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Old Apr 08, 2005, 09:31 AM
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Minimole's Avatar
Colwyn Bay, North Wales, UK
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Strange Noise coming from Main motor/main gear?!?!? Please Help!!!

Hi all,

Man am I annoyed right now!

I have got a new Feigao main motor and PHX10 from Like90, and thought I would just solder up the motor and esc connections, and just connect it to my battery just to check it all runs smoothly. Well, on its own its fine, seems to run smoothly, no strange noise e.t.c.

I then put it into my heli, which has no head assy or anything, just the frame, boom, LG and main gear. When I spool it up, it makes a terrible noise. Im not too sure how to describe it, but its kind of a vibration, but not really. Its quite high pitched. It sounds like something is scraping of something, but Im pretty sure there is nothing scraping/rubbing e.t.c.

I then treid to see if I could cancel out variables. So far I have tried 2 main frames (this is on a Hummingbird), 3 main gears, the new BL motor, and my old brushed motor, to no avail, I still get this noise.

The main gears spin smoothly on there own when in the frame, although they are bent a tiny bit, so that when they are spinning fast the disk appears to rise and fall, but Im sure they are not the cause.

As I said before, the BL motor is fine on its own, and so is the brushed. It just seems when they are all united (frame, gear and motor)it all messes up.

I have been using one of the frames, the brushed motor and 2 of the gears before, so I know that they worked together before.

However, this is the first time I have even run up a motor in my heli since like the end of November ( ),so I may of forgotten how the heli sounds, but Im almost certian its not meant to be this noisy!

Sorry for the ling post, and possibly stupid question. Im may be just doing something stupid, as I havent used it for soooo long... Please post even if you think it might be stupid, it may be correct.

Anyone else had anything similar to this?

Thanks a lot, hope you can help, Duane

EDIT: Just been talking to my brother about this.
There are no common factors. I have used all three main gears on both frames, and both motors in both frames. I suppose the only constant was that I didnt change the pinions, but then again two different pinions were used (one on BL motor, one on brshed).
I just rolled all three main gears along a table, the metal shafts all seem fine.
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Old Apr 08, 2005, 09:57 AM
Day by day...
LoopZilla's Avatar
Melbourne, FL
Joined Feb 2004
634 Posts
Hey, are the shaft bearings OK?

How freely does the main shaft spin in the frame without a motor?

How are you setting the gear mesh?

Just some questions to get more ideas...
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Old Apr 08, 2005, 10:02 AM
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ukgroucho's Avatar
Stratford upon Avon
Joined Jul 2004
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What screws are you using to mount the motors? Make sure that they are not too long causing them to scrape on the windings.

The main gear pinion rising / falling is not good (depends how much but generally 'not good'). May be an issue with the gears not being mounted properly on the shaft... or a bottom bearing issue. Whatever, if this is moving too much it will eat the main gear and motor pinion.
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Old Apr 08, 2005, 10:16 AM
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Minimole's Avatar
Colwyn Bay, North Wales, UK
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Quote:
Originally Posted by LoopZilla
Hey, are the shaft bearings OK?

How freely does the main shaft spin in the frame without a motor?

How are you setting the gear mesh?

Just some questions to get more ideas...
Well, I have about 5 bearings, and they all seem fine.
All three main shaft/gears spin very freely and smoothly without the motor.
Im setting the mesh by eye, just making sure there is a tiny bit of a gap, but not so much that the gears can slip.


Quote:
Originally Posted by ukgroucho
What screws are you using to mount the motors? Make sure that they are not too long causing them to scrape on the windings.

The main gear pinion rising / falling is not good (depends how much but generally 'not good'). May be an issue with the gears not being mounted properly on the shaft... or a bottom bearing issue. Whatever, if this is moving too much it will eat the main gear and motor pinion.
I am using the ones that came with the heli, and they are quite short. the actual threaded bit is only 4.5mm long (just measured it) so I dont think that the screws are the problem. Yeah, I know, the ones that I got from Like90 are way too long, they were about 7mm long!

The main gears are rising and alling about 1 or 2 mm, not much, but noticable if you look at them closely when they are spinning.


BTW, My main gears and shafts are attached, and dont come apart as far as I know.

