Wright R-2600 Twin Cyclone

{{short description|American WWII-era aircraft engine}} {{Use American English|date=April 2019}}  {{infobox aero engine |name = R-2600 |image = File:Wright R-2600 1.jpg |caption = Wright R-2600 Cyclone radial engine |engine_type= Radial engine |manufacturer= Wright Aeronautical |national_origin= United States |first_run= 1935 |major_applications= {{plainlist| * {{awrap|Curtiss SB2C Helldiver}} * {{awrap|Douglas A-20 Havoc}} * {{awrap|Grumman TBF Avenger}} * {{awrap|Martin PBM Mariner}} * {{awrap|North American B-25 Mitchell}} * {{awrap|Vultee Vengeance}} }} |number_built = 85,374<ref>{{cite web|archive-url=https://web.archive.org/web/20211010173806/http://enginehistory.org/Piston/Wright/WrightShipments1920-1930.pdf |archive-date=2021-10-10 | url=http://enginehistory.org/Piston/Wright/WrightShipments1920-1930.pdf| title=SUMMARY OF WRIGHT ENGINE SHIPMENTS 1920 – 1930| access-date=2023-09-18}}</ref> |developed_from = Wright R-1820 Cyclone |developed_into = |variants_with_their_own_articles = }}

The '''Wright R-2600 Cyclone 14''' (also called '''Twin Cyclone''') is an American radial engine developed by Curtiss-Wright, and widely used in aircraft in the 1930s and 1940s.

==History== In 1935, Curtiss-Wright began work on a more powerful version of their successful R-1820 Cyclone 9. The result was the R-2600 Twin Cyclone, with 14 cylinders arranged in two rows. The {{convert|1,600|hp|kW PS|lk=on|abbr=on}} R-2600-3 was originally intended for the C-46 Commando (being fitted to the prototype CW-20A). It was also the original engine choice for the F6F Hellcat; a running change (one which would not stop production) for the CW-20A, and one in late April 1942 for the second XF6F-1, led to the adoption of the {{convert|2,000|hp|kW PS|abbr=on}} Pratt & Whitney R-2800 Double Wasp in the R-2600's place for both designs.

The Twin Cyclone went on to power several important American World War II aircraft, including the A-20 Havoc, B-25 Mitchell, TBF Avenger, SB2C Helldiver, and the PBM Mariner.

Over 50,000 R-2600s were built at plants in Paterson, New Jersey, and Cincinnati, Ohio.

==Variants== The following is a list of known R-2600 models. Engines would receive a three-part designation from Curtiss-Wright. For example, "R-2600-1;" the "R" indicating a "radial engine," "2600" indicating an engine displacement of {{cvt|2,600|cuin|L}}, and "1" indicating the internal model number, usually assigned chronologically. Engines accepted by the U.S. government were assigned a separate, three-part governmental designation. For example, the "R-2600-13" was accepted into service as the "GR-2600-B655;" the "GR" indicating a {{nowrap|"(geared) radial engine,"}} the "2600" indicating an engine displacement of {{cvt|2,600|cuin|L}}, and "B655" indicating the governmental model number. The Curtiss-Wright designation is usually utilized more often than the governmental designation, and the U.S. government utilized both designations interchangeably and often together.

The Curtiss-Wright designation will be listed first, followed by the — when known — governmental designation in parentheses (the lack of a governmental designation does not indicate that the model was not accepted into governmental service). Engines known only by their governmental designation will be listed at the bottom.

