Putilov Stal-11

The Stal-11 (Stal – steel) was a high speed transport aircraft / reconnaissance aircraft designed and built in the USSR from 1933.

Development
The Stal-11 was intended to carry four passengers with mail and baggage as well as fulfil a military reconnaissance role. The Stal-11 was constructed an using Enerzh-6 stainless steel built up truss covered with Delta-wood for the fuselage, an all wood wing with built up ribs, two spars and very smooth skinning complete the structure. The prototype was completed in the Autumn of 1936, flight trials commencing shortly after, with wheels and skis. Results of the approx. 300 flight tests were promising but the aircraft was expensive to build, with high running costs so no production was authorised.