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Old Jun 22, 2011, 06:05 AM
no no no, a music gig
Chophop's Avatar
Pleasant Valley Modelport
Joined Sep 2006
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Motors that Whine Loudly

I have several motyors that make a loud whine. I replaced them with ones that are more quiet. They don't have to be top line motors to be reasonably quiet, but the better ones do seem to start at about $25, the $10 to $15 400 BLDC's are pretty sure to RRRRRRRRRRRRRrrrrrrrrRRRRRRRRR.


Any ideas on how to fix the whine ? I tried other low volume forums with no luck.
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Old Jun 22, 2011, 10:35 AM
Planes from 1oz to 55lb's
simo10's Avatar
USA, FL, Orlando
Joined Aug 2004
1,278 Posts
The timing settings on your ESC play a bit part with noise, so try that first.
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Old Jun 22, 2011, 11:51 AM
no no no, a music gig
Chophop's Avatar
Pleasant Valley Modelport
Joined Sep 2006
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I have been through all tries with these motors. now connect a Scorpion, Hyperion, that level of motor and practically no noise. I know I can simply pay the price, but maybe a simple rewind, etc. may solve it ?
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Old Jun 22, 2011, 12:45 PM
An itch?. Scratch build.
eflightray's Avatar
South Wales U.K.
Joined Mar 2003
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It wouldn't surprise me that the cheaper motors sound noisier. It can also happen when the ESC arms. On some motors those 'beeping beeps' are enough to fetch the kids over looking for the ice cream seller.

A bit of a guess, but as it's the motor that actually makes the 'beeps', (it's the windings oscillating), then cheaper motors probably use poorer quality winding methods. And as the cheaper ESC probably have lower frequency switching, perhaps that can still be heard throughout most of its speed range.

Or it could be poor bearings, could be the airframe acting as a resonator, could be.........
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Old Jun 22, 2011, 02:20 PM
no no no, a music gig
Chophop's Avatar
Pleasant Valley Modelport
Joined Sep 2006
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I did the testing on an Align BL-25G, a top quality ESC. All the cheaper motors make that RRRRR sound on any controller. Stick an Hyperion on and all I hear is a bit of prop noise and a very soft whirr that approxmates a nice Turboprop sound. Sounds VERY good.
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Old Jun 22, 2011, 02:32 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
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I know exactly what you're talking about. I've got a couple motors that make this fairly deafening, very obnoxious whine noise at certain points on the throttle range no matter which ESC I'm using. I'm thinking about testing with one of my Castle ESCs that have a lot of timing options to see if that affects it...
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Old Jun 22, 2011, 03:15 PM
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Lnagel's Avatar
Moab, Utah, USA
Joined Apr 2003
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Quote:
Originally Posted by TP16 View Post
...fairly deafening, very obnoxious whine noise ...
In my house it's not the motor. It's my wife whenever I buy a new plane.

Larry
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Old Jun 22, 2011, 03:50 PM
no no no, a music gig
Chophop's Avatar
Pleasant Valley Modelport
Joined Sep 2006
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Get a set of ear plugs and that 50cc Yak-54. You had to say new plane, well that's on the way sometime as soon as I can spring for it. I'm sure she'll consider you macho.
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Old Jun 22, 2011, 06:07 PM
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Joined Jan 2009
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My 24 gram blue wonder motors make a nasty noise like a dentists' drill... but knock wood I've never killed one, and they do a great job in spite of the grating sound. Blue wonder is of course the generic term for the motor, the ones I have are chrome/nickel-plate finish.
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Old Jun 22, 2011, 10:12 PM
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43851E's Avatar
College Station, TX
Joined Jul 2009
882 Posts
some early types of ESCs have more of a "square" wave and do not taper off the trailing edge of the pulse going to the motor making it ring. Some like the sound with jets. The extra noise is actually waisted power> heat.
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Old Jun 22, 2011, 10:24 PM
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efflandt's Avatar
United States, IL, Elgin
Joined Mar 2011
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Cheaper motors likely take short cuts in precision somewhere, type or tolerance of bearings, balance of the motor bell, materials, etc. So even if your prop is perfectly balanced, the motor may not be, shaft or prop adapter may not be as strong or straight, and/or bearings may be looser.
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Old Jun 22, 2011, 11:11 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
12,406 Posts
Quote:
Cheaper motors likely take short cuts in precision somewhere, type or tolerance of bearings, balance of the motor bell, materials, etc. So even if your prop is perfectly balanced, the motor may not be, shaft or prop adapter may not be as strong or straight, and/or bearings may be looser.
This sound isn't a bearing issue, and it's not caused by mechanical imbalances. It sounds like some type of whistle or something; it's hard to describe unless you can be sitting in the room with the motor when it's running. If you heard it, you'd know what I mean.

ESC-related explanations seem most logical. I'm gonna go test a bunch of ESCs in a little while. On the board for testing:

Motor:
Suppo BL2217/6 1500Kv outrunner

Possible ESCs:
Jeti 30A (blue)
HobbyKing SuperSimple 25A
Castle Creations Phoenix 25 (two versions)
HobbyKing SuperSimple 50-65A heli
Suppo 30A
Flying Legends 20A
Art-Tech 18A

That's a pretty decent sampling of brands and quality, I think. I'll check back later with results.
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Old Jun 23, 2011, 03:04 AM
no no no, a music gig
Chophop's Avatar
Pleasant Valley Modelport
Joined Sep 2006
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The only gold can type of Supo I have is a pretty good motor and makes only a small bit of noise. A good choice to look for ESC caused noise.The sound I am refering to is the CD Rom sound. I think some people could have a CD Rom motor running while blindfolded and identify it every time.

I asked this question before and one person said the bell can is flimsy and vibrating. Not on a CD ROM, they are thick. I do have an Optima motor with a thin bell and the shrink wrap over the can trick did a small bit of help. Still no smooth whirrr like the Scorps, Hyperions, Himax etc.

I wonder if it could have something to do with the magnet and stator configuration ? Those motors do make the same sound as when powered but at a low volume when in a steep glide, throttle off, and the prop is wind powered.
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Old Jun 23, 2011, 06:17 AM
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flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,740 Posts
A buddy had a motor with a real loud whine to it. He changed the timing and it quieted right down.

Gord.
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Old Jun 23, 2011, 08:15 AM
Registered User
United States, NY, Angola
Joined Jul 2010
304 Posts
I have a couple of cheap alpha370 motors from nitroplanes that do this. They whine at about 1/2 throttle for me(which is where I fly most of the time). I had them on different esc's and both did it. I have a park400 that now runs on one of the esc that the one whining motor ran on and it's perfectly quite. No whining noise what so ever. All you hear is prop sounds.
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