MiG-15S bis / SD UPB MiG 15R bis / SR

The MiG-15S bis and MiG-15R bis were both direct derivatives of the MiG-15 bis. The first was an escort fighter, the second a frontline photo­reconnaissance aircraft—two roles that demand long-range capabilities. The main difference between the MiG-15 bis and these two versions (other than the AFA-40 photo equipment on the MiG-15R bis) was the addition of two 600-1 (158-US gallon) drop tanks beneath the wing.

Considering the greater endurance made possible by those tanks, an additional 2-1 (0.53-US gallon) oxygen bottle was installed in the nose section, bringing the total oxygen reserve to 8 1 (2.11 US gallons). The additional takeoff weight also led the engineers to increase the tire pressure from 7 kg/cm2 (100 psi) to 8f05 kg/cm2 (113.8 psi) and to add restrictions to the flight protocols. Pilots were not allowed:

—to fly the aircraft under a negative load factor with full drop tanks —to make a long side-slip with full drop tanks (since a steady fuel draining could not be assured)

—to fly for a long time at speed limits

—to land with full drop tanks (they had to be jettisoned first)

The specifications and performance of the MiG-15S bis and MiG – 15R bis did not differ much from those of the MiG-15 bis, and both air­craft were held to the same speed and altitude limits as their precursor.