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. With a displacement of 18.4 litres (1,123 cu in), it produced up to 373 kW (550 hp) at 2,500 rpm.^[1]

Variants

Sagitta I-MR: 550 hp (410 kW) at 2,500rpm at 2,500 m (8,202 ft) - rated height^[2]
Sagitta I-SR: 535 hp (399 kW) at 2,500rpm at 3,800 m (12,467 ft) - rated height^[2]
Sagitta II R.C.: Fully supercharged, 388 kW (520 hp).^[3]

Applications

Fokker D.XXIII
Praga E-51
Rogožarski R-313
Savoia-Marchetti SM.86
VEF I-16

Specifications (Sagitta I-SR & I-MR)

Data from ^[2]

General characteristics

Type: 12-cylinder inverted vee piston engine
Bore: 118 mm (4.65 in)
Stroke: 140 mm (5.51 in)
Displacement: 18.4 l (1,122.84 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) - Direct drive, 385 kg (849 lb) - Geared 2:3

Components

Valvetrain: enclosed push-rod operated rockers, two valves per cylinder closed by triple springs
Supercharger: 8.7 times crankshaft speed - I-MR. 10.2 times crankshaft speed - I-SR
Fuel system: Automatic boost and mixture control by a horizontal carburrettor
Fuel type: 85 Octane Aviation Gasoline
Oil system: Dry sump, one pressure pump and two scavenge pumps
Cooling system: Air-cooled

Performance

Power output:
Take-off: 460 hp (343 kW) at 2,500rpm - I-SR, 560 hp (418 kW) at 2,500rpm - I-MR.
Rated power: 535 hp (399 kW) at 2,500rpm at 3,800 m (12,467 ft) - I-SR, 550 hp (410 kW) at 2,500rpm at 2,300 m (7,546 ft) - I-MR
Maximum Power: 540 hp (403 kW) at 2,600rpm at 4,000 m (13,123 ft) - I-SR, 600 hp (447 kW) at 2,500rpm at 1,750 m (5,741 ft) - I-MR.
Specific power: 24.29 kW/l (0.534 hp/in³)
Compression ratio: 6.25:1
Specific fuel consumption: 0.315 - 0.328 kg/kW/hr (0.525 - 0.548 lb/hp/hr)
Oil consumption: 0.004 - 0.0067 kg/kW hr (0.0067 - 0.11 lb/hp hour)
Power-to-weight ratio: 1.046 kW/kg (0.636 hp/lb)

References

Wikimedia Commons has media related to Walter Sagitta.

Notes

↑ Gunston 1989, p. 174.
↑ 2.0 2.1 2.2 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

Walter aircraft engines

Engines	Atlas M208

Opposed engines	Atom M202

Inline engines	M 332 M 337 Junior Major Mikron Minor

V-12 engines	Sagitta

Radial engines	NZ 40 NZ 60 NZ 85 NZ 120 Bora Castor Gemma Jupiter Mars Merkur Pegas Polaris Pollux Regulus Scolar Super Castor Vega Venus

Turbojets	M05 M06 M701

Turboprops	H80 M601 M602

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