Fiat A.24

A.24
	A.24R
Type	Water-cooled V-12
Manufacturer	Fiat Aviazione
First run	c.1926
Number built	at least 100

The Fiat A.24 was an Italian water-cooled aircraft engine from the 1920s.

Design and development

During the second half of the 1920s Fiat introduced several water-cooled aircraft engines, including the A.20, A.22, A24, A.25 and A.30.^[1] They were all upright V-12s with 60° between the cylinder banks; capacities ranged between 18.7 L and 54.5 L (1,141-3,326 cu in) and power outputs between 320 kW and 745 kW (430-1,000 hp).^[1]^[2] Producing 520 kW (700 hp) from 32.3 L (1,971 cu in), the A.24 was near the center of this range.

When Fiat was advised by the Italian government to simplify their water-cooled product line, they decided to focus on the A.20, A.22 and A.30 models such that the A.24 was not manufactured in large numbers.^[1]^[2]

Variants

A.24: Initial version, ungeared.
A.24 R.: Geared output.

Applications

From Thompson.^[3]

Specifications (A.24R)

Data from Jane's All the World's Aircraft 1938.^[2]

General characteristics

Type: water-cooled 60° upright V-12
Bore: 140 mm (5.51 in)
Stroke: 175 mm (6.89 in)
Displacement: 32.3 L (1,971 cu in)
Length: 1.770 m (69.69 in)
Width: 735 mm (28.9 in)
Height: 1.065 m (41.93 in)
Dry weight: Dry 550 kg (1,213 lb)

Components

Valvetrain: Two overhead camshafts, geared together, driving two inlet and two exhaust valves per cylinder. Housed under aluminium casings.
Fuel system: Twin water heated Fiat carburetters mounted between cylinder banks, one serving each bank. Two spark plugs per cylinder, placed horizontally and opposite each other, supplied by two Marelli MF.12 magnetos.
Oil system: One delivery pump and two scavenge pumps, in a single unit.
Cooling system: water, with centrifugal pump.
Reduction gear: 1.545:1 spur gear, lubricated via oil spout.
Cylinders: Forged steel barrels, with closed, flat ends.
Pistons: Aluminium alloy, two compression rings and two scraper rings above fully floating gudgeon pin.
Crankshaft: Each six throw, seven bearings.
Crankcase: Each an aluminium casting, split below crankshaft centre line. Bolted-on duralumin end caps.

Performance

Power output: 520 kW (700 hp) at 2,000 rpm, continuous.
Compression ratio: 5.7:1
Fuel consumption: 0.302 kg/kWh (0.496 lb/hph)

References

^ a b c Gunston, Bill (1989). World Encyclopaedia of Aero Engines (2 ed.). Wellingborough: Patrick Stephens Ltd. p. 57. ISBN 1-85260-163-9.
^ a b c Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. p. 69d. ISBN 0715-35734-4.
^ Thompson, Jonathan (1963). Italian Civil and Military Aircraft 1930-1945. Fallbrook, California: Aero Publishers, Inc.

[Gunston-1] Gunston, Bill (1989). World Encyclopaedia of Aero Engines (2 ed.). Wellingborough: Patrick Stephens Ltd. p. 57. ISBN 1-85260-163-9.

[JAWA38-2] Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. p. 69d. ISBN 0715-35734-4.

[Thompson-3] Thompson, Jonathan (1963). Italian Civil and Military Aircraft 1930-1945. Fallbrook, California: Aero Publishers, Inc.