Wankel rotary engine experiment

[dd.stork]

Hi,

I just wanted to share my experiment with anyone interested in relizing the mentioned engine in Fusion 360. I followed a renown Solidworks tutorial with the drastic improvement of using correct peritrochoid curve instead of other semplifications (such as circle arcs).

First I retrieved the parametric function of the curve and found the most accurate parameters for it (namely, e and R)

Then wrote a python script capable of drawing spline points of parametric curves, it draws profiles for housing, rotor and the basic revolving circles which realize the motion.

Then I built the parts as per the tutorial, "translating" the operations in real time. A good point for F360 which demonstrated capable of replicating all Solidworks features. Some where even more robust and quick, assuming that the tutorial author worked using state of the art methodologies.

A bad point, revealed when dealing with spur gears: while SW has a specific parametric command, I've stuck with the stock script for spur gears, which wasn't capable of generating internal spur gears. I solved by manually modifying a normal external one.

Joints and animation: actually very simple, given that in SW an actual "Gear" joint is used while in F360 i faked it using motion link. It just consists in a shaft mounted on a fixed housing. Then the rotor has a cylindrical joint with the eccentric part of the shaft. This causes just the center of mass of the rotor to move on a circle, not rotate.

Then I added a motion link between shaft and rotor, which consists in "360 * 2/3" because 2/3 is the fixed motion ratio of this specific engine geometry. This simulates the geared transmission between Rotor and Stationary gear (the small one). That's it

In conclusion, Fusion360 revealed to be capable of managing complex mcad stuff, I only hit some very specific issues when dealing with particular fillet types and other mcad-specific features such as fasteners and unified components.

Edit: I'm struggling to embed the screencast..

https://autode.sk/2W9vkRm

[michael.rungeUHQJ3]

Great to see Wankel interest in Italy. Hope you might be able to help me with trochoid generation.

[carrikea000]

I've been interested in making one of these to do compressed air for a project, but I haven't been able to find a way to actually make a sketch of the rotor or casing and I don't know python, I was wondering if you still had the script if you could share it so other people could make it with a little less frustration than I have been going through. Thanks if you can!