Their new aircraft was called MiG-9 or I-210 and was different from the MiG-3 in various aspects. It had a new and enlarged fuselage to fit in the engine with a widened rear fuselage and a more rounded section, wings were moved back 100mm, horizontal and vertical tailplanes were enlarged with greater chords than late MiG-3s, the engine cowling had four removable parts to allow easy access to the engine, cooling airflow was made out of shutters just like in the Lavochking La-9 or the Polikarpov I-185, that could retract away behind the spinner, it had four fuel tanks with a total of 488L (128.82 US Gals.) with a ventral tank still protruding, two oil coolers were installed in tunnel under the nose, main landing gear didn't have an opening access pannel and it was armed with 3 UBS 12.7mm (0,50in) cannons placed in the nose. Later, the last three prototypes were fitted with 2 extra 7.62mm (0.3in) ShKAS machine guns in the wings.
It was expected for this aircraft to achieve a top speed of 630km/h (391.46mph) at 6500m (21325.46ft) and 530km/h (329.33mph) at sea level. It flew for the first time on 23rd July 1941 manned by the NII-VVS (Soviet Air Force testing unit) test pilot M.I. Martselyuk with the second prototype performing armament testing on 25th August with one machine gun removed though. Further flight testing was made by NII-VVS test pilot A.P. Yakimov and their report was ready by the end of August 1941. They approved the installation of stronger armament and recommended to improve the take-off, high speed and rate of climb performances as the top-speed was rather disappointing achieving just 540km/h (335.54mph) at 5000m (16404.20ft) because of the defects in the air-cooling and cowling finish that, as it wasn't hermetically sealed, it created an unfavourable airflow.
During September 1941 the MiG-9 was tested in a very large wind-tunnel at TsAGI (Soviet Aeronautical Testing Institute) confirming the negative drag, requiring that way modifications in the fuselage. However, due to the German advance, it wasn't possible as the OKB-155 was evacuated to Kuybyshev in October. Three further prototypes were built there under harsh conditions, in the open air as the roof of the workshop wasn't build yet.
As the shortage of Mikulin engines were in order, Mikoyan followed the prototype with the M-82 engine and it was furtherly tested in January 1942 piloted by test pilot V.N.Savkin and, fortunately for them, engine overheating problems proved to be fixed.
During spring 1942 OKB-155 returned to Moscow and all the prototypes were finished, so on June 1942, the second, fully armed prototype was sent to the NII-VVS that assigned it to the 12th GvIAP, 6th IAK PVO and the rest of the prototypes were assigned to the 34th IAP, 6th IAK PVO to be tested operationally. Apparently they took part in some aerial combat and on 27th October an aircraft serving with the 34th IAP was returned to the OKB to fix some defects in the power plant.
In September 1942 it was oficially tested by the NII-VVS, however, it was unarmed. Tests were performed by chief engineer I.G. Lazarev and test pilot V.E. Golofastov. Tests showed the necessity of fixing the power plant, so it was sent back to the OKB-155, which it took them two more months with a top speed that was disappointing.
The poor visibility of the cockpit and the necessity of flying with the canopy opened to reduce the fumes, were defects inherited from the original MiG-3. Three prototypes were assigned to the 260th SAD, 7th VA and served in the Karelian front on 27th June 1943. They were used operationally for one year approximately before being written-off.
As the dissappointing performance of the I-210 showed that the adaptation of a radial engine to the narrow fuselage of the MiG-3 wasn't simple, it was decided to deeply redesign it, around the improved version of the M-82 engine, the M-82F, which was renamed in 1943 as the ASh-82F in honour of its designer Arkady Shvetsov. In order for the redesign, all previous experience with the I-210 an the recommendations of the TsAGI were taken into account, so Mikoyan redesigned and sealed the engine cowling, oil coolers were relocated to the wing roots, canopy was redesigned in order to allow better visibility, undercarriage was modified to make it smaller, slats were removed from the wings, tail surfaces were partially reshaped moving horizontal surfaces to a higher position, cockpit was provided with armoured bullet-proof glass, it was 280kg (617.29lb) lighter than the MiG-9 and it was armed with two 20mm ShVAK guns placed in the lower part of the engine cowling. It was called I-211 or MiG-9E.
First prototype flew for the first time on 24th February 1943 by V.N. Savkin and it achieved a speed of 670km/h (416.32mph) at 7100m (23293.96ft) and was able of reaching 4000m (13123,36ft) in just 4 minutes. However, maneouvrability wasn't good and the prototype was tested without radio or slats, so the installation of that equipment, vital for a 1943 fighter aircraft, was going to increase the weight of the fighter.
For those reasons, in spite of the good performance shown, the MiG-3 wasn't going to replace the Lavochkin La-5FN that was already in production and service. Apparently, 10 of then were built either completely or partially.
Sources:
1. http://www.airpages.ru/eng/ru/mig9.shtml
2. http://www.airpages.ru/eng/ru/mig9e.shtml
3. https://en.wikipedia.org/wiki/Mikoyan-Gurevich_I-211
4. Salamander Books - The Complete Book of Fighters
5. Signal Squadron - Aircraft In action 204 - Early Mig Fighters in Action
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