ok, first, look at this eshaft
http://cp_www.tripod.com/rotary/images/pg03_17b.gif\

now, this older design
http://cp_www.tripod.com/rotary/images/pg03_04b.jpg

now, will someone please tell me if the first pic really is a R26B shaft? does it look like the middle two rotors are phased 90 degrees appart on BOTH shafts?

also, a better view of the first shaft can be seen here.
http://www.mymazdarotary.com/mazda_r...paper_html.htm
the pic is on page 3

so, do all these shafts look like they are phased 90 degrees appart at the middle two rotors?

the reason i ask is that we are building a 4 rotor, and we were under the impression that we would have to use a counterweight in the middle between the 2nd and 3rd rotors.... but i see no counterweight on any of these shafts in the middle.

also, does anyone have an idea where the front and rear counterballances would go in relation to the rotors?

thanks.

 

Hm. Well hell. I think you're right.

If you look at the sectioned view, figure 4, you can spot the front and rear counterweight in the normal place.

Lemme think...

 

crap... let's try these links
http://cp_www.tripod.com/rotary/pg03.htm
look at the pic labeled 2002 eccentric shaft


look at the same link, but further down under
The Mazda 13J four rotor engine., the third pic to the right that has a red x on it. it works.


try these, and tell me what yall think compared to
http://www.mymazdarotary.com/mazda_r...paper_html.htm

thanks for your time!

 

ok, more people need to look at this.....

according to SAE and mazda, apperantly, if the rotors are phased 180, then no counterweights are needed. see fig 8 here it is labeled C i think http://www.mymazdarotary.com/mazda_r...paper_html.htm

if the rotors are phased 90 with a 90 degree seperation at the middle, and 180 deg between 1 and 2 as well as 3 and 4, (labeled A) in fig 8, same link
then i would think that 180 appart would be the best espically for the center bearings. ALSO best for least rotating mass.

so the question is why did mazda go with A? (look at the paragraph above fig 8 to see firing order, which can only be A i think)
this conflicts with data on this site http://cp_www.tripod.com/rotary/pg03.htm
look at the 3rd pic from left under "The Mazda 13J four rotor engine." this says that it is a R26B eshaft, and all eccentricies are 90 appart...

please help!!

 

nfi

 

designs A and B are the only ones that allow even firing, 4 bangs per rev, by way of the 90 deg plane offset. of those 2 , A had the lower balance needed. Mazda must have valused even firing.

the pics in craig's page show in plane up-dn-up-dn. This would require low balance corrections, but would fire 2 chambers at the same time.

balance doesn't mean no shaft flex. the C design is inherently balanced, but would tend to bow the shaft and load the bearings. C also would fire 2 chambers at the same time, as implied in the firing order.