Thanks for the help, Jon and Loopzilla,

Duane
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Old Apr 08, 2005, 10:22 AM
2 Turbos...Nope 1 Big one
skeppley's Avatar
United States, PA, Lake Wynonah
Joined Aug 2004
1,801 Posts
What pinions are you using? If it is the Micro RS4 pinions with grub screws, they can rub on the plastic frame a bit. If its a press on, do you have it on too far, so that it is hitting the frame between the motor and the top of the pinion?
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Old Apr 08, 2005, 10:25 AM
2 Turbos...Nope 1 Big one
skeppley's Avatar
United States, PA, Lake Wynonah
Joined Aug 2004
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Since you dont have the hed assembly on, just pull out the main gear, leaving the motor where it is, and see if it still makes noise, then you know if its a motor, motor screw, or pinion problem
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Old Apr 08, 2005, 10:26 AM
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se michigan
Joined Apr 2004
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Which KV Feiago are you using? There are reports of certain KVs with issues.
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Old Apr 08, 2005, 10:44 AM
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Minimole's Avatar
Colwyn Bay, North Wales, UK
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Quote:
Originally Posted by skeppley
Since you dont have the hed assembly on, just pull out the main gear, leaving the motor where it is, and see if it still makes noise, then you know if its a motor, motor screw, or pinion problem

What pinions are you using? If it is the Micro RS4 pinions with grub screws, they can rub on the plastic frame a bit. If its a press on, do you have it on too far, so that it is hitting the frame between the motor and the top of the pinion?
Thanks,
I just tried that, put motor on the frame without gear, runs fine, no strange noises.
On the brushed motor I am using a Piccolo plastic pinion (not sure what tooth it is) that I 'loctited' on, and on the Feigao I have a 9tooth pinion that Like90 put on for me, I think its the one for the Zoom.


Quote:
Originally Posted by gomojo99
Which KV Feiago are you using? There are reports of certain KVs with issues.
Thanks, its the Feiagao that Like90 sells: http://www.like90.com/index.asp?Page...ROD&ProdID=205
So it has a kv of 4680.
However, I doubt its the motor because I still get that noise weith my brushed motor.


This is really wierd (and annoying), becuase I seem to have cancelled evrything out, tried everything out, but I still get it...

Thanks all, Duane
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Old Apr 08, 2005, 11:14 AM
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Stratford upon Avon
Joined Jul 2004
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I don't like the sound (no pun intended) of the 1 - 2 mm up / down on the main gear. I saw this on an AeroHawk where I (badly) made a CF main shaft and did not get the main gear to seat properly... it made a horrible noise and was eating the brass pinion and plastic main gear.
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Old Apr 08, 2005, 11:19 AM
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Colwyn Bay, North Wales, UK
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Thanks Jon,

Ill have a better look at that. Its just that I have flown with 2 of these before, no problems, and I dont think they have become more bent since I last used them. If I have to, I will buy a new one.

Duane
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Old Apr 08, 2005, 11:36 AM
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U might also find that it sounds worse with no load (no main blades) which is why you notice a difference... You might try adding a head and blades and see if it's quieter - but check the pinions after you run it for a minute.
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Old Apr 08, 2005, 12:31 PM
That tree again!!!!
thanhTran's Avatar
Germantown, MD, US
Joined Sep 2004
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I know that you have had your heli running with the BUSHED motor. But could you do that again just to find out if the sound is different and how different that is? It could be that the noise coming from resonant which only appears at some certain speed. If the motor fully assembled to the chassis runs fine on its own then I think you are ok. But yeah, the noise is disturbing.
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Old Apr 08, 2005, 01:18 PM
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Minimole's Avatar
Colwyn Bay, North Wales, UK
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Thanks all,

I will try out the brushed motor, and with the baldes e.t.c. in a minute...

Thanks, Duane
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Old Apr 08, 2005, 06:02 PM
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Colwyn Bay, North Wales, UK
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OK, anyone else got any more ideas on what may be wrong, before I try it out with blades, and see if theres any difference between the brushed and BL motors? Ill probably do it tomorrow as its a bit late now, and I'm tired...

Thanks all, Duane
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Old Apr 08, 2005, 10:23 PM
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Joined Nov 2002
19 Posts
Hi Minimole,

I've got a humblebee in which some times i do hear a high pitch "screeching" noise. After checking around, i have found out that it is coming out from the main motor. Taking out the motor and spinning the motor shaft by hand causes the same sound. I hope this is the problem for you as it's easy to fix. Just change motor
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