Fiat AS.2 

The Fiat AS.2 was an Italian 12-cylinder, liquid-cooled V engine designed for the 1926 Schneider Trophy contest held at Hampton Roads, Virginia, the AS.2 featured separate steel cylinders and cast aluminium alloy cylinder heads. The starting point for the Italian engine was the earlier Fiat A.22. The 'S' in AS stood for 'Spinto' (thrust). A weakness of the engine was its magnesium alloy pistons, a new engineering material at the time. Many pistons were holed. Despite the engine's technical problems it was successful at the Schneider Trophy event, winning on 13 November 1926, with a second AS.2 powered aircraft placing third.

Applications
Macchi M.39

Specifications:

AS.2
Type: 12-cylinder V-engine
Bore: 140 mm (5.5 in)
Stroke: 170 mm (6.7 in)
Displacement: 30.955 litres (1,889 cu in)
Width: 720 mm
Height: 850 mm
Dry weight: 408 kg (900 lb)
Valvetrain: Two intake and two exhaust valves per cylinder
Fuel system: Carburettor
Cooling system: Liquid-cooled
Power output: 596 kW (800 hp) at 2,500 rpm
Compression ratio: 6:1
Power-to-weight ratio: 1.46 kW/kg (0.9 hp/lb)