Pobjoy Niagara

Niagara
Pobjoy Niagara on display at the Science Museum, London
Type Piston radial aero engine
Manufacturer Pobjoy Airmotors
First run 1934

The Pobjoy Niagara is a British seven-cylinder, air-cooled, radial, aero-engine first produced in 1934. The design ran at higher speeds than conventional engines, and used reduction gearing to lower the speed of the propeller. This led to a noticeable off-centre mounting for the propeller. The Niagara was a popular engine for light and experimental aircraft,[1] well regarded due to its small diameter, smooth operation, low noise and innovative engineering.

Variants

Niagara I
Bore/stroke 77 x 87 mm (3.03 x 3.43 in), swept volume 2,835 cc (173 cu in). Compression 6.25:1, gearing 0.47:1. Normal continuous power 84 hp (63 kW) at 3,200 rpm at sea level.[2]
Niagara II
Bore/stroke 77 x 87 mm (3.03x3.43 in), swept volume 2,835 cc (173 cu in). Compression 6.0:1, gearing 0.39:1. Normal continuous power 84 hp (63 kW) at 3,200 rpm at sea level.[2]
Niagara III
Bore/stroke 77 x 87 mm (3.03x3.43 in), swept volume 2,835 cc (173 cu in). Gearing 0.47:1. Normal continuous power 88 hp (66 kW) at 3,300 rpm at sea level.[2]
Niagara IV
Similar to Niagara III but with a higher operating rpm. Normal continuous power 98 hp (73 kW) at 3,500 rpm at sea level.[2]
Niagara V
Larger version of the basic Niagara. Bore/stroke 81 x 87 mm (3.19 x 3.43 in), swept volume 3,138 cc (191.5 cu in). Compression 8.0:1, gearing 0.47:1. Normal continuous power 125 hp (93 kW) at 4,000 rpm at sea level.[2][3]
Cataract I-III
De-rated, uncowled versions of Niagara I-III with simple inter-cylinder baffles for cooling and trickle-down lubrication for lower exhaust rockers. Compression 5.7:1, gearing 0.47:1.[2][3][4]
Cascade
Direct drive version of Cataract I. Normal continuous power 66 hp (49 kW) at 2,100 rpm.[4]

Applications

Airworthy Pobjoy Niagara installed in a Comper Swift at the Shuttleworth Collection

Niagara

Cataract

Cascade

Survivors

A Pobjoy Niagara powered Comper Swift G-ACTF that is owned and operated by The Shuttleworth Collection, Old Warden remains airworthy in 2017 and displays to the public at home airshows during the flying season.[5]

Engines on display

A preserved Pobjoy Niagara engine is on public display at the Science Museum (London).

Specifications (Pobjoy Niagara IV)

Data from Lumsden.[2]

General characteristics

  • Type: 7-cylinder, air-cooled, radial engine
  • Bore: 3.03 in (77 mm)
  • Stroke: 3.43 in (87 mm)
  • Displacement: 173 cu in (2.8 L)
  • Diameter: 26.5 in (673 mm)
  • Dry weight: 130 lb (59 kg)

Components

  • Valvetrain: 1 inlet and 1 exhaust valve per cylinder
  • Fuel system: 1 Claudel-Hobson carburettor
  • Fuel type: 70 octane
  • Cooling system: Air-cooled

Performance

See also

Related development

Comparable engines

Related lists

References

Notes

  1. ↑ Gunston 1989, p.111.
  2. 1 2 3 4 5 6 7 Lumsden 2003, p.179.
  3. 1 2 Jane's All the World's Aircraft p.26d
  4. 1 2 Ord-Hume p.589
  5. ↑ www.shuttleworth.org Retrieved: 28 February 2017.

Bibliography

  • Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. ISBN 0-7153-5734-4.
  • Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
  • Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.
  • Ord-Hume, Arthur W.J.G. (2000). British Light Aeroplanes. Peterborough: GMS Enterprises. ISBN 978-1-870384-76-6.
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