Avia M 337

M 337
	Right side view of a Walter M337; the front cylinder is hidden by the engine cowling
Type	six-cylinder inverted inline piston engine
National origin	Czechoslovakia
Manufacturer	Walter Aircraft Engines/Avia/LOM
Major applications	Let L-200 Morava ; Zlín Z 43

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 as the LOM M137. Production transferred to Avia in 1964, and to Letecke Opravny Malesice (LOM) in 1992.

Variants

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 - 175 kW (235 hp).
M 337BK: Aerobatic version of B.
M 337C: Increased compression ratio - 188 kW (252 hp)
M 137A: Unsupercharged version of M 337 130 kW (180 hp) take-off power. Aerobatics allowed.
M 137AZ: As M 137A, with filtered air feed
M 437: Gear ratio 0.7:1 180 kW (240 hp)

Applications

Specifications (M 337)

Data from Jane's All The World's Aircraft 1980-81 ^[1]

General characteristics

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)

Components

Valvetrain: OHC 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

Performance

Power output: 157 kW (210 hp) at 2,750 rpm (take-off)
Power-to-weight ratio: 1.06 kW/kg (0.64 hp/lb)

References

^ J W R Taylor 1980, p.692.

Taylor, John W R, ed. (1980). Jane's All The World's Aircraft 1980-81. London: Jane's. ISBN 0-7106-0705-9.
http://www.walterjinonice.cz/historie-spolecnosti-walter Archived 2019-08-03 at the Wayback Machine

[Janes_80p692-1] J W R Taylor 1980, p.692.

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