When we first got this "CAD/3D" page going, I tried to start three different "libraries" that we could all use. One for "Parts", as you suggest, one for "Engines", and one for "Design Specifications", so we could all compare ideas and trade information.

So far, those threads remain largely unanswered. (Look on pages 12, 13, and 14 in the past history here.)

Anyway, if you email me, we can trade some CAD parts. I have a pretty large collection of objects such as receivers, servos, odds and ends, and a couple of engines. (a scalable version of a typical 2-stroke and 4-stroke)