Originally Posted by Gunnycig
This is my 4th FPV plane flight and it seems there is a problem in the stock bixler motor or exceed 40 amp esc Im running. There is a high pitched squeal at random times. The attached link is from a 808 cam I had attached since its better quality than the cam I fly with. I lost my signal at 2 miles and when the Eagle Tree RTH kicked in I got the noise. My amps also jumped from about 7 to 18-20 during the noise. This has happened on 2 previous flights and the RTH also engaged then. Im not sure if this is a motor, esc, osd pro, or other problem. Any suggestions would be greatly appreciated.
As someone else mentioned, it is a problem with your ESC and your motor getting out of step. I had one motor/ESC combination where changing the timing of the ESC cured the problem completely. But some ESCs and motors just don't play together well. I have a Hacker motor in my Funcub and with the Plush ESC I tried at first they would not stay in step on any setting available in the ESC. I put a Hacker ESC in it and it never squeals at all. Try the timing. If that doesn't work. try a different ESC.
One other thing I saw somewhere was that over propping the motor can be another source of the problem. If the motor is not able to accelerate quickly enough it falls behind the pulses from the ESC. You probably noticed that the squeal occurred when the throttle was suddenly opened wide. Then, when it was closed temporarily and opened up more gradually everything was fine.