<!-- This article is a part of Wikipedia:WikiProject Aircraft. Please see Wikipedia:WikiProject Aircraft/page content for recommended layout. --> {{infobox aero engine |name=Niagara |image=Pobjoy Niagara Science Museum London.JPG |caption= Pobjoy Niagara on display at the Science Museum, London |engine_type=Piston radial aero engine |manufacturer=Pobjoy Airmotors |first_run=1934 |major_applications= }}
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,<ref>Gunston 1989, p.111.</ref> 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 {{cvt|2835|cc}}. Compression 6.25:1, gearing 0.47:1. Normal continuous power {{cvt|84|hp}} at 3,200 rpm at sea level.<ref name=Lum/>
;Niagara II :Bore/stroke 77 × 87 mm (3.03 × 3.43 in), swept volume {{cvt|2835|cc}}. Compression 6.0:1, gearing 0.39:1. Normal continuous power {{cvt|84|hp}} at 3,200 rpm at sea level.<ref name=Lum/>
;Niagara III :Bore/stroke 77 × 87 mm (3.03 × 3.43 in), swept volume {{cvt|2835|cc}}. Gearing 0.47:1. Normal continuous power {{cvt|88|hp}} at 3,300 rpm at sea level.<ref name=Lum/>
;Niagara IV :Similar to Niagara III but with a higher operating rpm. Normal continuous power {{cvt|98|hp}} at 3,500 rpm at sea level.<ref name=Lum/>
;Niagara V :Larger version of the basic Niagara. Bore/stroke 81 × 87 mm (3.19 × 3.43 in), swept volume {{cvt|3138|cc}}. Compression 8.0:1, gearing 0.47:1. Normal continuous power {{cvt|125|hp}} at 4,000 rpm at sea level.<ref name=Lum/><ref name=JAWA/>
;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.<ref name=Lum/><ref name=JAWA>Jane's All the World's Aircraft p.26d</ref><ref name="OH">Ord-Hume p.589</ref>
;Cascade :Direct drive version of Cataract I. Normal continuous power {{cvt|66|hp}} at 2,100 rpm.<ref name="OH"/>
==Applications== [[File:Pobjoy Niagara.jpg|thumb|Airworthy Pobjoy Niagara installed in a Comper Swift at the Shuttleworth Collection]]
===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
==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.<ref>[http://www.shuttleworth.org/collection/comperswift/ shuttleworth.org] Retrieved: 28 February 2017.</ref>
==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)== {{pistonspecs |<!-- If you do not understand how to use this template, please ask at Wikipedia talk:WikiProject Aircraft --> <!-- Please include units where appropriate (main comes first, alt in parentheses). If data are missing, leave the parameter blank (do not delete it). For additional lines, end your alt units with </li> and start a new, fully-formatted line with <li> --> |ref=''Lumsden.''<ref name=Lum>Lumsden 2003, p.179.</ref> |type=7-cylinder, air-cooled, radial engine |bore= {{cvt|3.03|in}} |stroke={{cvt|3.43|in}} |displacement=173 cu in (2.8 L) |length= |diameter= {{cvt|26.5|in}} |width= |height= |weight= {{cvt|130|lb}} |valvetrain=1 inlet and 1 exhaust valve per cylinder |supercharger= |turbocharger= |fuelsystem=1 Claudel-Hobson carburettor |fueltype=70 octane |oilsystem= |coolingsystem=Air-cooled |power={{cvt|98|hp}} at 3,625 rpm maximum at sea level |specpower= |compression=6:1 |fuelcon= |specfuelcon= |oilcon= |power/weight=0.75 hp/lb }}
==See also== {{aircontent <!-- other related articles that have not already linked: --> |see also=
<!-- designs which were developed into or from this aircraft: --> |related= *Pobjoy R <!-- aircraft that are of similar role, era, and capability this design: --> |similar aircraft=
<!-- relevant lists that this aircraft appears in: --> |lists= *List of aircraft engines
<!-- For aircraft engine articles. Engines that are of similar to this design: --> |similar engines= * Rotec R2800 * Warner Scarab <!-- See WP:Air/PC for more explanation of these fields. --> }}
==References==
===Notes=== {{reflist}}
===Bibliography=== {{refbegin}} *{{cite book |title= Jane's All the World's Aircraft 1938|last= Grey |first= C.G. |year=1972|publisher= David & Charles|location= London|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}}. *{{cite book |title= British Light Aeroplanes|last=Ord-Hume|first=Arthur W.J.G.| year=2000|publisher=GMS Enterprises |location=Peterborough |isbn=978-1-870384-76-6 }}
{{refend}}
==External links== {{Commons category}} * [http://www.oldengine.org/members/diesel/Duxford/ukaero3.htm Pobjoy Niagara at oldengine.org] *[http://www.flightglobal.com/FlightPDFArchive/1937/1937%20-%201595.PDF "A New Pobjoy Engine"] - article in ''Flight''
{{Pobjoy aeroengines}}
Niagara Category:1930s aircraft piston engines Category:Aircraft air-cooled radial piston engines Category:Seven-cylinder engines