What du you suggest is a good test-platform? Frankenstein!
Before Pixhawk I used two DJI FlameWheel F450 as testplatforms for lots of different controllers, cameras, gimbals, GPSs, sensors, propellers, batteries, weights, …
I pushed it a lot to test different settings, I tried to fly it hard to make it (not) crash, which I did several times and learned about it. I tried hard winds and turbulence, freezing conditions, snow, aso. The controller was wrapped in foam.
But then Pixhawk “1” and 2.1 came and I had learned a lot and developed my own checklist for a stable build and settings for next copters. Now I build them complete and ready to use, only a few flights with autotune and then use for mapping by a company. The previous model (Vulcan hexa) have been working for three years without any problems at all. The newest model (Vulcan octa) flew earlier this week and autotune soon.
But… I want to test more, like fence, ADS-B, sensors, LiIons, and so on. I need a test-copter again! A DJI F450 is too small. What do you suggest is a good work horse that is simple to rebuild and get parts to? Its the frame I am mostly interested in. Motorsetup and electronics is no problem to find.