brappp brappp rotary race bikes

[Drew]

Oh yep so we need to find a 10b rotary and cut it in half.....

Nope. Just change the ignition sequence so it only fires once, or at least less than twice (people who understand the Wankel rotary will understand that wording) per crank revolution, and you fit inside the rules...sort of. You would need to apply for a reword of the current rule still. To take out the "x 2" bit and add something about depending on firing sequence.

[peril 787b]

Oh yep so we need to find a 10b rotary and cut it in half.....

10a (there was never a 10b) and good luck with that...

They had 6mm apex seals which are near on impossible to locate now-a-days. The housing coating is also a bit crap (read that as totally) and it will not last for long.
If running a half engine, you'd need a custom eccentric shaft (crankshaft) and some serious balancing work. Not saying it can't be done, but the better option would be purchasing an Aixro engine, 294cc and 33kw. http://www.woelfle-engineering.com/P...engine_en.html
Or these guys... http://www.freedom-motors.com/

[koba]

One would also want to depart from heavy Cast Iron side plates too.
Uneaven heat distribution is a bit of a curse for them.

[peril 787b]

Cast iron end plates can be avoided with electrofusion coated alloy replacements, prepare to be raped (roastbusted?) on the cost though.
Longevity reduces, but weight is drastically reduced also.

[Jantar]

Hmmm, awesome bike...
Trouble with working out the displacement of a Rotory is that it is very complex... And at the end of the day even a "Single" is in fact a Tripple.... For each Revolution there are 3 firing events.
For cars a Factor of 2 was given to them to make them comparible to a piston engine...
Hence a 13B = 2.6L.. A very thursty one at that though....

So the 700cc single here is in fact a tripple... and freaken fast as the pistons don't have to stop and change direction....

One of the machinists wanted to make a 50cc one for the Mopedathon.
I said if he could build any size rotory and fit it in a 50's frame and make it last 6 hours I wouldn't pull it apart to measure it...

That is not correct. For each revolution of the rotor there are three firing events, but for each revolution of the crankshaft there is only a single firing event. The question of how to define the capacity of a Rotory engine has been argued about ever since Wankle put one into practical use.

1. Is it the swept volume per firing event multiplied by the number of combustion chambers? (under this definintion your 1000 cc four stroke would be rated as 2000 cc)

2. Is it the swept volume between maximum and minimum of a single combustion chamber multiplied by the number of combustion chambers? (This is what is used for 4 strokes)

3. Is it the total swept volume of all rotors during half of a crankshaft revolution. (This is what is used for two strokes)

4. Is it the swept volume of the rotor during a single rotor revolution multiplied by the number of rotors? (under this definintion your 1000 cc four stroke would be rated as 4000 cc)

My RE5 is rated as a 500 cc engine. Using definition 1 or 2 it is 165 cc. Using definition 3 it is 248 cc. Under definition 4 it is 495 cc. However if I want to race it then suddenly it is 1000 cc and no-one can explain why.

[peril 787b]

My RE5 is rated as a 500 cc engine. Using definition 1 or 2 it is 165 cc. Using definition 3 it is 248 cc. Under definition 4 it is 495 cc. However if I want to race it then suddenly it is 1000 cc and no-one can explain why.

Why? Because the wankel is an efficient engine (power wise) for it's size. They had an "unfair" advantage so were penalized as such. My 13b turbo Rx2 drag car (that I'll finish one day) with the multiplication factors of motorsport applied ends up being a 4 litre!!! Motorsport very kindly only have a multiplication factor of 1.8 but then another 1.7 as it's turboed...

[quickbuck]

That is not correct. For each revolution of the rotor there are three firing events, but for each revolution of the crankshaft there is only a single firing event. The question of how to define the capacity of a Rotory engine has been argued about ever since Wankle for put one into practical use.

1. Is it the swept volume per firing event multiplied by the number of combustion chambers? (under this definintion your 1000 cc four stroke would be rated as 2000 cc)

2. Is it the swept volume between maximum and minimum of a single combustion chamber multiplied by the number of combustion chambers? (This is what is used for 4 strokes)

3. Is it the total swept volume of all rotors during half of a crankshaft revolution. (This is what is used for two strokes)

4. Is it the swept volume of the rotor during a single rotor revolution multiplied by the number of rotors? (under this definintion your 1000 cc four stroke would be rated as 4000 cc)

My RE5 is rated as a 500 cc engine. Using definition 1 or 2 it is 165 cc. Using definition 3 it is 248 cc. Under definition 4 it is 495 cc. However if I want to race it then suddenly it is 1000 cc and no-one can explain why.

