Page "Rotary engine" Paragraph 12

Most rotaries however, had normal inlet valves, so that the fuel ( and lubricating oil ) were taken into the cylinders already mixed with air-as in a normal four-stroke engine.

Although a conventional carburetor, with the ability to keep the fuel / air ratio constant over a range of throttle openings was precluded by the spinning cylider block, it was possible to adjust the air supply through a separate flap valve or " bloctube ".

The pilot needed to set the throttle to the desired setting ( usually full open ) and then adjust the fuel / air mixture to suit using a separate " fine adjustment " lever that controlled the air supply valve.

Due to the rotary engine's large rotational inertia, it was possible to adjust the appropriate fuel / air mixture by trial and error without stalling it, although this varied between different types of engine, and in any case it required a good deal of practice to acquire the necessary " knack ".

After starting the engine with a known setting that allowed it to idle, the air valve was opened until maximum engine speed was obtained.