Draft:Walter M202

M202
An M202 on display
Type	Piston aircraft engine
National origin	Czechoslovakia
Manufacturer	Walter Aircraft Engines
First run	1994

The Walter M202 is a Czechoslovak air-cooled horizontal two-cylinder engine used on light aircraft.

Development

The previous two-cylinder engines produced by the Jinonice factory were the inverted Walter A from 1946 and the flat, horizontal Walter Atom from 1934. In the 1970s and 1980s, modified engines from Trabant cars and especially Austrian Rotaxes were used to power ultralight and amateur aircraft in Czechoslovakia. After the transformation into a joint-stock company in 1991, Jinonice decided to resume the development and production of aircraft piston engines. In 1991-1994, a team led by engineer Jiří Vyčítal developed and tested the M202 engine, which was a new design based on the M-30 engine prototype, originally designed by the Brno Technical University, intended for serial production in the Jinonice factory by decision of the General Directorate of the Aeronautical Engineering Department. The M202 engine received the type certificate of airworthiness No. 94-10 from the State Aviation Inspection according to the L8/S and JAR 22H regulations in November 1994. A total of 12 M-202 engines were manufactured by 2000. Experience from the development and production of the M202 engine was to become the basis for the M204 project.

Description

The flat, horizontal two-stroke two- cylinder M202 with opposed cylinders was equipped with a speed reducer based on the principle of a pair of simple spur gears with helical gears. It was designed with an eye to the optimal possibility of direct cooling of both cylinders without the use of a fan, it had a high specific power even without the use of a slide valve distribution and its entire design was focused on achieving high reliability and long service life. The spur reducer with helical teeth was located on the engine in the rear part of the housing between the crankshaft (the surface was strengthened by ballotinating , i.e. by blasting with glass balls) and the flywheel , which achieved an abnormally short overall length of the engine and at the same time had an advantage for the solution of the torsion system. The engine was equipped with an effective torsional vibration damper in the reducer. The enormous thermal stress on the pistons (up to 420°C in the piston crown area, 250°C in the piston ring area) was reduced by using plasma spraying technology to create a thermal, cermet barrier with a top layer based on stabilized zirconium oxide (ZrO₂).

Applications

• ZA-01
• MF-1 Vážka
• Ornis M-7
• Aero Vodochody Hroch
• MAT-20

Specifications

General characteristics

• Type: Horizontally-opposed 2 cylinder air-cooled
• Bore: 82 mm
• Stroke: 64 mm
• Displacement: 676 cu in)
• Length: 424 mm
• Width: 566 mm
• Height: 426 mm
• Dry weight: 32 kg

Components

• Valvetrain: 1 inlet and one exhaust valve per cylinder
• Fuel system: 2 Amal carburettors
• Cooling system: air

Performance

• Power output: 48 kW (28 hp) at 6300 RPM