I stopped in Nebraska and Kansas while visiting the US to help a young friend in Nebraska with his first quadplane build. We could use some help analyzing what’s causing it to toilet bowl on lift off.
First time we took off in QLoiter and it just rolled to the right and crashed. After repairs, we recalibrated the ESCs, did an accel calibration and the compass dance.
On the next test I took off in QStabilise. It was flying level but started to drift around me to the right. I thought it was just the wind so I switched to QLoiter but it continued to go around me nose out. As it circled around me the rear of the plane hit a tree which knocked the GPS off the airframe which was dangling from it’s cable. I increased the throttle to get it out of the tree and attepted to go in to FBWA thinking I might be able to use forward flight to get out of the unstable vertical lift. For whatever reason the forward flight motor didn’t kick in. So I let the plane come around as it was now heading for an empty field. I let it descend a bit but it was rolling quite a bit. I waited until the wings were level and cut the power so it would land on it’s belly. That worked out well as the airframe didn’t have too much damage. It did however break the motor support bars and we didn’t have spares.
I’ve left Kansas now but I think with a bit of help from other members here that my friend will be able to get the plane flying by himself. The log from the flight is available here https://www.dropbox.com/s/2b1wnvxj3007u5v/00000108.BIN?dl=0
I suspect the issue is either mag interference or vibration issues.
Photo of build here https://flic.kr/p/25RmtLX
TIA, really appreciate the time of anyone who can help out.