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/149316
Un d e r t h e C o w l noncounterbalanced, plain-bearing crankshaft is supported in seven main bearings and is fed high-pressure oil from a single, large mechanical pump. The heads and rocker boxes are machined in one piece, and fins carry all the way out to the covers. Traditional overhead valve actuation is mechanical, with screw adjusters. Four mounting points are located on the rear plate. For now, overhaul is done at the factory in Belgium, but U.S. importer Robert Helms said, "So far, in my territory, every owner has done his own maintenance or used a local A&P.; My plan is to have at least one overhaul facility in the U.S. and conduct training for owners and others. I also want a mobile repair/overhaul vehicle I can take to shows, OEMs, and maybe to do some field work." There are two engines in the 520 family: the base UL520i has 8-to-1 compression and delivers 170 hp at 2800 rpm (and 180 hp at 3300 rpm). The higher-compression (8.7-to-1) UL520iS makes 180 hp at 2800 rpm and has tested to 225 hp. An aerobatic version is planned—the 520iSA—which has an inverted oil system and weighs 3.8 kilograms more than the other two engines' 182-kilogram (242-pound) weight; and that's with the starter and 50-amp alternator. Dual ignition through a single electronic control unit (ECU) is standard, as is the full authority digital engine control (FADEC); there is a dual ECU option, though the factory advises to run just one ECU at a time. The second ECU is just there for the ride in the very unlikely event that the identical main unit conks out. Te engine case is machined from billet aluminum. The entire engine management system is a ULPower design, using proprietary and dedicated hardware (all the way to the wire looms), ECU, and software but employing mass-produced automotive spark plugs, sensors, coils, and injectors. All the engines use four liters of AeroShell 15-40 internally (more may be needed, if additional oil lines and coolers are added), and they run on high-octane auto fuel (the "i" uses 91 octane; the "iS" uses 93 octane) or 100LL avgas. The engines turn the props in the clockwise direction as viewed from the cockpit; the same, for example, as Lycoming and Continental, and opposite Rotax and VW. Prop weight is limited to 15 kilograms (33 pounds). On the Test Stand Some independent dynamometer work has yielded interesting comments. Scott Ehni is a private Zenith builder, and he and a friend are putting ULPower 350iS units into their next two Zeniths. (Scott already has built a CH 701 with a JFS 100 turbine. "It can't carry enough fuel for long distances," he said. His story was featured in the April Photography courtesy of ULPower Nearly fnished head shows generous fnning. EAA Experimenter 31