North American B-25 Mitchell

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R-2600-29 Wright "Cyclone" 14 cylinder, air cooled radial
engines
 
Specifications (GR-2600-C14)

General characteristics

  • Type: 14-cylinder supercharged air-cooled two-row radial engine
  • Bore: 6.125 in (155.6 mm)
  • Stroke: 6.312 in (160.2 mm)
  • Displacement: 2,603 in³ (42.7 L)
  • Length: 62.06 in (1,576 mm)
  • Diameter: 55 in (1,397 mm)
  • Dry weight: 2,045 lb (930 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 (1,305 kW) at 2,600 rpm at 3,200 ft (975 m) military power
    • 1,450 hp (1,080 kW) at 2,600 rpm at 15,000 ft (4,575 m) military power
  • Specific power: 0.67 hp/in³ (30.6 kW/L)
  • Compression ratio: 6.9:1
  • Power-to-weight ratio: 0.86 hp/lb (1.40 kW/kg)

 
 
 
 

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

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 1,600hp R-2600-3 was originally intended for the C-46 Commando and was fitted to the CW-20A prototype, but a running change led to the adoption of the 2,000hp Pratt & Whitney R-2800 in its place. The Twin Cyclone engine went on to power several key World War II production aircraft including the A-20 Havoc, B-25 Mitchell, TBF Avenger and SB2C Helldiver bombers, and the PBM Mariner flying boat.

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

wright_r-2600_1.jpg

b-25enginechange2.jpg

 
 
 

B-25

Mitchell

North American

2 Wright R-2600-9 Cyclone

5


 

B-25A

Mitchell

North American

2 Wright R-2600-9 Cyclone

5


 

B-25B

Mitchell

North American

2 Wright R-2600-9 Cyclone

5


 

B-25C

Mitchell

North American

2 Wright R-2600-13 Cyclone

5

PBJ-1C

TB-25C

Mitchell

North American

2 Wright R-2600-13 Cyclone


 

AT-24C

B-25D

Mitchell

North American

2 Wright R-2600-13 Cyclone

5

PBJ-1D

TB-25D

Mitchell

North American

2 Wright R-2600-13 Cyclone


 

AT-24A

XB-25E

Mitchell

North American

2 Wright R-2600-13 Cyclone

5


 

XB-25F

Mitchell

North American

2 Wright R-2600-13 Cyclone

5


 

XB-25G

Mitchell

North American

2 Wright R-2600-13 Cyclone

5


 

B-25G

Mitchell

North American

2 Wright R-2600-13 Cyclone

5

PBJ-1G

TB-25G

Mitchell

North American

2 Wright R-2600-13 Cyclone


 

AT-24B

B-25H

Mitchell

North American

2 Wright R-2600-13 Cyclone

5

PBJ-1H

B-25J

Mitchell

North American

2 Wright R-2600-13 Cyclone

6

PBJ-1J

CB-25J

Mitchell

North American

2 Wright R-2600-13 Cyclone


 


 

TB-25J

Mitchell

North American

2 Wright R-2600-13 Cyclone


 

AT-24D

VB-25J

Mitchell

North American

2 Wright R-2600-13 Cyclone


 


 

TB-25K

Mitchell

North American

2 Wright R-2600-13 Cyclone

6


 

TB-25L

Mitchell

North American

2 Wright R-2600-13 Cyclone

6


 

TB-25M

Mitchell

North American

2 Wright R-2600-13 Cyclone

6


 

TB-25N

Mitchell

North American

2 Wright R-2600-29A Cyclone

6


 

VB-25N

Mitchell

North American

2 Wright R-2600-29A Cyclone