Twin Mustang

The North American F-82 at War

Alan C. Carey

• Publisher: Pen & Sword Aviation
• Year: 2014
• ISBN:
  9781473834552
• Topic: History
• Subtopic: Military & Maritime History
• Index: History

"A comprehensive look at the 272-plane F-82 fleet... This is a fine addition to Carey's body of work and to anyone's aviation library."—HistoryNet One of the most unusual and remarkable American fighter aircraft, the F-82 Twin Mustang was the last mass production propeller-driven fighter acquired by the U.S. Air Force. Originally intended as a very long-range fighter escort for the Boeing B-29 Superfortress during World War II, it arrived too late to see combat and evolved into a night and all-weather fighter during the post-war years. Combat operations in the Korean War followed, along with a host of other dynamic episodes of deployment. This work traces the developmental, operational, and combat history of this unique American fighter and features 120 photographs and illustrations, many of which have never been published before. Seven chapters, all extensively illustrated, cover the aircraft's development, descriptions of the variants and sub-types, details of initial entry into service, three chapters covering the F-82's service in the Korean War, and a final chapter detailing the type's removal from the Korean War Theatre in February 1952, to see out its operational days in the Alaskan Air Defense Command. "If you're an historian like me, you'll love this book. It lists every F-82 to serve in Korea, every crewman lost in combat, every squadron which used them, and all the pertinent tech details about each version. Photos illustrate the planes from nearly every squadron (if not all) and captions offer in-depth information not included in the text—so they really add value."—My Hobby Info

Chapter One:

Development

Possibly one of the oddest American aircraft to go into full production after the end of the Second World War, the P- (later) F-82 Twin Mustang series was the last mass production propeller-driven fighter acquired by the U.S. Air Force. Originally designed as a long-range bomber escort during the Second World War, it evolved into a night and all-weather fighter during the post-war years. The original concept of the XP-82 traces back to the development of North American Aviation’s XP-51 Mustang in 1940 and the production of subsequent variants of that aircraft as a long-range fighter to protect Allied bombers against the German Luftwaffe and, subsequently, to provide cover for Boeing B-29 bombers in the Pacific. However, the Air Force lacked an interceptor with an extreme-range capability. The USAAF fighters with the longest range during that conflict were the P-51D Mustang, with a maximum range of 1,600 miles, and the Lockheed P-38J Lightning with a maximum range of 2,200 miles. Both aircraft were capable of escorting B-17 and B-24 bombers from bases in England to the heart of Germany; but it was another story in the Pacific.

The vast distances of the Pacific, where missions could last eight to twelve hours, required a fighter with a far better range than any existing aircraft in the Air Force’s inventory at the time, but such a design would need a two-man crew consisting of a pilot and co-pilot/navigator to reduce workload stress and fatigue. The concept for such a radical aircraft design, closely resembling two P-51 Mustang fighters joined together with a common centre wing and horizontal stabilizer, belonged to Edgar Schmued, North American Design Chief, who proposed the idea in November 1943 at the company’s factory in Inglewood, California. Two months later on 7 January 1944, when General of the Army Air Force Hap Arnold was taking a tour of the factory, Ed Schmued showed him the revolutionary design; the General quickly endorsed the project. After viewing a mock-up and wind tunnel model of the design, Air Force brass issued development contract AC-2029 on 8 February 1944 ordering the construction of three experimental prototypes (serial numbers 44-83886 through 44-83888), with the NAA company designation NA-120.

Frontal view of XP-82 scale model about to undergo wind tunnel testing by the National Advisory Committee for Aeronautics (NACA) Ames Research Center during late 1944. (NASA)

XP-82

North American engineers developed the two airframes and wings for the NA-120 from the basic fuselage and wings of the experimental XP-51F, which was used to develop the P-51H production model. Although the P-51 and XP-82 were quite similar in appearance, very few components were interchangeable. External design changes included lengthening the aft fuselage sections by fifty-seven inches, internal strengthening of the centre and outer wing sections to allow for fuel and armament on external pylons, increasing the length of the ailerons, inclusion of slotted flaps along the trailing edge of the centre section, and enlarging the dual vertical stabilizers to improve stability. Hydraulically operated wing flaps extended from the aileron to the fuselage on each wing panel and between the fuselages on the centre section interconnected and controlled by a lever located in the pilot’s cockpit only. Interestingly the XP-82’s entire wing area of 408 square feet was less than two Mustangs (470 square feet) but the overall length was six feet longer than the P-51H; a nine-foot difference with the F-82G model. The XP-82 prototypes and the subsequent P-82B variant, used counter-rotating Aeroproducts propellers powered by two liquid-cooled, supercharged, two-stage, two-speed, Packard Merlin V-1650 engines with, on the left (portside), a V-1650-23 and right (starboard), a V-1650-25 to compensate for torque. The aircraft’s fuel system consisted of four internal self-sealing wing tanks; one consisting of two interconnected cells in each outer wing panel and two in the wing centre section with a total fuel capacity of 575 gallons. This arrangement allowed each engine to operate with a separate and complete fuel system with the two cells interconnected by a cross-feed line. Range and flight time could be increased by the addition of either two 110, 165, or 310-gallon drop tanks installed under each outer wing panel.

North American’s one-quarter scale XP-82 model undergoes testing at in the California Institute of Technology (CalTech) wind tunnel in mid-1944. From the company’s model NA-120 proposal, the U.S. Army Air Force originally ordered four prototypes in fact consisting of two XP-82s and two XP-82As. One XP-82A, 44-83888, was constructed powered by Allison V-1710-119 engines: however, it appears that problems with the engines ended further development while the other XP-82A, 44-83889, was cancelled before its construction. (Nicholas A. Veronico)

One of the XP-82s under construction at North American Aviation’s California plant circa early 1945. The fuselages were developed from the company’s XP-51F Mustang design. (Robert F. Dorr)

Both XP-82s, serial numbers 44-83886 and 44-83887, were powered by two V-1650 Packard Merlin engines, the same type engine used in the P-51B Mustang and subsequent models. (Robert F. Dorr)

The first prototype, serial number 44-83886, rolled out of the Inglewood factory on 25 May 1945 and flew on 16 June 1945, with NAA test pilot Joe Barton and Edward M. Virgin at the controls. This was the second attempt; the month before it refused to get off the ground due to excessive drag caused by the props’ air flowing upwards to the centre wing section, an effect created by the rotation of the propellers – the left, counter-clockwise, and the right clockwise. Engineers solved the problem by switching the engines to the opposite sides resulting in successful flight testing. The second prototype, serial number 44-83887, made its initial flight of approximately one hour on 30 August 1945. The first and second prototypes showed the aircraft to have exceptional high speed, manoeuvrability, and rate of climb. The USAAF accepted the first prototype in August 1945 followed by the second the following month. The XP-82 was 39 feet in length with a wing span of nearly 52 feet and its two Merlin engines gave it a top speed of 468 mph, almost identical to the P-51H, and a maximum range of nearly 3,500 miles with internal and external fuel stores (over twice the range of the P-51).

The Twin Mustang’s command pilot’s port cockpit contained ...