SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Jan 15, 2007, 08:56 AM
Dale Lindsay
Mt Airy, Maryland, United States
Joined Sep 2001
653 Posts
Discussion
CX2 motor sounds strange

I noticed here recently that the upper rotor motor has started making a strange noise in the midrange. It's the speed about what it takes to hover at eye level. When coming off the throttle the motor makes a buzzing noise. When under load (as in throttle up to climb) the sound stops for a moment and eventually comes back once the load has lessened. It also seems to affect the gyro somewhat as I get a slight nose left twitch as I throttle down.

When holding the CX2 and powering up with right rudder I can get the sound. I've checked the linkage, nothing is binding, etc. Is this a sign that the brushes/bushings are already going out? I've had this since Christmas and fly a good bit, but not excessive and let things cool down between flights.

Just curious if anyone else has experienced the same noise.
DaleM is offline Find More Posts by DaleM
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 15, 2007, 09:20 AM
Registered User
Michigan
Joined Apr 2001
534 Posts
Have you checked to see that the motor mounting screws are tight?
Rob Hair is offline Find More Posts by Rob Hair
Reply With Quote
Old Jan 15, 2007, 09:37 AM
Dale Lindsay
Mt Airy, Maryland, United States
Joined Sep 2001
653 Posts
Yes, I checked the screws and made sure the gear lash didn't seem tight by 'slightly' loosening them and then retightened.
DaleM is offline Find More Posts by DaleM
Reply With Quote
Old Jan 15, 2007, 03:22 PM
Registered User
Joined Dec 2006
13 Posts
mine was making a similar sound.... I took the lower gear out and removed the inner shaft. Checked everything and put it back in being careful to pay attention to detail as I put it back together. It stippoed after that. I am not sure exactly what the issue was but I think when I installed my aluminum inner shaft and aluminum bearing I didnt line the keyway up with the screw at the base of the shaft where the gear goes on. I think it was trying to spin freely and was skipping over that keyway making a grinding noise.
venomoussvt is offline Find More Posts by venomoussvt
Reply With Quote
Old Jan 15, 2007, 07:24 PM
Lou
Registered User
United States, VA, Waynesboro
Joined Dec 2005
5,651 Posts
Tough to say, but a source for some noise can be found in the two screws that retain the lower rotor head to the outer shaft. In some cases the screws will protrude far enough into the inner shaft that they will be touched by the spinning inner shaft. This is particularly so if the inner shaft has a slight bend to it.

If you are confident that the mechanics are good, you can try reversing the motors to see if the noise moves with the motor. These are brushed motors and as the brushes wear they tend to change their 'sound'.
Lou is offline Find More Posts by Lou
RCG Plus Member
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Alert Brushless motor sounds strange, please help! D-Man Electric Plane Talk 3 Aug 08, 2005 02:06 PM
Question Brushless motor sounds strange...again D-Man Electric Plane Talk 0 Aug 07, 2005 08:42 AM
electric motor sounds like it is missing agriebel Power Systems 1 Aug 24, 2003 02:07 PM
Brushless Motor Acting Strange fly4fun Power Systems 20 May 27, 2003 11:00 AM
Motor sounds like a squealing pig. Balin Power Systems 4 May 05, 2001 12:27 AM