A rotor for an aircraft is described having: a support angularly fixed with respect to an axis and housing a power source; a unit rotatable about axis and housing an electrical load of the resistive type; and a power supply system for the electrical load and comprising: a first transformer electrically interposed between the power source and the load; the first transformer comprises: a first winding arranged on the support and a second winding arranged on the unit, a stator carried by the support, rotationally fixed with respect to axis and to which the first winding is fixed; and a rotor operatively connected to the unit and to which the second winding is fixed; the power supply system comprises a capacitive circuit electrically connected to the first transformer, so as to reduce the reactive power absorbed by the rotary transformer.

A measurement apparatus for determining a bending moment acting on a hollow cylindrical body in a current state as well as to a method of operating such a measurement apparatus. The measurement apparatus may include a sensor support structure, a sensor arrangement with sensors, and a processing system. The processing system may determine displacements of the inner surface of the hollow cylindrical body relative to the sensors based on the distances measured in the current state compared to the distances measured during an initial undeformed state, and determine the bending moment acting on the hollow cylindrical body based on the displacements.

A measurement apparatus for determining a bending moment acting on a hollow cylindrical body in a current state as well as to a method of operating such a measurement apparatus. The measurement apparatus may include a sensor support structure, a sensor arrangement with sensors, and a processing system. The processing system may determine displacements of the inner surface of the hollow cylindrical body relative to the sensors based on the distances measured in the current state compared to the distances measured during an initial undeformed state, and determine the bending moment acting on the hollow cylindrical body based on the displacements.

A propulsion assembly for a rotorcraft includes a raceway having a tapered inner surface and a mast configured to receive the raceway at a raceway receiving station. The mast has a tapered outer surface at the raceway receiving station. The propulsion assembly includes a mast bearing assembly having a plurality of bearings facing the mast to engage the raceway. The tapered inner surface of the raceway is friction welded to the tapered outer surface of the mast at the raceway receiving station to form a tapered friction weld line.

A propulsion assembly for a rotorcraft includes a raceway having a tapered inner surface and a mast configured to receive the raceway at a raceway receiving station. The mast has a tapered outer surface at the raceway receiving station. The propulsion assembly includes a mast bearing assembly having a plurality of bearings facing the mast to engage the raceway. The tapered inner surface of the raceway is friction welded to the tapered outer surface of the mast at the raceway receiving station to form a tapered friction weld line.

A rotor for an aircraft is described, comprising an input shaft rotatable around a first axis; an output member rotatable around a second axis; a coupling element functionally interposed between the input shaft and the output member and adapted to transmit the motion from the input shaft to the output member; the coupling element is configured to allow, in use, a fixed or variable inclination between the respective first and second axes; the coupling element comprises at least a first corrugated element made of an elastically deformable material; the first corrugated element allows the inclination through elastic deformation.

A rotor for an aircraft is described, comprising an input shaft rotatable around a first axis; an output member rotatable around a second axis; a coupling element functionally interposed between the input shaft and the output member and adapted to transmit the motion from the input shaft to the output member; the coupling element is configured to allow, in use, a fixed or variable inclination between the respective first and second axes; the coupling element comprises at least a first corrugated element made of an elastically deformable material; the first corrugated element allows the inclination through elastic deformation.

The invention discloses a propeller-driven helicopter or airplane which comprises a fuselage and a propeller comprising a plurality of blades, wherein a plurality of pressure pipes are uniformly distributed between windward sides and leeward sides of the blades; a plurality of first inlets are formed in the windward sides and are communicated with outside via first channels in the blades and second outlets at tails of the blades; a high-pressure fluid of a low-speed fluid layer formed when a fluid flows through the leeward sides in a widthwise direction flows towards a low-pressure fluid of a high-speed fluid layer formed when the fluid flows through the first inlets, the first channels and the second outlets; and an upward pressure generated by the high-pressure fluid is opposite to a downward pressure generated by an external fluid above the windward sides, so that a fluid pressure above the propeller is decreased.

The invention discloses a propeller-driven helicopter or airplane which comprises a fuselage and a propeller comprising a plurality of blades, wherein a plurality of pressure pipes are uniformly distributed between windward sides and leeward sides of the blades; a plurality of first inlets are formed in the windward sides and are communicated with outside via first channels in the blades and second outlets at tails of the blades; a high-pressure fluid of a low-speed fluid layer formed when a fluid flows through the leeward sides in a widthwise direction flows towards a low-pressure fluid of a high-speed fluid layer formed when the fluid flows through the first inlets, the first channels and the second outlets; and an upward pressure generated by the high-pressure fluid is opposite to a downward pressure generated by an external fluid above the windward sides, so that a fluid pressure above the propeller is decreased.

In an embodiment, a method includes acquiring a current condition indicator of a condition indicator set associated with an operating condition of a machine, the condition indicator set indicating sensor readings associated with an operating element of the machine under the operating condition. The method also includes determining, by a data server, a relative trend significance over a trend window of the condition indicator set based, at least in part, on an evaluation of the trend window in relation to a historical window of the condition indicator set. The method also includes determining, by the data server, whether trend criteria associated with the operating element is satisfied, where the trend criteria may include criteria related to the relative trend significance. The method also includes executing, by the data server, an alerting process in response to the determining that the trend criteria is satisfied.