I already had one OS.55AX, but bought another one yesterday for use in my Tower Kaos ARF models. As mentioned previously, I also ordered to Jett high performance mufflers for them.

I repeated the above so that no one would think that I am bad mouthing the OS.55AX engines. Also, as mentioned previously elsewhere, according to Dub, when using his high performance mufflers, you must use smaller props than those recommended in the owner's manual for these engines. This is because of the rpm range that the Jett mufflers were designed to operate, not because this engine will not lug big lumber.

If comparing the OS.55AX, using the stock muffler, against older baffle piston .60 size engines, I would not be at all surprised if the OS came out even, or even produced more power than the old pattern sixties. I'm giving a best estimate since I haven't ran the OS.55AX as yet. Some of you with experience should jump in here and alay the fears of those wishing to use this engine in place of an old timey pattern sixty. With the stock muffler, it should do a good job while swinging the same size props used in the old pattern days.

With that said, I have a friend that had an HP.60 (long, long time ago) mounted on the front of his silk and dope covered Taurus. He ran a 10x6 size prop on that HP .60. It flew the dickens out of that Taurus, permitting it to fly huge loops, all while using the stock muffler.

The point of the previous paragraph is that while using the OS.55AX with the Jett high performance muffler, which limits prop size on this engine, don't think that a 10x6, 10x7 or possibly an 11x6 equipped OS.55AX won't pull the dickens out of your model, whether Kwik Fli, Banshee or whatever.


Ed Cregger