Commando was a transport aircraft originally derived from a commercial high-altitude airliner design. It was instead used as a military transport during World War II by the United States Army Air Forces as well as the U.S. Navy/Marine Corps under the designation R5C. Known to the men who flew them as “The Whale,” or the “Curtiss Calamity,” the C-46 served a similar role as its counterpart, the Douglas C-47 Skytrain, but was not as extensively produced.
Design and Structure
- Type: Twin-engine transport aircraft designed for cargo, troop transport, and specialized missions.
- Wings:
- Configuration: Low-wing cantilever monoplane with all-metal construction, divided into three sections: a rectangular center-section and two tapering outer sections with detachable tips.
- Structure: The center-section features three built-up spars with extruded flanges, girder-type ribs, and a stressed skin of 24ST Alclad with spanwise hat-shaped stiffeners. Outer sections include two spars, girder-type ribs (with special web-type ribs near the roots), and a similar stressed skin. The leading edges feature flush riveting back to about one-third of the chord.
- Flaps and Ailerons: Hydraulically-operated flaps are present in the center and outer sections, inboard of the ailerons. Ailerons are dynamically and statically balanced, with metal-covered noses, stamped ribs, and fabric covering.
- Fuselage:
- Construction: All-metal semi-monocoque structure in four sections, with a cross-sectional shape formed by two intersecting circles. The structure includes a series of transverse rings, bulkheads, and longitudinal stringers, covered with smooth 24ST Alclad skin. Flush riveting is used in drag-sensitive areas.
- Tail Unit:
- Type: Cantilever monoplane with all-metal construction, featuring detachable tips on all surfaces. The tailplane consists of two interchangeable sections with three beams each. Elevators and rudder are dynamically balanced and equipped with trim-tabs.
Landing Gear
- Type: Retractable, consisting of Cleveland “Aerol” oleo-pneumatic shock-absorber struts. The landing gear retracts into the nacelles, with hydraulically-operated fairing doors that close after the gear is retracted. The tail-wheel is fully retractable and shimmy-dampened.
Power Plant
- Engines: Two Pratt & Whitney R-2800-51 Double Wasp eighteen-cylinder radial air-cooled engines, each delivering 2,000 hp.
- Propellers: Curtiss Electric four-bladed constant-speed full-feathering airscrews, with a diameter of 13 ft. 6 in. (4.12 m).
- Fuel System: Includes three self-sealing fuel tanks in each outer wing section, totaling 1,400 U.S. gallons, with an additional 800 U.S. gallons in eight fuselage tanks for long-range missions. Each engine has a separate oil system with a 40 U.S. gallon tank.
Accommodation and Cargo
- Cockpit: Accommodates a pilot, co-pilot, navigator, and radio operator. A door connects the cockpit with the main cargo compartment.
- Cargo Compartment:
- Dimensions: 48 ft. (14.6 m) long, 9 ft. 10 in. (3 m) wide, and 6 ft. 8 in. (2 m) high, with a capacity of 2,300 cu. ft. (69 cu. m.).
- Loading Door: Main loading door on the port side, measuring 8 ft. (2.4 m) wide and 6 ft. (1.8 m) high, divided vertically and positioned to facilitate level loading. Additional smaller openings are present for ventilation and access.
- Capacity: Can accommodate 40 fully-armed troops, 33 stretcher cases, or other cargo equivalent to five Wright R-3350 engines. There are additional cargo spaces beneath the main floor, accessible from the ground.
Performance
- Dimensions:
- Span: 108 ft. 1 in. (32.9 m)
- Length: 76 ft. 4 in. (23.3 m)
- Height: 21 ft. 9 in. (6.6 m)
- Wing Area: 1,360 sq. ft. (126.3 sq. m)
- Weights and Loadings:
- Empty Weight: 29,483 lbs. (13,385 kg)
- Normal Loaded Weight: 45,000 lbs. (20,430 kg)
- Maximum Overloaded Weight: 50,000 lbs. (22,700 kg)
- Performance (at 45,000 lbs. loaded weight):
- Maximum Speed: 265 mph (424 km/h) at 13,000 ft. (3,965 m)
- Cruising Speed: 227 mph (363.2 km/h) at 10,000 ft. (3,050 m)
- Climb to 10,000 ft.: 13.5 minutes
- Service Ceiling: 24,500 ft. (7,470 m)
- Service Ceiling (one engine): 12,000 ft. (3,660 m)
This aircraft was designed for versatility in cargo and personnel transport, with a robust structure and advanced features for its time.