Flightstar II C-IGRH Rotax 503 engine 03

The Rotax 503 is a , inline 2-cylinder,

two-stroke A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes of the piston, one up and one down, in one revolution of the crankshaft in contrast to a four-stroke engine which re ...

aircraft engine, built by BRP-Rotax GmbH & Co. KG of Austria for use in

ultralight aircraft Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and Aircraft flight control system, conventional three-a ...

.Raisner, William: ''LEAF catalog'', pp. 6-105. Leading Edge Airfoils, 1995. For decades the engine was one of the most popular and reputedly reliable aircraft engines in its class (two-stroke, under 60 horsepower),Johnson, Dan
"What’s Affordable in 2022? A New “503,” Wheeled-Carriages, and Two-Place PPGs,"
February 3, 2022, ByDanJohnson.com, retrieved June 29, 2023 and it remains widely used and supported.Prizio, Dave
"Firewall Forward: Rotax service Training,"
July 19, 2013, ''Kitplanes,'' retrieved July 5, 2023 As of 2011 the Rotax 503 is no longer in production. However, a Russian manufacturer has developed an approximate reproduction, the RMZ 500. Rotax subsequently offered only one other two-stroke engine for aircraft, the partially water-cooled

Rotax 582 The Rotax 582 is a two-stroke cycle, two-stroke, two-cylinder, rotary intake valve, oil-in-fuel or oil injection pump, liquid-cooled, gear reduction-drive aircraft engine manufactured by Rotax, BRP-Rotax GmbH & Co. KG. It is for use in non-ce ...

Design and development

The Rotax 503 is piston ported with air-cooled cylinders and heads, utilizing either an engine driven fan and cowl, or free air cooling. Lubrication is either by use of pre-mixed fuel and oil or oil injection from an externally mounted oil tank. The 503 has dual independent breakerless, magneto capacitor-discharge ignition (CDI) systems. It can be equipped with either one or two piston-type

carburetor A carburetor (also spelled carburettor or carburetter) is a device used by a gasoline internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the Ventu ...

s. It uses a manifold-driven pneumatic fuel pump to provide fuel pressure. An optional High Altitude Compensation kit is available. The engine's propeller drive is via a Rotax type B, C, or E style gearbox. The standard engine includes a muffler exhaust system with an extra after-muffler as optional. The standard starter is a

recoil start Rope start (also called ripcord , ''pull start'', or ''rewind start'') is a method of starting an internal combustion engine, usually on small machines, such as lawn mowers, chainsaws, grass trimmers, ultralight aircraft, small outboard mo ...

type, with an electric starter optional. An integral

alternating current Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in w ...

generator producing 170 watts at 12 volts with external rectifier-regulator is optional. The engine includes an intake air filter and can be fitted with an intake silencer system.

Limitations

Rotax recommends teardown and inspection every 150 hours, and overhaul every 300 hours. The manufacturer acknowledges the design limitations of this engine, warning pilots:

Applications

Specifications (503)

References

External links

{{Rotax aeroengines Air-cooled aircraft piston engines Rotax engines Two-stroke aircraft piston engines