Wright R-2600 Twin Cyclone

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.

R-2600
Wright R-2600 Cyclone radial engine
Type	Radial engine
National origin	United States
Manufacturer	Wright Aeronautical
First run	1935
Major applications	Curtiss SB2C Helldiver Douglas A-20 Havoc Grumman TBF Avenger Martin PBM Mariner North American B-25 Mitchell
Number built	85,374[1]
Developed from	Wright R-1820

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 1,600 hp (1,200 kW; 1,600 PS) 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 2,000 hp (1,500 kW; 2,000 PS) 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

• R-2600-1 - 1,600 hp (1,194 kW)
• R-2600-2 - 1,500 hp (1,118 kW)- Prototype variant; Few were made.^[2]
• R-2600-3 - 1,600 hp (1,194 kW)
• R-2600-4 - 1,650 hp (1,230 kW)^[3]
• R-2600-6 - 1,600 hp (1,194 kW)
• R-2600-8 - 1,700 hp (1,268 kW)
• R-2600-9 - 1,700 hp (1,268 kW)
• R-2600-10 - 1,700 hp (1,268 kW)- Experimental high-altitude R-2600 variant with a two-stage mechanical supercharger, vs the usual single-stage supercharger. The 2600-10 also served as a testbed for turbo-supercharging the 2600 series. Very few were produced.^[4][5]
• R-2600-11 - 1,600 hp (1,194 kW)^[6]
• R-2600-12 - 1,700 hp (1,268 kW)
• R-2600-13 - 1,700 hp (1,268 kW)
• R-2600-14 - 1,700 hp (1,268 kW)- One of the engines which powered Grumman's prototype F6Fs, the XF6F-1 (the two-stage supercharged R-2600-10 was also tested in the XF6F-1). Grumman was not happy with the performance, which led to the 2,000 hp Pratt & Whitney R-2800 engine replacing the R-2600 on F6F production models.^[7]
• 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 B-26 Marauder). The project was cancelled, and neither the prototype XB-33A or production B-33A were ever built.^[8]
• R-2600-16 - 1,700 hp (1,268 kW)- Similar to the R-2600-10 & -14, the -16 powered a Grumman prototype F6F, the XF6F-2.^[9]
• R-2600-19 - 1,600 hp (1,194 kW), 1,660 hp (1,237 kW)
• R-2600-20 - 1,700 hp (1,268 kW), 1,900 hp (1,420 kW)
• R-2600-22 - 1,900 hp (1,420 kW)
• R-2600-23 - 1,600 hp (1,194 kW)
• R-2600-29 - 1,700 hp (1,268 kW), 1,850 hp (1,380 kW)
• GR-2600-A5B - 1,500 hp (1,118 kW), 1,600 hp (1,194 kW), 1,700 hp (1,268 kW)
• GR-2600-A71 - 1,300 hp (969 kW)
• GR-2600-C14 - 1,750 hp (1,304 kW)

Applications

Wright R-2600-3 on a B-23 Dragon

Wright R-2600 Cyclone being fitted to a North American B-25 Mitchell, at North American Aviation, Inglewood, California

R-2600 on display at Museum of Aviation, Robins AFB

• Boeing 314 Clipper
• Brewster SB2A Buccaneer
• 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
• Lioré et Olivier LeO 451
• Martin Baltimore
• Martin PBM Mariner (versions prior to Double Wasp-powered PBM-5)
• Miles Monitor
• North American B-25 Mitchell
• Vultee A-31 Vengeance

Specifications (GR-2600-C14BB)

Data from Jane's.^[10]

General characteristics

• Type: 14-cylinder supercharged air-cooled two-row radial engine
• Bore: 6+1⁄8 in (155.6 mm)
• Stroke: 6+5⁄16 in (160.3 mm)
• Displacement: 2,604 cu in (42.67 L)
• Length: 62.06 in (1,576 mm)
• Diameter: 55 in (1,397 mm)
• Dry weight: 2,045 lb (928 kg)

Components

• Valvetrain: Two pushrod-actuated valves per cylinder with sodium-cooled exhaust valve
• Supercharger: Single-stage two-speed centrifugal type supercharger, impeller diameter 11 in (280 mm), blower ratio 7.06:1 at slow speed and 10.06:1 at high speed
• Fuel system: Stromberg PR48A downdraft carburetor with automatic mixture control
• Oil system: Dry sump with one pressure pump and two scavenge pumps
• Cooling system: Air-cooled

