Pobjoy Niagara

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 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.


 * Cascade
 * Direct drive version of Cataract I. Normal continuous power 66 hp (49 kW) at 2,100 rpm.

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

 * British Klemm Swallow
 * Hafner A.R.III Gyroplane
 * Hendy Hobo
 * Pitcairn PA-22

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.

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