I have been playing with airplanes for over 20 years but only recently got my first gas engine, a 3.2 FPE on a SIG Sundancer. The engine is sweet and flys the Sundancer with authority...unlimited vertical, no. On vertical, the engine begins to bog down at 10,00 feet ( Kidding!!). It does begin to load on vertical, but it's ok. Not that I'm a perfectionist, but I'd like to get maximum performance from my engine and I am not sure I'm getting what I should.

Props.... I have run a Bolly wood 22X10 most of the time and I also have run a Bolly wood 22X8. The Bolly website says the right prop is one that will let the engine run at the "rated" rpm to achieve the "advertised" HP. For the FPE 3.2, that is 3.95 HP @ 7300 rpm. My engine wouldn't turn 7300 rpms with a 12X6. I get 6000 rpm on the 22X10 and 6600 on the 22X8. I have run the 22X10 almost since I started and I like it better, the 22X8 feels like it's cavitating. The 22X10 seems faster.

Plugs....I read an article in Model Airplane News on plugs which said if the plug is black, it's rich; if brown, it's right; if white, it's lean. My plug is black but I have spent hours in my yard "tweaking" the needles and I have the needles set so that the engine runs good, transitions good, doesn't sputter in the air, idles good, etc. Am I too rich? Who knows, the engine is running good. Optimum? I wonder. My plug is black.

Carbs....at first, the engine burbled a lot in the air although it ran good on the ground. I talked to the mfg. and he suggested I remove the velocity stack because it was outside the cowl in the airflow, creating a vacuum and making the engine go rich in the air. I removed the stack and re-adjusted the needles unitl it now runs smooth, transitions good, idles good.

So, what's my complaint? None, really, the engine is running great but the rpm is not as advertised. Did you ever buy a car that would get the mileage advertised on the sticker. I never did, if it stated the highway mileage was 28 mpg, I'd be lucky to get 18 mpg. I am beginning to think airplane engines are the same. I have friends at the field with DAs that don't run as good as mine. But I still want to get optimum.

Any ideas?

Larry