Wright R-790 Whirlwind

{{Short description|Series of nine cylinder air-cooled radial aircraft engines}}  {{infobox aero engine |name = R-790 Whirlwind |image = File:Wright R-790 NASM.jpg |caption = Wright R-790 (J-5 Whirlwind) at [[National Air and Space Museum]] |engine_type=Air-cooled 9-cylinder radial piston engine |manufacturer=[[Wright Aeronautical Corporation]]<br>[[Škoda Works|Škoda Works (Czechoslovakia)]]<br>[[Avia (Polish works)|Avia (Poland)]] |national_origin=United States |first_run=1923 |major_applications={{ubl|[[Spirit of St. Louis]]|[[Fokker Trimotor]]|[[Ford Trimotor]]}} }}

The '''Wright R-790 Whirlwind''' was a series of nine-cylinder [[air-cooled]] [[radial engine|radial]] [[aircraft engine]]s built by [[Wright Aeronautical Corporation]], with a total [[Engine displacement|displacement]] of about {{convert|790|cuin|litre}} and around {{convert|200|hp|kW}}. These engines were the earliest members of the [[Wright Whirlwind]] engine family.

==Design and development== The R-790 Whirlwind began as the [[Lawrance J-1]], a nine-cylinder air-cooled radial developed in 1921 by the [[Lawrance Aero Engine Company]] for the U.S. Navy. The Navy was very enthusiastic about air-cooled engines, which it considered better suited for naval use than liquid-cooled ones.<ref name="wright j-5">[http://www.enginehistory.org/Wright/Wright%20J-5.pdf Wright J-5 "Whirlwind"] {{Webarchive|url=https://web.archive.org/web/20160304001401/http://www.enginehistory.org/Wright/Wright%20J-5.pdf |date=2016-03-04 }} (PDF), by Kimble D. McCutcheon, from the Aircraft Engine Historical Society</ref> Lawrance was a small company, though, and the Navy doubted it could produce enough engines for its needs.<ref name="wright j-5"/> Despite urgings from the Navy, the major U.S. aircraft engine makers, Wright and [[Curtiss Aeroplane and Motor Company|Curtiss]], were satisfied with their liquid-cooled engines and showed no interest in building air-cooled engines.<ref name="wright j-5"/> Since the Navy was already a major buyer of Wright engines, it pressured Wright into purchasing Lawrance and building the J-1 itself, by informing the company that the Navy would buy no more of its existing engines or spare parts.<ref name="wright j-5"/> To retain the Navy's business, Wright complied in 1923 and the Lawrance J-1 became the Wright J-1.<ref name="wright j-5"/>

By the time Lawrance merged with Wright, it had already developed the more powerful J-2, a version of the J-1 with slightly enlarged [[bore (engine)|bore]] and displacement. However, Lawrance decided the J-1 was large enough, and the J-2 never went into production; only two examples were built.<ref name="wright j-5"/>

Over the next two years, Wright gradually refined the J-1 engine, introducing the J-3, J-4, J-4A, and J-4B. The changes improved the engine's reliability, cooling, and fuel consumption, but the basic design, dimensions, and performance were unaltered.<ref name="wright j-5"/>

The J-4 was the first engine to bear the Whirlwind name; previous engines used only the alphanumeric code.<ref name="wright j-5"/>

The J-5 Whirlwind, introduced in 1925, was a complete redesign of the engine with greatly improved cooling and breathing, further increasing its reliability and reducing fuel consumption. Among the visible changes was the much wider separation between the valves, for better cooling airflow, and completely enclosed, instead of exposed [[pushrod]]s and [[rocker arm]]s.<ref name="wright j-5"/>

The U.S. government later designated the J-5 Whirlwind as the R-790, but it did not apply this designation to the older engines.<ref>[http://www.history.navy.mil/branches/avchr3.htm Naval Aviation Chronology 1920–1929] {{Webarchive|url=https://web.archive.org/web/20141015083231/http://www.history.navy.mil/branches/avchr3.htm |date=2014-10-15 }}, from the Naval Historical Center. See entries for 1928, February 1 and 28.</ref>

All these engines had a bore of 4.5 in (11.4 cm), a [[stroke (engine)|stroke]] of 5.5 in (14.0 cm), and a displacement of 788 in<sup>3</sup> (12.91 L).

