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Old Feb 22, 2015, 04:40 PM
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V911 tail motor weird noise & gets hot?

Hey guys,

I've been flying my v911 for 2 weeks now mainly indoors and have begun to notice that my tail motor is making a weird noise exactly what is happening to this guy in the video:

WLToys V911 problem with Tail Motor (1 min 54 sec)


After one fly 4-5 mins the tail motor is also unusually hot. It never used to behave this way until the last 2 days.

Another thing I noticed that this happened only after I charged the batteries with a wall USB charger. So I'm not sure if it overcharged the batteries or had to do something with the Voltage. To test this I recharged them normally the next time but still have the weird noise and the hot motor after 4-5 mins.

Any idea what is wrong? Please help!!

Thanks in advance
Jake
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Old Feb 22, 2015, 04:53 PM
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I really don't have any experience yet, but I do wonder if the motor is starting to go out and needs to be replaced.
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Old Feb 22, 2015, 04:59 PM
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Replace the motor and see if it makes any difference.
Sounds OK to me, some are noisier than others.
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Old Feb 22, 2015, 05:35 PM
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The first thing most would say is to check for any binding, or hair on the shaft that could be causing any issues.

Based on your video, I do want to ask if you experience tail blowouts, and is your tail holding like it should? If its holding fine, and acting fine, that might be normal for the most part. The tail on my v911s will make that sound if I hold it while its fighting the gyro because once the gyro initializes, it will want to try its hardest to keep its heading or position. With you holding it in your hand, and turning it, it wont stay silent at all, because the motor is working harder to keep its heading as your moving it around.

Another possibility could be the tail rotor, but like I said, mine makes the same noises when I hold it in my hand and turn it like that. Its just the tail motor working hard to keep its heading. My tail motors get pretty hot as well after some indoor flying and is normal after a 5min flight. The tail motor is constantly working so it will heat up by the end of your flight, but when your outside, flying faster usually helps as the wind will help cool the tail and even the main motor a bit, but when inside, it gets pretty warm after a flight. I also charge all my v911 batteries with USB wall chargers and have cycled each of them probably 30 times each (I have several). I test the voltage of them regularly and I've never had the kit charger overcharge past 4.13-4.15 volts.
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Old Feb 22, 2015, 11:37 PM
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Sounds normal to me.

Gyro Test
Gyro only tries to correct an uncontrolled rate of rotation using tail motor.
Hold the helicopter in your hand
Apply throttle
Tail motor speeds up when helicopter rotated counter-clockwise (nose-left)
Tail motor slows down or stops when helicopter rotated clockwise (nose-right)
Tail motor speeds up when throttle increased.

My motors overheat in summer. Touch the main and kiss the tail, get used to reading motor temperature.

Most likely you are ready to actually fly the V911 and advance out of the hover stage, and now simply notice things that you did not notice before..
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Old Feb 23, 2015, 06:45 AM
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All perfectly normal. The gyro is reacting to rotation and your rudder stick is working.
Pull off the tail rotor and make sure nothing is wrapped up behind it, then make sure it isn't pushed back on too far, happens often.
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Old Feb 23, 2015, 01:17 PM
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Tail motors work hard and get hot. check and follow what has been posted and good to go.
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Old Feb 23, 2015, 01:56 PM
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As a side note, and since you usually have a choice to turn left or turn right...

Turning nose left (CCW) gives the tail motor a rest.

Turning nose right (CW) makes the tail motor work harder.

All else being equal, do CCW orbits instead of CW orbits. Since the tail motor slows or stops, the flight time is also increased. The tail motor normally uses about 30% of the LiPo mah capacity.
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Old Feb 24, 2015, 11:10 AM
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Hey guys.

Thankyou all for the replies really helpful! I've learned a lot just by experiencing something like this and asking a question.

I did all the check mentioned over here (hairs, even pulled the rotor blade off and re-adjusted it etc) Did the gyro test and everthing seems normal to me although i never had it make that noise or maybe "I just didn't notice it as much".

However after flying it in my basement again last night it stuck me

Its much cooler down there right now (Being in Canada) - snow covering up the basement windows you can imagine lol. That's why I had a cooler motor down there even after 10 mins of flytime haha

That afternoon i posted this I flew in my bedroom where the heat is turned up atleast 20 degrees Celsius lol Thanks for all the help though i did learn a lot

----------------------------------------

Here is another question:

- I find that by the end of my flight 4-5mins the trim that actions the left rudder is trimmed all the way to the left. Do you have that happen as well ?

As the voltage drops there is more of a left turn and I have to compensate for it. This is something normal?

Thanks for all the help
Jake
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Old Feb 24, 2015, 11:27 AM
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Depending on the battery and how long you run the battery per flight, towards the end, the rudder will require more trim to the left, which signifies a drop in power due to battery drainage. Does it require left rudder trim at the beginning of the flight?

