The periphery ported engine's advantage, is that the intake port never closes.

 

In the side ported engine the side of the rotor actually closes off the intake port as each apex or rotor tip passes over the port. So, intake tuning has some connection to the tuning of a piston engine.

 

The length of inlet tubing has a somewhat more profound effect on performance than does the intake of the periphery ported engine. 

 

In the Renesis (RX-8) engine, both the intake and exhaust ports are in the irons so both are called side ports. Tuning of the intake is similar to early side port engines. Tuning of the exhaust is similar to a low output piston engine. Its outstanding feature is that there is never a connection between the intake and exhaust port. So there is zero overlap, where the intake and exhaust is open at the same time.  

 

Converting a Renesis engine to periphery intake port would seem to deliver the best of these two worlds.

 

With the possible exception of the center iron having exhaust ports for both front and rear rotor housings Siamesed. 

 

In general the one advantage of all is the ease of intake construction. Just two pipes into a flange to suit your throttle body or carb. Two tubes extended from the rotor housings, A length of Silicone hose and 4 hose clamps.

 

A properly assembled rotary that is kept cool in both oil and water is just about bullet proof. And bullet proof says airplane engine to me. 

 

The rotary will not happily ingest anything you left too close the aircraft. Piston engines do have an advantage in the trash eating department. Not a factor where an air filter is installed.

 

A side port engine could produce about 160 HP. A periphery ported engine could produce about 180 HP. 

 

The typical cruise RPM would be 5,500 to 6,000 RPM. There is very little strain on the pieces at this low an RPM. The racing versions are used up to 10,500 RPM with good reliability. 

 

Lynn E. Hanover

 

Racing rotaries since 1980.