Historical Overview of V/STOL Aircraft Technology

For over 25 years a concerted effort has been made to derive aircraft that combine the vertical takeoff and landing capabilities of the helicopter and the high cruise speeds of conventional aircraft. During this time, over 60 V/STOL types have been studied and flown with varying degrees of success. The requirements for satisfactory characteristics in several key technology areas are discussed and a review is made of various V/STOL aircraft for the purpose of assessing the success or failure of each design in meeting design requirements. This survey shows that in spite of many problems revealed, special operating techniques were developed to help circumvent deficiencies. For the most part performance and handling qualities limitations restricted operational evaluations. Flight operations emphasized the need for good STOL performance, good handling qualities, and stability and control augmentation. The majority of aircraft suffered adverse ground effects. There is a continued need to update and improve flight test techniques and facilities to ensure satisfactory performance and control before and during flight testing.