The rotary and most
other engines are a collection of small engines sharing a
crank shaft.??
So, the rotary is two
engines with about the same intake system. On the dyno and
on the flow bench, the biggest
influence on performance
is the shape of the intake horns. Should look like a
trumpet bell. The higher the RPM
the bigger the diameter
of the bell. Because: airflow into the bell comes from all
directions. A straight tube is the worst. Air flows up the
sides of the tube and has to make a 180 to enter the tube.
Air has mass and the 180 serves to choke off part of the
tube. (As though the tube developed a smaller diameter).
So, a big radius allows
for a slower turn in
that 180 and flow rate increases. You can find flow going
the wrong direction just inside the bell on poor designs.
The best design was on old SU carbs where the bell looked
like a ring slit into two pieces and mounted on a flat
surface. Cheap and the very best design. I will try to
find pictures and post them.?? ?? ??
Best is a large bell
shape and a taper to the port size. The tuned length is
for one RPM. The exact length you choose may be great or
just short of great. Anything will be better than a stock
air filter. Allow at least the diameter of the interior of
the bell as a distance to any structure like a tube wall
or a flat sided filter box.
A flat sheet with holes
the size of the bells is fine. In very few cases will both
housings be putting out best power at the very same time.
Round tube on a flat
side like a "D" shape works well. Anything flat must be
thick and stiff or it will die.
Lynn E. Hanover