to takeoff you had to trim elevators when the plane reach 300km/h and pull stick.
...and that's not even wrong.
The interesting thing is: You have to do it
when the plane reach 300km/h - and not before.
Because if you happen to do it before, your control surfaces might or might not be reset to neutral visually, but in any case the Java code resets their values internally.
The result is: You trim all the way up and pull the stick full back when you start your takeoff run (and keep it like that all the time), but it shows absolutely no effect.
Even if you do it when the plane reaches 299.999km/h - no effect.
And when the plane reaches 305km/h, it topples over.
That's what needs to be fixed: Don't mess up with control
input values, if at all, mess with control
output but if you do, take the current (unedited)
input values into consideration on each update.
Best regards - Mike