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Ultra Micro P-51 motor/gearbox problem

Old 06-10-2010, 09:23 PM
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Default Ultra Micro P-51 motor/gearbox problem

I bought a PZ ultra micro P-51 about 2 months ago and love it. Ihave approx. 25 flights on it and last weekend the motor started to make a loud noise. It also does not run smoothly, and it pulses badly. Ifigured that it may be on its way out so I ran to the hobby shop and bought a new motor and gearbox. I flew it 3 times tonight and on the third flight noticed that it was loosing power. I charged up one of the batteries after I got home and it made the loud shreaking, pulsingnoise again. Ihave read that the gearboxes need to be lubricated and hoping this is the problem. I've heard guys usingsome fine machine oil to lubricate the shaft. Has anyone had this problem and if so how often do you lubricate the gearbox. Ilove this airplane but I dont want to keep buying new motors every few flights. If you guys have any suggestions please feel free to share. Thanks!
Old 09-18-2010, 10:59 PM
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Default RE: Ultra Micro P-51 motor/gearbox problem

My PZ P-51 has a slight "thrum . . thrum" from the motor while flying, but it doesn't seem to affect performance yet. I'm thinking about a brushless conversion once the stock motor wears out. You can see what some people have done to their ultra-micros here:

Good luck!
Old 11-11-2010, 06:34 PM
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Default RE: Ultra Micro P-51 motor/gearbox problem

I have this problem too, I thought the gear was slipping on the prop shaft, I've changed the gearbox, but not the motor because I get the feeling it is something in the speed control and not the motor. That's one reason I haven't bought a motor for it. I can't slip the gear on the shaft at all, and it is a loud shreak shound, like tiny gears slipping, but none of the gears are stripped. Did you ever find a solution. I figured it was just toast and not worth messing with.

I've also noticed on mine that sometimes the light inside goes off and the motor stutters while I'm running it at low rpm's trying to observe what is going on. I hate to just make it a display model after spending $100 on it, but at the same time, it really wasn't anything speacial to fly to spend a lot of my time on.

Old 11-20-2010, 01:38 AM
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Default RE: Ultra Micro P-51 motor/gearbox problem

if the motor is screaming and shrieking that means it needs oil on each end of the shaft. if it has a gear box, you may need to disassemble it to access the actual motor.  i have had plenty of small motors make that noise.

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