Mikoyan-Gurevich MiG-3, part five

The many amounts of flaws detected in the Mikoyan Gurevich MiG-1, forced Mikoyan to make many changes to the design. Those testing were applied to a scale model and tested in the wind tunnel at the TsAGI (Central Aero and Hydrodinamics Institute). It was the I-200 ,technically the fourth prototype of the MiG-1, that saw those changes applied and it flew for the first time on 29th October 1940 and was accepted into production after passing its state acceptance trials. It was named as MiG-3 when the production chain was set in December 1940 with the first 20 of them released before the end of the year.
The changes were many:
The engine ,a 1350hp Mikulin AM-35A liquid cooled V12 engine, was moved forward 100mm (4in) to improve longitudinal stability, a new water radiator (OP-310) was fitted, an adittional 250 litres (66 US Gal) was added underneath the cockpit, outer wing panel dihedral was increased by one degree in order to increase lateral stability, another fuel tank was placed under the engine, piping was fitted to use cooled exaust gases to reduce the hazard of fire, the back of the pilot's seat war armoured with an 8mm (0.31in) plate which was increased to 9mm (0.35in) in later models, supercharger intakes were streamlined, main landing gear was also strengthned, canopy glazing was extended aft to improve the view of the rear, which allowed the installation of an RSI-1 radio equipment, later improved with an RSI-4, gunsight was improved, more ammo magazines for the 7.62mm ShKAS machine guns were fitted up to 750 rounds per gun and two additional hardpoints were added under the wings so total armament was one 12,7mm Berezin UB machine gun, two 7.62mm ShKAS machine guns placed in the cowl and either 6 RS-82 rockets or 2 100kg (220lb) of bombs. Later models had two additional 7.62mm machine guns placed in the wings.

Sources:
1. https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-3
2. Salamander Books - The Complete Book of Fighter
3. Signal Squadron - Aircraft In action 204 - Early Mig Fighters in Action