No abstract

Aircraft designers are working on VTOL and STOVL aircraft for more than 60 years now. Several VTOL research projects were launched with the aim to design, ground test and even flight test these new aircraft and propulsion concepts. This year DARPA launched a BAA for a VTOL X-Plane Demonstrator capable of reaching cruise speeds of more than 300 kts in combination with outstanding hover efficiencies. This paper describes the requirements analysis, a propulsion concept screening, finally the designed tilt wing concept for a demonstrator which is able to meet the DARPA X-Plane Demonstrator requirements. Next to the tilt wing design, it also shows the propulsion system selection and high level performance characteristics. Nomenclature AR= Aspect ratio BAA = Broad Agency Announcement C L = Lift coefficient c = chord FCS = Flight control system FOM = Figure of merit HOGE = Hover out of ground effect ISA = International Standard Atmosphere LIDAR = Light detection and ranging n z = Vertical acceleration SFC = Specific Fuel Consumption S/L = Sea level STOL = Short take-off and landing TAS = True air speed V/STOL = Vertical / Short take-off and landing VTOL = Vertical take-off and landing