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bob27s -> RE: BME .90 gasser (10/30/2006 5:12:10 PM)
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Hi, thanks for writing....
Since the stock ST90 responds pretty well to the jett-stream, this engine should as well - but as usual, you have to select a prop that will allow the top end rpm to hit the best rpm to perform with the muffler.
However none of us have seen or tried the new gasser yet.
On the longer 90T muffler, (same as the 1.20 size jett-stream), you will want to prop the engine to run somewhere around 10-12K rpm on the top end. The BME is showing a HP number at 14K rpm, so Id tend to prop closer toward 12K if possible.
You should be able to gain 400-800 rpm over the stock muffler. Does not seem like a lot, but with larger prop sizes and power levels, that is a big HP increase. But keep in mind, the tuned exhausts tend to work best for more steady-state rpm. The boost provided does affect rpm for a given throttle position - sometimes you will experience a pipe step.... but that tends to be minimized when using the longer (lower rpm) setups. For profiles and 3D work, yes, they can be effective, when you take time to setup the engine/throttle/aircraft to make the best use of the configuration.
There may be an un-forseen effect of the gas/exhaust gas temperature when using either the jett-stream or turbo-jett muffler. That will only be seen by some experimenting. But I do not believe it will be a problem (just off hand).
As for weight/size, the info for that is on the jett website. The 120 size jett-stream weighs appx 200 grams. You will have to compair that with the stock muffler being provided with the BME.
Bob
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