Fin beveling tips to minimize rocket spin

[SERG3ANTGUTTER]

Hey guys

Getting ready to start building and putting together my level 2 HPR certification rocket. Doing it on a Public Missles Endeavor kit with a K160 motor. Will be injecting epoxy for those internal fin fillets and adding a extra centering ring cause the K motor is pushing it.

Planning to have an onboard go pro camera. Really wanna capture the awesome ride up but worried about the rocket spin making the footage nauseating.

I did some looking around and ran into fin beveling.

Any advice where to bevel the fins to counter or minimize the spin? About how many degrees?

Working with a split fin design and 0.06" thick G10 fiberglass fins

 

[jderimig]

Beveling is a drag reducing measure, not a spin. However if your bevel is not symmetric it could generate some spin forces. Fin alignment to the axis of the rocket is all you need to do to minimize spin. Since the kit has a slotted airframe there should be no issues there. Don't bevel the edges opposite your fin splits. You'll kill the whistle.


Have a good flight.

 

[OverTheTop]

If you make sure your bevels are consistent and symmetrical, and your fins are on straight, you should be able to get a respectable roll rate.

Also you might not want to bevel the outside edge of the fin, parallel with the body of the rocket. This actually improves the stability of the rocket. If you want to bevel it for style the difference in minimal and you can fly either way.

 

[Rocketclar]

To OverTheTop, here's another sim quote by famous author and statistician, George Box, "all models are wrong, but some are useful."

 

[boatgeek]

You won't be able to counter spin by beveling fins. That's the realm of controlled airfoils and is far more difficult. You can minimize spin with good build practices--good fin alignment and consistent bevels and fin shape. As long as the camera is pointed down, the view usually isn't too bad even with some spin. After apogee when the rocket is under chute, it's usually a mess no matter what you do.

 

[OverTheTop]

To OverTheTop, here's another sim quote by famous author and statistician, George Box, "all models are wrong, but some are useful."

Thanks. I am familiar with that one. There is one I am thinking of adding to the sig line and it goes something like "The primary use of simulations is heuristic".