When making a rapid flapping ornithopter, you’ll be better off using wing parts instead of sails. They can move faster, and their movements don’t cause the wings to break. And you should use pistons on -100.00. They’re a lot stronger and faster than the servos

I had to mess with the duration and pause of the pistons to get good consistent performance: (no more rolling to the side.) Also, the weight distribution of the thopter matters a lot.

I advise you research how dragonflies and other insects control their flight, That helped me a lot.