To the Rotary People in the Know:

I am very interested in the power density and all-round performance of

the

rotary engine.  Below is the well-known PLANK formula for the

calculation of

theoretical HP for reciprocating engines.  My Question for the Rotary

People

in the Know is:  Is there an equivalent formula for theoretical engine

HP

for the rotary engine?

BTW, the formula shown is the theoretical HP for the eight-cylinder

Zoche

aero diesel engine, which I'm sure many of you have seen at Osh.  I

don't

know if he has anything in production yet but I doubt it.  Norman DeBoer

HP = PLANK / 33,000

146

P = Indicated mean effective pressure in psi.  [Bore: 3.74 inch  (mm):

95]0.31

L = Length of stroke in feet or fractions of a Stroke  [3.70 inch (mm) :

94]10.99

A = Area of the piston head or x-sectional area of the cyl. (in squared)

2500

N = No. of power strokes per min = rpm: 2-stroke;  rpm/2:  4-stroke 8

K = Number of cylinders.......Compression Ratio = 17 :1

HP =  300.......Total Displacement of Engine = 325.3 cubic inches

Not that I know of.

Paul Lamar

PLANK is not really a means of predicting pwer, it is just a relationship.
If you
can predict the pressure then you  have predicted the power (less friction
if
you use IMEP) normally the equation is reversed using stated power to
compute the BMEP (Brake meam effective pressure) . This is often used
as a reality check on advertised power of normally aspirated engines
(with boosted or nitro'd engines you can dial any amount of power
you want - right up to distruction) - I once wrote an article for Contact
magazine titled "Seperating the BS from BHP with BMEP"
Wankels are pressure/area/volume expansion engines like all the
rest, and the same rules apply - Vance

 
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