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What is that twaing noise???

Old 04-13-2014, 07:14 AM
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xmech2k
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Default What is that twaing noise???

So today I saw another plane that makes a funny noise when the motor is stopped. I don't know exactly how to describe it, but I joked that his plane would fly better if he got the guitar out of it. Sounds like someone plucking one guitar string really hard. Every time the motor stops. I think i've only seen it on larger models. Any idea what it is? Is it bad? And how do you get rid of it if you have to? Thanks!
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Old 04-13-2014, 01:25 PM
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gramps2361
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does the prop stop quick when he cut's the throttle? I have the brake set on 2 of my wings I do a lot of gliding with. They will make noise when they stop not like a guitar string though.
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Old 04-13-2014, 01:32 PM
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JetPlaneFlyer
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Yeah, that's the only thing i can think of, they might have the brake set on their ESC?
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Old 04-13-2014, 04:39 PM
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Thanks guys. I'll have to ask next time I see him.
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Old 04-13-2014, 05:08 PM
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JetPlaneFlyer
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It's easy to accidentally enable brake on many ESC's because it's usually the first item in the programming. If you inadvertently power up with the throttle stick wide open thereby entering programming mode, then realising your mistake you close the throttle, you may well enable the brake without knowing.

It's easy to tell if the brake is on. The motor will stop dead as soon as you close the throttle rather than free-wheeling for a few moments.
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Old 04-13-2014, 06:39 PM
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thepiper92
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Could be a debonded magnet. The motor in my mini switch had a debonded magnetic and I reglued it with ca and baking soda, still makes the noise however until past about half throttle, and is most noticeable when the prop just about stops turning Motor still works, but sound is like an oscillating whir noise. I suppose it could depend on the motor and the harmonics made by the sound within the motor, as well as whether or not the motor is situated inside a cowl. My motor works perfectly fine, same top end, no overheating. It is possible that it a bearing that isn't moving freely too.
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Old 04-14-2014, 02:45 PM
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Walt Thyng
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I had a HV Castle ESC on 10 cells w/ a cut down 18/10 prop. The brake was on and "twaing" is a perfect description of the noise it made when I engaged the brake. Used to scare the H--- out of the wet power guys (- :
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Old 04-14-2014, 03:30 PM
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Thanks guys. Good info. Suppose it's partly due to the airframe, from what you're saying.
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Old 04-14-2014, 10:50 PM
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Thepiper is who has it right. When my motor made sim noise it was mag that moved out of place. You will have take it apart. Darn!
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Old 04-15-2014, 01:31 AM
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It's not too difficult. I find eflite motors a pain to take apart, or at least the one I have. To fix magnet dab some ca glue, quickly sprinkle some baking soda on and pop the magnet in. When I fixed the turnigy motor I guess I didn't get the magnet in perfectly, so there is a bit of noise still.
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Old 04-15-2014, 01:34 AM
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xmech2k
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Not me. You might not have caught in my first post, when I've seem this it wasn't my planes. I last heard it on another club members rather large Cub. I'll have to pass the info on.
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