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Ames Research Center is a key team member on two NASA Revolutionary Concepts (REVCON) Phase I aeronautics projects, which focus on vertical lift technologies. The REVCON program is a Dryden Flight Research Center-led initiative that emphasizes the development and demonstration of high payoff aeronautics technologies that can be quickly taken from concept to flight. The REVCON projects are broken into two phases: a Phase I $300,000, 8-month-long, system analysis and overall concept-feasibility assessment study, and a Phase II effort which encompasses the actual vehicle/technology development and flight demonstration. Contractors for both Phases are competitively selected. Only Phase I projects are considered for Phase II award. Proposals for the Phase I effort were solicited by means of a NASA Research Announcement (NRA).
One of the two vertical-lift technology projects that Ames is participating in is the Advanced Technology, Incorporated (ATI) Swashplateless Flight project (fig. 1). This project seeks to demonstrate, on an unmanned air vehicle (UAV), ultralight helicopter flight-test platform primary flight control (rotor blade pitch angle, collective, and cyclic) using embedded flaps on the rotor blades, driven by advanced electromagnetic actuators and power electronics. (Primary flight control for conventional rotorcraft is provided by a complex assembly of mechanical components which make up the rotor control system--the chief component of which is the swashplate.) These same rotor-blade electromagnetic actuators--in addition to providing primary flight control--will be used to demonstrate high frequency (greater than once-per-blade revolution) active rotor control for noise and vibration reduction. Successful demonstration of this technology could yield an elegant design approach for rotorcraft flight control that will reduce helicopter parasite drag, improve range and endurance, improve reliability and safety of operation, and at the same time reduce noise and vibration. The team members for the Swashplateless Flight project are ATI, Diversified Technologies Incorporated (DTI), Science Applications International Corp. (SAIC), the U.S. Army Aeroflightdynamics Directorate, the NASA Ames and Langley Research Centers, and the Dryden Flight Research Center.
The second vertical-lift REVCON project in which Ames is involved is Sikorsky Aircraft's Variable-Diameter Tilt Rotor (VDTR) UAV demonstrator project (see fig. 2). The VDTR concept promises significant performance and safety advantages over conventional tilt rotors. The rotor blades of a VDTR aircraft telescope and retract radially along the blade span such that the rotors are at a larger diameter for hover and low-speed helicopter mode than they are in airplane-mode cruise. This rotor diameter change allows the VDTR aircraft to optimize its rotor disk loading and performance, for each flight condition. The comparatively lower VDTR rotor disk loading (compared with that of a conventional tilt-rotor aircraft) in low-speed helicopter mode allows for improved autorotation characteristics in case of an aircraft power loss. The team members for the VDTR project are Sikorsky, the U.S. Army Aeroflightdynamics Directorate, the NASA Ames, Langley, and Glenn Research Centers, and the Dryden Flight Research Center.
Phase I work for both projects has been completed and final reports submitted. Selection and award of the REVCON Phase II projects will be made by the end of FY01.
Point of Contact: Larry A. Young
(650) 604-4022
layoung@mail.arc.nasa.gov
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Fig. 1. ATI swashplateless flight project.
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Fig. 2. Sikorsky Aircraft's Variable Diameter Tilt Rotor (VDTR) UAV Demonstrator Project.
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