Actual Rotary Displacement Request

[vex]

Originally Posted by NoDOHC

As I stated before, it is merely a difference in frame of reference. Each rotor housing undergoes one full cycle during each revolution, but each rotor face will require 3 rotations for a complete cycle.

Because both the housing and the rotor are required to displace air, both frames of reference are valid.

I think that Peter, Barry and Vex have done a very good job of illustrating the concepts that we all need to take away from this discussion. This is a good thread.

No it's not, and you can't prove I've done a good jorb!

Yeah, I don't understand why people were getting all hot and bothered by this. The only thing I do not understand is where the 2.6L value comes from without using a multiplier. Anyone know?

[Monkman33]

Originally Posted by vex

No it's not, and you can't prove I've done a good jorb!

Yeah, I don't understand why people were getting all hot and bothered by this. The only thing I do not understand is where the 2.6L value comes from without using a multiplier. Anyone know?

I would agree completely. I cant think of any method that would make the 2.6l number viable.

[diabolical1]

Originally Posted by vex

Otto cycle is just the technical term of suck, squish, bang, blow.

no, i was familiar with the term. i had just never seen the graph you posted and i figured i would spend hours trying to get, but after looking at it that night, i had it in less than an hour and confirmed my understanding of it via Wikipedia (for what that's worth - wink, wink )

Originally Posted by vex

The only thing I do not understand is where the 2.6L value comes from without using a multiplier. Anyone know?

get your grain of salt ...

as i understand it, they are using a multiplier - based on the 720 degree theory. by itself, it does seem arbitrary though.

it's funny, when i first got into rotaries (back in the mid 80s), some people used to say two rotor engines were equal to 2.4 liter, 4 cylinder engines (most people i knew primarily messed with 12As at the time), but extending that way of thinking to a 13B, you'd get 2.6L. the thinking was that rotaries were more akin to 2-strokes in nature, so they multiplied by 2. i don't know where the 4 cylinder thing came from.

if you are inclined to think of each rotor face as cylinders (which i know you don't), then with a 2.6L 4-banger, you have exactly two-thirds of a 3.9L 6. so in that context, i guess it makes sense ... sort of. come to think of it, i think i just found the 2616 theory less valid.

[vex]

Originally Posted by diabolical1

no, i was familiar with the term. i had just never seen the graph you posted and i figured i would spend hours trying to get, but after looking at it that night, i had it in less than an hour and confirmed my understanding of it via Wikipedia (for what that's worth - wink, wink )

get your grain of salt ...

Why? I don't like counting grains

as i understand it, they are using a multiplier - based on the 720 degree theory. by itself, it does seem arbitrary though.

it's funny, when i first got into rotaries (back in the mid 80s), some people used to say two rotor engines were equal to 2.4 liter, 4 cylinder engines (most people i knew primarily messed with 12As at the time), but extending that way of thinking to a 13B, you'd get 2.6L. the thinking was that rotaries were more akin to 2-strokes in nature, so they multiplied by 2. i don't know where the 4 cylinder thing came from.

if you are inclined to think of each rotor face as cylinders (which i know you don't), then with a 2.6L 4-banger, you have exactly two-thirds of a 3.9L 6. so in that context, i guess it makes sense ... sort of. come to think of it, i think i just found the 2616 theory less valid.

I'm still not seeing it. With the 3.9 and 1.3 I understand it as the references are stated, but I can only achieve 2.6 with a multiplier. My contention is that if a multiplier must be used then it is less accurate in that it inherently makes assumptions about some process that doesn't come in to play. (I'll have to read over Peters post in more detail, but I was not convinced by the other links attempting to explain it)

[RICE RACING]

Barry your PTO shaft idea is a little off base.

We are not talking about "gearing down" the actual cycle itself, that is a non negotiable part of any engine cycle be it 2 cycle, 4 cycle or Wankel.

I can see what you and everyone else including Mazda is saying (1.3lt for 13B chamber capacity), that is a given. But its an odd engine by nature that it has common combustion chamber, intake and exhaust ports . I only look at all motors in their complete "cycles". See my earlier posts.

Equivalence (just based on the physical displacement to time across all three established engine types allows them to race).

The Mazda 787B only had "good economy" cause it had Group B weight breaks on its side V's the Sauber and Porsche and Jaguar cars, nothing more, it was a smaller and lighter car, and had allot less power (250+bhp less than the Sauber in race trim!)... It was very light weight with moderate power, but with EXCELLENT ROTARY ENGINE RACE DURABILITY. Mazda's have always expolited the rules to get a favorable advantage in racing, the one biggest factor they have had over others is astounding reliability and durability in race trim, rather than any outright speed.

[Libor]

Originally Posted by RICE RACING

The Mazda 787B only had "good economy" cause it had Group B weight breaks on its side V's the Sauber and Porsche and Jaguar cars, nothing more, it was a smaller and lighter car

This is correct. Mazda was allowed to weight 830kg compared to 950kg of Porsche and 1000kg of Sauber and Jaguar. Huge difference

Originally Posted by RICE RACING

and had allot less power (250+bhp less than the Sauber in race trim!)

I though that these outputs were used only in qualification?
I´m sure you know how it was!