Updated v2 - EXPERIMENTAL work in progress
Support structures for mounting a flat rotary switch onto a cylindrical rocket.
STL is for a 4" rocket with coupler. The SCAD has variables at the top for setting all parameters in mm (rocket outer diameter, rocket inner diameter, switch dimensions) and view options.
Interior curve-to-flat surface gives full contact between the screw on the switch and the rocket body. It will also as a washer, distributing the the forces across a broader surface area.
The exterior would have a flat-to-curve surface, |(, leaving gap. This fills the gap and includes a sphere 1/4 the diameter of the rocket body. The idea is to provide an aerodynamic curve between the rocket body and the top edge of the rotary switch. Acetone smoothing on the outer mount is recommended to reduce drag.
Print outer support w/ arch down. Test prints of both gave much better results in that orientation. You can sand the rafting on the inner side out to match the rocket profile A LOT easier than you can sand down the outer surface, which you want smooth.
Notch added at 45 degrees to account for the dimple in the rotary switch. This will align 110 as OFF perpendicular to the rocket body, and 220 as ON, parallel to the body.
Inner support widened.
.1mm added to switchOuterDiameter and switchInnerDiameter to give a bit of clearance. The parts are too tight otherwise. Print.
$fn=90 added to smooth parts out (I didn't like the default). I tried 180, but it was too slow to build for my tastes.
I'm still working on the maths to account for the sphere cap accurate across rocket dimensions. The print view should work (export your STL from that view). The others are for visualization and might be off. If you run into something that's off, message me.
I have not run aerodynamic simulations or wind tunnel tests on the design yet to see how it compares to a simple |( exterior mount without support. I'll upload some video of a tunnel test when I have v2 printed and assembled.