Help- throttle up, whining noise, rotates ccw

[fingerlessfred]

Hi all... And experts!!
Get the heli off the ground, get to less than 75%, and the tail starts to go, and the high pitched screeching/ whining sound happens... Heli starts to spin ccw.

Who got the knowledge!
Pease advise,
That's in advance for the time.

[everydayflyer]

Main blades turn clockwise thus the nose of the heli wants toturn left (CCW) due to the mains torque .

Phyics --- to every action there is an equal but opposite reaction.

The tail motor / rotor's job in part is to prevent this CCW rotaion.

What is making the high pitched screeching/ whining sound?

Did it work before , what did you change last?

[Tasteles]

First thing to check is that you don't have the tail motor wire plugged in backwards. But if you're able to get it off the ground, I would say the bearing on the tail motor is bad and needs a new tail motor.

[ronj]

Or you have hair, thread or some such wrapped around the tail motor shaft, or possibly the blade is pressed too close to the motor body. Or the tail blade has lost some of its pitch. You might try to bend it back or try a new tail blade.

[d12bn]

Sounds like a bad main motor

[helifixing]

Originally Posted by Tasteles

First thing to check is that you don't have the tail motor wire plugged in backwards. But if you're able to get it off the ground, I would say the bearing on the tail motor is bad and needs a new tail motor.

Yep, I also had a slightly bent tail motor shaft do exactly this too. I didn't notice the shaft was slightly was bent, so upon flying the heli would go into unrecoverable vibrational modes upon the first time the tail would spin at high speed. This caused the heli to 'work fine' until the tail hit high speed then things wouldn't settle down.

[fingerlessfred]

So I greased the bearing in the swash, as I feel this is where the whining is coming from, but I also greased the bearings in the body. The sound is gone for the most part... But there is no power. No hair in the tail... Maybe the main motor...?
The heli still doesn't fly stable as it should.. The tail is all over the place. Would the main motor going bad cause this effect?

[helifixing]

As a consistency check for the main motor you could remove the tail rotor (or better, unplug tail motor) and hold it in your hand while running it. Likewise you could remove the main gear with the tail in place and while running check the tail response by rotating it CW CCW etc.

[Nytflyer]

Originally Posted by d12bn

Sounds like a bad main motor

+1 The main motor squeels like a stuck pig when it goes.

[fingerlessfred]

Thanks all...
Main motor replaces and no more squeels! But the tail still goes when I'm in higher rpm.

Tail replace? Even though it's fairly new... Like 5 flights...

[Angrydad]

You're not using too much maximum pitch I don't suppose? I had that problem recently when I built a 450 TRex clone. Just a thought...

[everydayflyer]

Meaning of tail still goes?



Main blades turn clock wise and if the heli di not have a working tail rotor it would just spin around and around to the left ( CCW).

If you hold the rudder control all the way to the left as you advance the throttle the tail motor will (should) not run.

If you hold it all the way to the right it will run at max. speed or if you just leave it in the center the on-board gyro will apply the power required to genertae enoughg RPMs / speed / thrust for it to counteract the amins torque and keep the nose straight.