Paul, what can you tell us about the Woelfle/AIXRO engine? It looks
    really interesting for a single-seat project.


    David Josephson

    It is a good engine.

    Paul Lamar


    Here are some pictures.


    Paul Lamar


    Paul and Poul,

    The Center Needle Bearing cage, it looks like a light brownish plastic, is that the material "PEEK" that the 2 stroke guys are using now as coating or in total as a bearing race material?

    Poul, I read where you can get Ceramic Bearings for the Center Bearing , how is that working?

    My best,
    Anthony

    I have not idea.

    Paul Lamar

Paul,
I noticed the AIXRO rotor face looks more like a square and not a rectangle, do you have any literature on the length and width of the rotor face and how it changes engine performance?

Aaron Buster

I have not found any data on that yet. The AIXRO was based on the Norton geometry.
So was the Midwest engine. That became the Austro Engines rotary used in
motor gliders. There are plenty of UAV engines with the same geometry.

The wider rotor make sense to me as the surface area to volume ratio
is better than the Mazda Geometry. There is a company in Germany called
Wankel Supertec. http://www.wankelsupertec.de/ That went for a narrower rotor
than Mazda. So too is the Mazda 16X. Why is a mystery to me.

I under stand the Wankel Supertech has a higher compression ratio.
They were making some fantastic claims of low BSFC numbers at Aero but I never
saw one run let alone saw one in private hands. I suspect they are lying.

I suspect the surface to volume ratio is not the main problem.
I suspect the heavy fuel molecules are being thrown out towards
the rotor housing and become near stationary while half of the mixture
is attached to the rotor and moves with it. It is a similar aerodynamic
situation to that of a car moving over a stationary road. The air on the
ground is stationary while the air attached to the bottom of the car moves
with the car. So far I have not found a rotary CFD that addresses this issue.

It is well known fact  that a lot of fuel is NOT being burned in the
rotary. AKA high hydrocarbon emissions. Currently that is handled by the catalytic
converter. I suspect that two plugs side by side with multi strike ignition
would ignite some of that unburned fuel. Mazda achieved a 3% improvement in
the Lemans engine by using 3 spark plugs per rotor with another one above the top plug.

Any time you put a spark plug BTDC you lose a little compression due to
small leaks above the apex seal near the plug hole. In theory a flush surface
plug would be better but apparently nobody has been able to develop one that
worked over a long period of time or that was truly flush and did not leak compression.

Hopefully my new ignition will burn more of that fuel.

Paul Lamar


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