Swashplate

About: Swashplate is a research topic. Over the lifetime, 1014 publications have been published within this topic receiving 6718 citations.

Vibration reduction in helicopter rotors using an actively controlled partial span trailing edge flap located on the blade

Abstract: This report describes an analytical study of vibration reduction in a four-bladed helicopter rotor using an actively controlled, partial span, trailing edge flap located on the blade. The vibration reduction produced by the actively controlled flap (ACF) is compared with that obtained using individual blade control (IBC), in which the entire blade is oscillated in pitch. For both cases a deterministic feedback controller is implemented to reduce the 4/rev hub loads. For all cases considered, the ACF produced vibration reduction comparable with that obtained using IBC, but consumed only 10-30% of the power required to implement IBC. A careful parametric study is conducted to determine the influence of blade torsional stiffness, spanwise location of the control flap, and hinge moment correction on the vibration reduction characteristics of the ACF. The results clearly demonstrate the feasibility of this new approach to vibration reduction. It should be emphasized than the ACF, used together with a conventional swashplate, is completely decoupled from the primary flight control system and thus it has no influence on the airworthiness of the helicopter. This attribute is potentially a significant advantage when compared to IBC.

Enhanced flight control systems and methods for a jet powered tri-mode aircraft

Abstract: A method of stabilizing a jet-powered tri-mode aircraft as the aircraft travels in a helicopter mode, a compound mode, and a fixed-wing mode is disclosed. The method includes receiving a plurality of velocity vector component values and velocity vector commands derived from either (1) a number of pilot operated controllers or (2) a commanded array of waypoints, which are used for fully automated flights, and a rotor speed reference value, which is decreased with increasing forward speed to unload the rotor, thereby permitting conditions for stopping the rotor in flight. Stabilization of the commanded velocity vector is achieved in all modes of flight using blended combinations of rotor swashplate controls and aerodynamic controls such as elevons, canards, rudders, and a horizontal tail. Stabilization to the commanded velocity vector includes a plurality of control constraints applied to the pilot stick controllers that prevent penetration of envelope limits.

The Philips Stirling Engine

Abstract: 1. The Hot-Air Engine. 2. The Twentieth-Century Revival. 3. The Stirling Cycle. 4. Rhombic-Drive Engines. 5. Heating and Cooling. 6. Pistons and Seals. 7. Later Rhombic Engines. 8. Electric Generators and Heat Pumps. 9. Exotic Heat Sources. 10. The Stirling Engine and the Environment. 11. Swashplate Engines. 12. The Past and the Future. Appendices: A. Robert and James Stirling. B. The Stirling Patent of 1816/17. C. Formulae for Calculating Flow Resistance and Heat Transfer. D. The Rhombic-Drive Patent.

Autonomous Hovering of a Noncyclic Tiltrotor UAV: Modeling, Control and Implementation

Abstract: The aim of this paper is to present a mini tilt-rotor unmanned aerial vehicle which is capable to perform hover flight. Unlike conventional full-scale tiltrotors, in our design we avoid the use of swashplate and we propose a simpler mechanical design which use only the tilting rotors to stabilize the vehicle dynamics. A detailed mathematical model is derived via the Newton-Euler formalism. A nonlinear control scheme, incorporating bounded smooth function, is obtained from the decoupled dynamics and applied to real prototype for controlling hover flight.