I have 3 V911s. One that requires one or two bumps of left tail rotor trim by the end of the flight and one that requires more than 10 bumps by the end of the flight. I do suspect the one that requires more trim has a weaker tail though as it requires a left trim at the beginning of flight.

I'll mention that if you fly the 130-145 mAh batteries, keep flight times down to 4-5 minutes on a stock heli. Flown too long will damage the battery if the voltage drops too low.
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Old Feb 24, 2015, 12:17 PM
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Quote:
Originally Posted by jakeaheli View Post
left rudder is trimmed all the way to the left
Tail motor is overpowering main motor, trying to make V911 rotate nose right (CW).

Unlikely tail motor got stronger, meaning main motor is getting weaker.

Make sure tail boom is pushed all the way into frame and tail motor is pushed all the way in on tail boom.

Lubricate main gear and main motor pinion gear. Lubricate main shaft. If you are using a quality grease or oil, then also lubricate swashplate between upper plate and lower plate.

Also, when a V911 rudder starts acting up, it reminds me to recharge my transmitter NiMH batteries.
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Old Feb 25, 2015, 11:08 AM
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Quote:
Originally Posted by Vodarac View Post
Does it require left rudder trim at the beginning of the flight?

I'll mention that if you fly the 130-145 mAh batteries, keep flight times down to 4-5 minutes on a stock heli. Flown too long will damage the battery if the voltage drops too low.
No it usually doesn't require any left rudder trim at the beginning. If it does, its only a click or 2 but mostly not.
I didn't know that too low voltage drop in the batteries would damage them. However I don't run them till the heli stops either.

Quote:
Originally Posted by Ribble View Post
Tail motor is overpowering main motor, trying to make V911 rotate nose right (CW).

Unlikely tail motor got stronger, meaning main motor is getting weaker.

Make sure tail boom is pushed all the way into frame and tail motor is pushed all the way in on tail boom.

Lubricate main gear and main motor pinion gear. Lubricate main shaft. If you are using a quality grease or oil, then also lubricate swashplate between upper plate and lower plate.
Thanks i will lubricate. I hope any oil will do the job. I've got some olive oil that i could probably use. Will see how that plays out
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Old Feb 25, 2015, 11:11 AM
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Also, when a V911 rudder starts acting up, it reminds me to recharge my transmitter NiMH batteries

Speaking about Tx batteries...I use 6 * NiMH ones too. They are only 800mah each so they dont last too long.

Plus the battery indicator on my Tx mostly shows half full or on one bar. Is this due to the mah of the batteries in using or something else?

Also would this affect flight range and control if I did happen to take my v911 way high up in the skies?

Thanks again
Jake
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Old Feb 25, 2015, 11:58 AM
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I believe it is because the NiMH batteries have a lower voltage rating than alkaline, but discharge slower/last a little longer, but don't quote me on that. My NiMH batts, also only show 2 bars of life in my v911 transmitters, and displays less voltage in my Dx6i than VS alkalines, but My NiMH batteries discharge slower in my DX6i than alkaline. They are 2300 mah though.

I have gotten my V911 higher than I could ever be comfortable with and got no loss of signal. I was more worried about loosing it in a neighbors back yard than signal loss.
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Old Feb 25, 2015, 12:06 PM
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Quote:
Originally Posted by jakeaheli View Post
Also, when a V911 rudder starts acting up, it reminds me to recharge my transmitter NiMH batteries

Speaking about Tx batteries...I use 6 * NiMH ones too. They are only 800mah each so they dont last too long.

Plus the battery indicator on my Tx mostly shows half full or on one bar. Is this due to the mah of the batteries in using or something else?

Also would this affect flight range and control if I did happen to take my v911 way high up in the skies?
800mah NiMH charge should last about 10 hours or 1 month.

My V911 transmitter batteries are 2200 NiMH Low Self Discharge (LSD). Normal NiMH will lose their charge in about a Month. NiMH cells are nominal 1.2 volts and V911 transmitter is designed for Alkaline 1.5 volt cells so the battery meter will quickly read low for NiMH cells.

V911 transmitter measured 70ma at 7.5v battery power 6x NiMh 2200mah LSD cells. Transmitter RF Input power is about 110mw (20dbm) and runs off 3.3v regulator so relatively unaffected by transmitter battery voltage. Transmitter voltage can go quite low before it starts to fail.

Transmitter stops working at 5.15v, fast chirping like a gear grinding from transmitter and helicopter drops out of the sky.
http://www.rcgroups.com/forums/showp...ostcount=11780

http://www.rcgroups.com/forums/showt...a#post22546678
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