[leeK9]

Hi Leigh,
you can use the well proofed epitrochoid-parameters of the 294 ccm engines:
R= 71mm e= 11,6 mm a=0,5 mm
I’ve made a Excel-sheet to check the parameters:
In C2: 11,6 (e); in C3: 71 (R)
A5 – A605: 0 – 600
B5: =PI()/100*A5
B6: =PI()/100*A6
and so on to B605
C5: =$C$2*COS(B5)+$C$3*COS(B5/3)
C6: =$C$2*COS(B6)+$C$3*COS(B6/3)
and so on to C605
D5: =$C$2*SIN(B5)+$C$3*SIN(B5/3)
D6: =$C$2*SIN(B6)+$C$3*SIN(B6/3)
and so on to D605
marked C5 to D605 -> Point (XY) Diagramm gives the shape of the epitrochoid
column C5 - C605 is X; column D5 - D605 is Y
[a] is the parallel distance to the epitrochoid (because of the apex seal radius)

..Nipsel..

i'm a bit of noob when it comes to excel but have managed to make up a spread sheet to define the shape of the housing for CNC code purposes.

this was done using the formula i found above and the dimensions are basically home made to a shape that looks like it would show best the irregular geometry of the housing.

i took X and Y co-ordinates ranging from 0 degree to 360 degree and fed them into the graph on the sheet

if you have any dimensions or link to other sueful information that you may think is helpful that would be greatly appreciated as was your post already .

Kind of a cool project. Maybe get on ebay and find a small motor with gear deduction so you can talk to people while it slowly rotates.

yes thats the idea i had but was told to make something that is only a mechanism or linkage to show the motion....

thank you for your input it is greatly appreciated.