NZ 85
NZ 85 on display at the National Technical Museum (Prague)
Type	Radial aero engine
National origin	Czechoslovakia
Manufacturer	Walter Aircraft Engines
First run	1926
Number built	50
Developed from	Walter NZ 60
Developed into	Walter Venus

The Walter NZ 85 was a seven-cylinder, air-cooled, radial engine for aircraft use built in Czechoslovakia by Walter Aircraft Engines in the late-1920s.

Design and development

Using common cylinders and parts from the earlier Walter NZ 60 (Novák-Zeithammer) engine the NZ 85 and the nine-cylinder NZ 120 were designed together.^[1] Lightened and tuned developments were known as the NZ 90 and NZ 95.

Applications

• Aero A.34
• Avia BH-20
• Avia BH-29
• Breda Ba.15
• Couzinet 30 (intended application)
• Gribovsky G-8
• Hopfner HS-8/29
• IMAM Ro.5
• Letov Š-118
• Orta-Saint Hubert G.1
• Savoia-Marchetti S.56
• Shavrov Sh-1

Specifications (NZ 85)

Data from Němeček.^[2]

General characteristics

• Type: Seven-cylinder radial piston engine
• Bore: 105 mm (4.13 in)
• Stroke: 120 mm (4.72 in)
• Displacement: 7.27 L (444 cu in)
• Length: 741 mm (29.2 in)
• Diameter: 990 mm (39.0 in)
• Dry weight: 125 kg (276 lb)

Components

• Fuel system: Zenith carburettor
• Cooling system: Air-cooled

Performance

• Power output: 74 kW (99 hp)