Thankfully many controllers are open source, so testing and changes are only a matter of risking your quadcopter. [RcTestFlight] found that his FPV h-quad quad was relatively stable in free fall ...

It’s at the rear of this quad’s H-frame, attached to a shaft running down the spine with a pair of pulleys. All four rotors are driven by this spinning shaft. Because [Curtis] is an acrobatic ...