* '''R-2600-1''' – 1,600 hp (1,194 kW) * '''R-2600-2''' – 1,500 hp (1,118 kW); Prototype variant; Few were made.<ref name="Friedman 1">{{cite book |last1=Friedman |first1=Norman |url=https://books.google.com/books?id=OZMTDgAAQBAJ |title=Fighters Over the Fleet Naval Air Defence from Biplanes to the Cold War |edition=1 |publisher=Pen & Sword Books |date=30 October 2016 |page=61 |isbn=9781848324060 |quote="The prototype R-2600-2, rated at 1,500hp for take-off ..." }}</ref> * '''R-2600-3''' – 1,600 hp (1,194 kW) * '''R-2600-4''' – 1,650 hp (1,230 kW)<ref>{{cite press release |url=http://www.dtvmovements.co.uk/Archivesmonths/1982/1982%20-%20Oct.pdf |title=Teesside Aviation News |location=Teesside, UK |publisher=Teesside Aviation Society |date=1982-11-01 |access-date=2021-04-06 |quote="... for the RAF, 19 were experimentally fitted with R-2600-4-53 Cyclones ... engines of 1650 hp." }}</ref> * '''R-2600-5''' ('''GR-2600-A79''') – 1,600 hp (1,194 kW); Few made, possibly three or less. Utilized a three-speed supercharger.<ref>{{cite book|last=Bingham|first=Victor|title=Major Piston Aero-engines of World War II|publisher=Airlife|location=United Kingdom|year=1998|isbn=9781840370126|page=147|url=https://books.google.com/books?id=F5MgAQAAIAAJ|url-status=live|archive-url=https://web.archive.org/web/20250815001554/https://www.google.com/books/edition/Major_piston_aero_engines_of_World_War_I/F5MgAQAAIAAJ?hl=en&sa=X&ved=2ahUKEwjc_Y6JxIuPAxVhFlkFHQMtC38QiqUDegQIBRA_|archive-date=15 August 2025|access-date=15 August 2025|quote=[...] the R-2600-5 (or -A79) is of interest as it introduced a three-speed supercharger.}}</ref> * '''R-2600-6''' – 1,600 hp (1,194 kW) *'''R-2600-7''' — 1,700 hp (1,268 kW);<ref>{{cite document |title=AN 02-35HB-2: Service Instructions; R-2600-7, -8, -8A, -9, -12, -13, -31 Aircraft Engines |publisher=The Drury Printing Company |date=25 December 1943 |page=7}}</ref> Provisioned for a turbo-supercharger. Unknown use and unknown quantity produced. * '''R-2600-8'''<ref name="USAF_Parts">{{cite report |title=Parts Catalog; Models R-2600-8, 8A, 12, 13, 20, 22, 29, 31; T.O. 2R-R2600-4 (Formerly AN 02A-35H-4)|publisher=Secretary of the Air Force and the Chief of the Bureau of Aeronautics via Central Press, Inc. |location=Marion, Indiana, USA |date=1951-09-13}}</ref> – 1,700 hp (1,268 kW); Utilized, among other uses, by the National Advisory Committee for Aeronautics (NACA) to test water injection generally and in-regards to the R-2600 series, specifically. Without water injection, the R-2600-8 was capable of producing 1,700 hp (1,268 kW) at 2400 rpm for limited periods at take-off power. With water injection, testing was able to achieve 1,943 hp (1,449 kW) (maintaining the standard 2400 rpm), a 14.3% increase in power, with a fuel efficiency increase of 5%. By increasing to 2600 rpm, testing was able to achieve 2,060 hp (1,536 kW), a 21% increase in power, while providing a 4% boost in fuel efficiency. Water injection would feature heavily in mid- to late-WWII U.S. engines, including some early jet engines<ref>{{cite report |title=National Advisory Committee for Aeronautics Wartime Report "A Cooling Correlation of the Wright R-2600-8 Engine" |author=Robert J. Koenig and Helmuth W. Engelman |publisher=Aircraft Engine Research Laboratory via NACA |location=Cleveland, Ohio |date=February 1945 |url=https://apps.dtic.mil/sti/tr/pdf/ADB804996.pdf |archive-url=https://web.archive.org/web/20250405213648/https://apps.dtic.mil/sti/tr/pdf/ADB804996.pdf |archive-date=2025-04-05 |page=20}}</ref> * '''R-2600-8A'''<ref name="USAF_Parts"></ref> – 1,700 hp (1,268 kW); Powered the Brewster SB2A-4 Buccaneer, 162 SB2As built for the Kingdom of the Netherlands for service in the Dutch East Indies by the Royal Netherlands East Indies Army Air Force. The Dutch East Indies were overrun by Imperial Japan in early 1942 before a single Buccaneer was delivered. The Dutch SB2As were requisitioned by the U.S. Navy (USN). The USN provided them to the U.S. Marine Corps (USMC), complete with Dutch markings. The USN and USMC would designate these 162 models as the SB2A-4. The USMC utilized these models to establish their first night fighter squadron, VMF(N)-531<ref>{{cite book |last=Donald |first=David |title=American Warplanes of World War II |year=2000 |publisher=Barnes & Noble |location=United States |isbn=9780760722749 |page=37 |url=https://books.google.com/books?id=Bw980AEACAAJ |archive-url=https://web.archive.org/web/20250329225210/https://www.google.com/books/edition/American_Warplanes_of_World_War_II/Bw980AEACAAJ?hl=en |archive-date=2025-03-29}}</ref> * '''R-2600-9''' – 1,700 hp (1,268 kW); Powered the initial production run of the B-25 Mitchell, the B-25 (24 built), B-25A (40 built), and the B-25B (designated the "Mitchell Mk.I" by the Royal Air Force; 23 built). The B-25C (1,625 built) would see the -9 replaced with the R-2600-13<ref>{{cite book |last=Stemp |first=P. D. |title=Kites, Birds & Stuff - Aircraft of the U.S.A. - North American Aircraft |date=2016-11-20 |publisher=Lulu.com |isbn=9781326828158 |url=https://books.google.com/books?id=Ffv8DQAAQBAJ |archive-url=https://web.archive.org/web/20250331233501/https://www.google.com/books/edition/Kites_Birds_Stuff_Aircraft_of_the_U_S_A/Ffv8DQAAQBAJ?hl=en |archive-date=2025-03-31 |quote=Powered by two 1,700 hp. Wright R-2600-9 Cyclone radial engines.}}</ref> * '''R-2600-10''' ('''GR-2600-B676''') – 1,700 hp (1,268 kW); Experimental high-altitude R-2600 variant with an "advanced" two-stage mechanical supercharger, vice the usual single-stage supercharger. The 2600-10 also served as a testbed for turbo-supercharging the 2600 series (which would come to fruition with the R-2600-16). Very few were produced.<ref name="Francillon 2021-04-03">{{cite book |last1=Francillon |first1=Renè |url=https://books.google.com/books?id=MnZTAAAAMAAJ |title=Grumman Aircraft Since 1929 |publisher=Putnam Aeronautical |year=1989 |page=196 |isbn=9780851778358 |access-date=2021-04-03 }}</ref><ref name="Grossnick 2021-04-03">{{cite encyclopedia |last1=Grossnick |first1=Roy |title= TBF/TBM Avenger |encyclopedia=Dictionary of American Naval Aviation Squadrons |volume= I: The History of VA, VAH, VAK, VAL, VAP, and VFA Squadrons |chapter-url=https://www.history.navy.mil/content/dam/nhhc/research/histories/naval-aviation/dictionary-of-american-naval-aviation-squadrons-volume-1/pdfs/Dict-of-Amer-Avia-Sq-v1.pdf |chapter=Appendix 1: Aircraft Data—Technical Information and Drawings |location=Washington Navy Yard, Washington D.C. |publisher=Naval Historical Center, Department of the Navy |date=1995 |page=512 |isbn=0-945274-29-7 |access-date=2021-04-03 |via=Naval History and Heritage Command }}</ref> The R-2600-10 powered Grumman's * '''XR-2600-10''' – 1,900 hp (1,420 kW); Experimental version of the R-2600-10 uprated to 1,900 hp (1,420 kW), a 12% increase over the 1,700 hp (1,268 kW) R-2600-10. The XR-2600-10 powered two examples of the Grumman TBF Avenger, the XTBF-2 (1 built) and the TBM-2 (1 built). Neither the XTBF-2, TBM-2, nor the XR-2600-10 would enter serial production * '''R-2600-11''' – 1,600 hp (1,194 kW);<ref name="USCAA 2021-04-03">{{cite book |url= https://books.google.com/books?id=F5ovAAAAMAAJ |title=United States Civil Aeronautics Administration Aircraft Listing |publisher=United States Civil Aeronautics Administration |year=1949 |page=68 |access-date=2021-04-03 }}</ref> * '''R-2600-12'''<ref name="USAF_Parts"></ref> ('''GR-2800-B766''') – 1,700 hp (1,268 kW) * '''R-2600-13'''<ref name="USAF_Parts"></ref> ('''GR-2600-B655''')<ref>{{cite web |title=Wright Cyclone R-2600-13 (GR-2600-B655), 2-Row, Radial 14 Engine |url=https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-url=https://web.archive.org/web/20240816192341/https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-date=2024-08-16 |publisher=National Air and Space Museum |quote=...GR-2600-B655...