TWIST LOCK
This is now the fourth twist-lock I'm putting on a rocket. As always, it provides a secure and easy nose cone attachment for the payload section, allowing quick access to an altimeter, no dealing with friction fits. I'm glad I printed up a bunch of these when I first design them. Still working through my stock.
This being my fourth one, I have the installation process pretty well perfected. Here it is, installed:
Perfect. Or, well, not quite. When testing fit, I noticed:
When locked, the nose cone separated from the body tube slightly, indicating that the piece in the body tube was
slightly too close to the edge. This has never happened before, and the way I did the installation should have prevented it from happening. But there it is. I thought about leaving it like that, but since I knew how to fix it I realized I wouldn't be happy until I did.
(I'm also seeing some pitting at the edge of the nose cone that could use fixing. Ultra-closeups are not flattering).
The fix involved slightly reshaping the piece on the nose cone:
By thinning at the base with a needle file, and thickening the other piece with a few layers of foil duct tape, I was able to shift the opening slightly closer to the nose cone, and restore the proper fit when locked.
Turns out that the foil tape wrap is a very good method for tightening up the fit of the lock; slick and malleable and creates a nice smooth grab. Doesn't need to be tight, just enough so that it'll stay put if shaken.
Now to go clean up the base of the nose cone.
Here's the completed payload section. In my OR model for this rocket I separated the payload section as a separate stage, so I could override the mass and CG of the whole assembly. Came out pretty close to the model. I'll probably see bigger variations in the rear.