Hi there,
I wonder if there is anything to cope with big fuel tanks or sprayer tanks.
A big heli with long endurance and use case like field sprayer looses weight.
I saw configurations that shrink to half of the Takeoff weight due to fuel burn and spraying.
This should have definitely impact on control laws (pid) but I could not find anything in that direction.
Does arducopter expect always same weight and offers only one setup for the current weight?
Cheers patrick
Yes. I do this all the time. The helicopter just uses more collective pitch and is slower responding at max takeoff weight. Pretty much the same as for full size heli’s.
The one advantage with RC over full-size is that you can run different headspeeds to try to keep the collective pitch range about the same for the altitude controlled modes at different weights. This becomes important for fuel helicopters that can carry their own weight in payload.
So at minimum takeoff weight with my 800-class machines I’ll run around 1,400 rpm. At maximum takeoff weight I run 1,530 rpm. This reduces the “jump” from Stabilize to Auto or Pos Hold mode in the collective pitch range, as Pos Hold, especially, expects the collective to be at center for no altitude change.
As far as tuning PID’s, there is no need to retune for different weights. In fact, it would be highly not recommended. A 20lb helicopter lifting 20lb payload is no longer a hotrod - don’t expect it to fly like one. Especially with sling loads at that weight, the slower and more gentle it handles, the better it is. They become super-stable at high disc loading and 20kt wind doesn’t even faze them. Unlike a multicopter that will become highly unstable using a lot of throttle to lift a heavy load, a helicopter can pull full pitch lifting a load and still fly rock stable. You’re just not going to fly it at maximum cruise speed with that load, or make any high-G turns with it.
Hello,
I wonder change of the quad mass(weight) for a simulation. Which is parameter I can do this?