Pratt & Whitney Wasp Major R-4360-59B, Cutaway, Radial Engine


Display Status:

This object is on display in the Boeing Aviation Hangar at the Steven F. Udvar-Hazy Center in Chantilly, VA.

Pratt & Whitney Wasp Major R-4360-59B, Cutaway, Radial Engine

Collection Item Summary:

The R-4360 was Pratt & Whitney's last aircraft piston engine, as well as the largest and the most complicated piston engine produced in quantity in the United States. The 28 cylinders were in four rows of seven cylinders each, arranged in a spiral for better cooling, which contributed to the popular nickname of "corncob" applied to all multi-row radial engines.

The R-4360 (known by its commercial designation as the Wasp Major) mainly powered large American military aircraft, including the Boeing C-97, Douglas C-124, and Fairchild C-119 transports and the Boeing B-50 and Consolidated B-36 bombers. Early versions of the R-4360 produced 2,237 kW (3,000 hp); later models developed 3,207 kW (4,300 hp). It is believed that Pratt & Whitney crafted this cutaway from a production R-4360 as a teaching tool for military mechanics during World War II.

Collection Item Long Description:



Inventory Number


Physical Description

  • Type: Reciprocating, Radial, 28 cylinders, 4-spiral rows, air-cooled
  • Power rating: 2,237 kW (3,000 hp) at 2,700 rpm
  • Displacement: 71.5 L (4,360 cu. in.)
  • Bore and Stroke: 146 mm (5.8 in.) x 152 mm (6 in.)
  • Weight: 1,585 kg (3,490 lb)

Credit Line

Transferred from the U.S. Marine Corps Aviation Museum


Country of Origin

United States of America


Diameter 137.2 cm (54 in.), Length 245.6 cm (96.69 in.)

Data Source

National Air and Space Museum

Restrictions & Rights

Do not reproduce without permission from the Smithsonian Institution, National Air and Space Museum


PROPULSION-Reciprocating & Rotary