The Avia M 337 (originally designated the Walter M337) is an inverted six-cylinder air-cooled inline engine. It was developed by the Czechoslovak company as a six-cylinder derivative of the four-cylinder M 332 engine, going into production in 1960. An unsupercharged version of the M 337 is designated M 137. Production transferred to Avia in 1964, and to Letecke Opravny Malesice (LOM) in 1992.
M 337A
Basic supercharged engine - not rated for aerobatics
M 337R
Modified for pusher installation
M 337AK
modified oil system for unlimited inverted flying. "Snap" aerobatics permitted.
M 337AK1
AK fitted with alternator instead of generator
M 337B
Increased max running speed (3000 rpm) - increased power - 173 kW (235 hp).
M 337BK
Aerobatic version of B.
M 337C
Increased compression ratio - 185 kW (252 hp)
M 137A
Unsupercharged version of M 337 - 134 kW (180 hp) take-off power. Aerobatics allowed.
M 137AZ
As M 137A, with filtered air feed
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Zlín Z 43
Data from Jane's All The World's Aircraft 1980-81
Type: 6-cylinder inverted air-cooled supercharged inline engine
Bore: 105 mm (4.13 in)
Stroke: 115mm (4.53 in)
Displacement: 5.97 L (364.3 in³)
Length: 1,410 mm (55.51 in)
Width: 472 mm (18.58 in)
Height: 628 mm (24.72
Dry weight: 148 kg (326.3 lb)
Valvetrain: two camshaft operated valves per cylinder, sodium filled exhaust valve
Supercharger: Centrifugal
Fuel system: Low-pressure fuel injection
Fuel type: Min 72-78 Octane
Oil system: Dry sump pressure feed system
Cooling system: Air-cooled
Power output: 157 kW (210 hp) at 2,750 rpm (take-off)
