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, well regarded due to its small diameter, smooth operation, low noise and innovative engineering.
Variants
- Niagara I
- Bore/stroke 77 × 87 mm (3.03 × 3.43 in), swept volume 2,835 cc (173.0 cu in). Compression 6.25:1, gearing 0.47:1. Normal continuous power 84 hp (63 kW) at 3,200 rpm at sea level.
- Niagara II
- Bore/stroke 77 × 87 mm (3.03 × 3.43 in), swept volume 2,835 cc (173.0 cu in). Compression 6.0:1, gearing 0.39:1. Normal continuous power 84 hp (63 kW) at 3,200 rpm at sea level.
- Niagara III
- Bore/stroke 77 × 87 mm (3.03 × 3.43 in), swept volume 2,835 cc (173.0 cu in). Gearing 0.47:1. Normal continuous power 88 hp (66 kW) at 3,300 rpm at sea level.
- 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.
- Niagara V
- Larger version of the basic Niagara. Bore/stroke 81 × 87 mm (3.19 × 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.
- 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.
- Cascade
- Direct drive version of Cataract I. Normal continuous power 66 hp (49 kW) at 2,100 rpm.
Applications
Niagara
- Aeroput MMS-3
- Airspeed Fleet Shadower
- CLW Curlew
- Comper Kite
- Comper Swift
- General Aircraft Monospar ST-25
- General Aircraft Fleet Shadower
- Gribovsky G-25
- Lambach HL.I
- Moss M.A.1
- Pobjoy Pirate
- Saro Shrimp
- Shapley Kittiwake
- Short Scion Senior
- Short Scion
- Short S.31 (half-scale Stirling)
- Spartan Clipper
- Westland CL.20
Cataract
Cascade
Surviving engines
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.
Engines on display
A preserved Pobjoy Niagara engine is on public display at the Science Museum, London and one is also held at the Museum of Transport and Technology (New Zealand).
Specifications (Pobjoy Niagara IV)
Data from Lumsden.
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 (670 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
- Power output: 98 hp (73 kW) at 3,625 rpm maximum at sea level
- Compression ratio: 6:1
- Power-to-weight ratio: 0.75 hp/lb
See also
Related development
Comparable engines
Related lists
References
Notes
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.
External links
- Pobjoy Niagara at oldengine.org
- "A New Pobjoy Engine" - article in Flight