Paul and all,
 We would be bleeding pressure from the
 45deg ATDC big push on the rotor.

 But my problem is with the original
 premise... that we should divert the
 hurricane flow.
 And secondly that we should add surface
 area... both of which are a
 detriment to the Rotary.

 The spark kernel needs turbulence to
 develop quickly.  It is also helped
 by compression and temperature.
 Attached is a quote from Sir Harry
 Ricardo.

 On the GM patent I think if we could
 change the stainless by-pass
 inserts to non-bypass vacuum SS inserts
 (think thermos bottle) to
 minimize heat loss it would be a great
 help.

 Barry Bordes

 Why do you think surface area is a
 problem? There will be no combustion
 under a metal plate on top of the
 rotor. I am sure General Motors
 checked that before they applied for
 their patent. The area  is too thin
 at .1 inch to support combustion.

 A very important part of this idea is
 to relive the high pressure in the
 area where the aft part of the rotor is
 in close contact with the wall
 of the rotor housing. That will reduce
 the velocity of the wind storm.

 There is also not a reduction in
 pressure due to squish flow under the
 top plate on top of the rotor. There is
 a slight reduction in
 compression ratio but that could be
 made up  with a shallower bath tub.

 Turbulence is fine but a wind storm on
 top of the rotor blowing the
 mixture down stream is something else.
 That blows the combustion away
 from the optimum e-shaft angle.

 Yes I agree about a vacuum's ability to
 insulate but ceramic rotors have
 been built with no significant
 improvement in BSFC. I suspect GM found
 that out when the tested the 2 piece
 rotor.

 It is called the adiabatic Wankel but
 it was a big disappointment.

 The flow in the combustion chamber is
 the only really significant
 difference between the Wankel and a
 piston engine.

 ---------------------------------------------------------------------------------

 BTW if your planing on direct injection
 it may be better to inject up wind.

 Paul Lamar

 Paul,
      Are you saying that
 there is not enough turbulence in the
 combustion chamber, therefore reducing
 the speed of the flame front ? if
 so , maybe a simple "paddle" across the
 rotor "bath" could stir it up a
 little.
      Chris Hoskins.

 IMHO there may be turbulence but there
 is a also wind storm that is
 blowing the combustion
 away from the optimum e-shaft angle.
 Enough to reduce the BSFC 5 to 10%.

 The three dimensional CFD is this paper
 is very advanced.


 Paul Lamar


Paul
In the SAE 2015-01-0382 paper fig 25 depicts the flaw in their design.

Probably for the sake of safety/redundancy they use side by side spark plugs.
This results in a very slow burn-rate. (see attachment fig. 25)

As soon as the two burn areas collide the rate-slows (depicted by the trough in the initial rate).

To optimize the burn-rate they have to retard the ignition until they can use the squish for an increase in rate.

A long narrow rotor would allow a better burn rate (like 12a or 16x) allowing more space between the leading and trailing
which postpones the collision of flame fronts.

Barry Bordes

That is not the problem. Their side by side plug BSFC is no worse than the Mazda.
They both are bad by 5 to 10%.

Think of air as a bunch of tiny marbles coated in molasses. The air next the rotor
housing is stationary. Most of the air next to that sticks to it. The air next to the rotor moves
with the rotor. Now you have a shear going on  between those two groups of air molecules.

The same thing happens on a wing and that is what leads to a boundary layer.
Now add a wind blowing in the same direction as the rotor air. Do you see a problem?

Nothing like this happens in a piston engine as the combustion chamber is not moving.
You cannot apply what you learn in a piston engine to the rotary.

Paul Lamar

 The Rotary Engine free News Letter. Powered by Linux. If you want off
the list PLEASE let me know and I will remove  you.  ACRE NL web
site. http://www.rotaryeng.net You Tube http://tinyurl.com/beqqxas
Copyright 1998-2017 All world wide rights reserved.