 The five aircraft modified by the factory were given the Klimov RD @-@ 45 engine , the Soviet unlicensed copy of the Nene engine , and all six aircraft , used by the VVS for aircrew familiarization and training . The aircraft completed were later relegated to test duties . One aircraft was used for drone tests and another , redesignated as the Tu @-@ 12LL , mounted various pulse jet engines on a pylon above the fuselage . 
 The five aircraft modified by the factory <a href='uninflect' title='1'><mark>were</mark></a> given the Klimov RD @-@ 45 engine , the Soviet unlicensed copy of the Nene engine , and all six aircraft , used by the VVS for aircrew familiarization and training . The aircraft completed <a href='uninflect' title='2'><mark>were</mark></a> later relegated to test duties . One aircraft was used for drone tests and another , redesignated as the Tu @-@ 12LL , mounted various pulse jet engines on a pylon above the fuselage . 
The five aircraft modified by the factory was given the Klimov RD @-@ 45 engine , the Soviet unlicensed copy of the Nene engine , and alll six aircraft , used by the VVS for aircrew familiarization and training . da aircraft completed was later relegated to test duties . One aircraft was used for drone tests and another , redesignated as the Tu @-@ 12LL , mounted various pulse jet engines on a pylon above the fuselage .