Avia Rk.17

One of Avia's own designs and built in Czechoslovakia, the 1930s Avia Rk.17 was a 9-cylinder radial engine, developed from the 7-cylinder Avia Rk.12, with a rated output of 270 kW (360 hp).

Rk.17 in Letecké muzeum Kbely, Prague
Type 9-cylinder air-cooled radial
National origin Czechoslovakia
Manufacturer Avia (Avia akciova spolecnost pro prumysl letecky), Prague

Design and development

As well as producing aircraft and building Hispano-Suiza and Lorraine aero-engines under licence, Avia also designed and built their own radial engines. The Rk.17 was a 9-cylinder supercharged model, rated at 360 hp. It was a nine-cylinder version of their Rk.12.[1]

It was a conventional air-cooled radial: nitrided steel barrels with integral fins were screwed into heat treated Y alloy heads. The pistons were also of heat treated Y alloy. The crankcase was cast from heat treated silumin alloy, with some minor parts using magnesium alloy. The single throw two piece crankshaft was linked to the pistons with an I-section Y alloy master rod, with a single piece big end, which carried the other eight piston rods.[1]



Data from Jane's All the World's Aircraft 1938[1]

General characteristics

  • Type: 9-cylinder air-cooled radial
  • Bore: 130 mm (5.12 in)
  • Stroke: 140 mm (5.51 in)
  • Displacement: 16.72 L (1,020 cu in)
  • Length: 1,065 mm (41.93 in)
  • Diameter: 1,184 mm (46.61 in)
  • Dry weight: 260 kg (573 lb) with ancillaries, without propeller hub


  • Valvetrain: one inlet and one exhaust valve per cylinder, operated by push-rods via rocker gear. Eight cam push-rod disc drive.
  • Supercharger: impeller drive ratio 10.7:1
  • Fuel system: single barrel Stromberg NAR80G carburettor
  • Ignition system: Scintilla magnetos, automatic advance
  • Fuel type: petrol, 85 Octane
  • Oil system: dry sump, with one pressure and one scavenging pump
  • Cooling system: air-cooled
  • Reduction gear: direct drive


  • Power output: rated maintained up to 2,750 m (9,000 ft), at 2,200 rpm 270 kW (360 hp)
  • Power output: maximum continuous at 2,200 rpm 300 kW (400 hp)
  • Power output: take-off at 2,020 rpm 330 kW (440 hp)
  • Compression ratio: 6.4:1
  • Specific fuel consumption: 255 g/(kW.h) (0.562 lb/(hp.h))
  • Oil consumption: 8.7 g/(kW.h) (0.23 oz/(hp.h))


  1. Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. p. 31d. ISBN 0-7153-5734-4.

Further reading

  • Bridgman, Leonard, ed. (1947). Jane's all the World's Aircraft 1947. London: Sampson Low, Marston & Co. p. 37d.
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