Pobjoy Niagara Explained

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.

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.

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.

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 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.

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]

Cascade

Direct drive version of Cataract I. Normal continuous power 66 hp (49 kW) at 2,100 rpm.^[3]

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

Autogiro AC-35

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.^[4]

Engines on display

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

References

Bibliography

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

External links

Pobjoy Niagara at oldengine.org
"A New Pobjoy Engine" - article in Flight

Notes and References

Gunston 1989, p.111.
Jane's All the World's Aircraft p.26d
Ord-Hume p.589
http://www.shuttleworth.org/collection/comperswift/ www.shuttleworth.org