In a 1928 report on transcontinental aviation, the author disclosed the cost of a typical five-seat commercial aircraft as $12,500, of which $5,000 was for one of the 350 200 hp Whirlwind Engines available that year.<ref>{{cite journal|journal=Liberty Magazine|title=Blazing New Wing Trails|author=Florabel Muir|page=20|date=4 August 1928}}</ref> The J-5 was the last of the original nine-cylinder Whirlwinds. In 1928, it was replaced by the seven-cylinder [[Wright Whirlwind|Whirlwind J-6]].

<gallery>  Image:Wright_J-6.jpg|Partially sectioned Wright J-4B at [[Canada Aviation Museum]] Image:Wright_R790_2.jpg|Side view of the USAF museum's R-790 (J-5) </gallery>

==Operational history== Many Whirlwind engines were used in U.S. Navy aircraft, mostly in trainers, but also in some ship-based observation and fighter aircraft. As the engines were refined and their reputation for reliability grew, their use expanded to U.S. Army trainers and a wide range of U.S. civil aircraft, including the earliest versions of the [[Fokker Trimotor]] and [[Ford Trimotor]] airliners.

The reliability of J-5 Whirlwind engines also led aviators to use them for a number of record-setting distance and endurance flights. The most famous of these is [[Charles Lindbergh]]'s solo transatlantic flight from [[New York City]] to [[Paris]] on May 20–21, 1927, in the ''[[Spirit of St. Louis]]'', powered by a single Whirlwind J-5C. During Lindbergh's flight, the engine ran continuously for 33.5 hours. Lindbergh's achievement greatly boosted the Whirlwind's already good reputation.<ref>{{cite book | last=Hardesty | first=Von | title=Lindbergh: Flight's Enigmatic Hero | place=New York | publisher=Harcourt | year=2002 | isbn=9780151009732 | page=78}}</ref>

Some other historic long-duration flights made in aircraft powered by the J-5 Whirlwind:

* [[Clarence Chamberlin]] and [[Bert Acosta]] made a record endurance flight of 51 hours, 11 minutes, 25 seconds in a single-engined [[Bellanca WB-2|Wright-Bellanca WB-2]] over New York City in April 1927. * Chamberlin and [[Charles Levine]] flew nonstop from New York City to [[Eisleben, Germany]], in the same Wright-Bellanca on June 4–6, 1927, in a flight lasting 42.5 hours (3,920 mi). * The first successful flight from the continental U.S. to Hawaii was made by [[Albert Hegenberger]] and [[Lester Maitland]] in the Fokker C-2 ''Bird of Paradise'' from [[Oakland, California]], to [[Honolulu, Hawaii]], on June 28–29, 1927, lasting 25 hours 50 minutes (2,400 mi). * The first flight across the Pacific was made by Sir [[Charles Kingsford Smith]] in the Fokker Trimotor ''[[Southern Cross (aircraft)|Southern Cross]]'' from Oakland to [[Brisbane, Australia]], with stops in Hawaii and [[Fiji]], from May 31 to June 9, 1928. The leg from Hawaii to Fiji lasted 34.5 hours over 3,100 mi (5,000 km) of open ocean. * A record endurance flight of 150 hours, 40 minutes, and 14 seconds was made by U.S. Army fliers in the Fokker C-2A ''[[Question Mark (aircraft)|Question Mark]]'' trimotor over Southern California on January 1–7, 1929. Achieved with the help of [[aerial refueling]], this flight ended only when [[valvetrain]] failures stopped the portside engine, and [[Question Mark (aircraft)#End of the flight|excessive valvetrain wear]] was slowing the nose and starboard-side radials.

