Actual Rotary Displacement Request

[Barry Bordes]

Originally Posted by Barry Bordes

Request to use Actual Rotary Displacement

If someone started talking about a 2.6 liter Rotary would they be referring to a 4 rotor or are we dealing with someone who doubles displacement of a two rotor?

In the interest of clarity I believe that we should describe the displacement of our rotary engines by its actual scientific size.

Some very experienced individuals have doubled and sometimes even tripled its size. This has become confusing to new impressionable members trying to communicate ideas correctly.

One would think that a physical measurement like displacement would be rudimentary but on a rotary it is more complicated than π X radius² X stroke X number of cylinders. Finding max volume from trochoid and peritrochoid shapes is a lot tougher.

I won’t bore you with formulas but all of the manufacturers signing licensing agreements to develop, and those producing Wankel engines including Alfa Romeo, American Motors, Citroen, Ford, General Motors, Mercedes-Benz, Nissan, Porsche, Rolls-Royce, Suzuki, Toyota and of course NSU and Mazda…and motorcycle manufactorers Sachs, DKW/Hercules, Norton and Suzuki… add John Deere, Artic Cat, Curtiss-Wright, also miscellaneous outboard and unmanned arcraft manufactures all agree on way actual displacement is determined and refere to them acordingly.

And yes, some sanctioning bodies use a multiplier which penalizes the Rotary as they do the two-stroke to help even out the competition. Displacement, however is a scientific measurement not up for opinions.

What size would Felix Wankel or Kenichi Yamamoto say that it is?

My Thoughts,
Barry

This would probably be a good time to reiterate my initial request of having us use the Industry Standard in referring to rotary sizing when corresponding with one another.

Interesting side note… I checked the websites of both Rotarygod and Rice.

It was reassuring to note that they both use the requested Industry Standards for clarity. There were no 26B or 39B 2-rotors noted.
Barry

[RICE RACING]

There is no question at all that its a 13B.

There is also no question at all that it displaces 3.9lt when you count the whole engine.

They are two different things, its only when you are talking equivalence to other types of engines you need to know how much it displaces in time (without repetition)... like for your formulas (all based around 2 stroke and 4 stroke) then you just use 1.3 or 2.6 respectively.

It's the common shared chambers that allow all the 3 rotor faces *per rotor* to do their work (Wankel cycle) which confuses many people & to be honest its not really worth debating as we are all really talking about the same thing.

As you well know when you do a health check on the Wankel (two rotor) you will get in most cases 6 different readings as each chamber is different most times (seal wear, tolerances and rotor cavity disparity) ALL of these go to providing work and a health engine overall and ALL need to be counted you will agree to validate that assessment. Otherwise we would only ever need to measure two faces? *stirring pot*...... You and everyone get what I mean here who has anything ever to do with Wankels.

This is why I count all faces and rate the true capacity of the engine as per its cycle, no matter what type it is. And that is the basis of my points on the topic. So its a 13B that displaces 3.9lt over its Wankel cycle.

[FC Zach]

Originally Posted by RICE RACING

This is why I count all faces and rate the true capacity of the engine as per its cycle, no matter what type it is. And that is the basis of my points on the topic. So its a 13B that displaces 3.9lt over its Wankel cycle.

Well said! short, simple, and to the point. That's easy enough for me to comprehend.