| Manufacturer | Letov |
| Model | S-139 |
| Modification | S-139 |
| Country | Czechoslovakia |
| Years | 1933 |
| Type | Light aircraft |
| Main rotor diameter | - |
| Tail rotor diameter | - |
| Wingspan | 10.00 m |
| Length | 6.14 m |
| Height | - |
| Wing area | 14.00 m2 |
| Zero fuel weight | - |
| Empty weight | 315 kg |
| Maximum takeoff weight | 515 kg |
| Normal takeoff weight | - |
| Flight duration | - |
| Engine | 1 Pobjoy R |
| Power | 1 x 85 HP |
| Thrust | - |
| Maximum speed | 174 km/h |
| Cruising speed | 154 km/h |
| Rate of climb | - |
| Practical range | 480 km |
| Service ceiling | 4700 m |
| Hovering ceiling | - |
| Crew | 2 |
