Another strange noise

[Bob Gray]

I missed Basildon Biggles's video  so don't know if his noise is the same as my noise???.  My noise is an irregular but persistent metallic sounding click. It happens in the lower rev range and most often at 400 - 500 revs.  The motor is a new Turnigy 42-60 500kv and the ESC is a HiModel 80 amp SBEC, I'm running a 14x7 APC E prop.  I've tried various power setups i.e. 3, 4 and 6 cells, (the ESC is rated 3-6 cells) the noise is more persistent at the lower voltage. The prop doesn't seem to stutter.

I have two other setups both at the higher end of the price range, neither of them exhibit this noise. Any advise would be much appreciated.

 Bob

[Former Member]

[This posting has been removed]

[Frank Skilbeck]

I have a Turnigy TR 42-50 700kv and 60 amp SBEC combo  with a 4s lipo and it does sound a "little rough" at very low revs but then it smooths out and gives very good power, 8,900 rpm on a 13 x 6 and runs very cool.

Can you detect anything catching when you turn the motor over by hand.

Can you post a video so we can hear the noise.

14 x 7 on a 6s might be pushing it a bit as well. 

[Bob Gray]

Eric and Frank,

Thanks for the reply

Eric I don't think there is any material in the motor, I dismantled it (on the suppliers advice) and found nothing.

Frank I will try and post a video but your comment is useful. At full power it sounds OK.

 Thanks both

Bob

[Owen Hailey]

Hi all.

The noise sounds a bit like it mite be a bearing cage and with the higher reeves will go away when the C of G in the bearing takes over had this happen to me in the past.

hope you find out soon Owen.

[Bob Gray]

Many thanks for your replies.

 It's taken me the last 4 hours to make a video and learn to upload it. Here it is  

http://www.youtube.com/watch?v=AK7JlXWa4rs

I think the rattle may be vibration amplified by the airframe but the click worries me a little.

Unless you know better

Bob

[Former Member]

[This posting has been removed]

[Frank Skilbeck]

The click doesn't sound like it anything metallic to me, more of a switch being flicked. Could it be the caused by the sudden cut in power to the motor and the current surging into the feed capacitors.

Does it do it if you slowly reduce the throttle.

Other than that the sound of your Turnigy running is pretty similar to mine. 

[Bruce Richards]

I have several Turningy motors and this exact one and I hear nothing out of the ordinary.  If you apply the power quickly the motor will attempt to reach that speed instantly and hence the click or bang as the power surges in.

[Owen Hailey]

Hi all.

I have lisend to the noise and this is my two peneth worth, the fact that you are shuting the throtle quickley then the motor sends volts back to the speed controler and will be dischargeg in the speed controler this should be avoided as it could cause damage and as for any other noise this is just prop noise this will not be heard if the model is in the air. 

let it fly Owen.  

[Bob Gray]

Eric, It's a pain but I think your idea is good, I'll do it. I can test it for runout at the same time.

Frank, I'll try reducing the throttle slowly and check later.

Bruce, do your motors make any untoward noises if you reduce the throttle quickly?

It sounds as if I'm being over critical, I am comparing this combination with others costing about twice as much. I think I'll stop testing it and start flying and see what happens.

 Many thanks to you all for your help .

Bob

[Bob Gray]

Owen, you posted while I was composing, great minds?  well yours!!!

 Thanks

Bob

[Bruce Richards]

Bob,

I must admit I take little notice of noises unless it sounds like the motor is being damaged I just fly and if it works that's fine by me. May be I am just a bit of a philistine!

[Andy Gates]

Personally I would not use the brake feature on an ESC unless it has a folding propeller or you belly land.

The knocking while it is running sounds like a rough bearing, you could try lubricating the bearings since you have already had the motor apart.

The other thing I wonder is how is the shaft held into the motor backplate when it pulls forwards? Could it be something hitting or pushing the rear bearing shield?

I would try flying it, you have shown it seems to be running fine in all other respects.

[Tim Mackey]

M2PW

Its nothing. Some of the Turnigy gear does seem a little like that ( I have many of their motors ) and certain ESCs are not the smoothest of switches. I take it you have the timing set correctly ( Hard ) and if so... I reckon its just a small "kick" as it throttles up. On a separate issue - I do think lower evs and bigger props are better on old style Bipes - which I assume this one is?

[Jon]

  I agree with Timbo... its worth checking the settings.. 

As I found out just recently, some ESCs can be reset in error if ever you switch on with the throttle not set to off... My motor was screeching at times but when I reset it I tried the other settings to see what the results were and my motor made similar sounds while set to anything other than Hard...

 

[BB]

Hi Bob,

The sound I reported on, was found to come from the ESC.  Yours sound is probably something lose in either the motor bell housing, or, possibly a result of the harmonic frequency causing something in the fuzz to behave badly....

[Tim Mackey]

Exactly what in the ESC was making a sound Bas ?

There are no moving parts or other components that should emit any sound at all within an ESC - I am puzled .....and curious