a rotary engine has no throttle and only one magneto.
you can control the engine speed by "blipping" the magneto, that is switching it off for periods then on again.
the engine slows while the magneto is off and surges back to full rpm if the magneto is left on and firing.
you don't realise just how much of an advance the modern aero engine is until you've seen a rotary engine in operation.
