F-82E Twin Mustang
The F-82E main upgrade was in its two Allison liquid cooled engines, V-1710-143 and V-1710-145 (Each of these 12 cylinder engines developed 1,600 horsepower at takeoff; each of the F-82B's Packard built V-1650 engines, only 1,380.). Otherwise, the twin fuselage (joined by a center wing panel and tailplane) low wing, long range, F-82E escort was similar to the F-82B. The wing had a NACA low drag, laminar flow air foil section and could haul external fuel tanks, bombs, or rockets. Both the F-82B and E could be provided with jettisonable canopies, hydraulic boost controls for all movable surfaces, thermal anti-icing, anti-G suits, adequate cabin heating and ventilation, lowpressure oxygen system, and armorplating to protect the two pilots.
The $35 million procurement contract of October 1946 covered 250 F-82Es plus tools and spare parts. $17 million was for the first 100 planes, $14.5 million for the remaining 150, and $3.5 million for special tools and ground handling equipment. Delivery of the first F 82Es was scheduled for November 1946, and the contract would be reviewed after completion of 100' airplanes. However, these plans fell through. Overall procurement of F-82s remained intact, but total costs rose to more than $50 million, and the number of E models was quickly reduced by more than one half.
Malfunctions of government furnished, Allison built engines plagued the shrunken F-82E program from the start. The government had always wanted to give its Twin Mustang F-82 a purely American and stronger engine than the foreign born P-51's V-1650 (built at Packard plants, dismantled after the war). It therefore negotiated in August 1945 with the Allison Division of the General Motors Corporation for a new version of the V-1710. Various models of this engine had equipped the P-38, P-39, and P-40 of WW II fame, and Allison promptly agreed to buy surplus government V-1710 parts for the new project. Even so, the F-82 program's new V-1710 engines proved costly in the long run reaching $18.5 million after many amendments. The airplane engine combination was never satisfactory. Yet, no damages could be assessed against Allison, because the engines has passed the 150 hour qualification tests and met procurement specifications. Nonetheless, the contract was cut back in early 1948, and the Air Force made Allison store special engine tools for 2 years at no cost to the government.
While waiting for acceptable engines, North American had to bear the expense of storing unequipped F-82 airframes (The planes were kept at the Consolidated Vultee Aircraft Corporation, Downey, Calif. Assembly lines were set up at Downey to install the engines and deliver the F-82s, rather than taking them back to the North American plant in Inglewood, Calif. Storage costs, paid by North American, included rent, plant protection, maintenance and insurance. Many F-82s stayed at Downey for nearly 2 years, exposing their electrical and radar equipment to damage from moisture. Special precautions had to be taken to prevent corrosion. The Air Force figured this alone raised costs by more than $2 million.) The situation grew so bad that the contractor requested and was granted in December 1947 greater partial payments, even though only four planes had been delivered.
First flight of the production aircraft took place in April 1947.
Although the engine had passed its 150 hour test and test in October 1946, troubles appeared on the first flight. Hence, this F82E and three later ones underwent special engine tests at once. By year's end, the Air Force had accepted and restricted to testing these four F 82Es, redesignating them F-82As. One was accepted in September 1947, one in November, and two in December.
Spark plug fouling, auxiliary stage super charger failure, oil loss by spewing, backfiring at high and low power, plus engine oil leakage, roughness, and surging were but a few of the V 1710 143 and V 1710 146 deficiencies. Spark plug fouling was an early and most difficult problem. Oil accumulation required a new set of plugs for nearly every flight. By December 1947, North American was about ready to give up flight testing the F 82. But the combined efforts of Allison, North American, and the Air Force were beginning to pay off. Nonetheless, extensive engine flighttests continued through June 1948 months after the first F 82Es entered service. The first 200 engines could only be operated at lower than the specified power rating. They were accepted to avoid further F-82 slippage, after Allison promised to later align them to specification.
The plane entered operational service in May 1948, (The F-82 program (as twice revised after the war) slipped about 1 year, but the North American storage problem lasted almost 2).
Three months after the Strategic Air Command had received the first B-50 bomber (The Boeing B-60 was basically an improved B-29 Superfortress the Twin Mustang had been programmed to escort the B-29, back in 1944.) the aircraft entered operational service. By 31 December, SAC counted 81 F-82E long range escorts among its tactical aircraft.
A total of 96 F-82Es were accepted (excluding the 4 that were booked as F 82As).
Production ended in December 1948 with delivery of the last F-82E.
The Air Force accepted 72 F-82Es in fiscal year 1948 (between January and June 1948), and 24 in fiscal year 1949 (22 in July 1948, 1 in October, and 1 in December).
The flyaway cost amounted to $215,164. Except for the F-82B, every F-82 carried the same price tag.
F-82Es (last piston engined fighters to enter Air Force service) quickly disappeared from the SAC inventory. The first sizeable lot was declared surplus in March 1950.
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