Marc Wiese wrote:

Ah so right Tom!
2 rotor = 80 cu. 3 rotor= 120 cu in (as spec by Mazda...). Mass flow

>from calcs 20B=41.3 lbs min; mass flow from 13 b =27.3 lbs min. So

actually 41.3/27.3=1.5128205
You add more of course than just a rotor, or displacement!
Marc Wiese

Is this 80 cu per rotor, or per rotor face.?
Royce

Now you are getting into a real can of worms :-)
Considered as a two cycle it is 1.3 liter but it is not a two cycle.
It is equivalent, as far as the volume of air it pumps, to a 2.6 liter
4 cycle 4 cylinder engine. However the volumetric efficiency is at
least 20% higher than any piston engine. No poppet valves to get in the
way of the intake ports. Therefore in terms of turbo charger
selection I would use about a 3 liter equivalency.


Paul Lamar

Royce, its 40 cu per rotor face. Each face as it makes its pass by the
intake "scoops" up approx 40 CID of air/fuel mixture..   A two rotor has 6
rotor faces (3 per rotor) x 40 CID= 240CID.  For a 3 rotor that would be 9 x
40 = 360CID equivalent. But, as Paul points out - with considerably better
flow due to the lack of a poppet valve so the 240 CID for the two rotor is
more equvilant to 240 x 1.20 = 288 CID in a reciprocating engine.

Ed Anderson

I did not really want to get into this as we will hear from Vance :-)
Engines are rated on displacement related to output shaft revolutions.
Forget rotor faces. The rotor rotates at one third output shaft
RPM. The 13B engine displaces 1.3 liters or about 80 cubic inches 
per output shaft revolution and it fires twice just like a two
cylinder two cycle engine would do. It pumps the same amount of air 
per rev as a two cycle 1.3 liter engine but with higher vol eff.
A three rotor is therefore about 2 liters or about 119 cubic
inches. This is important as it explains the small physical size 
and weight of the rotary related to its large amount of HP generated.

Paul Lamar
 
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