Funny how that works, no? The 4-cycle motors seem quieter since the lower tone isn't as abrasive, yet they often pump out more noise. If there is a complaint, it's usually because of some .40-size pylon-racer that sounds like a hive of cyborg bees on nitro. It meets specs, but the sound is so high-pitched it drives people nuts.

In the electric world, this is why so many pilots are using outrunner motors. The gear-drives used on inrunners make a high-pitch whine that gets you noticed at the parks. And those electric ducted fan motors scream at such a high RPM that they might as well be flying glo.

- Jim