[[Charles L. Lawrance]], who developed the original Whirlwind series and became president of Wright, won the 1927 [[Collier Trophy]] for his work on air-cooled radial aircraft engines.

==License-built versions== The J-5 Whirlwind was built by [[Hispano-Suiza]] in [[France]].<ref name=revhs28jun>{{cite web|title=Revue Hispano-Suiza|url=http://dev.museesafran.com/wp-content/uploads/2012/10/1350047524-revues-hispano-suiza-saf2012_0047824.pdf|website=dev.museesafran.com|publisher=Societe Francais Hispano-Suiza|access-date=20 October 2014|language=fr|archive-date=20 October 2014|archive-url=https://web.archive.org/web/20141020160743/http://dev.museesafran.com/wp-content/uploads/2012/10/1350047524-revues-hispano-suiza-saf2012_0047824.pdf|url-status=dead}}</ref>

The Whirlwind J-5 was also produced under license in Poland by several makers. Among these were ''Polskie Zakłady Skody'', the Polish branch of [[Škoda Works]], which built about 350 to 400 engines from 1929 to 1931, and the Polish firm [[Avia (Polish works)|Avia]], which manufactured a further 300 engines from 1935 to 1938. Polish-built J-5s were used in numerous Polish aircraft, mostly in military training, observation, and liaison aircraft.

==Variants== * '''J-1''': [[Lawrance J-1]] as built by Wright Aeronautical in 1923. * '''J-3''': Wright's first refined version, 1923. * '''J-4''': Improved version, 1924. First to be named "Whirlwind". * '''J-4A, J-4B''': Further refinements of J-4. * '''J-5 (R-790)''': Complete redesign with improved reliability and performance, 1925.

==Applications==

===U.S. aircraft=== {{Columns-list|colwidth=20em| *[[Boeing NB]] *[[Buhl-Verville CA-3 Airster]] (J-4) *[[Buhl-Verville CA-3A Airster]] (J-5) *[[Consolidated NY]] *[[Consolidated O-17]] *[[Consolidated PT-3]] *[[Curtiss AT-5 Hawk]] *[[Curtiss N2C-1 Fledgling]] *[[Curtiss-Wright CW-14 Osprey]] *[[Fairchild FC-2]] *[[Fokker F.VII]] *[[Fokker Universal]] *[[Ford Trimotor 4-AT]] *[[Keystone Pronto]] *[[Lockheed Vega]] *[[Hamilton H-18]] *[[Naval Aircraft Factory N3N-1 Canary]] *[[New Standard D-25]] *[[Pacer Monoplane]] *[[Pitcairn Mailwing]] *[[Ryan B-1 Brougham]] *[[Spirit of St. Louis]] *[[Stearman NS-1]] *[[Stearman C2B]] *[[Stearman C3B]] *[[Stinson Detroiter]] SB-1 and SM-1 *[[Stinson Junior]] SM-2AB *[[Swallow New Swallow]] *[[Texas-Temple Aero C-4]] *[[Texas-Temple Commercial Wing]] *[[Travel Air 2000]] *[[Travel Air 3000]] *[[Travel Air 4000]] *[[Vought FU]] *[[Vought UO]] *[[Waco 10]] }}

===Polish aircraft, using Polish-built engines=== *[[Bartel BM-5]]d *[[Lublin R-X]] *[[Lublin R-XIII]] *[[PWS-18]] *[[PWS-26]] *[[PZL Ł.2]]

===Aircraft from other countries=== *[[Heinkel HD.20]] *[[Nieuport-Delage NiD 640]]

