Wright R-975 Whirlwind

{{Short description|Radial aircraft engines in the US}}  {{infobox aero engine |name= R-975 Whirlwind |image= File:Wright R-975 für Sherman-Panzer.jpg |caption= A Continental-built R-975 from a Sherman tank |engine_type= Air-cooled 9-cylinder [[Radial engine|radial piston engine]] |manufacturer= [[Wright Aeronautical]] |builder= [[Continental Aerospace Technologies|Continental Motors]] |national_origin= United States |first_run= |major_applications= {{ubl|[[Beechcraft Staggerwing]] | [[North American BT-9]] | [[BT-13 Valiant|Vultee BT-15 Valiant]] | [[M4 Sherman|M4 Sherman tank]] | [[Piasecki HUP Retriever]] | [[M18 Hellcat]]}} |produced=1929-1950s |number_built = {{ubl|over 7,000 by Wright|over 53,000 by Continental}} |developed_from = |variants_with_their_own_articles = |developed_into = }}

The '''Wright R-975 Whirlwind''' was a series of nine-cylinder, air-cooled [[radial engine|radial]] [[aircraft engine]]s built by the [[Wright Aeronautical]] division of [[Curtiss-Wright]]. These engines had a displacement of about {{cvt|975|cuin|L}}, and power ratings ranging from {{cvt|300|hp}} to {{cvt|550|hp}}, depending on variant and rating basis.<ref name=NASM_R975_46A>{{cite web |title=Continental (Wright) R-975-46A, Radial 9 Engine |url=https://airandspace.si.edu/collection-objects/continental-wright-r-975-46a-radial-9-engine/nasm_A19690364000 |website=Smithsonian National Air and Space Museum |publisher=Smithsonian Institution |access-date=2026-02-09 }}</ref> They were the largest members of the [[Wright Whirlwind]] engine family to be produced commercially, and they were also the most numerous.

During [[World War II]], [[Teledyne Continental Motors|Continental Motors]] built the R-975 under license as a powerplant for Allied tanks and other armored vehicles. Tens of thousands of engines were built for this purpose, dwarfing the R-975's usage in aircraft, where it was overshadowed by the similar [[Pratt & Whitney R-985]]. After the war, Continental continued to produce its own versions of the R-975 into the 1950s; the Continental R-975-46A was rated at {{cvt|550|hp}} at 2,400 rpm.<ref name=NASM_R975_46A />

The R-975 powered the American World War II M18 Hellcat tank destroyer, which is claimed to have been the fastest tracked armored fighting vehicle ever built.<ref name=AmGIMuseum_M18>{{cite web |title=M18 Hellcat (1943–1944) |url=https://americangimuseum.org/collections/restored-vehicles/m18-hellcat-1943-1944/ |website=American G.I. Museum |access-date=2026-02-09}}</ref>

==Design and development== Wright introduced the J-6 Whirlwind family in 1928 to replace the nine-cylinder [[Wright R-790|R-790]] series. The J-6 family included varieties with five, seven, and nine cylinders. The nine-cylinder version was originally known as the '''J-6 Whirlwind Nine''', or '''J-6-9''' for short. The U.S. government designated it as the '''R-975'''; Wright later adopted this and dropped the J-6 nomenclature.

Like all the members of the J-6 Whirlwind family, the R-975 had larger cylinders than the R-790. The piston [[stroke (engine)|stroke]] of 5.5 in (14.0 cm) was unchanged, but the cylinder [[bore (engine)|bore]] was expanded to 5.0 in (12.7 cm) from the R-790's bore of 4.5 in (11.4 cm). While the R-790 was [[Naturally aspirated engine|naturally aspirated]], the R-975, like the other J-6 engines, had a gear-driven [[supercharger]] to boost its power output.

Wright gradually developed the R-975, at first using suffix letters to indicate successive versions. The original R-975 (or J-6-9) was rated for 300 hp (224 kW),<ref name=CW40p11>Curtiss-Wright (1940), p. 11</ref> while the R-975E of 1931 could do 330 hp (246 kW) thanks to an improved [[cylinder head]] design.<ref name=CW83>Curtiss-Wright (1983), p. 2</ref><ref name=CW40p13>Curtiss-Wright (1940), p. 13</ref><ref name=ATC21>FAA Type Certificate Data Sheet ATC 21</ref> Wright later added numeric suffixes to show different power levels. The R-975E-1, introduced the same year as the R-975E, was rated at 365 hp (272 kW) thanks to [[Compression ratio|higher-compression]] pistons and a slightly greater [[revolutions per minute|RPM]] limit.<ref name=CW83 /><ref name=CW40p14>Curtiss-Wright (1940), p. 14</ref><ref name=TC87>FAA Type Certificate Data Sheet TC 87</ref> An even more powerful version, the R-975E-3, was also introduced that year, with greater supercharging and a still higher RPM limit, and was progressively refined until the final model of 1935 could reach 450 hp (336 kW) for takeoff.<ref name=CW83 /><ref name=CW40p18>Curtiss-Wright (1940), pp. 14, 16, 18</ref><ref name=TC125>FAA Type Certificate Data Sheet TC 125</ref>

