Praga D
Type	Air-cooled piston engine
National origin	Czechoslovakia
Manufacturer	Praga
First run	1936

The Praga Hostivař D was a four-cylinder, air-cooled, horizontally opposed aircraft engine first produced in Czechoslovakia in 1936 but which enjoyed its greatest success after World War II due to the explosion in popularity of sports flying. A version for helicopters was produced post World War II as the Praga DH

Applications

• Mráz M-2 Skaut
• Aero XE-II
• IFIL-Reghin RG-6 (1957)

Specifications (Praga D)

Data from Jane's All The World's Aircraft 1951–52.^[1]

General characteristics

• Type: four-cylinder, air-cooled, horizontally opposed
• Bore: 95 mm (3.74 in)
• Stroke: 100 mm (3.93 in)
• Displacement: 2.836 L (173 cu in)
• Length: 894 mm (35.19 in) (with propeller boss)
• Width: 810 mm (31.89 in)
• Height: 546 mm (21.5 in)
• Dry weight: 67 kg (148 lb)

Components

• Valvetrain: 1 inlet and 1 outlet valve per cylinder
• Fuel system: Zenith carburettor
• Fuel type: 72 octane
• Oil system: Dry sump pressure lubrication
• Cooling system: air

Performance

• Power output: 56 kW (75 hp) at 2,650 rpm
• Cruising power: 42 kW (56 hp) at 2,400 rpm
• Specific power: 19.7 kW/L (0.43 hp/cu in)
• Compression ratio: 6:1
• Specific fuel consumption: 235 g/hp hour (0.52 lb/hp hr) at rated power, 220 g/hp hour (0.48 lb/hp hr) at cruise power
• Oil consumption: 2 - 6 g/hp hour (0.004–0.013 lb/hp hour)