Performance

• Power output:
  
  • 1,750 hp (1,300 kW) at 2,600 rpm at 3,200 ft (1,000 m) military power
  • 1,450 hp (1,080 kW) at 2,600 rpm at 15,000 ft (4,600 m) military power
• Specific power: 0.67 hp/cu in (30 kW/L)
• Compression ratio: 6.9:1
• Power-to-weight ratio: 0.86 hp/lb (1.41 kW/kg)

See also

• Gunderson Do-All Machine - incorporates an R-2600 into an educational network of machines that is also kinetic art.

Related development

• Wright Cyclone series
• Wright R-1300 Cyclone 7
• Wright R-1820 Cyclone
• Wright R-3350 Duplex-Cyclone
• Hispano-Suiza 14AA

Comparable 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^[11]

Related lists

• List of aircraft engines

References

Notes

1. "SUMMARY OF WRIGHT ENGINE SHIPMENTS 1920 – 1930" (PDF). Archived from the original (PDF) on 2021-10-10. Retrieved 2023-09-18.
2. Friedman, Norman (30 October 2016). Fighters Over the Fleet Naval Air Defence from Biplanes to the Cold War (1 ed.). Pen & Sword Books. p. 61. ISBN 9781848324060. The prototype R-2600-2, rated at 1,500hp for take-off ...
3. "Teesside Aviation News" (PDF) (Press release). Teesside, UK: Teesside Aviation Society. 1982-11-01. Retrieved 2021-04-06. ... for the RAF, 19 were experimentally fitted with R-2600-4-53 Cyclones ... engines of 1650 hp.
4. Francillon, Renè (1989). Grumman Aircraft Since 1929. Putnam Aeronautical. p. 196. ISBN 9780851778358. Retrieved 2021-04-03.
5. Grossnick, Roy (1995). "Appendix 1: Aircraft Data—Technical Information and Drawings" (PDF). TBF/TBM Avenger. Dictionary of American Naval Aviation Squadrons. Vol. I: The History of VA, VAH, VAK, VAL, VAP, and VFA Squadrons. Washington Navy Yard, Washington D.C.: Naval Historical Center, Department of the Navy. p. 512. ISBN 0-945274-29-7. Retrieved 2021-04-03 – via Naval History and Heritage Command.
6. United States Civil Aeronautics Administration Aircraft Listing. United States Civil Aeronautics Administration. 1949. p. 68. Retrieved 2021-04-03.
7. Thomas, Cleaver (19 Oct 2017). "The Pacific Theater". Pacific Thunder The US Navy's Central Pacific Campaign, August 1943–October 1944 (1 ed.). Bloomsbury Publishing. p. 45. ISBN 9781472821867. The XF6F-1 was powered by the Wright R-2600 14- cylinder Twin Cyclone radial engine. After meeting O'Hare, Grumman suggested a power increase which ... put the super new Pratt & Whitney R-2800 ... in the second prototype.
8. Andrade 1979, p 51
9. Thruelsen 1976, p 193
10. Jane's 1998, p. 317.
11. Liss, Witold (1967). The Lavochkin La 5 & 7. Aircraft Profiles. Vol. 149. Leatherhead, Surrey, UK: Profile Publications. p. 3.

Bibliography

• Andrade, John (1979). U.S.Military Aircraft Designations and Serials since 1909. Midland Counties Publications. ISBN 0-904597-22-9.
• Bridgman, Leonard, ed. (1998). Jane's Fighting Aircraft of World War II. London: Studio Editions Ltd. ISBN 0-517-67964-7.
• Gunston, Bill (2006). World Encyclopedia of Aero Engines: From the Pioneers to the Present Day (5th ed.). Stroud, UK: Sutton. ISBN 0-7509-4479-X.
• Thruelsen, Richard (1976). The Grumman Story. New York: Praeger Publishers. ISBN 0-275-54260-2.
• White, Graham (1995). 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. Warrendale, Pennsylvania: SAE International. ISBN 1-56091-655-9.

External links

Media related to Wright R-2600 at Wikimedia Commons