==Operational history== As the most powerful Whirlwind to be produced, commercially, it was also the most successful. It powered a wide variety of civil utility aircraft, such as the [[Beechcraft Staggerwing]], and various airliners, such as the [[Ford Trimotor|Ford 4-AT-E Trimotor]] and the [[Lockheed Model 10 Electra|Lockheed 10B Electra]]. In addition, it powered U.S. military training aircraft including the [[North American BT-9]] and [[BT-15 Valiant|Vultee BT-15 Valiant]] for the Army and the [[Curtiss-Wright SNC Falcon]] for the Navy. The [[F9C Sparrowhawk|Curtiss F9C Sparrowhawk]] [[parasite fighter]] operated from U.S. Navy airships was also powered by the R-975.

One notable record set by a Wright J-6 Whirlwind-powered aircraft occurred during July 28–30, 1931, when [[Russell Norton Boardman]] and [[John Louis Polando]] flew non-stop from [[Floyd Bennett Field]], on [[Long Island, NY|Long Island]] to [[Istanbul, Turkey]] in the [[Cape Cod (aircraft)|''Cape Cod'']], a [[Bellanca CH-300|Bellanca Special J-300]] high-wing [[monoplane]] in 49:20 hours, establishing a distance record of {{convert|5011.8|mi|km|1}}, the first nonstop record flight to surpasse {{cvt|5000|mi}}.<ref>{{cite news |title='Cape Cod's' Success Climaxes 5 Years [of] Bellanca Records |work=The Sunday Morning Star, Wilmington, DE |date=August 2, 1931 |url=https://news.google.com/newspapers?nid=2293&dat=19310802&id=pM4mAAAAIBAJ&sjid=OgIGAAAAIBAJ&pg=3141,5940038 |access-date=September 4, 2013}}</ref>

However, the R-975 faced heavy competition from [[Pratt & Whitney]]'s [[Pratt & Whitney R-985|R-985 Wasp Junior]] and from their larger [[Pratt & Whitney R-1340|R-1340 Wasp]]. Pratt & Whitney R-985 outsold the Wright R-975 by a wide margin.

Wright's production of the R-975 ceased in 1945, with over 7,000 engines being produced by the company.<ref name=CW83 /><ref>{{Citation|title=Summary of Wright Engine Shipments: 1920 to 1963|url=http://enginehistory.org/Wright/WrightProd.pdf|format=PDF|access-date=December 15, 2009|archive-date=March 3, 2016|archive-url=https://web.archive.org/web/20160303223130/http://enginehistory.org/Wright/WrightProd.pdf|url-status=dead}}. Transcribed from Wright Aeronautical documents by Robert J. Neal T; available from the Aircraft Engine Historical Society's [http://enginehistory.org/reference.htm reference page] {{webarchive|url=https://web.archive.org/web/20100204132400/http://www.enginehistory.org/reference.htm |date=2010-02-04 }}.</ref>

===Production by Continental Motors=== [[File:R-975 engines for M-3 tanks.png|thumb| Tank manufacture (Chrysler). M-3s, the twenty-eight ton "medium" tanks being turned out in [[Detroit Arsenal (Warren, Michigan)|Detroit at the Chrysler tank arsenal]], are powered by nine-cylinder, 400-horsepower Wright Whirlwind aviation-type engines. These men are working on the engine wiring sub-assembly.]]

