I am building a large cargo helicopter with a rotor diameter of 7 meters and a takeoff weight of 800 kg. I am currently encountering a problem. During the takeoff phase, in the approximately 3 to 4 meter altitude range, I need to constantly manually increase the throttle to get it to lift off. Then, at an altitude higher than about 4 meters, it starts to climb automatically, requiring manual throttle reduction to stabilize. However, once above 4 meters, it can fly stably and maintain altitude. During descent, when below 4 meters, it cannot maintain a stable hover and continues to descend with increasing speed. I have to manually push the throttle higher to stabilize it. If I don’t increase the throttle, it will slowly but constantly accelerate and fall to the ground from 4 meters. I roughly estimate that this is caused by changes in air pressure due to ground effect, preventing stable altitude lock. What parameters need to be adjusted to solve this problem?
Do you have logs? In stabilize mode (manually controlling throttle) such things possible, while in althold/loiter mode this should be managed by autopilot.
1 Like
Changed category to Traditional Helicopter
Baro will we problematic in the ground effect with such a big vehicle.I recommend a lidar or a radar altimeter.
There is ground effect compensation, but it weights in the accelerometers which also not a good idea with a large vehicle (high vibrations)
1 Like