This is a rather odd question, but here goes. I had Tivo’d the 1933 movie “Ace of Aces” Most of the aerial footage is pretty terrible, but they did have one of what appeared to be a Nieuport 28 that the lead character flew at one point in the movie. The first time he takes off in his “new” mount, he flies out over the field, and the engine sounds like it is cutting in and out on a relatively regular basis. I assumed they were trying to intimate that it was running rough, and that trouble was brewing. Odd thing was, it seemed that the odd choppy running applied every time that Nieuport flew on screen. If the sound effect was intentional, does anyone know why?
That’s how they operated the “throttle” back then. Seriously.
Winks
It is called a “blip” switch. The rotary engines had very little throttle capability, that is, they couldn’t idle. In order to reduce power enough to land the airplane, they would cut out the ignition with the switch. When the switch was released, the engine roared back to life, hopefully. One small problem is that while the ignition is interrupted, raw fuel is dumped out the exhaust stacks. Sometimes this would accumulate in the engine cowl and catch fire. C’est la guerre.
About the best explanation of how rotary engines were operated is in Alex Imrie’s book on the Fokker Triplane.
Yep. What Ashley said. Rotary engines had to run at full throttle, so the only way to control airspeed was to interrupt the ignition spark. Also, just in case you didn’t know, a rotary engine’s cylinders spin instead of the crankshaft. The propeller is bolted directly to the crankcase. The crankshaft is bolted directly to the firewall, so that it can’t spin. In this way, the pistons are still able to reciprocate, and cooling air is constantly flowing over the cylinders, even if the aircraft is stationary. Played hell on the designers, though, who couldn’t devise a simple way to control the fuel-air mixture. So, interrupting the ignition was used to control engine speed.