Hughes D-2

D-2
Howard Hughes inspecting the port engine c. 1943
Role	Fighter aircraft, Bomber
Manufacturer	Hughes Aircraft
Designer	Howard Hughes
First flight	20 June 1943
Introduction	Cancelled
Retired	1944
Primary user	U.S. Army Air Corps (intended)
Number built	1 prototype
Variants	Hughes XF-11

The Hughes D-2 was an American fighter and bomber project begun by Howard Hughes. It never proceeded past the flight testing phase but was considered the inspiration for the later Hughes XF-11.

Design and development

Howard Hughes began the design of an advanced twin-engine, twin-boom interceptor prior to World War II that was similar to the Lockheed P-38 that won the 1939 United States Army Air Corps design competition. Rather than abandoning the project, he later recounted in the 1947 Senate investigation that he "decided to design and build from the ground up, and with my own money, an entirely new airplane which would be so sensational in its performance that the Army would have to accept it."

Most of the airframe of the "DX-2" was made of Duramold plywood, a plastic-bonded plywood molded under heat and high pressure. Initially, the aircraft was to have been equipped with a tail wheel but the landing gear was later changed to a tricycle configuration with the main undercarriage units retracting rearwards into the twin booms and the nosewheel retracting rearwards and rotating 90 degrees to lie flat in the small central fuselage. The powerplants were to have been a pair of experimental Wright Tornado forty-two cylinder, liquid-cooled radial engines. The D-2 was built in secret at the Hughes Culver City, California factory with longtime associate, Glenn Odekirk, providing engineering inputs. Final assembly was done at the Hughes Harper Dry Lake facility in the Mojave Desert. The fighter that emerged from the Hughes experimental shop looked like a scaled-up P-38 Lightning and, on paper, sported similar performance potential.

Difficulties encountered in obtaining the Wright Tornado engines led to the substitution of proven Pratt & Whitney R-2800s.

The XP-73 was a temporary designation applied to the D-2 after the Material Command at Wright Field obtained approval to purchase "one Hughes DX-2 airplane in present commercial form as a prototype ..." Within three days the D-2 had been redesignated as the XA-37 for purposes of administering the contract. Howard Hughes decided not to sell the airplane to the Army Air Force however, so that neither of the above AAF designations ever officially applied to any airplane.

Operational history

Testing

After it was readied for flight in 1942, Hughes himself took over the flight test program. However, after only a few brief hops, it was clear that high control forces were a problem. When full flight tests were finally conducted in 1943, modifications still had not been made to correct this problem. Hughes reluctantly concluded that the D-2 needed major modifications, including a complete redesign of the wings and a change in aerofoil section. The wing center section, which was continuous through the fuselage nacelle, was to be revised to increase the size of the proposed bomb bay. Following these changes, the aircraft was to be assigned the company designation D-5. After only a few test flights, the sole prototype was destroyed by a freak lightning strike at its desert hangar in November 1944.

Aftermath

In 1943, Colonel Elliott Roosevelt, the President's son, had recommended that the D-2 or its successor be ordered as a photo reconnaissance aircraft. Despite his leadership in a military reconnaissance mission, the USAAF did not immediately act on Roosevelt's recommendation, partly due to Hughes' insistence that the D-2 development costs be factored into the proposed contract. Finally in mid-1944, Hughes agreed to develop a high-altitude, high-speed version of the D-2/D-5, known as the XF-11.

Variants

XP-73 

XA-37 

Specifications

Data from McDonnell Douglas Aircraft since 1920: Volume II

General characteristics

• Crew: one pilot, crew of two (in bomber version)
• Length: 57 ft 10 in (17.6 m)
• Wingspan: 60 ft (18.29 m)
• Height: 27 ft 4 in (8.3 m)
• Wing area: 616 ft² (57.23 m²)
• Loaded weight: 31,672 lb (14,366 kg)
• Powerplant: 2 × Pratt and Whitney R-2800-49, 2,000 hp (1,500 kW) each

Performance

• Maximum speed: 433 mph (697 km/h) at 25,000 ft (7,620 m)
• Cruise speed: 274 mph (441 km/h)
• Range: 1,000 miles (1,610 km)
• Service ceiling: 36,000 ft (10,975 m)
• Rate of climb: 2,620 ft/min (13 m/s)

References

Bibliography

• Barton, Charles. "Howard Hughes and the 10,000 ft. Split-S." Air Classics, Vol. 18, no. 8, August 1982.
• Francillon, René J. McDonnell Douglas Aircraft since 1920: Volume II. Annapolis, Maryland: Naval Institute Press, 1990. ISBN 1-55750-550-0.
• Winchester, Jim. "Hughes XF-11." Concept Aircraft: Prototypes, X-Planes and Experimental Aircraft. Kent, UK: Grange Books plc., 2005. ISBN 1-84013-309-2.

External links

• Photo of the D-2 under construction
• Hughes XP-73