UPDATED: Mach 2.1 level flight! Spinner M2 is the result of MANY hours of building and testing, rebuilding and testing again and a bit of blind luck. Thanks to Squiddy and others who have posted guides and shared their craft - I wouldn't have started this project otherwise. Max level speed is 705 m/s (Mach 2.1) at 4500m altitude. It can maintain this speed indefinitely. I have observed the craft moving at 620 m/s, mach 1.8 in a dive. The craft doesn't handle high G's well so manoeuvre slowly