ORIGINAL: DaveR
Bob,
This setup is for a H9 Phoenix 7. Perhaps traditional, but an 11X7 works very well for this airplane, and most vintage pattern planes from the 70's. I probably should try a full tuned pipe, but i hate dealing with tuned pipes. The Jettstream just seems like the easy way out, just wished they were a bit more quiet. Oh, one more important question, can you tell me if the Jettstream provides at least as much muffler pressure as the stock muffler? It's important on this plane as it tends to go lean on outside maneuvers due to tank location and low muffler pressure will just exacerbate the problem.
Do not get hung up on prop size numbers. An APC 11x6 puts out a bunch more speed and thrust in flight than an old Rev-UP 11-7 did 20 years ago. And as I noted, there is a lot of experience with the OS55/Jett/11x6 combination. Yes, you can run the 11x7, but get some run time on the engine first learn its tendencies, then experiment with props. Key as I noted rpm select a prop that will get you easily over 14K peak ground rpm.... then back off 500-600 rpm for flight.
If you have your heart set on an 11x7, get one from Vess. Outstanding good looking wood blades.
The Master Airscrew noted also works great too. Worth trying.
The jett stream will put out more muffler pressure than most stock mufflers. It also has a better balance of back pressure that makes fuel delivery second to none.