Vertical/short take-off and landing - INTRODUCTION

INTRODUCTION

Fig. 18-1 Michel Wibault's ground attack gyropter (concept) 1956

1. Vertical take-off and landing (VTOL) or short take-off and landing (STOL) are desirable character- istics for any type of aircraft, provided that the normal flight  performance  characteristics,  including payload/range, are not unreasonably impaired. Until the introduction of the gas turbine engine, with its high power/weight ratio, the only powered lift system capable of VTOL was the low disc loading rotor, ason the helicopter.
2. Early in 1941, the late Dr A. A. Griffiths, the then Chief Scientist at Rolls-Royce, envisaged the use of the jet engine as a powered lift system. However, it  was not until 1947 that a light weight jet engine, designed  by  Rolls-Royce  for  missile  propulsion, existed and had a high enough thrust/weight ratio for the first pure lift-jet engine to be developed from it.