APR 2015

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: https://experimenter.epubxp.com/i/492505

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32 Vol.4 No.4 / April 2015 UNDER THE COWL To drive the compressor, an aluminum pulley is flanged to the original Rotax alternator. A 1.2-inch (30 mm)-wide toothed Poly-V belt drives the compressor, which is located below the rear part of the engine. Because of this mechanical coupling, the compressor wheel always rotates at a fixed rotation ratio to the engine. The atmospheric air is sucked in, compressed, and then sent through the proprietary (alumi- num) air-box, which serves the two original Bing carburetors. The Flygas air-box looks similar to the original Rotax one; only the warm-air intake is missing. The warm-air port is not necessary because the air warms up when passing through the fast rotating compressor wheel. The original carburetors get new fuel jets, and different spark plugs are used. For the lubrication of the compressor, Flygas developed an autono- mous oil system that consists of an additional oil pump (bolted on top of the stock engine oil pump), aluminum 1-quart oil tank, filter, and low oil pressure switch. The cen- trifugal supercharger is held in position by two sturdy aluminum brackets. Two different bracket sets are available for the round or conventional engine mount. The Flygas kit also includes: an oil pressure regulator, electric fuel pump, and fuel pressure regulator. Along with the aforementioned parts, the customer also gets all the necessary tubes, clamps, and fixing materials. The tuning kit for stock 80-hp Rotax engines is somewhat simpler because these engines come with a lower compression ratio than the 100-hp engines. The compression ratio on 912 ULS engines is lowered by means of gaskets that are placed under the cylinder base; the compression ratio decreases from 10-to-1 to 9-to-1. The performance increase of the Flygas kit also depends on the diameter of the pulleys used on the alternator and on the supercharger. For aircraft constantly operating at high altitudes, a faster spinning supercharger can be used. For those who require less power increase at sea level but want to keep the sea-level power output in climb or simply don't want to constantly overstress the engine, Stefano of ers an optional proprietary mechanical blow-of valve that limits the intake (over)pressure and consequently the engine power to a desired preset level. In this case, the customer gets almost a "turbonormalized" engine. The tuning kit costs 4,580 euros for the 80-hp Rotax engines and 4,950 euros for engines with 100 hp. (All prices are plus applicable tax and shipping; please consult current exchange rates.) Currently Flygas ships 2.5 sets per month. Nearly 60 of these tuning kits are already in use worldwide, mostly in moun- tainous regions of the United States, Colombia, Brazil, Canada, New Zealand, and most recently France. For more information, visit www.Flygas.info . Illustrations courtesy of Flygas Engineering

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