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Old Jul 18, 2015, 10:39 PM
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V120d02s problem - motor, ESC or RX?

Hi everyone. So a few months ago, I had a pretty spectacular crash with my V120D02s V2. Slammed into the ground pretty hard, but surprisingly enough, all I did was bust the landing skids and split the canopy. Replaced the parts and it flew fine afterwards for several flights.

Just tried to fly it, and something is very wrong. The motor is incredibly jerky, the rotor speeds up, slows down, surges and stutters. I removed the motor to make sure nothing was binding mechanically, and everything is smooth. I ran the motor out of the heli, and noticed it has very little torque. I can grab it with my fingers while it's running at a moderate speed, and it just stops and then starts stuttering.

Any ideas what it could be? I don't have that much experience with brushless motors, so I'm not sure if that's a typical symptom of a damaged motor. Since it flew perfectly find probably 6-8 times after the big crash, I'm just not sure what it could be.

Thanks in advance.
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Old Jul 19, 2015, 04:13 AM
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Had a very similar problem on a brushless mcpx. After a crash the motor lost torque and it was very easy to stop it from full rpm. Replaced the esc and made no difference. Resistance was the same on all windings.
Replaced the motor and all was fine.
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Old Jul 19, 2015, 08:28 AM
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When you crashed did you hit TH to kill power to motor ? If you ran it stalled most likely could have fried motor. New motor is about $21.00-25.00 depending on vendor. Or you could upgrade motor to one cell HP08s.
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Old Jul 21, 2015, 12:33 AM
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Originally Posted by dankar04 View Post
When you crashed did you hit TH to kill power to motor ? If you ran it stalled most likely could have fried motor. New motor is about $21.00-25.00 depending on vendor. Or you could upgrade motor to one cell HP08s.
Or you could try to rewire it
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Old Jul 21, 2015, 02:01 AM
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Several month back made mistake of tighting blades on my #1 -V120. motor wouild not start. I bought another good used motor and esc. same problem. Then IHW said to lossen blades and bird was then fine. Point now I have extra motor/ esc that work prefect extra. If any interest let tem go for $25.00 for pair and few $$ for postage. , The guy who i got them from went to two cell operation GY280 RX/ HP08s two cell motor.
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Old Jul 21, 2015, 10:22 AM
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Thanks guys, yea, this confirms my suspicion that it's the motor. Like I said, I'm fairly new to brushless, so wasn't sure if this was a typical symptom of a failed motor. I thought I chopped the throttle before the crash, but hard to really say.

Jamichx, that's a great idea, I'm always up for trying to fix something, and I can't possibly make it any worse!

Dankar, thanks for the offer, I'll contact you depending on how my rewiring attempt goes.

Thanks guys.
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Old Jul 23, 2015, 01:18 AM
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Originally Posted by Chris3D View Post
Thanks guys, yea, this confirms my suspicion that it's the motor. Like I said, I'm fairly new to brushless, so wasn't sure if this was a typical symptom of a failed motor. I thought I chopped the throttle before the crash, but hard to really say.

Jamichx, that's a great idea, I'm always up for trying to fix something, and I can't possibly make it any worse!

Dankar, thanks for the offer, I'll contact you depending on how my rewiring attempt goes.

Thanks guys.
If you decide to rewire your motor check my blog it may give you some hints

http://www.rcgroups.com/forums/showt...4#post32228864
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Last edited by jamichx; Jul 23, 2015 at 01:23 AM.
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