Control system for ornithopter

#This invention relates to the field of ornithopters which develop lift and thrust through vertical movement of the wings to develop high aerodynamic propulsive efficiency. Further, the invention includes provision for damping the vibration resulting from movement of the wings.

#1. Background of the Invention

#There is a long history of aerial vehicles which attain flight through the movement of the wings. Of course, the most successful derivation of this concept is the helicopter. Modern helicopters and conventional aircraft have comparable characteristics of speed, lifting capacity and passenger comfort. These characteristics of the helicopter result from the rotary wing design wherein the wings or blades rotate in a plane parallel with the longitudinal axis of the fuselage.

#FIG. 1A is a perspective of the ornithopter of this invention;

#FIG. 1B is a front view of the wing spars and stationary shaft with the wing at the lower limit of the stroke;

#FIG. 1C is a front view of FIG. 1B with the wing at the upper limit of the stroke;

#The ornithopter 10 has a fuselage 11, wings 12, landing gear 13, and cockpit 100 as shown in FIG. 1. The fuselage 11 has a rigid forward portion 14 and a flexible empennage 15. The fuselage 14 has a central support beam extending along the roll axis to reinforce and rigidify the fuselage section. A passenger compartment 100 and/or a load carrying apparatus is attached to the rigid forward fuselage 14 by an articulating connection 101. The vertical movement of the wings 12 is shown in FIGS. 1B and 1C which illustrates the journals 38 and 39 at the base of the spars 40 and 41. FIGS. 1B and 1C also illustrate the stabilizing links 78 and 79 between the wings and the fuselage. Each link is rotatably attached at one end to the wing spar by a pin 80 and rotatably attached to the fuselage 14 by another pin 81. In this manner, the wing spar may rotate about the attachment and the link may wobble between both pins during the power strokes.

#As shown in FIG. 1A, the flight control system 200 includes the wing warping device 202. A change of direction in the pitch and roll axes is partially controlled by the movement of the foot of the wing. A vertical post 203 is mounted in the fuselage and supports a horizontal bar 204. Control rods 205 and 206 extend from each end of the bar to a respective foot of opposite wings, as shown in FIG. 1A. As shown in FIGS. 3 and 4, the bar 204 has two movements executed by different control inputs. The bar 204 can move along post 203 to change the angle of attack of both wings equally or the bar pivots about a horizontal axis perpendicular to post 203 to simulate the action of ailerons. The wing warping is only shown on one set of wings but it may be on both sets. This wing warping may be integrated with control inputs to the downhaul 76 and vang 77 to further change the shape of the flexible wings 12. The wing warping may be integrated with the lateral movement of the empennage and cockpit through a control stick in the cockpit or it may be a separate control input.

#The cockpit or payload compartment 100 is mounted on the fuselage 14 through an articulating joint 101. Extending the cockpit 100 from the fuselage 14 acts as passive dampening of the vertical vibrations by moving a mass further from the center of gravity to increase the inertia of the vehicle. The joint 101 has movement in the pitch and yaw axes of the ornithopter. The movement in the pitch axis serves to passively and actively dampen the vibratory oscillations inherent in the ornithopter as a reaction to the flapping of the wings. As shown in FIG. 3, the cockpit or payload compartment moves vertically parallel to the front of the fuselage 14 by a pair of wishbone shaped pivot arms. The wishbones 102 maintains approximate equal space between the cockpit and the fuselage. A tubular member 103 is vertically attached to the rear of the cockpit. The apexes of the wishbones 102 have pins 104 attached to the tubular member 103 so as to move in opposite response to the vibrations caused by the power stroke and flapping wings. The opposite ends 105 of the wishbone are pivotally attached to the fuselage wall to absorb some of the vertical forces on the wishbone. The tubular member 103 and the aperture 104 also function in the flight control system, to permit the cockpit to pivot in the yaw axis. Of course, this installation could be reversed, with the opposite ends of the wishbone connected to the cockpit and the apex connected to the fuselage. Further, the bar could be replaced with a channel and the wishbone apex could have a pivoting shuttle sliding in the channel.