Hi Paul/Rolf;

I was taking another look at the chamber volume as a function of intake
close angle for porting.
I was using the formulas from the 1981 edition of the Rotary Engine and
my results do not appear to be correct.

Can someone run through the formula/calculation for an intake close
angle of say 45 degrees?
Assuming a 13b:
e=15mm
R=105mm
b=80mm

Thanks
Cary


What page number are you looking at Cary?

Sorry,
'81 Edition, page 14, Section 2.4.2, bottom right - formula 2.24
V=volume
e=eccentricity=15mm
R=Generating circle radius= 105mm
b=width of rotor housing= 80mm
alpha= degrees eshaft rotation
Vmin=minimum volume at TDC (long formula 2.25) =~  56.5cc or
in the case of a 9.4CR rotor 654/(9.4-1)= 77.9cc

V = Vmin + ( 3 * root(3)  / 3) * e * R * b ) * (1 - sin(2/3 * alpha +
pi/6) )

Formula makes more sense if you look at Figure 2.9 on page 15.  Shows
the chamber volume
changes as a sine wave based on eshaft rotation compared to a piston engine.

I just noticed the formula is different in the '71 edition.
3 * root(3) * e * R * b =~ 654cc (swept volume) - the  "/ 3" term
appears to be incorrect.
The "/ 2" in the '71 edition appears to be correct.

Still need to work out the intake close timing angle.  Not sure if the
alpha value can be replaced with the
degrees of eshaft rotation?

Thanks
Cary

There are errors every once in awhile in the book.
I am not sure I understand the goal here.
I have a lot of intake timing diagrams for both the side
ports and the P-ports verses VE.

Perhaps the angles are expressed in radians and not degrees.