard vertically while you spin
about - and note that despite having zero vertical velocity and zero
angle of attack, the cardboard generates drag.

As I said, you are confusing two subtly different effects.

The vehicle could have a large attitude rate, but with a zero angle of
attack, the fin is not doing anything

As shown above, this is demonstrably wrong.

D.
--
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

On Apr 9, 7:54 am, (Derek Lyons) wrote:

Wrong. Try holding a piece of cardboard vertically while you spin
about - and note that despite having zero vertical velocity and zero
angle of attack, the cardboard generates drag.


you are wrong on very many levels

You are describing a roll. The "drag" you are describing would
require either substantial roll rates or large surfaces, neither are
present on the Saturn V. Fins on vehicle don't prevent roll by
creating drag like a paddle, they do it by creating lift to oppose
the motion. Lift is normal to the surface and requires airflow along
the surface. Even for an engine hard over which creates a pitch or
yaw movement, the correcting force is from the fin due to lift created
by an angle of attack and not the fin platform moving thru the air as
you describe. This is basic aerodynamics .The fins would have be
huge in your case. Due to the slow speed at liftoff, the fins are
not able to provide enough correcting force to counter a engine hard
over

PS. Also you are wrong about the angle of attack, it is not zero, it
is 90 degrees in your case

On Apr 9, 4:54 am, (Derek Lyons) wrote:
"Ken S. Tucker" wrote:

A famous astronaut informed me he did NOT know why
the Saturn V had wings, and went on to humorously
suggest von Braun liked putting wings on all his rockets.

The Saturn V had fins, not wings. But famous or not, that doesn't
mean the astronaut was an expert on booster design.

You can see in this diagram,
http://en.wikipedia.org/wiki/Jupiter...RBM_specificat...
the Jupiter didn't have fins, but it was monkey rated.
The Redstone did and was used successfully in the
Mercury program.

Different design generations - the earlier Redstone was essentially an
A4, while the Jupiter builds on the experience gained in the MX-774
tests.

Also read the next batch of Saturn V's (never ordered)
were to lose the wings because the 1st batch proved
to work so well, suggesting they were a safety.

The Saturn V future developments shown at the Encyclpedia Astronuatica
(http://www.astronautix.com/lvs/saturnv.htm) show the fins as being
retained.

Thanks that's a neat link, though I'm not sure I'd
call Von Braun the "Manufacturer" of the Saturn V.

See the first sentence here, about the fins,
http://en.wikipedia.org/wiki/Saturn_...o_developments
(you might know the fella who wrote the article, I'll
leave it to you experts to decide if it's ok).

D.
Touch-twice life. Eat. Drink. Laugh.

http://derekl1963.livejournal.com/

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

Cheers
Ken

Hi behlin, I studied your post.

On Apr 8, 2:04 pm, wrote:
On Apr 8, 9:38 am, "Ken S. Tucker" wrote: Acknowledged 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.wikipedia.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

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

A given Yaw or Pitch excursion also stresses the entire
frame in that proportion, so the fins should be designed
to be of sufficient area to provide a safe delay prior to
disassembly.

man rating is not a big deal, mostly smoke and mirrors for the
uninformed. After all, Atlas and Titan were "man rated" after the
fact

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