Yeah...
Thanks for spending more time on that to explain how complicated it was for me.....
Mine is too valuable to sit down and write it all out.

[Jantar]

Why? Because the wankel is an efficient engine (power wise) for it's size. They had an "unfair" advantage so were penalized as such. My 13b turbo Rx2 drag car (that I'll finish one day) with the multiplication factors of motorsport applied ends up being a 4 litre!!! Motorsport very kindly only have a multiplication factor of 1.8 but then another 1.7 as it's turboed...

"Because the wankel is an efficient engine" is not sufficient reason to penalise it. However even using a 2x penalty on the 165 cc should only take it to 310 cc not 1000 cc. So it is actually a 6x penalty.

[peril 787b]

"B However even using a 2x penalty on the 165 cc should only take it to 310 cc not 1000 cc. So it is actually a 6x penalty.

Hang on a second there buddy, I wasn't saying it was a fair reason.

One thing you have forgotten here is the single chamber wankel of the RE5 is 165cc PER FACE. As there are 3 faces of the rotor, the 165cc PER FACE is multiplied by 3 as there are 3 firing chambers (for want of a better term), hence the 165cc x 3 = 495cc. It's not a 6X penalty at all.

[Jantar]

...
One thing you have forgotten here is the single chamber wankel of the RE5 is 165cc PER FACE. As there are 3 faces of the rotor, the 165cc PER FACE is multiplied by 3 as there are 3 firing chambers (for want of a better term), hence the 165cc x 3 = 495cc. It's not a 6X penalty at all.

There is no measurable volume per face, only an area. E.g. What is the volume of the face of a piston in a 4 stroke?

Volume is area x stroke in a piston engine, or the difference in volume between maximum volume in the combustion chamber and minimum volume in the combustion chamber. In a single rotor rotary engine there is only one combustion chamber not three (Ok you called it a firing chamber, but same thing), and it takes 3 revolutions of the crankshaft for each face to be presented to the combustion chamber.

[peril 787b]

You make it sound like I have no idea how a wankel engine operates...

There are 3 combustion chambers in a single rotor engine, as there are 3 faces of the rotor. There may only be one position that combustion takes places as far as the housing goes, but there are clearly 3 combustion locations.

There IS an obvious difference in minimum volume to maximum volume of a wankel engine, if you follow the hypertrochoidal path of the rotor, you will see where the rotor face to housing area starts of at a minimum just as the leading apex of the 1 rotor face passes the intake port and then opens up to maximum volume just as the trailing apex passes the intake (to close it off).

The rotor face then begins the compression phase, becoming smallest volume just as the firing sequence occurs. Taking into account that during the intake phase of one rotor face, a second is partway through compression and the 3rd is near completing the power "stroke".

Yes, you are correct that 1 face of the rotor takes 3 revolutions of the "crank" (eccentric shaft) to complete a full power "stroke", but two other rotor faces are also using those same 3 revolutions to do their power "stroke".

So in essence, one revolution of the crank has a full power phase taking place, hence the double capacity penalization.

[husaberg]

All this is Moot the reason the wankel is penalised with regards to capacity is to even things out, same as two stroke vs 4 stroke.
Letting the 588 Norton run with the 750cc in bsb for a few years (with a special dispensation) proved this quite dramatically

[peril 787b]

All this is Moot the reason the wankel is penalised with regards to capacity is to even things out, same as two stroke vs 4 stroke.

Exactly, as with a 2 stroke, each cylinder fires every revolution of the crank, the wankel engine does the same. A 4 stroke, fires every 2nd revolution. So a two stroke is penalized with the same "double capacity" formula (500cc smoker vs. 1000cc 4 banger)

[Jantar]

Exactly, as with a 2 stroke, each cylinder fires every revolution of the crank, the wankel engine does the same. A 4 stroke, fires every 2nd revolution. So a two stroke is penalized with the same "double capacity" formula (500cc smoker vs. 1000cc 4 banger)

Back in 1975 when the RE5 came out there was a 500cc production class, the Suzuki T500 Titan and Kawasaki 500 tripple two strokes and Honda CB500 four stroke all ran in the 500 cc class. The RE5 was in the open class.