We have a 35:1 gear ratio on high speed motors. A single motor 3 1/2 inch spacing. Motors burn out and can’t get the distance what should we do?
I assume you mean a single flywheel?
Anyways, try to reduce your compression, 3.5" seems like a lot to me. If your motors continue to burn up after changing your compression, you should check for any spots where extra friction could be applied. Make sure you are using straight shafts and bearings. You could also try applying lubricant to your motors and bearings.
Also, a 35:1 external WITH high speed motors (5600 rpm?) seems like it could be too much for the motors to turn without burning up after a few shots. Try high strength gearing in the motors if none of the other solutions help.
I assume by single motor you meant single flywheel. Check for sources of friction like bent axles, make sure your bearings are aligned perfectly, etc. You might also want to try regular speed motors instead of high speed and see if that fixes it.
How many motors are you using?