Fin development

Evolution of fin design

Fin development is one of the hardest parts of designing and building a stabilization system in my experience. It has to be aerodynamically sound, servo compatible and not break when initial liftoff forces kick in.

Integration can V1 completed

Finished printing the integration can. It is based around the modified upper retaining plate that was designed so long ago.

Fin can design

Preliminary fin printing, lessons learned.

Yesterday I moved the fin into preliminary 3D printing. Initial print was flat on the print bed, apparently the support structure caused it to warp and the layers stacked strangely. Vertical printing worked a heck of a lot better! Also reprinted the baseplates to the correct size and spacing of servos.

Adding on to code for opposite fin pair drive, fixing a MAJOR problem

Today I decided to fix the issue of opposite servo pairs actuating in opposite directions which would result in a uncontrolled spin and subsequent destruction of airframe. It only took a few modifications totaling in 10 additional lines of code. This site was extremely helpful in explaining the servo drive code for opposite servo pairs.

Null1.write(valNull);

Obfuscated = valNull;

Null2.write(180-valNull);

Obfuscated = valNull;

What this does is take the opposite servo and drive it 180 degrees in the opposite direction of the reference servo(1)[Yes I censored the code because this is ITAR regulated, Deal with it. If you really do want to take a look at my code, you will have to prove you are based in the US and sign a waiver that transfers all responsibility for what you may do with my code to you].

Working on the fins

Started work on the servo-actuated fins today, Simple extrudes and lofts based around a standard servo arm, will print these before the end deadline