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.
Sagitta I-MR
550 hp (410 kW) at 2,500rpm at 2,500 m (8,202 ft) - rated height
Sagitta I-SR
535 hp (399 kW) at 2,500rpm at 3,800 m (12,467 ft) - rated height
Sagitta II R.C.
Fully supercharged, 388 kW (520 hp).
Fokker D.XXIII
Praga E-51
Rogožarski R-313
Savoia-Marchetti SM.86
VEF I-16
Data from
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) - Direct drive, 385 kg (849 lb) - Geared 2:3
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
Power output:
Take-off: 460 hp (343 kW) at 2,500 rpm - I-SR, 560 hp (418 kW) at 2,500 rpm - I-MR.
Rated power: 535 hp (399 kW) at 2,500 rpm at 3,800 m (12,467 ft) - I-SR, 550 hp (410 kW) at 2,500 rpm at 2,300 m (7,546 ft) - I-MR
Maximum power: 540 hp (403 kW) at 2,600 rpm at 4,000 m (13,123 ft) - I-SR, 600 hp (447 kW) at 2,500 rpm at 1,750 m (5,741 ft) - I-MR.
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)
