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UAS Airframe Design
Published in R. Kurt Barnhart, Douglas M. Marshall, Eric J. Shappee, Introduction to Unmanned Aircraft Systems, 2021
Michael T. Most, Michael Stroup
Examples of UAS rotary-wing designs that are neither helicopter nor multirotor exist. One is the Eagle Eye tiltrotor, powered by a single Pratt & Whitney Canada (P&WC) turboshaft producing more than 600 shp. Designed and constructed by Bell, the Eagle Eye closely resembles the larger manned versions of the company’s tiltorotor designs. To transition from helicopter mode to airplane mode, the tiltrotor is capable of rotating the nacelles, located at the end of its wings, from the vertical position to a horizontal orientation and then back to vertical for a landing. Although the Eagle Eye is capable of flying like an aircraft, it is strictly a VTOL aircraft—the blades of the rotor-props are too long to accommodate a conventional, run-on landing. In 2002, the U.S. Coast Guard placed an order for Bell Eagle Eyes to bolster the USCG’s deep water surveillance program, but the order was subsequently frozen due to lack of funding.
UAS Airframe and Powerplant Design
Published in Douglas M. Marshall, R. Kurt Barnhart, Eric Shappee, Michael Most, Introduction to Unmanned Aircraft Systems, 2016
Examples of UAS rotary-wing designs that are neither helicopter nor multi-rotor exist. One is the Eagle Eye tiltrotor, powered by a single Pratt & Whitney Canada (P&WC) turboshaft producing more than 600 shp. Designed and constructed by Bell, the Eagle Eye closely resembles the larger manned versions of the company’s tiltorotor designs. To transition from helicopter mode to airplane mode, the tiltrotor is capable of rotating the nacelles, located at the end of its wings, from the vertical position to a horizontal orientation and then back to vertical for a landing. Although the Eagle Eye is capable of flying like an aircraft, it is strictly a VTOL aircraft—the blades of the rotor-props are too long to accommodate a conventional, run-on landing. In 2002, the U.S. Coast Guard placed an order for Bell Eagle Eyes to bolster the USCG’s deep water surveillance program, but the order was subsequently frozen pending restoration of funding.
Grasping the future
Published in Henry H. Perritt, Eliot O. Sprague, Domesticating Drones, 2016
Henry H. Perritt, Eliot O. Sprague
VTOL (vertical takeoff and landing) aircraft now in military and commercial service are attracting wider interest and will influence drone configurations. The terminology is misleading. By definition, a helicopter is a VTOL aircraft because it takes off vertically, but in professional usage, VTOL has come to signify aircraft other than helicopters that are capable of taking off vertically. Typically they use shrouded or ducted fans in their wings or tilt their wings or rotors to direct thrust downward as well as backward. The V-22 Osprey is an example of a tilt-rotor design, imitated by the commercial AgustaWestland AW609. The Harrier and the newer F-35B achieve VTOL capability by deflecting jet thrust downward.
Coupled CFD/MBD Method for a Tilt Tri-rotor UAV in Conversion of Flight Modes
Published in International Journal of Computational Fluid Dynamics, 2020
Guilin Wen, Dong Wu, Hanfeng Yin, Daibing Zhang
One of the most interesting solutions that have the potential to revolutionise the modern air transportation is represented by the tilt-rotor aircraft (Reber 1993), especial for the field of unmanned aerial vehicle (UAV). The concept of tilting represents that the postures of the rotor may rotate from the horizontal direction to the vertical direction and vice versa. The dynamic conversions of flight modes achieved by the performance of the tilting rotors switching rotationally between horizontal and vertical directions can make the tilt-rotor aircraft obtain the capabilities of low-speed vertical taking-off and landing of the helicopter and high-speed cruise of the traditional propeller aeroplane. These capabilities have been expected for an aircraft with none runway operations.