I was wondering if the (Displacement x RPM x .5 x Ev) / 1728 calculation for air flow on a regular piston motor is still the same equation used for rotaries. The only variable I'm having problems is the .5, would that value go up since the rotary produce power at a different rate then a piston?

Thanks.

 

A rotor has one intake stroke per crank revolution, unlike a piston engine which has one intake stroke per two crank revolutions, so the 0.5 disappears. One 13B/20B rotor displaces 654cc or 0.654L per crankshaft revolution, so 0.654L x no. of rotors x rpm = L/min.

e.g. a 13B at 7000rpm would be 0.654L x 2 rotors x 7000rpm = 9156L/min or 153L/s.

If metrics scare you, 39.9cu.in. x 2 rotors x 7000rpm = 558600cu.in./min = 323cfm.

Then multiply by volumetric efficiency to get actual flow.