I test flew my MFE Believer a few days ago and it crashed. I would like some help with figuring out what may have gone wrong.
I had had the aircraft set to auto takeoff mode and armed it. I threw the plane and it flew smoothly while gaining a little bit of altitude. Then at around 40 ft downrange and at an altitude of maybe around 6-8 feet, the plane banked sharply to the left. This caused it to lose altitude resulting in the left wing striking the ground and causing the plane to cartwheel once. The nose got broken off into several pieces, one of the v tail mounts broke off (at the glued joint) and there are some scratches on the wings but remarkably, the airframe is mostly intact. I’ve glued the nose back together and sanded it back into the correct shape. Now is the issue, I had my smartphone camera propped up to record the takeoff and a microsd card to record telemetry. However, by the time I took off, the phone battery died and post crash, I discovered the logging failed. The only data I have is what I saw and what I recovered.
hardware setup:
airframe: mfe believer 1960mm survey drone
motors: T-motor navigator series 3110 700 kv
esc: hobbywing x rotor 40A
propeller: apc 11x5.5e
servos: emax 3054
flight controller: matex f405 wte
receiver: radiomaster elrs rp2
gps: matek gps
battery: turnigy 6s 10000mah lipo
transmitter: radiomaster tx16s
NOTE: I was unable to get counter clockwise screw adapters for one of the motors so i locktited down both cone spinners. After the crash, I didn’t notice either being loose but in a previous ground test, the propeller did loosen one of the spinners. looking at the plane head on, the prop in the left ins spinning counterclockwise and the right is spinning clockwise. The plane veered left, so i suppose the left propeller(in the frontal orientation, right) could have been the cause if there was some kind of loss of thrust.
Radio setup:
radio setup: Standard elrs setup with yapuu. I got all the correct sensors with updating values but yapuu kept on not being able to read anything. I think this is just a version error and will be updating the script later. I also had a rare error where the plane would randomly give full bank to the ailerons. I think this only happened when messing with the packet ratio and wasn’t an issue(no way to know since no logging).
packet ratio: 1/8
transmitter module: elrs internal
scripts: yapuu(not functional)m yapuu maps(also not functional)
Parameters: The parameters are what I think most likely killed the plane. I have never tried auto takeoff as all my previou ardupilot planes were vtol.
If I had to take a stab at guessing what the issue is, it’s either something wrong with the parameters, the left prop nut coming loose causing lose of thrust, or
the radio sending strange readings causing full left ailerons.
mfe.param (19.1 KB)