Although the complete clarification of the flight characteristics some experiments will be needed, however, there are generally no difficulties for the construction of a "duck" -Flugzeuges. The aircraft experiments with the built Focke-Wulf in 1927 "duck" were quite satisfactory, and a further failed probably mainly due to the unfavorable conditions at that time. Apparently -type are just in the last few years the possibilities of "duck" has been recognized in several countries; so acquired, for example, in the US, the Lockheed Aircraft Corp. in 1939 two patents on designs for "duck" type.. are indicated as the author of CL Johnson, the chief research engineer of this company, and WardW.Beman. Around the same time appeared a technical note of the NACA (Technical Notes No. 758) entitled: "Measurements and analyzes the motion of a" duck "-Flugzeuges gusts"; a proof that