A tuned pipe has a tremendious appeal for many people, especially young newcomers. For a tuned pipe to work most efficiently, it must be used in a primarily high speed situation, also the engine must be run in the upper levels of it's rpm range ( like 15 - 16,000 rpm) with a smaller diameter - higher pitch prop. Also the engine must have some pretty radical timing to utilize the physical properties offered by the pipe.

There are some few exceptions to this as in pattern flying whereas the pipe is also used as rpm stablizing device but the engine is still used primarily WOT.

A tuned pipe to use in a 3D application is a waste of your money. Just use a more powerful engine.

There are people who will show up at the field with a LA40 W/tuned pipe and a 10-6 prop on a trainer plane proclaiming how much better it is. If there was any increase with this setup, it would be absorbed by the extra drag and weight of the pipe.

These people would have gotten just as much extra performance by putting a new decal on the plane?

Enjoy

Jim