}}</ref> – 1,700 hp (1,268 kW);<ref>{{cite web |title=Wright Cyclone R-2600-13 (GR-2600-B655), 2-Row, Radial 14 Engine |url=https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-url=https://web.archive.org/web/20240816192341/https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-date=2024-08-16 |publisher=National Air and Space Museum |quote=R-2600-13... Power rating: 1,268 kW (1,700 hp) at 2,600 rpm...}}</ref><ref>{{cite book |title=Dictionary of American Naval Fighting Ships, Volume 5 |author=Mary F. Loughlin, Samuel Loring Morison, Robert J. Devlin, Everett Gordon Bowen-Hassell, John M. Patton, James L. Mooney, U.S. Naval Historical Center, United States Naval History Division |publisher=Navy Department, Office of the Chief of Naval Operations, Naval History Division |date=1970 |language=English |pages=589 |url=https://books.google.com/books?id=8Sosw4sYOpYC |archive-url=https://web.archive.org/web/20250529001156/https://www.google.com/books/edition/Dictionary_of_American_Naval_Fighting_Sh/8Sosw4sYOpYC?hl=en |archive-date=2025-05-29 |quote=...Wright R-2600-13, 1700 h.p....}}</ref> Powered the Brewster SB2A-4; Curtiss P-37; Douglas A-24A/B/C; Martin A-30A/B; North American XB-25E/F/G, B-25C/D/G/H/J, CB-25J, TB-25J, and F-10; Lockheed O-56/RB-34B/B-37/RB-37; Short Brothers Stirling; and the Vultee A-35A & A-35B.<ref>{{cite web |title=Wright Cyclone R-2600-13 (GR-2600-B655), 2-Row, Radial 14 Engine |url=https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-url=https://web.archive.org/web/20240816192341/https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-date=2024-08-16 |publisher=National Air and Space Museum |quote=R-2600-13 powered the: Brewster SB2A-4; Curtiss P-37; Douglas A-24A/B/C; Martin A-30A/B; North American XB-25E/F/G, B-25C/D/G/H/J, CB-25J, TB-25J, and F-10; Northrop A-35; Lockheed B-37; Short Brothers Stirling; Vega O-56; and Vultee A-31A, Vultee XA-35A, A-35A/B.}}</ref> The -13 would also power a maritime patrol-bomber variant of the B-25, the PBJ-1D.<ref>{{cite book |title=Dictionary of American Naval Fighting Ships, Volume 5 |author=Mary F. Loughlin, Samuel Loring Morison, Robert J. Devlin, Everett Gordon Bowen-Hassell, John M. Patton, James L. Mooney, U.S. Naval Historical Center, United States Naval History Division |publisher=Navy Department, Office of the Chief of Naval Operations, Naval History Division |date=1970 |language=English |pages=589 |url=https://books.google.com/books?id=8Sosw4sYOpYC |archive-url=https://web.archive.org/web/20250529001156/https://www.google.com/books/edition/Dictionary_of_American_Naval_Fighting_Sh/8Sosw4sYOpYC?hl=en |archive-date=2025-05-29 |quote=Data For: PBJ-1D... Power Plant: Two Wright R-2600-13, 1700 h.p....}}</ref> 13,494 R-2600-13s were built between April 1941 and January 1944<ref>{{cite web |title=Wright Cyclone R-2600-13 (GR-2600-B655), 2-Row, Radial 14 Engine |url=https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-url=https://web.archive.org/web/20240816192341/https://airandspace.si.edu/collection-objects/wright-cyclone-r-2600-13-gr-2600-b655--2-row-radial-14-engine/nasm_A19660456000 |archive-date=2024-08-16 |publisher=National Air and Space Museum |quote=R-2600-13 powered the: Brewster SB2A-4; Curtiss P-37; Douglas A-24A/B/C; Martin A-30A/B; North American XB-25E/F/G, B-25C/D/G/H/J, CB-25J, TB-25J, and F-10; Northrop A-35; Lockheed B-37; Short Brothers Stirling; Vega O-56; and Vultee A-31A, Vultee XA-35A, A-35A/B. A total of 13,494 R-2600-13 engines were built between April 1941 and January 1944... Power rating: 1,268 kW (1,700 hp) at 2,600 rpm...}}</ref> * '''R-2600-14''' – 1,700 hp (1,268 kW); Powered at least one of the prototypes of the Grumman F7F Tigercat (a twin-engined heavy fighter-interceptor), the XF7F-1. The R-2600-14 was a development of the R-2600-10 and featured "advanced supercharging" for high-altitude performance. The R-2600-14 was developed specifically for the Tigercat project. The engines were replaced in initial production versions by the 2,100 hp (1,566 kW) R-2800-22, ultimately trading superior high-altitude performance for the R-2800-22's significantly improved low- and medium-altitude performance.<ref>{{cite journal |title=Naval Aircraft; F7F Tigercat |author=Hal Andrews |journal=Naval Aircraft |date=1998 |url=https://www.history.navy.mil/content/dam/nhhc/research/histories/naval-aviation/Naval%20Aviation%20News/1990/1998/july-august/tigercat.pdf |archive-url=https://web.archive.org/web/20231129024155/https://www.history.navy.mil/content/dam/nhhc/research/histories/naval-aviation/Naval%20Aviation%20News/1990/1998/july-august/tigercat.pdf |archive-date=2023-11-29 |quote=Both the Army and Navy planned to use Wright R-2600 engines with advanced supercharging... XF7F-1 engineering design began in late spring 1942, with mockup inspection in September. By summer 1943, production was being negotiated and a major engine change from Wright's R-2600 to the Pratt and Whitney R-2800 eliminated supporting an engine model unique to the F7F...}}</ref> * '''R-2600-15''' – 1,800 hp (1,342 kW); Planned to power the XB-33A, a prototype model of the B-33 Super Marauder (itself a high-altitude version of the Martin B-26 Marauder). The project was cancelled, and neither the prototype XB-33A or production B-33A were ever built.<ref name="Andrade 1979, p 51">Andrade 1979, p 51</ref> * '''R-2600-16''' – 1,700 hp (1,268 kW); Similar to the R-2600-10 & -14, the -16 was tuned for high-altitude performance; The -16 was designed to be mounted alongside a turbo-supercharger system. The -16 would power the second Grumman F6F, the initial XF6F-2.<ref name="Thruelsen 1976, p 193">Thruelsen 1976, p 193</ref> The XF6F-1 and XF6F-2 was found to be lacking in performance; The XF6F-2 designation was re-used on a third prototype, an R-2800-powered XF6F-2. The R-2800 would carry-over into the final prototype, the XF6F-3, as well as production models.<ref>{{cite book |last=White |first=Graham |title=R-2800: Pratt & Whitney's Dependable Masterpiece |location=Warrendale, Pennsylvania, United States |publisher=Society of Automotive Engineers |year=2001 |isbn=9780768002720 |page=508 |url=https://books.google.com/books?id=6OObEAAAQBAJ |archive-url=https://web.archive.org/web/20250401023051/https://www.google.com/books/edition/R_2800/6OObEAAAQBAJ?hl=en |archive-date=2025-04-01 |quote=XF6F-2*... This designation was used twice... Intended to be powered by turbocharged version of Wright R-2600-16, instead re-engined with R-2800.