First, the Peripheral port rotaries are NOT narrow band engines. The P-port rotary we  been running on the test stand makes more power than a side port, at a lower RPM than a similar side port. It also idles at 1200 engine RPM with no problem. The only reason the cars aren't peripheral port is that the p-port engine makes less torque at 20% than the side port and the cars all run down there. I have have long claimed that the rotary makes a better airplane engine than a car engine! Very few people are running the engine in their planes at less than 40% power. Even then the P-port is fine you just can't port it for max power at 10,000 RPM. If you port for 6-7K the rotary is very flexible. We have been reluctant to show this until the engine is flying in that airplane but I'm including a link showing what I'm talking about. This is the engine on the aircraft dyno. This video was made while tuning the airflow performance aircraft FI so the engine isn't even at its best yet. This small port engine is running through a muffler designed to fit under the cowl of an RV-3! It tested in this configuration to 185 HP at 6400 engine RPM. We put a larger muffler that would work in a bigger plane and got 195 HP. The engine has hours on the dyno but the proof is really when it's flying. 

Bill