I thought I would start a new project to keep my busy between breaks in my big projects. I was able to pick up an Estes Saturn V pretty cheap. I started building right away and after about a day's work, I got to the fins. I wanted to build by the plans and well, that's where I went wrong Man I hate those .010 vacuum-formed fins. I built them per the instructions, but...well they just sucked. So I had to do better. The old fins weighed in at 1 gram and the new ones came in at 2 grams. So I 'll add 4 grams to the base (meaning the new fins are heavier). Here is what I did:

1. Using the kit fins as a guide, cut out new fin sides from .030 sheet styrene.
2. Mark and scribe the contour line on the fins. This will give you the shape of the real fin. The contour is about a 1/2 in up from the base. It's marked in the first picture with a dashed line.
3. Add to the fin sides the triangle shaped bottom and middle support. The middle support will be glued to the contour line once the bottom is glued on to give the fin the desired shape.
4. Tape the leading edge and end together. These will be glued later. Don't glue them now or it will mess up the process.
5. Using a Squadron Panel Scriber, scribe the contour line. This will only require one or two good passes. The way to tell if it's a good pass is teh styrene will cut a "pig tail" curly-que when you pull the scribe. Don't scribe too much or the styrene will cut through ......

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__________________
Bravo52
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Jerry Little
TRA #11767
Level 1

6. Add a slight bend along each of the scribed lines. It will give the fin the contour shape needed.
7. Tape the leading edge and ends together.
8. I used Tenax-7.R liquid glue to add the bottom triangle shape. Once dry, add the middle support.
9. Remove tape and glue the leading edge and end. Be carful not to pinch the edges. If you do, you might distort the styrene.
10. Four new fins.

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__________________
Bravo52
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Jerry Little
TRA #11767
Level 1

Clean lookin' fins. Those original fins ( at least the Centuri originals), while less likely to break than balsa, did have tendency to get 'bent' on touchdown at times.

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Earl L. Cagle, Jr.
NAR# 29523
TRA# 962
SAM# 73
Owner/Producer
Point 39 Productions

Rocket-Brained Since 1970

Great job on the replacements, but those vacuform fins do not look so bad to me. You may want to hang on to those for awhile; someone here may want them.


Bill

Yes, those are exceptional fins! I was going to hand-scrape a set from plywood, but I may try YOUR method instead. I don't like the ones that came with the kit.

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Never trust an atom. They make up everything.

4 out of 3 people struggle with math.

Chemically, alcohol IS a solution.

NAR# 94042
SAM# 0078

"So I 'll add 4 grams to the base."


You want to add 4 grams to the nose, not the base. The fins are at the base or bottom of the rocket.


http://rmitz.org/AYB3.swf

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-Fred Shecter NAR 20117 (L2)
Southern California Rocket Association, NAR Section 430

He probably meant to say base of the capsule. Either that, or he was testing you Fred! Jerry is a very intelligent and skillful modeler. I'll bet his brain was moving faster than his fingers!

Uhhh.....what? I guess I wasn't clear. How about this "By using the newly constructed fins in place of the weaker, less detailed kit provided fin stock, I've added 4 grams to the base of the scale model rocket of the Saturn V. In fact, the original weaker, less detailed kit provided fin stock, weighed 1 gram each. The new better looking, stronger, well engineered replacement fins weigh 2 grams thus increasing the mass below the center of gravity of the scale model rocket. Therefore, an appropriate amount of counter weight will be added to a portion of the scale model rocket forward of the center of gravity in order to offset the additional mass created when adding the new fin stock in an effort to maintain a pre-determined proportion as it relates to the relationship between the center of pressure and the center of gravity."

Or better yet, I like this; "Nun of yer stuff makes no matter cause Ima gunna stick a big O'l motor in it..... Hey yall...watch this! "

I prefer reloads over the recommended D12.

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Bravo52
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Jerry Little
TRA #11767
Level 1

A D12 in ANY version of the Estes or Centuri (which is what the new Estes kit is) Saturn V is a BAD JOKE. Even the old cluster of 3xC6-3 or C5-3 is little better. A cluster of 3x D10 or D21 18mm SU Aerotech D's IS impressive as it has the oomph of 3.5 Estes D12's with 60 n-sec vs the D12 with 17n-sec.

I picked up the upgrade fin set from I think commonwealth which solves the problem; they are solid resin and far tougher than any vacu-form baloney. Just going to throw some ballast in the nose.
I converted mine to 29 mm as well (which is a good MINIMUM motor size for ANYTHING that is 4" diameter) along with a nice baffle for wadding-less flight.
My Saturn will never fly on anything less than a 40 n-sec RMS24 E28/SU E30, most likely on F24's, F52's and G76's. May feel really lucky and send it up on a G138 or H128.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !

Your new fins look excellent!

But I want to make sure I understand what was wrong with the originals. From the picture it looked like the styrene was too thin to allow for a crisp clean finished look. Is that what you found? Also have you found any other styrene parts in the kit that don't make the grade?

Again the fins you crafted look great!

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I plan ahead that way I don't have to do anything right now.

Oh by the way, I'm not here just for the "olde" rocket discussions.