<< Didn't the Lemans engine have peripheral ports (of same diameter as the
intake
 > > > runners)?
 > > >
 > > > Shooting in the dark here.
 > > >
 > > > Finn

 > > Yes, that is a possibility but the data shown is for a piston engine
with a
 > > poppet valve in the way. If you are going to get standing waves I would
think
 > > you are more likely to get them with a piston engine that has the valve
 > > closed 75% of the time. With the rotary the port is open 80% of the time
 > > peripheral port or no peripheral port.

 In the side port engine, the intake ports open and close during operation.
In the periphery port engine, the port never closes, but is valved by the
apex seal, between the retreating combustion chamber and the exhaust header
via the combustion chamber in the face of the rotor during overlap. When the
exhaust system is anything like tuned, and the RPMs are high enough, the
inlet column is exposed to a pressure that is always well below ambient. It
is difficult to screw this up to the extent that is doesn't make a bunch of
power. The tuning of the inlet tract is the icing on the cake.

 Lynn E. Hanover

I agree Lynn. In the six port the closed time is slightly less than the four port.
In other words it is only completely closed for an instant.

I fail to completely understand why tuning works at all in the peripheral
port unless the back pressure from the exhaust has something to do with it.
I expect it does as the exhaust chamber and the intake chamber are connected
together through the recess in the rotor for awhile. That is why I would like to see
Finn instrument the intake runners with high speed pressure sensors.

This peripheral port pressure chart is from SAE 841017 by Mazda.
The pressure sensors are right next to the port openings in exhaust
pipe and in the rotor housing next to the intake port.

It is interesting that the exhaust pressure is below atmospheric
most of the time. It is also interesting that the pressure in the 
intake port starts building up when the port opens and reaches
a peak just as the intake port closes. Fascinating stuff.

We would get a much better picture of what was going on with three
or more pressure sensors located along the length of the intake pipe.

My scanner is down so I had to take a picture.

Paul Lamar
 
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