In 1939 the U.S. Army, which had been using [[Continental R-670]] radial engines in its [[light tank]]s, chose Continental Motors to build the R-975 under license as the engine for its [[M2 Medium Tank|M2]] [[medium tank]]s. Subsequently, the same engine was selected for the [[M3 Lee]] medium tank, the [[M4 Sherman]] medium tank, the Canadian [[Ram tank]] (which used the M3 chassis), the [[M7 Priest]] [[self-propelled gun]], the [[M18 Hellcat]] [[tank destroyer]], and other Allied armored vehicles based on these. Continental versions of the R-975 for armored vehicles included the R-975E-C2, the R-975-C1, and the R-975-C4. In contrast to the 7,000 built by Wright, Continental built over 53,000 R-975 engines.<ref name=CW83 />

When installed in a tank, the R-975 did not have the benefit of being cooled by air slipstream or propeller blast, so a cooling fan was attached to the power shaft and surrounded by a shroud to provide the same effect.

After the war, Continental introduced its own R-975 version for aircraft, the '''R9-A'''. Though it was basically similar to other R-975 engines, and its compression ratio and supercharger gear ratio were unchanged from the R-975E-3, other improvements in the R9-A allowed it to achieve {{cvt|525|hp}} for takeoff,<ref name=E245>FAA Type Certificate Data Sheet E-245</ref> surpassing any Wright version. A military version, the R-975-46, could reach {{cvt|550|hp}}, and was used in [[Piasecki HUP Retriever|Piasecki's HUP Retriever and H-25 Army Mule]] helicopters. Continental's production of R-975 engines continued into the 1950s.

===Other license-built R-975s=== The engine was built in [[Spain]] as the '''Hispano-Suiza 9Q''' or '''Hispano-Wright 9Q''' without modification apart from the use of Hispano's patented [[Nitriding|nitriding finishing]] process and, on one version only, the 9Qdr, an epicyclic output speed reducer.<ref>Lage (2004) pp152-163</ref> The R-975 was also produced under licence by [[Fábrica Nacional de Motores]] in [[Brazil]].<ref>{{cite web | title=O bom caminhão a casa torna | website=Jornal O Globo | date=March 21, 2013 | url=https://oglobo.globo.com/economia/o-bom-caminhao-casa-torna-7905433 | language=pt | access-date=October 1, 2018}}</ref>

==Variants== ;J-6-9 (R-975) :{{cvt|300|hp}} at 2,000 RPM.<ref name=CW40p11 /> ;R-975-20 :{{cvt|300|hp}} for airship use ;R-975E :{{cvt|330|hp}} at 2,000 RPM. Higher power from an improved cylinder head.<ref name=CW83 /><ref name=CW40p13 /><ref name=ATC21 /> ;R-975E-1 :{{cvt|365|hp}} at 2,100 RPM. Higher compression ratio.<ref name=CW83 /><ref name=CW40p14 /><ref name=TC87 /> ;R-975E-3 :{{cvt|420|hp}} at 2,200 RPM up to {{convert|1400|ft|abbr=on}}, {{convert|450|hp|kW|abbr=on}} at 2,250 RPM for takeoff. Increased supercharging, slightly higher compression ratio.<ref name=CW83 /><ref name=CW40p18 /><ref name=TC125 /> ;R-975E-C2 :{{cvt|400|hp}} at 2,400 RPM. Built by Continental Motors under license for use in armored vehicles.<ref name=CW83 /><ref name=CW40p19>Curtiss-Wright (1940), p. 19</ref> ;Continental R9-A :{{cvt|500|hp}} at 2,300 RPM at {{cvt|4000|ft}}, {{cvt|525|hp}} at 2,300 RPM for takeoff. Continental's improved post-war version.<ref name=E245 /> ;Continental R-975-46A :{{cvt|550|hp}} ({{cvt|410|kW|abbr=on}}) at 2,400 RPM. Post-war Continental variant.<ref name=NASM_R975_46A /> ;Hispano-Suiza 9Q :Licence-built R-975 J-6 Whirlwind ;Hispano-Suiza 9Qa :variant of the licence-built R-975 J-6 Whirlwind ;Hispano-Suiza 9Qb :variant of the licence-built R-975 J-6 Whirlwind ;Hispano-Suiza 9Qc :variant of the licence-built R-975 J-6 Whirlwind ;Hispano-Suiza 9Qd :variant of the licence-built R-975 J-6 Whirlwind ;Hispano-Suiza 9Qdr :variant of the licence-built R-975 J-6 Whirlwind

