To get the  16X displacement and they also narrowed the rotor width.
 They are doing that after finding out the flame propagation does not
 get  all the way to the sides when the width is over 75mm. The 13B
is 80mm.

To increase  displacement from 1146cc (12A) which was 75mm wide
rotors, to about 1600cc the eccentricity and radius need to be
increased. E of 17.5mm and radius of 122.5mm which is up from 15 mm
and 105mm. E17.5,R 122.5, W 70 gives 1560cc. E 18, R 126, W 70 gives
 1660cc. Either would  increase torque and help the combustion
efficiency.

Dale  Davies


They did not try side by side plugs. Austro engines has a wide rotor
 with plugs side by side.

Paul Lamar

If you pushed the rotor  width to 80mm and dual s x s plugs with your
coils would give 3.6 to 3.8 liter displacement with gobs of torque.
For  autos run lower  RIM for a bit better fuel economy.

Dale Davies

You mean wider than 80 MM right? The current displacement is 2,6
liters.

For 3.9 it would be 120 mm  wide.

Paul Lamar

The side-by-side plugs are  probably done for redundancy. Mazda's
16X paper describes the best width and length ratios  and  their
effect on flame speed. When the flame front touches the side walls or
the adjacent spark plug's  flame front  it slows down.    The 12A has
the proper ratio.  The 13 B does not.  As Dale Davies just pointed
out the 16 X would return to the proper ratio.

Barry Bordes

Do you have a scanned copy of that paper?

Paul Lamar


Paul, it is from a Patent 2009 0101103 0A1 attached in a word doc.

Barry Bordes

Thanks for the patent Barry. Too big to publish just yet. I'll
convert it to a pdf and see if I can make it smaller.

No mention of side by side plugs nor are there any illustrations of
side by side by side plugs in the patent.

The text runs on to pages and pages. It is an attempt to over whelm
the patent office with bull shit :-)

Super Tech in Germany has built some engines with narrower rotors. I
 am surprised Mazda was granted a patent on it.

Here is a view of the Austro wide rotor. Note the cooling fins inside
the rotor. Will work real well with the oil squirter.  Here too is a
picture of the Kantana powered with a 2 rotor. Most of these picture
were taken at the factory by Mark Wrathal and myself.

Paul Lamar


Mazda went to the narrower rotor for 16X design to get the fuel burn
 to the rotor sides with single plugs. Dual would help also
especially in aircraft. The leading/trailing is not really dual plug
as certification would go. You might be able to baffle the powers
that be with BS. 4 Dale Davies


It will run on either one. Your can diddle with the plugs until you
are blue in the face.

Someone needs to focus on heat loss.

A good start would be a stainless steel rotor. SS conducts heat much
 less than cast iron.

Paul Lamar

Paul , The first attachment is the essence of the Patent showing the
 ratio of length to breadth and how it slows flame speed after
collision. This is why Mazda changed "bore to stroke" ratio in the
16X. (our "rectangular bore" is 22 sq in and our stroke is only
.625")

The second attachment  shows how Mazda addressed this problem with
the 13B by moving the leading plug down a few millimeters but this
just presented a new problem. Notice the that the most critical water
passage in the engine is made smaller!

Compare this to the same water passages on the 26B LeMans
engine.(attachment 3)

On the last attachment, the I find most difficult for people to
comprehend, notice the small crooks in the burn rates when the
collision of flame fronts occur.

Barry Bordes


I am not disagreeing with any of that.

........................SO WHAT?

THEY DID NOT TRY TWO SPARK PLUGS SIDE BY SIDE !!!!!

Far far cheaper to do that to the current engine instead of buying a
 new 2 billion dollar factory to build 16B's.

Paul Lamar


Paul, Mazda did not include their tests on side by side plugs
because it is the worst of two worlds. With the plugs side-by-side
the flame front hits both the sidewall and each other... Causing a
double slowing of the burn rate.

This kills the fuel economy, and adds emissions, and lowers power.

This is probably done only in air cooled charge engines because as
you know and have described Max power would make more heat... They
are cooling the engine with unburned fuel!

Barry Bordes

NOT TRUE!!

Your assuming a fixed 13B rotor width. Lets say we made it twice as
wide as the 12A and we used two spark plugs side by side (or four).
Then the distance to the second flame front and the distance to the
wall would be exactly the same.

THE REAL PROBLEM IS HEAT LOSS TO ALL THE WALLS OF THE COMBUSTION
CHAMBER.

A sphere is ideal, second is a cylinder, third is a cube. fourth is
rectangular box. That led to the Chrysler Hemi and is the  REAL
reason the rectangular box  Wankel is less efficient.

A square chamber (or cube) has less surface area than a rectangular
chamber of the same displacement so lets make the rotor as wide as
it is long.

We are still not done. We need to change the material the square box
 is made of to further reduce the heat transfer to the coolant.

Everett Hatch and I discussed this years ago we decided that a cast
iron rotor housing would be better than an aluminum  rotor housing.

The Mazda rotor housing is better than most aluminum rotor housing
Wankels as it has a chrome plated chrome molly hard steel liner.

The chrome reflects the heat radiation  (just like a thermos bottle)
and chrome molly is almost as good as stainless steel in low heat
transfer.

Bottom line. So we need  a wider rotor made from stainless steel
chrome plated. Maybe a vacuum chamber in the rotor surfaces.

GM has a patent on a multi piece rotor for that reason.

"3995602

HIGH COMBUSTION SURFACE TE11PERATURE ROTOR FOR AN INTERNAL
COMBUSTION ROTARY ENGINE This invention relates to a high combustion
surface temperature rotor for an. internal combustion rotary engine
and more particularity to such a structure wherein the combustion
surface temperatures limited to below the per-ignition temperature.
In internal combustion engines it is known that raising the
combustion chamber wall temperature can be effective in reducing HC
emissions reducing the quenching effect of the wall. In the current
production type rotary engine whose chambers have a higher
surface-to-volume ratio than a piston engine there are thus believed
to be even greater possible gains HC  reduction by this method.
Typically such rotary engine combustion chambers are formed by a
peripheral wall and opposing side walls which are cooled by
circulating coolant therein past while the rotor which forms the
remainder an a substantial part of the moving moving chambers is
cooled by circulating therein a portion of the oil used in
lubrication."


Paul Lamar




Paul, I agree that a stainless steel faced rotor would be great. The patent showing an airgap would also be good ... where temperature and boost would cause it to make contact to support it when needed.

A complete paradigm shift would be to lower the temperatures in the combustion chamber by using active radicals to ignite leaner mixtures.

My thoughts on the Austro wide rotor are that they are also using it because they are air cooled and the wider breadth allows for more cooling fins on the underside of the rotor face.  That being said it would be a great experiment for someone to do.... one experiment is worth 1000 theories.

Barry Bordes


The basic design was done by Norton. It was a motor cycle engine to start.

Rich Goldman owns one and he will fill you in on the history shortly.

Rich consider installing rotor cooling my oil squirter.

Paul Lamar



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