}}</ref> * '''R-2600-17''' – 1,700 hp (1,268 kW); May have powered a Vultee A-31 Vengeance (or A-35) variant. May have also powered one of the C-55 prototypes, a derivative of the C-46 Commando<ref>{{cite book |title=The Illustrated Encyclopedia of Aviation |volume=20 |location=United States |publisher=Marshall Cavendish Corporation |year=1979 |page=2304 |isbn=978-0-85685-318-0 |url=https://books.google.com/books?id=SZpTAAAAMAAJ |archive-url=https://web.archive.org/web/20250401225808/https://www.google.com/books/edition/The_Illustrated_Encyclopedia_of_Aviation/SZpTAAAAMAAJ?hl=en&gl=US |archive-date=2025-04-01 |quote=...clean design was maintained in the Vengeance, though the cranked wing panton made some observers think (wrongly) that the aircraft's centre of gravity had given problems. Power was provided by a 1,600hp Cyclone R-2600-9 or 1,700hp R-2600-17.}}</ref> * '''R-2600-17A''' – 1,750 hp (1,305 kW); Uprated R-2600-17 * '''R-2600-19''' ('''GR-2600-A5B''') – 1,600 hp (1,194 kW), 1,660 hp (1,237 kW) * '''R-2600-20'''<ref name="USAF_Parts"></ref> – 1,700 hp (1,268 kW), 1,900 hp (1,420 kW)<ref name="Grossnick 2025-03-22">{{cite encyclopedia |last1=Grossnick |first1=Roy |title= TBF/TBM Avenger |encyclopedia=Dictionary of American Naval Aviation Squadrons |volume= I: The History of VA, VAH, VAK, VAL, VAP, and VFA Squadrons |chapter-url=https://www.history.navy.mil/content/dam/nhhc/research/histories/naval-aviation/dictionary-of-american-naval-aviation-squadrons-volume-1/pdfs/Dict-of-Amer-Avia-Sq-v1.pdf |chapter=Appendix 1: Aircraft Data—Technical Information and Drawings |location=Washington Navy Yard, Washington D.C. |publisher=Naval Historical Center, Department of the Navy |date=1995 |page=512 |isbn=0-945274-29-7 |access-date=2025-03-22 |via=Naval History and Heritage Command }}</ref> * '''R-2600-21''' ('''GR-2600-A5B''') – 1,500 hp (1,118 kW), 1,600 hp (1,194 kW), 1,700 hp (1,268 kW); Experimental R-2600-19 engines modified with new carburetors and cylinder baffles. -21s were "converted" back into -19s and retained their governmental GR-2600-A5B designation * '''R-2600-22'''<ref name="USAF_Parts"></ref> – 2,100 hp (1,566 kW); Powerplant of the experimental XSB2C-6 Helldiver<ref>{{cite book |last1=Kinzey |first1=Bert |last2=Roszak |first2=Rock |title=U. S. Navy and Marine Carrier-Based Aircraft of World War II |year=2018 |publisher=Detail & Scale |location=N.p. |page=82 |isbn=9780999195901 |url=https://books.google.com/books?id=uMA7EQAAQBAJ |quote=...the XSB2C-6 was an attempt to solve this problem. Wright developed the R-2600-22 which developed 2,100 horsepower for takeoff...}}</ref> as well as the PBM-3D Mariner.<ref>{{cite report |title=Ground-stand Cooling Investigation of an R-2600-22 Engine in a PBM-3D Nacelle |author=Prince, William R. |date=1946-01-01 |publisher=NACA (National Advisory Committee for Aeronautics) |id=NACA-WR-L-754, NACA-MR-L5L18 |access-date=2013-08-16 |url=https://ntrs.nasa.gov/citations/19930093215}}</ref> Power is referenced as low as 1,900 hp (1,418 kW)<ref>{{cite book |last=Johnson |first=E.R. |title=American Flying Boats and Amphibious Aircraft: An Illustrated History |year=2016 |publisher=McFarland, Incorporated, Publishers |location=United Kingdom |page=182 |isbn=9780786457083 |url=https://books.google.com/books?id=AtqOSxG9N1YC |quote=An upgrade to 1,900hp R-2600-22 engines...}}</ref><ref>{{cite journal |last=Dorr |first=Robert F. |title=Variant Briefing: Martin Flying Boats: Mariner, Mars and Marlin |journal=Wings of Fame |volume=7 |year=1997 |page=125 |location=London |publisher=Aerospace Publishing |isbn=1-874023-97-2}}</ref> and as high as 2,100 hp (1,566 kW)<ref>{{cite book |last1=Kinzey |first1=Bert |last2=Roszak |first2=Rock |title=U. S. Navy and Marine Carrier-Based Aircraft of World War II |year=2018 |publisher=Detail & Scale |location=N.p. |page=82 |isbn=9780999195901 |url=https://books.google.com/books?id=uMA7EQAAQBAJ |quote=...the XSB2C-6 was an attempt to solve this problem. Wright developed the R-2600-22 which developed 2,100 horsepower for takeoff...}}</ref><ref>{{cite book |last=Kammen |first=Michael G. |title=Operational History of the Flying Boat: Open Sea and Seadrome Aspects: Selected campaigns, World War II |year=1959 |publisher=Office of the Scientific Historian, Bureau of Aeronautics |location=United States |page=71 |url=https://books.google.com/books?id=aDGsLNqsQEIC |quote=Engine take-off horse power [sic]... 2,100... Engine...R-2600-22}}</ref> * '''R-2600-23''' ('''GR-2600-A5B-0''') - 1,600 hp (1,194 kW), 1,675 hp (1,250 kW); The R-2600-23 required 91 octane fuel (other R-2600 models accepted higher-octane fuel).<ref>{{cite report |title=Aircraft Listing: July 1, 1949 |date=1949-07-01 |publisher=U.S. Department of Commerce, Civil Aeronautics Administration |location=United States |page=68 |url=https://books.google.com/books?id=lI9aBDLDbBwC |archive-url=https://web.archive.org/web/20250330210944/https://www.google.com/books/edition/Aircraft_Listing/lI9aBDLDbBwC?hl=en&kptab=overview |archive-date=2025-03-30 |quote=R-2600-23... 91 Octane... Sea level... 1600 hp...}}</ref> The -23 was normally rated at 1,600 hp (1,194 kW) at sea level while at take-off power, but could be "uprated" to 1,675 hp (1,250 kW). These "uprated" -23s were utilized in the Douglas A-20G Havoc, the most-produced (2,850 built) A-20 model<ref>{{cite book |last=Johnson |first=E.R. |title=American Attack Aircraft Since 1926 |year=2012 |publisher=McFarland, Incorporated, Publishers |location=United States |isbn=9780786471621 |page=67 |url=https://books.google.com/books?id=oWorAwAAQBAJ |archive-url=https://web.archive.org/web/20250330212430/https://www.google.com/books/edition/American_Attack_Aircraft_Since_1926/oWorAwAAQBAJ?hl=en |archive-date=2025-03-30 |quote=The A-20G was the most widely produced version of the series, a total of 2,850 being built at Douglas's Santa Monica plant in 1943 and 1944. Influenced largely by Pacific-based A-20As and Cs, the G model introduced a solid nose equipped initially with four fixed 20-mm and two .50-caliber machine guns, along with R-2600-23 engines uprated to 1,675-hp.}}</ref> * '''R-2600-25''' – 1,350 hp (1,007 kW)<ref>{{cite book |last=Griffiths |first=Harold |title=Mathematics for Aircraft Engine Mechanics |year=1944 |publisher=McGraw-Hill |location=United Kingdom |page=317 |quote=R-2600-25 has a 100 per cent normal rated hp. of 1,350 at 2,300 r.p.m. with a manifold pressure of 37.0 "Hg at 5,800' altitude...}}</ref> * '''R-2600-27''' – 2,000 hp (1,491 kW)<ref>{{cite web |title=North American B-25 Mitchell |url=https://www.classicwarbirds.co.uk/american-aircraft/north-american-b-25-mitchell.php |archive-url=https://web.archive.org/web/20241110142056/https://www.classicwarbirds.co.uk/american-aircraft/north-american-b-25-mitchell.php |archive-date=2024-11-10 |publisher=Classic Warbirds |quote=...the 2,000-hp Pratt & Whitney R-2600-27 engine.