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Old Nov 24, 2012, 06:27 PM
OkiThumper is offline
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Originally Posted by OkiThumper View Post
17 Nov 2012 Anyway, I was able to successfully run my Fuji .099S-II R/C engine today on O'Donnell 30% Heli Fuel with a Swanson Associates Fireball Hot Standard plug. Some time back I could not get it to run reliably on standard glow fuel, ended up using an OS Max 15FP that did. [....] It is baffle piston by design, but uses ABC construction with an aluminum baffle piston run in a chrome plated brass sleeve. It's got a rather low compression ratio of 5.5:1, putting out 0.16 horsepower at RPM's of 2,500 - 12,500, recommended props 7x4 (FF) or 7x5 (CL and RC). Weighs 4.3 oz. without muffler, heavy like an Enya. Interesting that they don't recommend the 8x3 or 8x4 props like Enya and older OS Max baffle piston engines do.
The instructions state a break in prop of 8x3. I found out from others that Fuji might have been seeking a flywheel effect with the heavier prop. Out of curiosity, I tried the Masters Airscrew (MA) 8x4 prop, not having an 8x3. I figured that at least should have the same flywheel effect, but might cause the engine to overheat because at higher RPM's it has greater resistance. Interestingly, the best flywheel action I had was from an MA 7x4 prop. It is heavier than the Tornado 7x4.

Now that I've got some time built up on the engine, I again tried the 8x4 prop. It spun it without complaint, a little lower in RPM but with respectable thrust. I don't have a tachometer; otherwise I could quantify it for others. There is an advantage to it's lower 5.5:1 compression. I haven't tried it yet on a 9x4 prop. The test will really be when test flying, TBD.

So, this little jewel, the last of the Fuji 099S-II as a baffle piston ABC (earlier were iron/steel piston in a lapped steel sleeve), is a respectable powerhouse for "A" size "nitro" slow flyers.

There is one caveat; thus far it still remains a hard to start engine, taking me over a dozen flips to start it. OTOH, my OS Max .10 baffle, .15 Magnum and .15 OS FP plain bearing Schneurles are easy to hand start, with only a couple flips on a chicken stick. (Didn't have an electric starter to verify the Fuji with.)

One good thing about this engine is the very finely threaded needle valve assembly. So, as cantankerous as it is, I've gotten her to work. (There's no welfare in my engine drawer.

I'm just curious if there are others out there who have had a stubborn to cooperate engine out there.

Oh, and I have a comment about the O'Donnell 30% Heli Fuel with 18% synthetic oil. Even peaked out, the Fuji was putting out an nice steely blue oil vapor mist from the muffler. So, it appears that the synthetic even on the 8x4 prop was doing its job. Perhaps it is time to bust some myths on non-Castor oil fuels?
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