Model Rocket Engine/Motor Test Firing Stand

I had some very old Estes model rocket engines that I wanted to test to see if they're still good, so I created this stand. The rocket engine should be inserted with the ignition nozzle facing upwards. :-) Up to you if you want to rig a digital scale & timer for measuring the force over time/etc.

Default dimensions are for a D-size (24mm diameter) engine, with "shims" provided for holding 13mm and A-C (18mm diameter) size engines. SCAD file included for customization.

Ideally the stand should be screwed down to a piece of wood, or placed in a large metal canister.

Non-flammable filament recommended, or at least place some wadding inside for the ejection charge. (The ejection charge will also result in the engine popping out afterwards - be careful of the ejection time delay.)