==Applications==

===Wright J-6-9 and R-975=== {{colbegin}} * [[ASJA L2]] * [[Avro Anson|Avro Anson Mk IV]] * [[Beechcraft Staggerwing]] B17R, C17R, and D17R * [[Bellanca CH-300 Pacemaker]] * [[Berliner-Joyce OJ|Berliner-Joyce OJ-2]] * [[Stinson L-13|Caribbean Traders Husky III]] * [[Cessna DC-6|Cessna DC-6A Chief]] * [[Curtiss Kingbird]] * [[Curtiss-Wright CW-14 Osprey|Curtiss-Wright CW-14 Travel Air/Speedwing/Sportsman Deluxe/Osprey]] * [[Curtiss-Wright CW-22]] * [[Curtiss-Wright CW-22|Curtiss-Wright SNC-1 Falcon]] * [[de Havilland Hawk Moth|de Havilland DH.75B Hawk Moth]] * [[Dewoitine D.31]] * [[Dewoitine D.35]] * [[Douglas Dolphin|Douglas RD-1 & C-21/OA-3 Dolphin]] * [[Emsco B-2 Challenger|Emsco B-5 Challenger]] * [[K-1 (airship)|Goodyear K-1]] * [[Curtiss F9C Sparrowhawk]] * [[Fokker Universal]] * [[Fokker F.10|Fokker C-5]] * [[Fokker F.VII|Fokker C-7]] * [[Fokker C.XIV]] * [[Fokker T.VIII]] * [[Ford Trimotor|Ford 4-AT-E Trimotor]] * [[Interstate XTD3R]] * [[Ireland N-2B Neptune]] * [[Keystone XOK]] * [[Keystone-Loening Commuter|Keystone-Loening K-84 Commuter]] * [[Koolhoven F.K.56]] * [[Lockheed Model 12 Electra Junior|Lockheed Model 12B Electra Junior]] * [[McDonnell XV-1]] * [[Messerschmitt M 18]] * [[Noorduyn Norseman|Noorduyn Norseman Mk.1]] * [[North American BT-9]] * [[North American NA-57]] * [[North American NA-64 Yale]] * [[Pitcairn PA-19]] * [[Pitcairn OP-1|Pitcairn-Cierva PCA-2/OP-1]] * [[Pitcairn PA-34|Pitcairn PA-33 & 34/OP-2]] * [[Ryan B-5 Brougham]] * [[Spartan C4|Spartan C4-300]] * [[Stearman Cloudboy|Stearman Model 6C Cloudboy]] * [[Stinson Detroiter|Stinson SM-1F Detroiter]] * [[Timm T-840]] * [[Townsend Thunderbird]] (as rebuilt) * [[Travel Air 2000|Travel Air B9-4000]] * [[Travel Air 6000B]] * [[Travel Air Type R Mystery Ship]] * [[VL Pyry]] * [[Vultee BT-15 Valiant]] * [[Waco JTO]] * [[Waco JYO]] * [[Waco Mailplanes|Waco JWM and JYM mailplanes]] * [[M4 Sherman]] {{colend}}

===Continental R-975=== [[File:The British Army in North Africa 1942 E13233.jpg|thumb|A Grant tank R-975 engine being removed by Royal Army Ordnance Corps mechanics]]

* [[Beechcraft Model 18|Beech D-18C]] * [[Grizzly I cruiser]] – Canadian production of M4A1 Sherman tank * [[Kangaroo (armoured personnel carrier)|Kangaroo]] [[armoured personnel carrier]] modification of M7 Priest and other vehicles * [[Kellett XR-10]] * [[M3 Lee]] * [[M4 Sherman]] * [[M7 Priest]] * [[M18 Hellcat]] * [[M12 gun motor carriage]] * [[M40 gun motor carriage]] * [[McDonnell XV-1]] * [[Piasecki HUP Retriever]] * [[Ram tank]] * [[Sexton (artillery)|Sexton]] self-propelled gun * [[Sikorsky XHJS-1]] (S-53) – prototype helicopter * [[Skink anti-aircraft tank]] – anti-aircraft vehicle based on Grizzly I

