## Use LitioLAB in different ways to draw the Wankel engine housing and any epitrochoid

The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion.

Check the following video:

The housing of a Wankel engine can be mathematically defined as a pair of parametric equations for X and Y, for the formula parameter varying from 0.0 to 2*PI. The formulas can be rewritten into a calculator-like form, as follows.

X = c1*cos(r2d(3*u)) + c2*cos(r2d(u))
Y = c1* sin(r2d(3*u)) + c2*sin(r2d(u))
The parameters for this example are:
c1 = 10.0
c2 = 60.0
u = 0.0 to 2*PI

ZwCAD users need to check LitioLAB user manual to review the math functions available and how to adapt the formulas to ZwCAD.

The R2D (radians-to-degrees) conversion function is not available in ZwCAD. Use 180/PI as a multiplying factor instead.

Since the oval-like housing of a Wankel engine is an epitrochoid, this can also be done with the Spirograph function of LitioLAB.

The Spirograph parameters of this example:

D = 40.0 Turns = 3
C = 1.0
R = -30.0
A0 = 0.0
L = 60.0
B0 = 0.0
N = 1000

And since these graphs are polylines, they can be extruded and used to generate CAD solids for further processing and eventually, for CNC machining, or 3D printing.

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