Abstract: A vertical take-off or landing (VTOL) aircraft is disclosed that includes a propulsion system comprising at least four tilting propulsion assemblies and two or more lifting propulsion assemblies. Actuation of the tilting mechanisms can convert the aircraft from a hover configuration, in which all propellers produce thrust generally upward to counteract the aircraft's weight, to a forward flight configuration, in which the four or more tilting propellers produce thrust generally in a forward direction parallel to the fuselage to overcome drag in cruise flight and the lifting propellers produce no thrust or a level of thrust generally less than that required in the hover configuration.

Abstract: Various embodiments (20; 50; 50; 120) of variable length piston and connecting rod assemblies for imparting a variable compression ratio to an internal combustion engine. The embodiments incorporate novel arrangements of relatively movable parts (32, 34; 60, 62; 84, 86; 124, 126) related by various elastomeric elements (38; 58; 96, 104; 136) and oil passages (42; 116, 118; 140, 142) to change compression ratios.

Abstract: A variable length connecting rod assembly for imparting a variable compression ratio to an internal combustion engine. The assembly contains a first part (22; 72), a second part (20; 74), and a third part (34; 70) assembled together to form the large end of the connecting rod assembly and provide a variable length for the connecting rod assembly. The first part is a semi-circular cap. One (20; 74) of the second and third parts is fastened tight to the first part (22; 72). Guides (36, 38, 48; 88, 90, 92) disposed at opposite sides of the large end operatively relate the other (34; 70) of the second and third parts and the fastened parts to provide for relative sliding motion between the other of the second and third parts and the fastened parts over a limited adjustment range to change the length of the connecting rod assembly.

Abstract: A low friction cam shaft for actuating at least one valve of an internal combustion engine includes a shaft member extending longitudinally, at least one cam secured to the shaft member, the cam being made of a plurality of density metal materials and having an outer surface impregnated with a solid film lubricant that has an affinity for oil and promotes rapid formation of a stable oil film to reduce friction therebetween.

Abstract: A sealing assembly that significantly reduces or eliminates blow-by, peristolic pumping and sealing element flutter while, at the same time, reducing to ultra low levels friction between the sealing element and its assembly. The assembly has surfaces in at least one of the bore wall or piston to form a groove facing the other of the wall or piston, the groove having exposed smoothly curved shoulders which face each other. A sealing element is positioned in the groove, the element having smoothly curved side surfaces mateable with the groove shoulders for supporting the element in the groove. The sealing element has an exposed outer surface (crown) which also is smoothly curved with a pair of mirror image shoulders, The crown is effective to tangentially contact the cylinder wall while the element side surfaces each tangentially contact their respective mating groove shoulders.