content_image/520042.jpg content_image/520051.jpg content_image/520052.jpg
<img src='content_image/520042.jpg'>

<img src='content_image/520051.jpg'>

Takeoff power is rated at 85 at 3350 rpm. The additional power comes from a bore of 94mm plus lengthening of the R-2200’s connecting rods, plus increasing the stroke from 78 to 84 mm. The longer stroke results in more displacement, and longer connecting rods yield better vibration and power characteristics. The lower cruise rpm allows the use of longer propellers, and the higher peak horsepower can be felt in shorter takeoffs and steeper climbs. 

The Revmaster’s four main bearing crankshaft runs on a 60 mm center main bearing, is forged from 4340 steel, and uses 

<img src='content_image/520052.jpg'>

nitrided journals. Thrust is handled by the 55 mm #3 bearing at the propeller end of the crank. Fully utilizing its robust #4 main bearing, the Revmaster crank has built in oil-controlled propeller capability, a feature unique in this horsepower range; non-wood props are usable with these engines. 

Moving from the crankcase and main bearings, the cylinders are made by using centrifugally cast chilled iron. The pistons are forged out of high quality aluminum alloy, machined and balanced in a set of four. There are two sizes of pistons, 92mm and 94mm, designed to be compatible with a 78mm to 82mm 

