A coupleof sharp motor tuners and a day or so on a good repeatable
dyno can zero in on acceptable intake design that should set a good baseline
for what really works. You can sliderule / use fancy computer programs and
other methods of determining optimum designs but nothing trumps real time data
in a running engine. Just my .02 cents worth.
Ben
Haas
Oh, to have my own dyno again.
The point was that there are many rotary engines to think about. Now days
you probably have a 13B side intake port, periphery exhaust, or the now common
Renesis with side intake and exhaust. And now converting both styles to a home
made periphery intake. Neither exsists in nature, so you may well be on your
own tuning wise.
Stick to the basics. Velocities reversions, harmonics DIE, radius, Mach
numbers. As in radio wave reception, you are probably operating in the
1/4 wave regeion. Remember the thing you built in the attic to get killer
reception on the black and white TV? The lower channel numbers had such a long
wave length that it took a big attic to hang just a 1/4 wave length antenna.
And the UHF antenna was just a loop with barely 12" of wire involved.
Remember the Cross Ram Dodges, with 4 barrel carbs hanging outboard of
the rocker covers. 460 foot pounds of torque. The runners were at least 4
times the length of the dual plane regular manifold.
So was the cross ram the full tuned length and the regular street
manifold runners were the 1/4 wave length? Or was the cross ram the half wave
length? Usually the best harmonic peaks will be divisable by 4.
So all of this harmonic, standing wave, pulse tuning stuff applies to one
dynamic situation based on that engine RPM. Change the RPM and everything else
changes too. There is nothing static about airplane engines. So the best guess
is to get it close to cruise RPM and then tune the daylights out of it. The
airplane is a kind of dyno. It provides a variable load. The engine controller
provides the tuning capability. Every flight can be used to recover usefull
data.
Use the SAE tables to return all data to the SAE standard day at sea
level. Make only one change per test. Record everything. Keep the records.
Or, just copy the Mistral intake.
Lynn E. Hanover