bulletbob

I started flying with an electric glider, 600 size can motor and 8 by 4 folding prop, D35 motor controller and 7 cell batteries. Excellent full throttle performance but lots of crashes learning to fly. I destroyed one glider and bought another exactly like the first one and then my problems started. Each flight resulted in a burned out motor. I bought new controller. Same problem. New battery. Same problem. Always low speed break in is no problem but full powered flight results in a fried motor. So hot it can't be touched. In no case is the 25 amp fuse blown. Electric power is to expensive for me and I intend to put a .049 gasser on it. Less weight and more reliability. Everyone says that this should not happen but has no idea why it could. Does anyone have any magical suggestions?

JBoss

My Feedback: (1)

Gliders are designed to get to altitude quickly , a minute or so of powered flight and then motor should be shut down. glide down power back up to altitude. Still sounds a little strange though.

I am interested because I have been looking into powered gliders

JimB

sierra gold

In reading your story, it seems you replaced every possible problem source.

However jboss may have hit on the problem:

Assumptions:

1. In flying your first plane all flights were short due to "learning to fly" problems.

2. You are now running down the battery pack until motor "melt down" with a long continuous motor run at full throttle.

Many motorized gliders have very inadequate cooling for sustained motor runs. The theory is you will power up to altitude and then shut down the motor and do some thermal searching and soaring. This "break in operation" allows the motor to cool down.

If you are doing one long motor run, that may indeed be your problem. Look at adding some cooling scoops and exits if none exist. Enlarge existing ones. Try the shortened motor runs and patial throttle operation.

Are we depicting your motor use correctly?

sierra gold

One additional thought:

What glider are you using? Is it designed as a motorized glider?

Don 07tncav

And perhaps the motor is over-propped similar to the stock Ascent motor. A fantastic glider with a simple prop switch.

bulletbob

Thanks for the comments and help. I recently took the motor glider out again with a new cheap can motor and after rewiring the system with a 25 amp fuse for protection. I also spent the last 4 months intensively flying other powered planes and increased my flying skills tremendously. I increased ventilation in the interior and then chose to run the motor at about 80% of capacity for short periods. Everything works fine now, my first flight included a thermal lasting over 30 minutes with heights at limits of vision. No one factor did it but the combination works.