F-82 Twin Mustang

In 1945 the United States Army Air Forces were vexed by a difficult problem: pilot fatigue. The vast distances of the Pacific Ocean pushed aircraft to the limits of their fuel range and pilots to the extremes of their endurance. Attempts had been made with both the twin-engine P-38 Lightning and the single-engine P-51 Mustang to solve this problem with the incorporation of externally mounted expendable fuel tanks. This extended the range of the aircraft significantly, but did nothing to enhance the operational range of their pilots. On January 7, 1945, North American Aviation approached Pentagon officials with an interesting solution: modify two P-51H airframes to join at the wing, forming an aircraft with a twin-engine, twin-boom configuration similar to that of the P-38. Both of the joined Mustang airframes retained their cockpits, enabling one pilot to rest while the other flew the airplane. This arrangement would allow the two pilots to avoid stress- and fatigue-induced error while at the same time taking advantage of the aircraft's phenomenal range.

Development of the new aircraft proceeded quickly -- the P-51 was a proven design and was even then considered one of the best fighters of the war. Funding was approved for 3 prototypes in February 1945, and such was the level of confidence in the design that an order was placed for 500 production models before the month was out. The first prototype, designated the XP-82, flew on June 6, 1945. This plane was approved by the USAAF in August. The two remaining prototypes were approved in September and October, and delivery of the first 15 planes was completed before the year was out.

Despite the rapid development, approval, and production of the then-P-82, the aircraft never saw deployment in World War Two. The end of the war resulted a massive military demobilization: the armed forces simply had more hardware (aircraft, tanks, warships, etc.) than they could use. The initial order of 500 P-82's was ultimately cut to 272 -- the initial 3 prototypes, 19 test aircraft, and 250 production aircraft of various models. Although the (by then) F-82 saw action in the Korean War and was credited with the first 3 "kills" of North Korean aircraft in that conflict, the Twin Mustang and her propeller-driven kin were radically outclassed by newer, jet-powered aircraft. Shortages of replacement parts also hampered F-82's deployed in Korea. By 1951 disused and disabled airframes were being used as towing targets in training missions, and by June of 1953 the last of the Double Mustangs were retired from service.

Primary Function: Long-Range Fighter, Night Fighter
Builder: North American Aviation
Power Plant: Two Packard V-1650s of 1,380 hp.
Thrust: 24,800 lbs.
Length: 38 feet, 1 inch
Height: 13 feet, 8 inches
Wingspan: 51 feet, 3 inches
Speed: 482 mph
Ceiling: 39,900 feet
Maximum Takeoff Weight: 37,500 pounds (16,875 kilograms)
Range: 2,240 miles
Armament: 6 .50 Caliber Machine Guns; up to 4,000 lbs. of bombs or rockets
Unit cost:$228,000
Crew: 2 (pilot, copilot/radar operator)

A Word On Nomenclature
This writeup references the Twin Mustang using both the P-82 and F-82 designators. This is because of a major restructuring the U.S. military underwent following World War Two. The Department of the Air Force was created as an independent entity within the Defense Department by President Truman on July 26, 1947, and began independent operations on Sep. 18, 1947. In this same year the nomenclature used to designate aircraft was changed, and planes previously tasked as "pursuit" aircraft (and given the designator P-#) were given the new "fighter" (F-#) designation. The P/F-82's deployment straddles this change in designation, ergo both P-82 and F-82 are used in this writeup, as appropriate.

Sources:
Federation of American Scientists
USAF Museum