Abstract: A yo-yo with the hubs made of either acetal or polycarbonate is disclosed. These materials allow the axle to be press fit into the hubs of the inertial disks with the capability of adjusting the gap between the inertial disks by rotating the two inertial disks relative to each other while pushing or pulling. The high mechanical stability of these materials result in a tight fit between the hub and the axle even after many cycles of gap adjustments and or axle replacements. The performance is improved by adding a smooth sloped transition at the periphery of lapper disks to the larger gap between the two inertial disks. A knot is tied in the tether approximately 2.0 inches from the periphery of the inertial disks. The knot wedges in the sloped transition, which substantially reduces tether slippage. A finger strap is used to attach the tether to the hand.

Abstract: An air bag landing system for an aircraft. The landing system has an air bag assembly which is stored in the fuselage of the aircraft during cruise and which extends for landing. The assembly consists of a rigid arm with either two or three folding portions and an inflatable bag attached to the underside of the arm. The inflatable bag cushions the impact of the aircraft at landing. Actuators are provided to extend and retract the assembly.

Abstract: An air cushion landing system for an aircraft. The landing system has an air cushion assembly which is stored in the fuselage of the aircraft during cruise and which extends for landing. The assembly consists of a rigid arm with two folding portions, inflatable bags attached to the underside of the arm, and flaps to define an area of cushion air. The inflatable bags provide primary attenuation of landing impact. Actuators are provided to retract the assembly following takeoff and extend it for landing.