Airframe noise certainly plays a part, as you say. It can either dampen or resonate the motor. I saw a .20-size trainer with the foam-coated nose and the "rubber bolts" holding the motor mount. On it was an OS 25FP with the new muffler, swinging a prop that seemed a tad over-propped, but it ran okay. Being that I've been in electrics the past few years, I was amazed at how quiet it flew compared to the other gassers. You could barely hear it in the air. So, it's apparent that gas planes CAN be quiet, and electric planes CAN be nosiy as heck.

It wouldn't suprise me if many future fields simply incorporate stricter noise rules as an agreement to the city. Only the racers would be inconvenienced, since it's apparent we have the technology to run quiet if there is a market for it.

- Jim