Patent ID: 7059562

Claim:
A flying craft comprising: (a) a suspension structure having a first end and a second end; (b) a lift unit coupled to the first end of the suspension structure including: (1) at least one pair of torque producing propulsion systems including counter-rotating propellers, (2) wherein the lift unit is freely rotatable, within a predetermined angular range about only one rotational axis perpendicular to an axis passing through the first and second ends of the suspension structure, and (3) the lift unit is substantially restricted in movement relative to the first end of the suspension structure in a direction parallel to the rotational axis; and (c) a payload unit coupled to the second end of the suspension structure and positioned, by the suspension structure, to impart pendular stability to the lift unit; (d) wherein the suspension structure further includes a damned elastic mechanism to moderate movement of the suspension structure parallel to the rotational axis, thereby improving yaw control of the aircraft in vertical flight.