Walter Sagitta

Sagitta
Type	Piston aero engine
National origin	Czechoslovakia
Manufacturer	Walter Aircraft Engines
First run	1937

The Walter Sagitta was a Czechoslovakian, air-cooled, inverted V-12 engine that first ran in 1937. This was one of several smaller, low-mass medium power pre-war V-12 engines produced. With a displacement of 18.4 liters (1,123 cu in), it produced up to 373 kW (550 hp) at 2,500 rpm.^[1]

Variants edit

Sagitta I-MR: 410 kW (550 hp) at 2,500rpm at 2,500 m (8,200 ft) - rated height^[2]

Sagitta I-SR: 400 kW (535 hp) at 2,500rpm at 3,800 m (12,500 ft) - rated height^[2]

Sagitta II R.C.: 388 kW (520 hp), fully supercharged.^[3]

Alfa Romeo 122

Licensed production.

Applications edit

Specifications (Sagitta I-MR) edit

Left side view

Data from Jane's.^[2]

General characteristics

Type: 12-cylinder inverted vee piston engine
Bore: 118 mm (4.65 in)
Stroke: 140 mm (5.51 in)
Displacement: 18.372 L (1,121.1 cu in)
Length: 1,914 mm (75.35 in)
Width: 725 mm (28.54 in)
Height: 796 mm (31.34 in)
Dry weight: 372 kg (820 lb)

Components

Valvetrain: Enclosed push-rod operated rockers, two valves per cylinder closed by triple springs
Supercharger: 8.7 times crankshaft speed
Fuel system: Automatic boost and mixture control by a horizontal carburettor
Fuel type: 85 Octane petrol
Oil system: Dry sump, one pressure pump and two scavenge pumps
Cooling system: Air-cooled

Performance

Power output:
- Take-off: 418 kW (560 hp) at 2,500 rpm
- Rated power: 410 kW (550 hp) at 2,500 rpm at 2,300 m (7,500 ft)
- Maximum power: 447 kW (600 hp) at 2,500 rpm at 1,750 m (5,740 ft)
Specific power: 24.29 kW/L (0.534 hp/(cu in))
Compression ratio: 6.25:1
Specific fuel consumption: 0.315 - 0.328 kg/(kW h) (0.525 - 0.548 lb/(hp h))
Oil consumption: 0.004 - 0.0067 kg/(kW h) (0.0067 - 0.11 lb/(hp h))
Power-to-weight ratio: 1.046 kW/kg (0.636 hp/lb)

References edit

Notes

^ Gunston 1989, p. 174.
^ ^a ^b ^c Jane's All the World's Aircraft 1938. London: Sampson, Low & Martin company Limited. 1938.
^ Flight - 14 October 1937, p. 381. Retrieved: 8 November 2012

Bibliography

Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9

[1] Gunston 1989, p. 174.

[JAWA1938-2] Jane's All the World's Aircraft 1938. London: Sampson, Low & Martin company Limited. 1938.

[3] Flight - 14 October 1937, p. 381. Retrieved: 8 November 2012

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