An engine designed specifically for helicopters. It is a variant of the Soviet Ivchenko AI-26W engine, produced in Poland under licence by PZL Rzeszow. In the mid-1950s, Poland purchased a licence for the production of the Mi-1 helicopter and its engine.
Equipped with a single-stage supercharger, the engine features a drive transmission to the main rotor and tail rotor via a bevel gear, a clutch for smoothly engaging and disengaging the drive from the rotor and control system, and a cooling fan.
Engine starting was performed using compressed air. It was used in the SM-1 (licence-built Mi-1) and SM-2 helicopters.
| Configuration | 7-cylinder radial |
| Cooling | air |
| Compression ratio | 6.4 |
| Displacement | 20.6 l |
| Maximum power | 575 hp at 2200 rpm |
| Rated power | 460 hp at 2050 rpm |
