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Wright R-2600-13

DAYTON, Ohio -- Wright R-2600 on display in the World War II Gallery at the National Museum of the United States Air Force. (U.S. Air Force photo)

DAYTON, Ohio -- Wright R-2600 on display in the World War II Gallery at the National Museum of the United States Air Force. (U.S. Air Force photo)

(Excerpted from North American Aviation Field Service Manual for B-25C and D)

The Wright Cyclone, Model C14B, carries the Army Air Forces designation R-2600-13. The "R" stands for radial type of engine, "2600" stands for the number of cubic inches piston displacement, and the "13" is the model number.

The engines are air-cooled, static, staggered, twin-row radial type having two speed superchargers. Owing to the high compression ratio of 6.9:1, the engine operates on 100-Octane fuel. No other fuel may be used except in the event of an emergency, when a fuel of the next highest Octane rating may be used.

Under normal operating conditions, the engines develop a maximum of 1700 bhp (brake horsepower) for take-off at 44.3" Hg. (manifold pressure -- in inches of mercury -- of the fuel-air mixture in the engine intake pipes after passing through the supercharger) and 2600 rpm (revolutions per minute of the crankshaft, not the propeller).

The cylinders are numbered in a clockwise direction when looking from the rear, or anti-propeller end, forward to the propeller end. No. 1 cylinder is the top cylinder of the rear row. No. 2 is to its right in the front row. Thus, all odd numbered cylinders are in the rear row and all even numbered cylinders in the front row.

Model: R-2600-13 (Wright Cyclone Model C14B)
Type: Static Radial, Air Cooled, Double Row
Number of cylinders: 14
Bore: 6.125 in.
Stroke: 6.312 in.
Piston displacement: 2603 cu.in.
Compression ratio: 6.90:1
Blower gear ratio: 7.06:1 and 10.06:1
Blower diameter: 11.00 in.
Rated rpm of crankshaft: 2400
Rated bph/rpm at 6700 ft.: 1500/2400
Rated bhp/rpm at 13,000 ft.: 1350/2400
Takeoff bhp/rpm: 1700/2600
Rotation of crankshaft (from anti-propeller end): Clockwise
Rotation of propeller (from anti-propeller end): Clockwise
Propeller reduction gear ration (crankshaft to propeller): 16:9
Average weight of engine: 1978.50 lbs.
Overall length of engine: 63.10 in.
Overall diameter of engine: 54.26 in.

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Mask Policy:
In accordance with the updated guidance released by the Center for Disease Control and Prevention (CDC), the Department of Defense (DoD) and Wright-Patterson Air Force Base, the National Museum of the U.S. Air Force will require all visitors to wear face masks indoors effective July 30, 2021 until further notice.

Visitors ages three and up will be required to wear masks while indoors at the museum. This policy applies to all visitors, staff and volunteers regardless of vaccination status. Visitors may wear their own masks or a free paper mask will be provided. Cloth masks will also be available for purchase in the Museum Store.
Additional information available here.

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