Aviation of World War II
The mass production of the powerful Shvetsov M-82 two-row radial engine began in May 1941 at Zavod 19 in Perm. A.I. Mikoyan, N.N. Polikarpov, P.O.Sukhoi and A.S. Yakovlev were given the task of trying to install this engine in their fighters. The first flyable engine was delivered to OKB-155 on 18 May, and the drawings for the prototype were ready in mid June, July 1 being the deadline for the first flight.
The new machine, called I-210 or MiG-9, differed from the standard MiG-3 by:
• new enlarged fuselage to accommodate the new engine; the rear fuselage was widened too and had a more rounded section;
• wing moved back by 100 mm for eg reasons;
• new plywood panels on the fuselage sides;
• aerodynamically balanced rudder;
• horizontal and vertical tailplane enlarged (apparently greater chord than on late MiG-3s);
• NACA engine cowling with four easily removable panels;
• cooling airflow control as on the La-5 and I-185; it was made of shutters (probably 12+12) that could retract away behind the spinner by rotating on a side pin;
• two side exhaust stacks;
• four fuel tanks for a total of 488 l; the ventral tank was still protruding;
• two oil coolers VMS-8 installed in a tunnel under the nose;
• AV-5-127A propeller, with 3 m diameter;
• armed with 3 UBS 12.7 mm with 200 rounds each, (and 2 ShKAS 7.62 mm with 650 rounds each on the last 3 prototypes); all weapons were installed in the nose;
• main landing gear doors without opening access panel
A top speed of 630 km/h at 6500 m and 530 km/h at sea level were calculated. The first example, n.6501, first took off on July 23, 1941, flown by the NII-VVS test pilot M.I.Martselyuk. The second prototype, n.6502, started armament tests on August 25; the left-hand ShKAS was removed. Flight tests were conducted by test pilot A.P. Yakimov. The NII-VVS made its report on the MiG-9 tests at the end of August. They approved of the stronger armament, the better take-off properties and higher speed and rate of climb at low altitudes. The top speed was disappointingly low, 540 km/h at 5000 m. This was partially due to defects in the oil cooler and cowling finish (this wasn't hermetically sealed, and created unfavourable air flows), and to the use of an AV-5L-156 propeller instead of the still unavailable AV-5-127A.
During September 1941, MiG-9 n.6501 was tested in the large T-104 wind tunnel at TsAGI, that confirmed the negative influence of the engine cowling on drag. This would require modifications to the fuselage, but this wasn't possible because of the evacuation of Zavod I and OKB to Kuybyshev in October. Three further machines. n.6503, 6504. 6505 were built in Kuybyshev under difficult conditions. They were assembled in the open air because the roof of the workshop wasn't yet built.
They were provided with a Hucks starter dog on the spinner, and ShKAS guns in a lower position than on n.6502. Shortage of Mikulin engines due to the Il-2's priority was already in the air, and Mikoyan hoped to maintain his aircraft in production with the new M-82 engine.
Further tests were made in January 1942 with n.6502, flown by test pilot V.N. Savkin. This demonstrated the absence of engine overheating, and that spin properties were better than the original MiG-3.
When OKB-155 returned to Moscow from Kuybyshev during the spring, all the prototypes were finished. On June, n.6502 was delivered to NII VVS, that sent it to 12th Gv.IAP, 6th IAK PVO. Aircraft n. 6503, 6504, 6505 were delivered to 34th IAP, 6 IAK PVO on June 1942 . They took part in combat operations. On 27 October the aircraft of 34th IAP returned to OKB-155 to remedy some defects of the power plant.
On September, n.6502 started the NII-VVS official tests. All the ShKAS were removed, leaving 3 UBS guns. Tests were headed by chief engineer l.G.Lazarev and test pilot V.E. Golofastov. It was necessary to send the aircraft repeatedly back to OKB-155 for work on the power plant, so tests lasted two months. A disappointingly low speed was reached, no more than 565 km/h at 6150 m; besides, the engine installation was unsatisfactory both as regards ease of maintenance and functioning at low rpm.
The poor visibility and the necessity to fly with an open canopy to reduce fumes in the cockpit were defects common to the original MiG-3. The aircraft n.6503, 6504, 6505, after modifications, were delivered to 260 SAD 7 VA on the Karelian front on 27 June 1943. They were employed operationally for about a year before being written off.