The Fiat A.24 was an Italian water-cooled aircraft engine from the 1920s, built in modest numbers. It produced 520 kW (700 hp).
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. 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).
Producing 520 kW (700 hp) from 32.3 L (1,971 cu in), the A.24 was towards the centre of this range. When Fiat were advised by the government to simplify their water-cooled product line, they decided to focus on the A.20, A.22 and A.30 models so that the A.24 was not manufactured in large numbers.
A.24
Initial version, ungeared.
A.24R
Geared output.
From Thompson.
CMASA MF.5
Fiat BRG
Savoia-Marchetti S.55A
Savoia-Marchetti S.66
Data from Jane's All the World's Aircraft 1938.
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)
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.
Power output: 520 kW (700 hp) at 2,000 rpm, continuous.
Compression ratio: 5.7:1
Fuel consumption: 0.302 kg/kW/h (0.496 lb/hp/h)