==Engines on display== Some museums which have R-975 engines on display: *[[Pima Air & Space Museum]] in [[Tucson]], [[Arizona]] has a Wright R-975.<ref>{{Citation|title=Wright R-975 Whirlwind 9|url=http://www.pimaair.org/collection-detail.php?cid=334|access-date=2009-12-25|archive-date=2013-12-02|archive-url=https://web.archive.org/web/20131202235137/http://www.pimaair.org/collection-detail.php?cid=334|url-status=dead}}.</ref><ref>{{Citation|title=Image Galleries by Gary and Janet Brossett: Pima Air and Space Museum in Tucson, Arizona|url=http://www.enginehistory.org/pima.htm|access-date=2009-12-15|url-status=dead|archive-url=https://web.archive.org/web/20090827014529/http://www.enginehistory.org/pima.htm|archive-date=2009-08-27}}. This page has a photo of a Wright R-975.</ref> * [[Hiller Aviation Museum]] in [[San Carlos, California|San Carlos]], [[California]] has a Wright R-975.<ref>{{Citation|title=Aircraft Engines|url=http://passion-aviation.qc.ca/engines.htm|access-date=2009-12-17|archive-date=2017-07-28|archive-url=https://web.archive.org/web/20170728192438/http://www.passion-aviation.qc.ca/engines.htm|url-status=dead}}. This personal collection of museum aircraft engine photos includes a photo of the museum's R-975 under the section for the Hiller Museum.</ref> * [[National Museum of Naval Aviation]] near [[Pensacola]], [[Florida]] has a Continental R-975.<ref>{{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=2009-12-15|url-status=dead|archive-url=https://web.archive.org/web/20090827015231/http://www.enginehistory.org/nmna.htm|archive-date=2009-08-27}}. This page has a photo of a Continental R-975-46A.</ref> * [[Southern Museum of Flight]] in [[Birmingham, Alabama|Birmingham]], [[Alabama]] has a Continental R-975.<ref>{{Citation|title=Continental R-975-46|url=http://www.southernmuseumofflight.org/Continental%20R-975-46L/index.html|access-date=2009-12-16}}.</ref> * [[Queensland Air Museum]] in [[Caloundra]], [[Queensland]], [[Australia]] has a Continental R-975.<ref>{{Citation|title=Queensland Air Museum: The Engine Collection|url=http://www.qam.com.au/engines/engines.htm|access-date=2009-12-15|url-status=dead|archive-url=https://web.archive.org/web/20091004070233/http://www.qam.com.au/engines/engines.htm|archive-date=2009-10-04}}.</ref><ref>{{Citation|title=Queensland Air Museum: Courtesy of Bruce Vander Mark|url=http://www.enginehistory.org/Museums/QAM/index2.html|access-date=2009-12-15}}. This page has a [http://www.enginehistory.org/Museums/QAM/wrightr975.html photo of a Continental R-975].</ref>

==Specifications (Whirlwind R-975E-3)== {{pistonspecs|   |ref=[[FAA]] [[type certificate]] data sheet for the R-975E-3;<ref name=TC125/> dimensions from Curtiss-Wright (1983). |type=9-cylinder supercharged air-cooled radial piston engine |bore=5.0 in (127 mm) |stroke=5.5 in (140 mm) |displacement=972 cu in (15.93 L) |length=43.0 in (109.2 cm) |diameter=45.0 in (114.3 cm) |width= |height= |weight=675 lb (306 kg) |valvetrain=2 [[4-stroke cycle engine valves|valves]] per cylinder, [[pushrod]]-actuated |supercharger=gear-driven, 10.15:1 [[impeller]] [[gear ratio]] |turbocharger= |fuelsystem= |fueltype=80 [[Octane rating|octane]] |oilsystem= |coolingsystem= |power=420 hp (313 kW) at 2,200 RPM up to 1,400 ft (427 m); 450 hp (336 kW) at 2,250 RPM for takeoff |specpower=0.43 hp/cu-in (19.7 kW/L) |compression=6.3:1 |fuelcon= |specfuelcon= |oilcon= |power/weight=0.62 hp/lb (1.02 kW/kg) |designer= |reduction_gear=Direct drive |general_other= |components_other= |performance_other= }}

{| class="wikitable" style="text-align:center" |+ Specifications for different R-975 variants |- ! Engine !! Power, continuous !! Power, takeoff !! Compression ratio !! Supercharger gear ratio !! Octane rating !! Dry weight |- ! R-975E<ref name=ATC21 /> | 330 hp (246 kW) at 2,000 RPM || || 5.1:1 || 7.8:1 || 73 || 635 lb (288 kg) |- ! R-975E-1<ref name=TC87 /> | 365 hp (272 kW) at 2,100 RPM || || 6.1:1 || 7.8:1 || 73 || 660 lb (299 kg) |- ! R-975E-3<ref name=TC125 /> | 420 hp (313 kW) at 2,200 RPM || 450 hp (336 kW) at 2,250 RPM || 6.3:1 || 10.15:1 || 80 || 675 lb (306 kg) |- ! Continental R9-A<ref name=E245 /> | 500 hp (373 kW) at 2,300 RPM || 525 hp (391 kW) at 2,300 RPM || 6.3:1 || 10.15:1 || 91 || 705 lb (320 kg) |- ! Continental R-975-46A<ref name=NASM_R975_46A /> | — || 550 hp (410 kW) at 2,400 RPM<ref name=NASM_R975_46A /> || — || — || — || 730 lb (331.1 kg)<ref name=NASM_R975_46A /> |}

