Heliquad Help - No Throttle sent to Channel 8 ESC / Motor won't spool up


I’ve been trying to set up a Stingray 500 with a Hex Cube (Pixhawk 2) running ArduCopter V3.6.9.

I am able to arm the heliquad with no problems, but the motor connected to the ESC will not spool up. I am unsure whether I have my parameters set wrong, the ESC is not calibrated correctly, or my transmitter is not set correctly.


The servo output for 8 does not respond to throttle. It stays put.

Here are the results of my transmitter calibration:

Channel 8 has CH8_OPT set to 32 (motor interlock) as recommended in https://ardupilot.org/copter/docs/heliquads.html. I use a Futaba T14SG, and I mapped both channels 3 and 8 in the transmitter to the throttle stick (J3).

I calibrated the ESC by plugging it directly to channel 8 in the Futaba receiver. Should I have calibrated it through the PixHawk?

I also attach my parameter list in case I set something up incorrectly:

5-26-20 Stingray.param (14.1 KB)

Any help resolving this issue would be greatly appreciated as I am a beginner when it comes to drone set up and would really like to get the collective pitch quad setup working.

This is not right. channel 3 of the RC transmitter should be connected to the throttle stick. That provides collective pitch input to the heliquad. Channel 8 is used for motor interlock feature as well as the rotor speed control passthrough (RSC Mode 1). If you have an ESC with a built in governor then use it and set the RSC mode to 2 (RSC Setpoint). Mode 1 is passthrough and it will pass to the ESC the PWM that is sent by RC channel 8. You have to be careful with mode 1 because if the pixhawk loses connection with your transmitter then it could cause your motor to stop which depends on the failsafe setting of your RC receiver.