How dangerous is it to run an electric for a full flight run on the ground?   I have run them for about a minute with no problems but never the full 4.5 min.  I do it all the time with IC but they don't have timers and esc's, just needle valves.  I am concerned that the plane needs the forward motion to get the proper draw on the battery and enough breeze for cooling.

One more of the seemingly endless list of things to learn about electric.

Ken

Not sure what you are trying to learn here, BUT.  Use a prop 2"-3" smaller than your flight prop to keep current draw reasonable.  It will also help cool the motor.

I basically never try to run the motor on the round any more than maybe 20 seconds.  There just isn't any useful data to be gained.

Something caused the motor to pull out of the ship about two laps into the flight that is the reason for having to rebuild the mounts.  I am not convinced that it was simply poor workmanship on the mount and I wanted to let the motor run long enough to make sure that the esc or something wasn't causing it.  The motor came out like it simply went from full power to full break and just snapped the mounts.  I know from 65' away with my mind on all the things you think about on that first lap with a new ship I probably only remember seeing it throw the motor after it actually happened.  One thing that really bothers me is that the prop separated from the motor and there is a circular dent in it on the backside.  The only way I can mentally picture that happening is the collet coming lose and the prop spinning off and hitting the shaft knocking the motor out of the plane. I have never had a collet even so much as slip before but that doesn't mean it didn't.  I have had two "crashes" on this plane where things that can't happen did and not put a scratch on the airframe itself.   Basically I am paranoid!

Thanks for the warning,  I will take your advice and only run it about 20 seconds.

Ken