The 'no throttle' engine you're thinking of was the Gnome Monosapaupe ('single valve') rotary, in which the mixture was fed to the cylinders from the crankcase via transfer ports rather like a two-stroke (or through a flap valve in the piston crown in the very early examples). With no conventional inlet valve or proper carburretor, the Gnome Mono (and its German copy, the early Uberursel)
were either 'on' or 'off' and were controlled by switching off the fuel and cutting the ignition. Woe betide the pilot who forgot to turn off the fuel supply, because the engine would continue to ingest and exhaust unburnt petrol/oil mixture all the time it was spinning around; when he switched back on again, all too often - BOOOOOOM.
In-line 'stationary' engines as used by the Bristol F2B and Fokker D.VII usually had separate throttle and mixture levers which provided a fair rev-range when operated properly. Later rotary engines like the Le Rhone and Clerget used on the Camel and Dr.I (Uberursel copied them too!) had the same (fuel inlet to the combustion chamber was a conventional poppet valve at the end of an inlet pipe from the crankcase) but were far more sensitive and pilots were reluctant to change the settings once they'd established optimum revs, so they made coarse changes the same as the Gnome, with the added 'luxury' of a 'blip switch' that supposedly could cut the ignition of any number of cylinders. Same danger applied as the Gnome, only even worse because the pilot couldn't turn off the fuel to the 'live' cylinders, so he either used the device for only a very few seconds at a time or reverted to a simple 'all on or all off' switch.
The ol' Dawn of Aces Camel and Fokker Dr.I triplane were modelled 'all on or all off', which was fair enough and easily mastered because the 'turn around its crankshaft in the opposite direction to the engine's rotation' characteristic of the rotary-engined aircraft (same as the helicopter) was modelled as pretty mild.
Should be fun in the WWI arena - happy trails, amigo.
