Aviation of Word War II
High-altitude Fighter (prototype)
The work on I-200 drawings began on 25 November 1939. It differed from Project X because it had to be equipped with the Mikulin AM-35 engine; this was because the AM-37 was not yet ready for production. The AM-35A had the same dimensions, but its power was 200 hp lower. The drawings were completed and were submitted to the authorities on 8 December 1939, and on 25 December a mock-up was completed and approved. It was used for tests in the TsAGl T-101 wind tunnel. Such tests were concluded on January 2, 1940 and confirmed the good aerodynamic shape of the airframe, even if they judged that the projected performance was optimistic. Thanks to the help of technicians at Zavod 1, and his experience as production technician, Mikoyan divided the I-200 into sub-assemblies that could be produced separately and then easily assembled together by a small number of simple connections. This modular conception was favourable both for mass production and for maintenance, allowing quick removal and replacement of damaged sub-assemblies even under field conditions. Wide use was made of cast and moulded pieces, which were particularly suited for mass production. All the detail drawings were completed by February 10, 1940. There were only 2500 drawings, thank to the simplification created by the use of moulded parts.
As with many other Soviet fighters of the time, the I-200 was made partially of plywood; this led to a higher weight than aluminium alloy structures, but reduced the need for scarce strategic materials. The rear fuselage and the outer parts of the wing were similarly constructed. The mid and aft fuselage was made with a structure of welded steel tubes, covered with aluminium alloy panels fixed by Dzus-type fasteners. The central part of the wing was made of aluminium alloys, integral with the fuselage: the control surfaces were an aluminium alloy frame covered with fabric.
Thanks to a great effort from his bureau, the I-200 prototype was completed on March 31, 1940. Then it was critically examined by A.G.Brunov, senior test pilot of Zavod I and leading engineer for the tests, and by Colonel M.I. Martseliuk and Major M.N. Yakushin of the VVS.
The I-200 n.OI was first flown on April 5th, 1940, by test pilot A.N. Ekatov of Zavod 1. On the whole, the tests were satisfactory, though there was a fire in the inlet pipe due to a engine backfire on the 3rd flight, and some other difficulties: engine overheating, the canopy that was side hinged and impossible to open in flight, and there was insufficient braking power. On 1st May 1940 Ekatov flew the I-200 n.01 over Moscow's Red Square. On May 24 it reached a speed of 648 km/h at a height of 6,900 m, an exceptional performance not just in the Soviet Union. The only faster production built aircraft of the time was the Heinkel Hel 00.
The I-200 no.02 was completed for tests on April 25, and it was first flown by M.N. Yaskushin on May 9. It was externally distinguishable from the Nr. 1 by the oil coolers on both sides and the by the presence of slots in front of the windshield. The I-200 no.03 began ground tests of the armament on May 13, 1940. The prototype was completed on June 1, and was flown on June 6 by M.I. Martselyuk. This prototype had metal outer panels on the wings, but this modification wasn't used on later aircraft. It was also equipped with radio.
The performance demonstrated during the tests was highly satisfactory, particularly concerning speed. The I-200 no. 1, flown by Ekatov, reached 648.5 km/h at 6900 m in the nominal operating range of the engine on May 24. I-200 n.02 flown by Yakushin reached 651 km/h at 700 m, at nominal power as well. It reached 579 km/h at 2220 m and 605 km/h at 3630 m. The fighter reached an altitude of 5,000 m in 5.1 min, and 7.000 m in 7.15 min.
On May 25, 1940, even before the tests were completed, the Committee for Defence and the NKAP ordered the I-200 into production at Zavod 1, where it replaced the BB-22. It was expected than 125 I-200s would be built by the end of 1940. Such hurry was influenced by the enthusiasm of Stalin for the display in Red Square on May 1, and from the results of the tests, but the design team knew it was an error. In fact, tests also showed that the aircraft was demanding to fly, as it was longitudinally unstable and had neutral lateral stability. A list of 112 defects and corrections was made, including:
• improve stability;
• protection for the centre section fuel tanks;
• install wing slats;
• enlarge the wheels to provide for an increase in weight;
• install 2 further removable machine guns;
• increase the fuel tank capacity to reach a range of 1000 km.
The I-200 was first shown to the public at the Tushino Air Show on August 18,1940, where the I-200 no.03 flown by Yakushin made a demonstration flight. On September 13, 1940, at a meeting between the ОКО and Nil-VVS to discuss the results of tests, the chief test pilot Suprun commented NII-VVS to discuss the results of tests, the chief test pilot Suprim commented that "... the I-200 was the only prototype to pass the state tests at the first attempt": by comparison, the I-26 (later Yak-1) and I-301 (later LaGG-1) had to repeat the state tests several times.
* - by results of state official tests in AF Scientific Research Institute
** - more precisely after recalculation: maximum speed was 636 km/h at the altitude 7600 m.