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Wolseley Scorpio Mk II


The Wolseley Aries III or A.R.9 was a British nine-cylinder, air-cooled radial aero engine that first ran in 1933, it was designed and built by Wolseley Motors. Intended for the military trainer aircraft market few were produced as Wolseley withdrew from the aero-engine market in 1936, see Airspeed Ltd.. A larger capacity version was known as the Wolseley Scorpio, further enlarged versions, the Leo and Libra were test run but did not fly.


A.R.9 Mk I
203 horsepower (151 kW).

A.R.9 Mk II
205 horsepower (153 kW). Higher permissible rpm version of Mk I.

A.R.9 Aries Mk III
225 horsepower (168 kW), low boost supercharger fitted.

Scorpio I
250 horsepower (186 kW), (230 bhp at 2,250 rpm), increased bore (111mm x 120 mm) to give a displacement of 9,477 cc, increased compression ratio. Reduction gearing.

Scorpio II and III
250 horsepower (186 kW), designed to run on 87 octane fuel with 6.5:1 ratio.

280 horsepower (209 kW), few details, not flown or produced.

390 hp at 6,000 ft. 725 lbs (329 kg). Tested but not flown or produced.


Airspeed Envoy
Hawker Tomtit


A.R.9 Aries Mk III
Type: 9-cylinder, single row, radial engine
Bore: 4.19 in (106 mm)
Stroke: 4.75 in (120 mm)
Displacement: 588.6 cu in (9.654 L)
Length: 42 in (1,067 mm)
Diameter: 41.25 in (1,048 mm)
Dry weight: 510 lb (231 kg)
Valvetrain: Overhead valve
Supercharger: Single speed, geared induction fan, slight positive pressure
Fuel type: Petrol
Cooling system: Air-cooled
Reduction gear: Epicyclic spur geared, right-hand tractor, reduction ratio 0.629:1
Power output: 225 hp (168 kW) at 2,475 rpm (maximum power)
Specific power: 0.38 hp/cu in (17.4 kw/L)
Compression ratio: 5.35:1
Power-to-weight ratio: 0.49 hp/lb (0.72 kW/kg)







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