An aircraft engine has a hollow driveshaft with a spool coaxial with the driveshaft and extending through the driveshaft to rotate independently of the driveshaft. A first harmonic cam is mounted on the driveshaft and a second spaced apart harmonic cam is mounted on the spool. At least one combustion cylinder is positioned between the cams along a combustion cylinder axis that is parallel with but radially spaced apart from the driveshaft. A piston assembly is disposed in each end of the combustion cylinder, with each piston assembly engaging a separate cam. A high-pressure compressor turbine is mounted on the driveshaft and driven by movement of a piston assembly, compressing air for the combustion cylinder. A rotating component is mounted on the spool and driven by movement of the other piston assembly. The rotating component may be another compressor turbine, a drive turbine, a fan or a propeller.

System for the reversible transformation of a reciprocating motion in a rotary motion, which may include one or more actuating devices adapted to cooperate with a rotor which has a spiral shaped section, and has at least one interaction surface for interacting with said one or more actuating devices. Each actuating device of said plurality of actuating devices is an internal combustion cylinder and piston device. Each actuating device is associated with a rod which incorporates a slider with a follower which engages with said at least one interaction surface of said rotor.

System for the reversible transformation of a reciprocating motion in a rotary motion, which may include one or more actuating devices adapted to cooperate with a rotor which has a spiral shaped section, and has at least one interaction surface for interacting with said one or more actuating devices. Each actuating device of said plurality of actuating devices is an internal combustion cylinder and piston device. Each actuating device is associated with a rod which incorporates a slider with a follower which engages with said at least one interaction surface of said rotor.

A piston arrangement comprising: a piston; a rotatable element, rotatable about an axis, having a first engagement profile; and a mechanism comprising: a first connecting element connected to the piston; a second connecting element pivotable about a fixed point and pivotally connected to the first connecting element; and a second engagement profile coupled to the first and/or second connecting element, configured to mechanically engage and disengage with the first engagement profile of the rotatable element.

A piston arrangement comprising: a piston; a rotatable element, rotatable about an axis, having a first engagement profile; and a mechanism comprising: a first connecting element connected to the piston; a second connecting element pivotable about a fixed point and pivotally connected to the first connecting element; and a second engagement profile coupled to the first and/or second connecting element, configured to mechanically engage and disengage with the first engagement profile of the rotatable element.

A piston arrangement includes a piston movable within a cylinder in reciprocating motion along a piston axis, a rack movable with the piston, a sector gear configured to engage and disengage the rack and rotatable around a sector gear axis, a track adapted to rotate relative to the cylinder around a track axis of rotation, the piston being coupled to the track. The sector gear and the track are coupled in rotation. The track may have a shape such that the movement of the piston coupled to the track is substantially non simple harmonic. Also, an internal combustion engine comprising the piston arrangement.

The present invention provides a system for the reversible transformation of a reciprocating motion in a rotary motion, which comprises one or more actuating devices (11) adapted to cooperate on at least one interaction surface of a spiral profiled rotor (3), the system it is characterized in that each actuating device of said plurality of actuating devices (11) comprises hydraulic or internal combustion cylinders; the arrangement being such that each actuating device (11) urges a tubular slidable rod coupled to a respective cylinder, said tubular rod being associated with a slider (5), the slider (5) being adapted to transmit the thrust of said tubular rod (6) on said at least one interaction surface of the spiral profiled rotor (3) creating a torque on said rotor (3).

The present invention provides a system for the reversible transformation of a reciprocating motion in a rotary motion, which comprises one or more actuating devices (11) adapted to cooperate on at least one interaction surface of a spiral profiled rotor (3), the system it is characterized in that each actuating device of said plurality of actuating devices (11) comprises hydraulic or internal combustion cylinders; the arrangement being such that each actuating device (11) urges a tubular slidable rod coupled to a respective cylinder, said tubular rod being associated with a slider (5), the slider (5) being adapted to transmit the thrust of said tubular rod (6) on said at least one interaction surface of the spiral profiled rotor (3) creating a torque on said rotor (3).

An improvement to a rotor is provided adapted to be rotated by at least two linearly moving support bearings linearly driven by an engine that comprises an outer ring provided on a circumference of the rotor; and an inner ring that is concentric to the outer ring. The support bearings are confined to rotate within a restraining path formed between the outer ring and the inner ring. It is also provided an improved engine having at least two traverses linearly actuated that comprises the improvement.

An improvement to a rotor is provided adapted to be rotated by at least two linearly moving support bearings linearly driven by an engine that comprises an outer ring provided on a circumference of the rotor; and an inner ring that is concentric to the outer ring. The support bearings are confined to rotate within a restraining path formed between the outer ring and the inner ring. It is also provided an improved engine having at least two traverses linearly actuated that comprises the improvement.