Experimenter is a magazine created by EAA for people who build airplanes. We will report on amateur-built aircraft as well as ultralights and other light aircraft.
Issue link: http://experimenter.epubxp.com/i/271000
36 Vol.3 No.3 / March 2014 UNDER THE COWL inspection with a boroscope. Through these holes, located in cylinder heads and in the engine "basement," the engine can be inspected throughout. For inspection of the crankshaft and its bearings, the entire engine block, piston heads, and cylinders, little more than 20 minutes are needed, without a need to remove any engine component. Usually, crankshafts and connecting rods are rotating on slide bearings in aircraft engines. Those bearings have higher friction and require higher oil pressure; that's why MW Fly decided to use ball/needle bearings instead of plain bearings. Therefore, the MW Fly oil pump produces a lower pressure and is less stressed. In the case of the total loss of the mechanical oil pump, oil mist in the engine is already sufficient for adequate lubri- cation for a several hours of flight at reduced power. Even af- ter completely losing oil, the engine will run for 15 minutes. The connecting rods are built monolithic, a contribution to greater robustness. The Aeropower engines are wet-sump engines, where the oil is contained in an oil sump located below the engine. So-called "gravity" valves are installed between the crankcase and the oil sump and let the oil flow from the crankcase to the oil sump, but they stop the flow in the opposite direction in case of an inverted flight. Aeropow- er engines have two overhead cams (OHCs) with two timing chains (one for each cylinder bank) that are driven by the secondary shaft and assisted by a chain tensioner. REDUCTION GEAR All Aeropower engines can be delivered with or without the reduction gear; the basic 95-hp B22D engine is an excep- tion as this engine is produced only as a direct-drive engine. This is the rear side of the engine. In the middle is the water pump and internal fl uid ducts. On the engine outer perimeter are the four engine-mount points. One of the unusual characteristics of all MW Fly engines: the crankshaft rotates in ball bearings. E A A E X P _ M a r 1 4 . i n d d 3 6 EAAEXP_Mar14.indd 36 3 / 3 / 1 4 1 0 : 3 4 A M 3/3/14 10:34 AM