U1 -
1 plane, engine mount extented 15 cm
U2 -
1 plane, testbed for RZ 65 73 mm rocket racks
U3 -
1 plane, reconnaisance fighter with RB 50/30 cameras
U4, reconnaisance
fighter with RB 12.5/7X9 cameras
U7 -
3 planes, high altitude fighter with reduced weight, only
armaments was 2 X MG 20 mm 151/20