General Motor screeches when hot ( Align BL600MX, Trex 600 EFL)

[helicc16]

Gentlemen, I've been consistently noticing a screeching sound after just one flight when motor's temperature measured roughly 140 F. The noise goes away during low altitude auto-rotations. The helicopter has seen less than 20 flights. I squirted a few drops of transmission fluid onto the motor bearing (attached to the frame). That didn't help any. Please advise.

 

[heli-maniac]

Have you oiled the bearings in the motor it self

 

[helicc16]

Thought I would get more opinions on this. But thank you, Jesse. I will remove the motor from the frame and try to oil the bearings. Is the oil ( I am going to use transmission fluid) going to wreak havoc to the motor if it gets on the windings?

 

[heli-maniac]

I would get some good light wait bearing oil and not use transmission fluid

 

[Lee]

Check the pinion isn't slipping in the Motor shaft.

 

[murankar]

Also trans fluid has conditioners in it that may prevent the oil from bonding to the bearings. Clean them with break cleaner really well the use a high quality bearing oil. I use tri-flo that comes in a refillable pen applicator.

 

[pvolcko]

Only clean them with the bearings out of the motor!

 

[coolgabsi]

please remember your transmission fluids and oils for the car are made to withhold rpms upto I think 10000rpm ... Now I am not an expert on those.. but I think that is what it is.. but on your helis.. the motor is going at 2100*8.5(avg gear ratio) = 17800rpm atleast.

SO like Jesse said, thin bearing oil MADE to withstand those many rpm's . I have scorpion's own motor oil, or Red triflo's oil..

Screeching noise sometimes points towards one way bearings. check that carefully

You might have to take the motor apart and change the bearings in it. and then after that keep oiling them every once in a while

btw.. have you cheked the pinion if its slipping by chance. check that too

 

[helicc16]

Thanks, guys. After removing the motor from the frame, I grabbed the pinion with one hand and the motor can with the other and tried to twist the motor shaft. I (barely) felt a tiny bit of play. Don't know if this is normal. The pinion is now off the shaft. I will make sure it will be fully tightened when putting it back on the shaft.

Now I am just waiting for the Triflow oil to come in from Amazon. I've been using transmission fluid on bearings , not knowing it is not suitable. Will report the results after the test.

 

[Tony]

Make sure to check the grub screws that hold the shaft into the motor can. If you are feeling play with your fingers, then just imagine what it's like at full power. Remove all grub screws, clean them and the holes with alcohol, make sure the flat of the shaft is facing the hole, apply thread locker and tighten moderately tight. Done and done. Well, after the bearings it will be done lmao.