Actual Rotary Displacement Request

[diabolical1]

Originally Posted by NoDOHC

Peter and Barry, I have too much respect for both of you to stand idly by while you dispute so vehemently.

It's Ok to disagree, but let's not turn this into an personal argument. This is a case where the only important factor is that we understand how the engine works. It is accurate to say that a rotary engine completes an intake, compression, power and exhaust stroke on each rotor during a single rotation of the engine. However it requires 3 revolutions of the engine for all faces of each rotor to see all four strokes.

The difference between you is that Barry is looking at a single rotor housing as the displacement-providing chamber, while Peter is looking at the rotor as the displacement-providing chamber. Neither of you is right or wrong, it is a difference of perception.

How each of us slices this up depends on personal preference and nothing more. There is no right answer here.

I appreciate the information and clarification provided in this thread, but I don't want two knowledgeable and intelligent members of this community bogged down in this senseless argument.

Let's leave it with the cycle explanation and keep this thread informative.

^ this!

i'm not an engineer. i have mechanical experience, but no paper credentials. i just want that out of the way before i offer my thoughts.

i've read through this thread a couple times now (and i read the rotarygod link last night) and it seems to me that no one of these assertions is wrong because they clearly state the context for which they claim.

the 1308 chamber derivation is irrefutable. the 2616 argument is just as valid in the context of the 2 rotor derivation. finally, the 3924 is also valid in terms of absolute displacement because it's the only conclusion that takes all 6 chambers into account regardless of their phase during a crank rotation.

i think the only true argument left is which, if any, is MORE right. i'm not qualified to make that determination. hell, i'm still trying to find out how 80 and 240 yield 1308. however, while i don't dismiss any of the others, i will say that i'm tending to lean toward the 3.9 assertion now. i think a part of the lingering ambiguity is simply us not knowing when and where to draw the line with the reciprocating engine comparisons. rotaries are different, there's no getting around that.

the points made for 3.9 are compelling (to me) simply because none of the piston calculations leave any cylinder uncounted, while the 1.3 and 2.6 assertions for the 13B do. that said, none of the piston calculations require 3 revolutions - though, in all fairness, revolutions are not relevant. when you plug bore and stroke numbers into the volume of a cylinder formula, then multiply by the number of cylinders, none of that takes revolutions of the engine into consideration. it's just the number for the engine's absolute capacity. crank lobe angles/phasing have no bearing. my MR2 Turbo was 1998 cc, not 500. my Audi engine is 2671 cc, not 445.

as for the dust-up, by now Rice should know i respect him very much. i actually like his un-PC style, it's a breath of fresh air to me - not to mention sometimes it's just bloody hilarious (see my sig ). being somewhat socially inept myself, i won't comment on his interpersonal skills and i certainly won't judge him, but i think he should just step back and reasses the discussion. i don't see where anyone attacked or offended him (i know its not my call, but it is my observation) so he should return to the discussion with no hard feelings.