A-7
Hall-Scott A-7a at the National Air and Space Museum
Type	Piston aero engine
National origin	United States of America
Manufacturer	Hall-Scott Motor Car Company
First run	1910s

The Hall-Scott A-7 was an early liquid-cooled aircraft engine manufactured by the Hall-Scott company of Berkeley, California. Using a straight-4 configuration, the engine developed 90 horsepower (67 kW) as the A-7 and 100 horsepower (75 kW) as the A-7a. In service these engines suffered from reliability problems and were prone to catch fire while in operation.

Variants

• A-7: The A-7 used the same cylinders as the earlier Hall-Scott A-5. Bore: 5 in (127.00 mm), stroke: 7 in (177.80 mm), displacement: 549.78 cu in (9.01 L), weight: 410 lb (190 kg), power: 90 hp (67 kW) at 1,400 rpm, weight: 410 lb (190 kg)^[1]
• A-7a: The A-7a used the same cylinders as the earlier Hall-Scott A-5a. 100 hp (75 kW) 5.25 in × 7 in (133 mm × 178 mm)^[1]

Applications

• Aeromarine 39 (A-7a)
• Aeromarine M-1 (A-7a)
• Dayton-Wright FS (A-7a)
• Standard J-1

In 2017 about seven A-7a engines were still in use in Edwardian racing cars, mostly in the United Kingdom.

Engines on display

• A Hall-Scott A-7a is on public display at the Aerospace Museum of California.
• A Hall-Scott A-7a is in ownership of the National Air and Space Museum.
• A Hall-Scott A-7a is on public display at the Museum of Flight.

• A Hall-Scott A-7a is on public display at the Hiller Aviation Museum.

Specifications (A-7a)

Data from Airplane Engine Encyclopedia ^[1]

General characteristics

• Type: Four-cylinder inline piston engine
• Bore: 5.25 in (133.35 mm)
• Stroke: 7 in (177.80 mm)
• Displacement: 606.14 cu in (9.93 L)
• Dry weight: 420 lb (190 kg)

Components

• Valvetrain: 1 intake and 1 exhaust valve per cylinder, SOHC
• Fuel system: Miller or Zenith carburetors
• Cooling system: Water

Performance

• Power output: 100 hp (75 kW) at 1,400 rpm