For a long time the only Czechoslovak engine for light aircraft, the first to be tested according to the new technical requirements introduced by the Chicago Convention for civil aviation in 1944. It was used to power the Aero C‑104, Aero Ae‑45, Zlin Z‑26 and Z‑126 aircraft.
| Configuration | 4-cylinder inverted inline |
| Cooling | air |
| Compression ratio | 6.0 |
| Displacement | 3.98 l |
| Weight | 90 kg |
| Maximum power | 105 hp at 2500 rpm |
| Rated power | 80 hp at 2300 rpm |