}}</ref> * '''R-2600-28''' – No known information; Occasionally the 2,100 hp (1,566 kW) '''R-2600-22''' is referred to as the R-2600-28 * '''R-2600-29'''<ref name="USAF_Parts"></ref> – 1,700 hp (1,268 kW),<ref>{{cite report |title=Aircraft Engine Listing, May 15, 1950 |date=1950-05-15 |publisher=U.S. Department of Commerce, Civil Aeronautics Administration |location=United States |page=42 |url=https://books.google.com/books?id=x5cRMjex7QsC |quote=R-2600-29... Take-off... HP... 1700...}}</ref><ref>{{cite book |title=United States Marine Corps Aircraft Since 1913 |author=E.R. Johnson and Lloyd S. Jones |publisher=McFarland & Company |date=2018-04-17 |isbn=9781476663470 |pages=146–147 |url=https://books.google.com/books?id=J5hUDwAAQBAJ |archive-url=https://web.archive.org/web/20250528033055/https://www.google.com/books/edition/_/J5hUDwAAQBAJ?hl=en&sa=X&ved=2ahUKEwjJq8DJnMWNAxXCGVkFHYZGKdYQ7_IDegQIERAC |archive-date=2025-05-28 |quote=...1,700hp Wright R-2600 29...}}</ref> 1,850 hp (1,380 kW);<ref>{{cite book |last1=Kittel |last2=Graf |last3=Mantelli |last4=Brown |title=B-24 Liberator - B-25 Mitchell - B-26 Marauder |year=2017 |publisher=REI (Rifreddo) |isbn=9782372973243 |page=72 |url=https://books.google.com/books?id=u0ctDgAAQBAJ |quote=R-2600-29 — 1.850 hp (1.380 kW)}}</ref><ref>{{cite book |last1=Mantelli |last2=Brown |last3=Kittel |last4=Graf |title=North American B-25 Mitchell |year=2015 |publisher=Edizioni R.E.I. |isbn=9782372971997 |page=19 |quote=R-2600-29 — 1,850 hp (1,380 kW)}}</ref> Likely the most-produced R-2600 variant, with at least 17,848 produced. The R-2600-29 powered the B-25C and -25D (including the PB1-1J, a maritime patrol bomber variant of the B-25)<ref>{{cite book |title=United States Marine Corps Aircraft Since 1913 |author=E.R. Johnson and Lloyd S. Jones |publisher=McFarland & Company |date=2018-04-17 |isbn=9781476663470 |pages=146–147 |url=https://books.google.com/books?id=J5hUDwAAQBAJ |archive-url=https://web.archive.org/web/20250528033055/https://www.google.com/books/edition/_/J5hUDwAAQBAJ?hl=en&sa=X&ved=2ahUKEwjJq8DJnMWNAxXCGVkFHYZGKdYQ7_IDegQIERAC |archive-date=2025-05-28 |quote=PBJ-1J... Powerplants: Two 1,700hp Wright R-2600 29...}}</ref> as well as the A-20G and -H. An '''R-2600-29A''' is also referenced in various manuals and reports as the powerplant of the twin-engine TB-25N medium bomber trainer aircraft. The R-2600-29A is referenced interchangeably with the '''R-2600-35'''.<ref>{{cite report |title=Department of Defense Appropriations for 1959: Hearings Before the Subcommittee of the Committee on Appropriations, United States Senate, Eighty-fifth Congress, Second Session, on H.R. 12738, Making Appropriations for the Department of Defense for the Fiscal Year Ending June 30, 1959, and for Other Purposes |year=1958 |publisher=U.S. Government Printing Office |location=United States |url=https://books.google.com/books?id=p340AAAAIAAJ |quote=R-2600-29A/35}}</ref> * '''R-2600-31'''<ref name="USAF_Parts"></ref> – 1,700 hp (1,268 kW); The Lockheed B-34 Ventura, originally powered by the R-2800, was chosen to be converted into a large, armed reconnaissance and observation aircraft, designated as the "O-56." This was later changed to "RB-34B," then to "B-37," and finally to "RB-37." 500 RB-37s were ordered, but the contract was cancelled after 18 were delivered. As the RB-37 was not expected to carry bomb loads, it was felt a lower-powered engine would suffice; The 2,000 hp (1,491 kW) R-2800 was replaced by either the 1,700 hp (1,268 kW) R-2600-31 or, with early models, the R-2600-13 * '''R-2600-33''' – 1,700 hp (1,268 kW)<ref>{{cite report |title=National Air and Space Museum Technical Reference Files: Propulsion |author=NASM staff |year=2017 |publisher=Smithsonian National Air and Space Museum |url=https://sirismm.si.edu/EADpdfs/NASM.XXXX.1183.B.pdf |archive-url=https://web.archive.org/web/20240722173019/https://sirismm.si.edu/EADpdfs/NASM.XXXX.1183.B.pdf |archive-date=2024-07-22 |quote=...R-2600-33...}}</ref> * '''R-2600-34''' – 2,100 hp (1,566 kW); Two R-2600-34s served as the powerplants of the early versions of the PBM-5 Mariner, before the switch-over to the R-2800<ref>{{cite book |last=Wilson |first=Stewart |title=Aircraft of WWII |year=1998 |publisher=Aerospace Publications |location=United Kingdom |page=116 |isbn=9781875671359 |quote=PBM-5 — two 2100hp (1566kW) R-2600-34; four-bladed propellers.}}</ref> * '''R-2600-35''' – 1,700 hp (1,268 kW),<ref>{{cite report |title=Aircraft Engine Listing, May 15, 1950 |date=1950-05-15 |publisher=U.S. Department of Commerce, Civil Aeronautics Administration |location=United States |page=42 |url=https://books.google.com/books?id=x5cRMjex7QsC |quote=R-2600-29... Take-off... HP... 1700...}}</ref> 1,850 hp (1,380 kW);<ref>{{cite book |last1=Kittel |last2=Graf |last3=Mantelli |last4=Brown |title=B-24 Liberator - B-25 Mitchell - B-26 Marauder |year=2017 |publisher=REI (Rifreddo) |isbn=9782372973243 |page=72 |url=https://books.google.com/books?id=u0ctDgAAQBAJ |quote=R-2600-29 — 1.850 hp (1.380 kW)}}</ref><ref>{{cite book |last1=Mantelli |last2=Brown |last3=Kittel |last4=Graf |title=North American B-25 Mitchell |year=2015 |publisher=Edizioni R.E.I. |isbn=9782372971997 |page=19 |quote=R-2600-29 — 1,850 hp (1,380 kW)}}</ref> An '''R-2600-29''' or '''R-2600-29A''' modified with a Bendix Stromberg PR48A4 carburetor. The -29, -29A, and -35 may have been considered interchangeable to a degree.<ref>{{cite report |title=Department of Defense Appropriations for 1959: Hearings Before the Subcommittee of the Committee on Appropriations, United States Senate, Eighty-fifth Congress, Second Session, on H.R. 12738, Making Appropriations for the Department of Defense for the Fiscal Year Ending June 30, 1959, and for Other Purposes |year=1958 |publisher=U.S. Government Printing Office |location=United States |url=https://books.google.com/books?id=p340AAAAIAAJ |quote=R-2600-29A/35}}</ref> * '''GR-2600-A71''' – 1,350 hp (1,007 kW); May have been a simplified name of the '''GR-2600-A71-3'''<ref name="A71">{{cite book |last=Stemp |first=P. D. |title=Kites, Birds & Stuff - Aircraft of the U.S.A. - North American Aircraft |date=2016-11-20 |publisher=Lulu.com |isbn=9781326828158 |url=https://books.google.com/books?id=Ffv8DQAAQBAJ |archive-url=https://web.archive.org/web/20250331233501/https://www.google.com/books/edition/Kites_Birds_Stuff_Aircraft_of_the_U_S_A/Ffv8DQAAQBAJ?hl=en |archive-date=2025-03-31 |quote=NA-40-2/B - The engines were replaced by two 1,340 hp. Wright GR-2600-A71 Cyclone radial engines.}}</ref> * '''GR-2600-A71-3''' – 1,600 hp (1,193 kW); Early R-2600 model, developed in late 1938 or very early 1939. Powered the North American NA-40B, a twin-engine medium bomber of which only one was built. The NA-40 would lead the to B-25 Mitchell. May also be referred to as the '''GR-2600-A71'''<ref name="A71"></ref> * '''GR-2600-C14''' – 1,750 hp (1,304 kW)

