Calsir wrote:

This your statement is not fully correct.
Some time ago I was talking with my friend Maurizio Longoni and we noted that the WW1 pilots controlled the rotary engine output by switching it off to switch it on again using the propeller's inertial force. They generally avoided the system of switching off the magnets of some of the engine's pistons, the system invented to provide some power output control on the rotary engines, since it wasn't sure that all the pistons would have started working again when required.

By the way, since you are in Milan, have you had the occasion to go and see the SPAD on which the AReA restoration team is presently working on?