Hey Darzeelon,

Not to discredit your last post. But if the engine cannot remain in the resonance rpm, how can the helicopters then tune their pipes for engines running at almost constant rpm?

No, I would like to see the resonance rpm as where the tuned pipe "sets in", like a turbo that builds upp pressure. The engine can remain at that rpm, but the torque is at its peak.

Also for your info ep124, their are a number of layouts of tuned pipes. There are pipes for high rpms and others for low. Look at the OS 140 RX pipe. It is designed to peak at 7600 rpm!

In the other end, their are pylon racing pipes, designed for engines running screaming at 20 000 rpm.

There are lots of parameters to take into consideration; the length of the pipe, the length of the pipe + manifolder, the design of the pipe itself, the bore to stroke ratio of the engine, and more.

Speak to your dealer, and he will gladly help you in the pipe jungle.

Best regards, Fredrik