==Applications== [[File:B-23 Dragon Wright R-2600-3 engine.jpg|thumb|Wright R-2600-3 on a B-23 Dragon]] [[File:Mounting motor on a Fairfax B-25 bomber, at North American Aviation, Inc., plant in Inglewood, Calif.jpg|thumb|Wright R-2600 Cyclone being fitted to a North American B-25 Mitchell, at North American Aviation, Inglewood, California]] [[File:20-09-105-R 2600.jpg|thumb|R-2600 on display at Museum of Aviation, Robins AFB]]

* Boeing 314 Clipper * Brewster SB2A Buccaneer * Consolidated PB4Y-2 Privateer ("Super Privateer" conversions) * Curtiss SB2C Helldiver * Douglas A-20 Havoc * Douglas B-23 Dragon * Grumman F6F Hellcat (XF6F-1 & -2 prototypes only, pre-April 1942) * Grumman TBF Avenger * Latécoère 631 * Lioré et Olivier LeO 451 * Martin Baltimore * Martin PBM Mariner (versions prior to the R-2800 "Double Wasp"-powered PBM-5, though early models of the PBM-5 mounted the 2,100 hp (1,566 kW) R-2600-34)<ref>{{cite book |last=Wilson |first=Stewart |title=Aircraft of WWII |year=1998 |publisher=Aerospace Publications |location=United Kingdom |page=116 |isbn=9781875671359 |quote=PBM-5 — two 2100hp (1566kW) R-2600-34; four-bladed propellers.}}</ref> * Miles Monitor * North American B-25 Mitchell * Vultee A-31 Vengeance

