Avia Rk.12
| {{Infobox aircraft begin
| name=Rk.12 | image= | caption= }}{{Infobox Aircraft Engine |type=Seven-cylinder air-cooled radial |manufacturer=Avia (Avia akciova spolecnost pro prumysl letecky), Prague |designer= |national origin=Czechoslovakia |first run= |major applications= |produced= |number built= |program cost= |unit cost= |developed from= |variants with their own articles= }} |
One of Avia's own designs, the 1930s Avia Rk.12 was a seven-cylinder radial engine with a rated output of 150 kW (200 hp), built in Czechoslovakia.
Design and development
As well as producing aircraft and building Hispano-Suiza and Lorraine aero-engines under licence, Avia also designed and built their radial engines. Their Rk.12 was a seven-cylinder supercharged model, rated at 200 hp.
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 aluminium 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 six piston rods.
Applications
Specifications
{{pistonspecs
|ref=Jane's All the World's Aircraft 1938
|type=Seven-cylinder air-cooled radial
|bore=130 mm (5.12 in)
|stroke=130 mm (5.12 in)
|displacement=12.08 L (737 cu in)
|length=1,047.5 mm (41.24 in)
|diameter=1,110 mm (43.7 in
|weight=dry, with ancillaries, without propeller hub 215.5 kg (475 lb)
|valvetrain=one inlet and one exhaust valve per cylinder, operated by push rods via rocker gear. Six cam push rod disc drive.
|supercharger=impeller drive ratio 10.7:1
|turbocharger=
|fuelsystem=single barrel Zenith 70P or Stromberg NAR68 carburettor
- Ignition system: Scintilla magnetos, automatic advance
|fueltype=petrol, 74 Octane
|oilsystem=dry sump, with one pressure and one scavenging pump
|coolingsystem=air-cooled
|power=rated, maintained to 3,000 m (9,840 ft), at 2,200 rpm: 150 kW (200 hp)
- Power output: maximum continuous 195 kW (260 hp)
- Power output: take-off 210 kW (280 hp)
|specpower=
|compression=5.3:1
|fuelcon=62 L/hr (13.64 Imp gal/h, 16.4 US gal/h)
|specfuelcon=
|oilcon=at cruising speed, 2 kg/h (4.4 lbs/h)
|power/weight=
|designer=
|reduction_gear=direct drive
|general_other=
|components_other=
|performance_other=
}}
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