The two seat Spitfires used by the Red Air Force were not supplied as such by the RAF.
The Russian MKIX UTI Spitfires were converted "in the field". Therefore they did not conform
to the twenty built by Vickers Supermarine to Type 509 after the war. The new second cockpit
was positioned imediately behind the standard cockpit position. Thus these aircraft retained
the full size fuselage fuel tanks. These aircraft were fitted with clipped and standard
wing tips, with cannon and without. It is unkown how many were converted but as many as
one for each 40-aircraft regiment is possilbe. They were used as fighter trainers and
communication aircraft.