==Specifications (GR-2600-C14BB)== {{pistonspecs |  |type=14-cylinder supercharged air-cooled two-row radial engine |ref=''Jane's''.<ref>Jane's 1998, p. 317.</ref> |bore= {{cvt|6+1/8|in|mm|1}} |stroke= {{cvt|6+5/16|in|mm|1}} |displacement= {{cvt|2,604|cuin|L|2}} |length= {{cvt|62.06|in|mm|0}} |diameter= {{cvt|55|in|mm|0}} |width= |height= |weight= {{cvt|2,045|lb|kg}} |valvetrain=Two pushrod-actuated valves per cylinder with sodium-cooled exhaust valve |supercharger=Single-stage two-speed centrifugal type supercharger, impeller diameter {{cvt|11|in|mm}}, blower ratio 7.06:1 at slow speed and 10.06:1 at high speed |turbocharger= |fuelsystem=Stromberg PR48A downdraft carburetor with automatic mixture control |fueltype= |oilsystem=Dry sump with one pressure pump and two scavenge pumps |coolingsystem=Air-cooled |power=<br /> ** {{cvt|1,750|hp|kW|-1}} at 2,600 rpm at {{cvt|3,200|ft|m|-2}} military power ** {{cvt|1,450|hp|kW|-1}} at 2,600 rpm at {{cvt|15,000|ft|m|-2}} military power |specpower= {{cvt|0.67|hp/cuin|kW/L}} |compression=6.9:1 |fuelcon= |specfuelcon= |oilcon= |power/weight= {{cvt|0.86|hp/lb|kW/kg}} }}

