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

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

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

Specifications (Sagitta I-MR)

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)