==Engines on display== Some museums which have J-5 Whirlwinds (or the military R-790 equivalents) on display: * [[National Air and Space Museum]] in [[Washington, D.C.]]<ref>{{Citation|title=Collections Database: Objects: A19791508000|url=http://collections.nasm.si.edu/code/emuseum.asp?profile=objects&quicksearch=A19791508000&newstyle=single|access-date=2008-09-06}}.</ref> * [[National Museum of the United States Air Force]] near [[Dayton]], [[Ohio]].<ref>{{Citation|title=Wright R-790 Radial|url=http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=860|archive-url = https://web.archive.org/web/20130404183525/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=860|access-date=2017-07-17|archive-date = 2013-04-04}}.</ref><ref>{{Citation|title=National Museum of the USAF|url=http://www.enginehistory.org/usaf.htm|access-date=2008-09-06|archive-date=2010-07-25|archive-url=https://web.archive.org/web/20100725091325/http://www.enginehistory.org/usaf.htm|url-status=dead}}. The section "Images from Gary Brossett" has a photo of the museum's R-790.</ref><ref>{{Citation|title=National Museum of the United States Air Force: Images by Tony Ward|url=http://www.enginehistory.org/Museums/NMUSAFWard/nmusaf.htm|access-date=2008-09-06|archive-date=2012-02-12|archive-url=https://web.archive.org/web/20120212213117/http://www.enginehistory.org/Museums/NMUSAFWard/nmusaf.htm|url-status=dead}}. This page has several photos of the museum's R-790.</ref> (This engine, also pictured above, was one of the three used by ''Bird of Paradise'' on its flight to Hawaii.) * [[National Museum of Naval Aviation]] near [[Pensacola]], [[Florida]].<ref name="nmna">{{Citation|title=Image Galleries by Gary and Janet Brossett: National Museum of Naval Aviation in Pensacola, Florida|url=http://www.enginehistory.org/nmna.htm|access-date=2008-09-06|archive-date=2009-08-27|archive-url=https://web.archive.org/web/20090827015231/http://www.enginehistory.org/nmna.htm|url-status=dead}}. This page has photos of a J-5 and two J-4s, one a cutaway.</ref> * [[EAA AirVenture Museum]] in [[Oshkosh, Wisconsin|Oshkosh]], [[Wisconsin]].<ref>{{Citation|title=Image Galleries by Gary and Janet Brossett: Experimental Aircraft Association AirVenture Museum – Oshkosh, WI|url=http://www.enginehistory.org/eaa.htm|access-date=2008-09-06|archive-date=2008-12-12|archive-url=https://web.archive.org/web/20081212083709/http://www.enginehistory.org/eaa.htm|url-status=dead}}. This page has a photo of an R-790A.</ref> * [[Old Rhinebeck Aerodrome]] in [[Rhinebeck (town), New York|Rhinebeck]], [[New York (state)|New York]],<ref>{{Citation|title=Old Rhinebeck Aerodrome – Wright Whirlwind J-5|url=http://www.oldrhinebeck.org/index.php?option=com_k2&view=item&id=57:wright-whirlwind-j-5&Itemid=107|access-date=2009-12-13}}.</ref> as one powers the museum's recently completed [[Spirit of St. Louis#Old Rhinebeck Aerodrome's reproduction|''Spirit of St. Louis'']] airworthy Ryan NYP reproduction. * A Wright J-5-CA is on public display at the [[Aerospace Museum of California]] Also on display at the San Francisco International Airport, International Terminal. Older Whirlwinds on display are harder to find. The National Museum of Naval Aviation has two J-4s, one of which is a cutaway.<ref name="nmna" /> The [[New England Air Museum]] in [[Windsor Locks]], [[Connecticut]], has a [[Lawrance J-1]], the Whirlwind's direct predecessor.<ref>{{Citation|title=New England Air Museum – Engine Profile: Lawrance J-1|url=http://www.neam.org/inventory/engprofile.asp?ID=38|access-date=2009-12-13|archive-date=2011-07-17|archive-url=https://web.archive.org/web/20110717125520/http://www.neam.org/inventory/engprofile.asp?ID=38|url-status=dead}}.</ref><ref>{{Citation|title=New England Air Museum in Windsor Locks, Connecticut|url=http://www.enginehistory.org/Museums/neam.htm|access-date=2009-12-13|archive-date=2010-04-10|archive-url=https://web.archive.org/web/20100410162213/http://www.enginehistory.org/Museums/neam.htm|url-status=dead}}. The section "Images from Kimble D. McCutcheon" has photos of the museum's J-1.</ref>

