FIAT A 74 R1C 38 Ciclone
1935 - primi anni '40
Description
The FIAT A.74 Ciclone is a twin-row, radial aircraft engine with 14 cylinders, with a max. power of 940 hp. Before the 1930’s FIAT mainly developed liquid-cooled aircraft engines so the FIAT A 74 and the FIAT A 80 have been the first high power air-cooled airplane engines produced by FIAT in the 30’s. These engines, produced in various version, have been derived from a Pratt and Whitney model and have been then developed by FIAT with several original design improvements. Despite they have been produced in a large number up to the first part of the 1940’s, due to several reasons, only few specimen survived up to nowadays. These engines have been widely used for many aircrafts up to the 1940’s, mainly in military aircrafts.
Technical specifications
| Manufacturer | FIAT Aviazione, Turin, Italy, from 1935 up to early 1940s |
| Type | A 74 R1C 38 Ciclone |
| Description | twin-row 14-cylinder radial engine, crankcase, heads and pistons made of aluminium-alloy, streel-made cylinders screwed into the heads, hemispherical combustion chambers, crankshaft composed of two parts connected by bolts |
| Stroke | 145 mm |
| Bore | 140 mm |
| Displacement | 31250 cm³ |
| Compression ratio | 6.7 |
| Power | 840 hp (standard output) at 2400 rpm, at 3800 m with an absolute intake manifold pressure of 1.00 bar |
| Specific fuel consumption | 270 g/hp/h |
| Specific power | 26.9 hp/litre |
| Valvetrain system | 2 overhead valves per cylinder, operated by pushrods and rocker arms, with exhaust sodium-cooled valves |
| Fuel feeding system | with one single-barrel gasoline Zenith-Stromberg carburetor, placed upstream of the compressor and equipped with pressure limiter and air-fuel mixture preheating |
| Supercharging system | with a single-stage centrifugal compressor, driven by the crankshaft by means of a spur gears drive with a speed ratio of 8.78:1, for a full-throttle height of 3800 m |
| Ignition system | two spark plugs per cylinder fed by two independent Marelli magneto distributors |
| Cooling system | air-fed |
| Lubrication system | forced by gear pumps |
| Starting system | compressed air type with a 12 litres tank at a max. pressure of 15 bar (sufficient for 2 starts) and a Garelli air compressor for re-charging |
| Weight | 590 kg |
| Mass-to-power ratio | 0.70 kg/hp |
| Propeller speed ratio | 0.725:1 by means of a Farman-type bevel gear epicyclic reducer (the standard version RC.38 has a reduction ratio 0.655:1) |
Application
FIAT CR.42 Falco (fighter), powered with R1C 38 version
Fiat G.50 Freccia (fighter)
FIAT CR25 (light bomber, heavy fighter escort and armed reconnaissance)
FIAT G.12 (airliner and transport aircraft)
Fiat CANSA F.C.20 (multi-purpose attack aircraft)
FIAT CMASA RS14 (maritime reconnaissance seaplane)
Caproni Vizzola F.5 (fighter)
IMAM Ro.51 (fighter)
IMAM Ro.57 (fighter and dive-bomber)
Macchi M.C.200 Saetta (fighter)
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