WSK_SO-3
The PZL Rzeszów SO-1 and PZL Rzeszów SO-3 are Polish turbojet engines designed by the Instytut Lotnictwa (Institute of Aeronautics ) and manufactured by WSK PZL Rzeszów, to power the PZL TS-11 Iskra jet trainer. Thirty SO-1s were built, this being superseded by the improved SO-3, of which a further 580 were built.[1] The engine has a seven-stage compressor, annular combustion chambers, and a single-stage turbine.