==See also== {{aircontent  |see also= * Gunderson Do-All Machine - incorporates an R-2600 into an educational network of machines that is also kinetic art.  |related= * Wright Cyclone series * Wright R-1300 Cyclone 7 * Wright R-1820 Cyclone * Wright R-3350 Duplex-Cyclone * Hispano-Suiza 14AA |similar engines= * BMW 801 * Bristol Hercules * Fiat A.74 * Gnome-Rhône 14N * Mitsubishi Kasei * Pratt & Whitney R-2800 * Shvetsov ASh-82 - derived and metricated from Wright Aeronautical radial engine designs<ref>{{cite book |last= Liss |first= Witold |date= 1967 |title= The Lavochkin La 5 & 7 |volume= 149 |series= Aircraft Profiles |publisher= Profile Publications |location= Leatherhead, Surrey, UK |page= 3}}</ref> |lists= *List of aircraft engines  }}

==References== ===Notes=== {{Reflist}}

===Bibliography=== {{Refbegin}} * {{cite book |last= Andrade |first= John |date=1979 |title= U.S.Military Aircraft Designations and Serials since 1909 |publisher= Midland Counties Publications |isbn=0-904597-22-9}} * {{cite book |editor-last= Bridgman |editor-first= Leonard |date= 1998 |title= Jane's Fighting Aircraft of World War II |location= London |publisher= Studio Editions Ltd |isbn= 0-517-67964-7}} * {{cite book |last= Gunston |first= Bill |date= 2006 |title= World Encyclopedia of Aero Engines: From the Pioneers to the Present Day |edition= 5th |location= Stroud, UK |publisher= Sutton |isbn= 0-7509-4479-X}} * {{cite book |last= Thruelsen |first= Richard |date= 1976 |title= The Grumman Story |location= New York |publisher= Praeger Publishers |isbn= 0-275-54260-2}} * {{cite book |last= White |first= Graham |date= 1995 |title= Allied Aircraft Piston Engines of World War II: History and Development of Frontline Aircraft Piston Engines Produced by Great Britain and the United States During World War II |location= Warrendale, Pennsylvania |publisher= SAE International |isbn= 1-56091-655-9}} {{Refend}}

==External links== {{Commons category-inline}}

Category:1930s aircraft piston engines Category:Aircraft air-cooled radial piston engines R-2600