Powered by an 850-hp R-1830-9, the P-35 had a guaranteed top speed at 10,000 feet of 300 mph and a stalling speed of 65 mph, but actual test results were 281.5-mph top and 79-mph stalling. Since performance guarantees were not met, payments were reduced to $22,610 each and Seversky lost money on the contract.
The P-35s went to the First Pursuit Group at Selfridge Field. They were 20% faster and had over double the range of the P-26s they replaced. The usual two guns were fitted, but the P-35s were the first Air Corps fighters to replace bar sights with the N-2 optical reflector gun sights that would be common to WW II fighters. They were also the first Army production fighters delivered in unpainted natural metal and powered by the Pratt & Whitney Twin Wasp.
The new power plants presented their own problems and the Severskys had to be grounded on April 28, 1938, due to engine bearing failures, until Pratt & Whitney solved the problem. The last of 76 P-35 fighters was delivered to Selfridge Field on August 8, 1938. When they were replaced by more advanced types in 1940-41, they were passed on to the 31st, 49th, and 53rd groups for training.
Seversky wrote the Air Corps on June 7, 1938, to propose using a new engine and wheels retracting flat into the center section. Such an aircraft, his AP-2 racer in June 1937, did 307 mph at 10,000 feet, he claimed. On June 27, 1938, the Army ordered that the last plane on the P-35 contract be completed as the XP-41 with a 1,200-hp R-1830-19 and wheels retracting inwardly.
Private versions of the P-35 for Frank Fuller and Jacqueline Cochran won the Bendix air race three years in a row (1937-39). Two Cyclone-powered examples were also built; one similar to the AP-1 for Navy fighter tests (see NF-1 in Chapter 22) and the other for James Doolittle.*
A two-seat export version known as the 2PA “Convoy Fighter,” with an 875-hp R-1820-G3, was developed in July 1937 by reworking the Sev-XBT advanced trainer demonstrator. This aircraft arrived by ship in Argentina by September 29, 1937, but that country chose the Curtiss Hawk 75 as its standard fighter.
The Soviet Union bought one 2PA-L two-seater, first flown November 2, 1937, with a GR-1820-G7, and one 2PA-A delivered in March 1938 with amphibian floats and extended wings. Armament on both included a .30-caliber flexible gun, two fixed guns with bar sight, and up to 600 pounds of bombs. Manufacturing rights were also acquired by the Soviet Union, although its air force subsequently decided against replacing their DI-6 biplanes with more two-seat fighters.
Twenty more Convoy Fighters, 2PA-B3, were built from April to August 1938, for the Japanese Navy (which called them the A8V1), although the company had claimed that Siam was their destination. They were the only American-built combat planes used operationally by a Japanese squadron, the 12th Kokutai. Their landing gear was similar to the P-35, and they had extended 41-foot wings to add fuel capacity.
A 950-hp R-1830-S3C3-G with 92-octane fuel, the intake for the downdraft carburetor moved to the top, and a longer, flush-riveted fuselage was used on the two-seat 2PA-202 first flown October 23, 1938. It was joined by a similar single-seat version called the EP-1 (Export Pursuit).
Company publicity credited the EP-1 with 320 mph and the 2PA-202 with 315 mph, and Seversky took both prototypes to Europe on a sales tour in November. While he was abroad, the company tried for an Army contract with the single-seat AP-9, with an 825-hp R-1830-S3C5, flush riveting, the top intake for the downdraft carburetor, a sharper leading edge, and wheels retracting flat into the center section. Reaching Wright Field on January 17, 1939, it only placed last in the pursuit competition won by the P-40.
They might have had better luck with the XP-41, which was the last aircraft of the P-35 contract, but also had the wheels retracting inwardly, and introduced a 1,050-hp R-1830-19 with a two-stage supercharger. However, it was delivered too late for that competition and will be seen in the next chapter.
Seversky’s bad luck continued when the 2PA-202 was wrecked after a demonstration in England on April 1, 1939, and he returned from Europe to learn that he had lost control of the company he founded. An expected Chinese contract for 54 fighters fell through in June 1939, although the EP-1 prototype, the AP-7, Sev-DS, and the Sev-S2 were eventually sold to Ecuador in October 1941 to counter a Peruvian threat.