> > Hello all,
> >
> > This is in regard to the spark plug cool that is being discussed. I
came
> > across this on the RX7club.com site. I pleasantly surprised to see the
> > amount of technical experimentation that some on this board try. I send
> > the good nuggets I come across.
> >
> > http://www.rx7club.com/showthread.php?t=751977
> >
> >
> > Rob Woods
>
> Interesting thread. So far it has been unnecessary to modify the
rotor housings
> for rotaries used as aircraft engines. These guys may be at the 150
to 200 HP
> per rotor level. Here is a trick all should do if they get a chance.
> It relives any steam pockets that may be generated around the spark
plug area.
>
> Also the 3rd gen water pump and RX8 water pump are less than ideal.
> The Rx8 in particular as it is much smaller than the 2nd gen water pumps.
> Somebody is already making a better impeller for the RX8 engine but I
have not
> tracked it down yet.
>
> The bottom line is you need to know what is happening and the only way
> to know that is measure the "cylinder head" temperature with thermal
couples
> embedded in the roto housings.
>
> Paul Lamar

Mr. Lamar, you wrote:  "The bottom line is you need to know what is
happening . . . ".  I have a question about what might happen.  Yes,
this does have a direct bearing on cooling the Wankel rotary engine, but
it comes from a different direction than usual.

Mr. Lamar, in earlier posts in this newsletter, you have mentioned the
optimum shapes for combustion to occur in, and the shape of the
combustion chamber of the Wankel rotary engine.  With the shape of the
Wankel combustion chamber as it now exists, is or are the location(s) of
the ignition source(s) (the spark plug{s}) optimally placed to maximize
combustion to its fullest extent?  If not, to what extent are the
placements of the ignition point(s) (the spark plugs) compromised?  How
and for what reason(s)?

The next two questions are the most important.  If we were in an ideal
world, and combustion could occur at any three-dimensional place inside
the Wankel rotary engine combustion chamber, where would it ideally
occur: at a single point, in a line, in a circle, in a plane, in a
globe, in an arc or in something else, either two- or three-dimensional
shape?  Then, when ideal combustion has taken place, what would be the
distribution of the heat be?  How would it differ from the chart Mr.
Yamaguchi [Yamamoto?] has so admirably supplied us?

Of course, when we know the idea shape of ignition in the Wankel
combustion chamber, and the resultant heat distribution, we can answer
the question: how do we cool the engine from the resulting ideal combustion?

Les Nordman :-)

Mazda and others did a lot of experimentation on this subject and as I recall
they made a few changes along the way. One of the factors is compression
leakage across the spark plug holes. Also the Le Mans engine had 3 spark
plugs per rotor but the improvement was less than 3% as I recall.

The ideal combustion chamber is a sphere with combustion starting in the center.
A sphere has an optimum volume to surface area ratio for minimal heat loss. A square box is second. A flattened square box is third and a flattened rectangular box is fourth.

The 16B is moving in the fourth direction while the AIXRO is moving in the
third direction.

Paul Lamar