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-   -   E-Flite Power 15 high RPM vibration (http://www.rcuniverse.com/forum/e-flight-power-sources-126/11390247-e-flite-power-15-high-rpm-vibration.html)

Striker 01-30-2013 09:32 AM

E-Flite Power 15 high RPM vibration
Hi Guys,

I know this is a shot in the dark question but dont know if anyone here has the same problem.

I have put together an Acro Master and got a new E-Flite Power 15 brushless motor for it. I have not flown this thing as yet all because I am getting a violent vibration at high RPMS just around 6500 RPM.

I have a perfectly balanced APC 13X6.5 prop and an E-Flite prop hub. If the battery's peak power drops, it runs OK. I can reduce my throttle by about 10% but that's a band aid patch approach which I hate, it does this 2 clicks below full throttle.

I have read that some people said these motors are not balanced well etc. All I did to it was to use my vice and a socket to push the shaft to the other end since it has to be front mounted. I am an electronic tech and a huge mechanical background so I cant see it being screwed up by that.

Anyone had these issues with this motor? This is annoying me to the core.


whitecrest 01-31-2013 02:27 AM

RE: E-Flite Power 15 high RPM vibration
Is there any vibration with the prop off? That ought to rule out any fundamental motor imbalance. I would think a mechanical imbalance in the prop or hub would be evident well before 6500RPM. It might be worth trying a slightly smaller prop or programming higher ESC timing. Timing issues usually crop up when a motor is being pushed.

Another thought is to check the motor mount for any looseness or play.

Striker 01-31-2013 05:31 AM

RE: E-Flite Power 15 high RPM vibration
Everything is tight and balanced, I am beginning to think after doing some more testing that its a resonance issue.

chuckk2 02-07-2013 03:22 AM

RE: E-Flite Power 15 high RPM vibration
The ESC may be faltering at higher settings, or the battery cannot supply the current required.

Striker 05-27-2013 05:54 AM

RE: E-Flite Power 15 high RPM vibration
Hi Guys,

I never like leaving a thread hanging if a solution to a post regarding a problem has been found.

I bought an aluminum motor mount from Horizion Hobbies, one made by Multiplex and Rig Ga Da Bing Bang, vibration is gone.

I did not like the way the right thrust and down thrust adjustment was designed by Multiplex, in reality you only had two screws holding the motor mount to the bulkhead.

I simply drilled out the threads from the adjustment holes on the aluminum mount, drilled holes on the bulkhead smaller than the screws, took a digital caliper to measure washers with the same thickness recommended for the two thrust adjustments.

I placed the washers between the motor mount and the bulkhead in the right corners in order and used hex head screws instead of the slotted screws, so now there are six screws holding the motor onto the airplane.

This makes for a vibration free installation while maintaining thrust adjustments and prevents the motor from ripping it self out from the two mounting holes like many have reported.

Happy landings and have many tail dragging torque rolls.

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