A propeller arrangement for an aircraft, and an aircraft having a propeller arrangement of said type, are specified. The propeller arrangement has a first propeller blade and a second propeller blade, and a propeller mount on which both the first propeller blade and the second propeller blade are mounted. The propeller arrangement furthermore has a drive shaft with a holding unit, and a first connecting unit. The first propeller blade is rotatable about a first axis of rotation and the second propeller blade is rotatable about a second axis of rotation. The propeller mount is pivotable about a pivot axis. The first connecting unit is coupled to the first propeller blade and to the holding unit, such that, in the event of a pivoting of the propeller mount about the pivot axis, the first propeller blade is set in rotational motion about the first axis of rotation.

In one aspect, a rotor assembly includes a hub and a plurality of rotor blades; at least one blade root actuator configured to adjust at least one of the plurality of rotor blades independently of the other rotor blades to accommodate forces on the aircraft; and at least one controller couplable to the at least one blade root actuator and configured to send signals to the at least one blade root actuator to enable adjustment of the at least one of the plurality of rotor blades. In another embodiment, at least one blade flap is associated with a rotor blade can be actuated to adjust the shape of the rotor blade. In some embodiments, there are methods and systems incorporating at least one of the root blade actuator and the blade flap for stabilizing a tiltrotor aircraft by counteracting destabilizing forces on at least one rotor blade.

The present invention relates to a free propeller assembly structure and an aircraft structure has the free propeller assembly. The free propeller assembly structure has at least one free propeller assembly. Each of the at least one free propeller assembly has a circular shaft, a main rotor, a signal transmitting device, and a rotor blade assembly. The main rotor has a shaft hole and multiple blade mounting structures radially disposed. Each blade mounting structure is provided with a positioning recess for mounting a driving motor in each positioning recess. The signal transmitting device includes multiple signal transmitters that are able to transmit interpretable electronic signals or photonic signals. The rotor blade assembly includes at least two rotor blades. One end of each rotor blade is connected with an open end of the positioning recesses of a corresponding one of the blade mounting structures.

One example of a rotorcraft blade control system includes a mechanical linkage to connect to a rotorcraft blade including a feather axis and a pneumatic muscle connected to the mechanical linkage. The system also includes a movement member connected to the mechanical linkage, the pneumatic muscle and the movement member to move the mechanical linkage to control movement of the rotorcraft blade on the feather axis. The pneumatic muscle can be a first pneumatic muscle and the movement member can be a second pneumatic muscle or a bias spring.

There is provided a training system capable of performing work. The system has a shape memory alloy (SMA) actuator exhibiting a generally planar transformational behavior. The system further has one or more heating elements for transforming the SMA actuator from an original shape to a trained shape, thereby performing work.

There is provided a method of training a shape memory alloy (SMA) workpiece. The method includes applying a force couple to a shape memory alloy (SMA) workpiece to impart a generally planar transformational behavior to the SMA workpiece to obtain a trained shape memory alloy (SMA) workpiece.