==Specifications (R-790 Whirlwind J-5)== {{pistonspecs|   |ref=''[[Type certificate]] data sheet for the Whirlwind J-5'';<ref>[https://archive.today/20120719034918/http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/E68A34E7A9B5DBF1862572C0006DB044?OpenDocument Approved Type Certificate No. 13 (ATC 13) data sheet], available from the [[FAA]]'s [http://rgl.faa.gov Regulatory and Guidance Library] {{Webarchive|url=https://web.archive.org/web/20161112071304/http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/E68A34E7A9B5DBF1862572C0006DB044?OpenDocument |date=2016-11-12 }}.</ref> ''dimensions from "Model Designations of U.S.A.F. Aircraft Engines"'' <ref>[http://enginehistory.org/moddesig.htm "Model Designations of U.S.A.F. Aircraft Engines"] {{Webarchive|url=https://web.archive.org/web/20080820172145/http://enginehistory.org/moddesig.htm |date=2008-08-20 }}, [http://enginehistory.org/ModDesig/I1%201.tif Section I, p. 11 (TIF image)] {{Webarchive|url=https://web.archive.org/web/20160304031906/http://enginehistory.org/ModDesig/I1%201.tif |date=2016-03-04 }}.</ref> |type=9-cylinder [[naturally aspirated]] air-cooled radial piston engine |bore=4.5 in (114 mm) |stroke=5.5 in (140 mm) |displacement=788 cu in (12.91 L) |length=34 to 40 in (86 to 102 cm) |diameter=45 in (114 cm) |width= |height= |weight=520 lb (236 kg) |valvetrain=2 valves per cylinder, pushrod-actuated |supercharger= |turbocharger= |fuelsystem=single three-barrel carburetor<ref>[http://www.machinedesign.com/technologies/100-years-aircraft-engines Machine Design] (retrieved 30 May 2017)</ref> |fueltype=50 [[Octane rating|octane]] |oilsystem= |coolingsystem= |power=220 hp (164 kW) at 2,000 rpm |specpower=0.279 hp/cu-in (12.7 kW/L) |compression=5.1:1 |fuelcon= |specfuelcon= |oilcon= |power/weight=0.423 hp/lb (0.696 kW/kg) |designer= |reduction_gear= |general_other= |components_other= |performance_other= }}

==See also== {{aircontent  |see also= *[[Wright Whirlwind]]  |related= *[[Wright R-540|Wright J-6-5/R-540]] *[[Wright R-760|Wright J-6-7/R-760]] *[[Wright R-975|Wright J-6-9/R-975]]  |similar aircraft=

|lists= *[[List of aircraft engines]]

|similar engines=

}}

==References== {{Commons category|Wright R-790}} ===Notes=== {{Reflist}}

===Bibliography=== * {{Citation | last=McCutcheon | first=Kimble D. | title=Wright J-5 "Whirlwind" | url=http://www.enginehistory.org/Piston/Wright/WrightJ-5.pdf | access-date=2018-04-26 }}. A detailed technical article on the Whirlwind's history and development up to the J-5, from the [http://www.enginehistory.org Aircraft Engine Historical Society]. * {{Citation | title=The Wright J-5 'Whirlwind': An American Engine Which Has Made History | periodical=[[Flight International|Flight]] | volume=XIX | pages=390–392 | date=June 16, 1927 | url=http://www.flightglobal.com/pdfarchive/view/1927/1927%20-%200428.html | issue=24 }}. A contemporary technical article on the features and performance of the J-5.

[[Category:Wright aircraft engines|R-790]] [[Category:1920s aircraft piston engines]] [[Category:Aircraft air-cooled radial piston engines]]