| Popis: |
For a period covering approximately the past 15 years, a large portion of the subsonic aerodynamic research and development conducted in this country and Europe has dealt with various aspects of the problem of producing an aircraft incorporating very short field landing and take-off capabilities with a cruising speed considerably higher than that obtainable from conventional helicopters. Many schemes and configurations have been studied. Some have placed emphasis on high speed capabilities and hence have employed jet propulsion. Others, desiring higher efficiencies at the lower speeds, have made use of propellers or rotors. None has so far demonstrated such outstanding success that it clearly represents the most satisfactory solution to the problem. Moreover, at the present time no such machine has enjoyed more than limited production for evaluation purposes. |
