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Project Description

A tailsitter is a fixed wing aircraft with vertical takeoff and landing (VTOL) capabilities but requires no additional moving parts as tilt-rotor, tilt-wing or vectored thrust aircraft do. This type of aircraft combines the flexibility of rotorcraft and endurance of fixed-wing aircraft. (See for more details.)


Problem Statement

  • Autonomous flight desired from takeoff through landing, including transition between hover and level flight
  • Platform must be robust to external disturbances such as wind during all flight regimes.


  • Aircraft inherently unstable in hover
  • Characterizing aerodynamics during transition
  • Traditional methods of attitude description (Euler Angles) not sufficient
  • Maintaining control authority while descending during hover


  • Hardware-in-the-Loop Simulation o Interface Kestrel 3 Autopilot with the X-Plane flight simulator
  • Control Algorithms o Implement previously developed control algorithms on Kestrel 3 Autopilot o Validate algorithm robustness to external disturbances, specifically during hover and landing o Improve transition controller: - Banking during transition - Minimize altitude gain while controlling horizontal position
  • System Identification o Wind tunnel testing for general aircraft parameters o Flight Testing for aerodynamic and other physical parameter o Simulator Validation


BYU: Dr. Randy Beard, Dr. Tim McLain, Matthew Argyle, Nathan Edwards, and Jason Beach

MLB Company: Steve Morris


MLB was recently awarded a Phase II contract from the Air Force Research Lab. MLB has chosen BYU to develop the flight controls.

Project Duration

Summer 2011 - 2015