Large fin ideas

Hi all,

I'm doing a scratch built 7.5" rocket that will have large fins, similar to the shape of an Estes Alpha. I'm trying to keep the weight down and hence, and trying to decide how to make strong, yet light fins. 1/4" plywood with some glassing could work. Also, some combination of wood, glass and foam could work.

Does anyone have an not too exotic process that might produce a strong light fin? Thanks for any ideas.

Try skeletonizing similar to the Mega Mosquitos fins, the skeletonized areas could be filled with a aramid honeycomb and the whole fin glassed/carbon covered. hcmbanjo's site has the pick of the Mega Mosquitos fins https://modelrocketbuilding.blogspot.com/2014/06/mega-mosquito-build-part-4-fin.html

Aramid honeycomb is available at https://www.acpsales.com/OnlineStore.php?cat=426

Thank you Rich , excellent idea. I had considered some type of that kind of structure, but this is a good start!! Lyle

Composite fins can be as light as you like and still be stuff as needed: Composite Nike fins.

Big fan of lightweight core (plywood) with a layer or two of 4oz glass. It keeps the aft weight down and can take the stress of fairly large motors.

Great Idea Mat...that's the direction I was heading!

You could go the MDRM way, and have plywood fins with hollow sections, and a little balsa on top and bottom.

There are any number of ways to make large lightweight fin structures. Listed below are a few and you will find many more searching this and other forums...

https://www.rocketryforum.com/showthread.php?3797-12-quot-Talon-on-a-P&p=62112#post62112

https://ausrocketry.com/forum/viewtopic.php?f=72&t=4524&start=25

https://www.rocketryforum.com/showt...cal-engineer-in-the-house&p=749652#post749652

https://www.rocketryforum.com/showthread.php?9044-10-quot-diameter-JayHawk&p=81454#post81454

Thank you Mr. Dixon..greatly appreciated.