Mods- Nice job on the cowl, Great Planes are notorious for terrible cowls too, Cheap crappy plastic, they need to change that. And I didn't have any luck with the Pitts style Muffler either, the whole bottom of the cowl had to be cut away because no matter what I did I couldn't fit it on there, I see the trick was to use 2 cowls. Very Clever Good job. I originally had the Pitts on the US Bipe but it kept falling off, then I finally stripped it, so I just put the stock muff back on and it hasn't given me a problem since, I also tried for a smoke system, But I never used one before, (unbelieveable as it is for the years I've been involved) but everyone kept telling me it wasn't worth it in a 40 size aircraft cause it wouldn't produce enough smoke to be worth it, but I'm still researching that. After all,,,, whats a Bipe without smoke. [&o]