Fiat AS.2

For the aircraft of the same name, see Fiat AS.2 (aircraft)

AS.2
Type	Piston V-12 aero engine
Manufacturer	Fiat Aviazione
First run	c. 1925
Major applications	Macchi M.39
Developed from	Fiat A.22
Developed into	Fiat AS.3

The Fiat AS.2 was an Italian 12-cylinder, liquid-cooled V engine designed and built in the mid-1920s by Fiat Aviazione especially for the 1926 Schneider Trophy air race.¹

Designed for the 1926 Schneider Trophy contest held at Hampton Roads, Virginia, the AS.2 was inspired by the American Curtiss D-12 engine. Unlike the D-12 the engine featured separate steel cylinders and cast aluminium alloy cylinder heads.² The starting point for the Italian engine was the earlier Fiat A.22.³ 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.⁴

• Macchi M.39

Data from Eves⁵

• 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)