==See also== {{Aircontent |see also= * [[Wright Whirlwind]] series |related= * [[Wright R-790|Wright J-5/R-790]] * [[Wright R-540|Wright J-6-5/R-540]] * [[Wright R-760|Wright J-6-7/R-760]] |similar engines= * [[Alvis Leonides]] * [[Pratt & Whitney R-985 Wasp Junior]] * [[Bristol Mercury]] |lists= * [[List of aircraft engines]] }}

==References== ===Notes=== {{reflist}}

===Bibliography=== {{refbegin}} *{{Citation|title=Wright Engines - Past and Present|url=http://enginehistory.org/Wright/CWthrough1940.pdf|format=PDF|last=Curtiss-Wright|author-link=Curtiss-Wright|year=1940|pages=11, 13, 14, 16, 18, 19|access-date=December 14, 2009|url-status=dead|archive-url=https://web.archive.org/web/20100215023451/http://enginehistory.org/Wright/CWthrough1940.pdf|archive-date=February 15, 2010}}. Available from the Aircraft Engine Historical Society's [https://web.archive.org/web/20100204132400/http://www.enginehistory.org/reference.htm reference page]. *{{cite book |title= Hispano Suiza in Aeronautics|last=Lage|first=Manual| year=2004|publisher=SAE International|location=Warrendale, USA|isbn=978-0768009972}} *{{Citation|title=Historical Engine Summary (Beginning 1930)|url=http://enginehistory.org/Wright/CWafter1930_2.pdf|format=PDF|last=Curtiss-Wright|author-link=Curtiss-Wright|year=1983|page=2|access-date=December 14, 2009|url-status=dead|archive-url=https://web.archive.org/web/20101031225258/http://enginehistory.org/Wright/CWafter1930_2.pdf|archive-date=October 31, 2010}}. Available from the Aircraft Engine Historical Society's [https://web.archive.org/web/20100204132400/http://www.enginehistory.org/reference.htm reference page]. The following [[Federal Aviation Administration]] [[type certificate]] data sheets, all 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 }}: *R-975E: {{Citation|title=Type Certificate Data Sheet ATC 21|url=http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/822FDD7BD56E5A35862572C0006DAC21?OpenDocument|access-date=December 14, 2009|archive-date=January 25, 2019|archive-url=https://web.archive.org/web/20190125082735/http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/822FDD7BD56E5A35862572C0006DAC21?OpenDocument|url-status=dead}}. *R-975E-1: {{Citation|title=Type Certificate Data Sheet TC 87|url=http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/89D2F878A9A91AE78525670E0066AF85?OpenDocument|access-date=December 14, 2009|archive-date=January 25, 2019|archive-url=https://web.archive.org/web/20190125062143/http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/89D2F878A9A91AE78525670E0066AF85?OpenDocument|url-status=dead}}. *R-975E-3: {{Citation|title=Type Certificate Data Sheet TC 125|url=http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/AE008274229AEC838525670E0066BF4B?OpenDocument|access-date=December 14, 2009|archive-date=January 25, 2019|archive-url=https://web.archive.org/web/20190125060104/http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/AE008274229AEC838525670E0066BF4B?OpenDocument|url-status=dead}}. *Continental R9-A: {{Citation|title=Type Certificate Data Sheet E-245|url=http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/D1B47D14E078F2428525670E004371FE?OpenDocument|access-date=December 15, 2009|archive-date=January 25, 2019|archive-url=https://web.archive.org/web/20190125095103/http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgMakeModel.nsf/0/D1B47D14E078F2428525670E004371FE?OpenDocument|url-status=dead}}. {{refend}}

==External links== {{Commons category|Wright R-975}} * Engine Data Sheets: US Aero Engines — [http://www.oldengine.org/members/diesel/Duxford/usaero16.htm R-975 page] {{Webarchive|url=https://web.archive.org/web/20090628105342/http://www.oldengine.org/members/diesel/Duxford/usaero16.htm |date=2009-06-28 }}

[[Category:Aircraft air-cooled radial piston engines]] [[Category:Wright aircraft engines|R-975]] [[Category:1920s aircraft piston engines]] [[Category:Tank engines]]