Drawing by Tapani Tuomanen

In early 1942, many UT-1 were converted to the role of night intruders, with the addition of two/four underwing rails for RS-82 rockets and of two ShKAS machine guns over the wing surfaces. The ammo were lodged inside the wings. The planes could have had different armament options, including bombs.

The conversion work was made during the defence of Sevastopol as an initiative of Air Major General Ostryakov, commander of the Black Sea Fleet Air Force.

The converted planes were renamed UT-1b (or UT-1B) and painted with a green-black camouflage with light blue undersurfaces.

They saw action in night raids for the defence of Sevastopoland and on North Caucasus area, flying over than 2000 sorties. They equipped some regiments, including the 46 AP of the Black Sea Fleet.

Germans nicknamed these planes 'Russian mosquito aviation'.

One of the tactics was to make an old I-5 fighter fly ahead of the group at medium altitude to serve as bait, provoking the fire of the enemy AA that, in such way, revealed their position to the small intruders that attacked them.

UT-1b were replaced by Il-2s in March 1943.

Here is plane 'White 4' , s/n 47445 of 23th Aviation Regiment, during trials in February 1942.

Images from Mir Aviaciya 1/98.