An unmanned aerial vehicle (UAV) including a fuselage frame and a propulsion system coupled to the fuselage frame. The propulsion system includes a first propulsion device and a second propulsion device. The first propulsion device includes a first rotor blade assembly and a first rotor mount assembly, and the second propulsion device includes a second rotor blade assembly and a second rotor mount assembly. The first rotor mount assembly is configured to not allow the second rotor blade assembly to be assembled to the first rotor mount assembly.

An aircraft includes an airframe; an extending tail; a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly; and a translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe; wherein a ratio of (i) the hub separation between the hub of the upper rotor assembly and the hub of the lower rotor assembly to (ii) a radius of the upper rotor assembly is between about 0.1 and about 0.135.

A system for driving a tilt rotor between vertical and horizontal using a variable displacement motor controlled in response to a swash angle of the motor measured in a feedback loop.

An aircraft is provided including an airframe, an extending tail, a counter-rotating, coaxial main rotor assembly having an upper rotor assembly and a lower rotor assembly, and a translational thrust system including a propeller positioned at the extending tail. The translational thrust system is configured to provide translational thrust to the airframe when the aircraft is in a non-autorotation state and to generate power when in an autorotation state. A gearbox interconnects the propeller and the main rotor assembly to drive the main rotor assembly and the translational thrust system in the non-autorotation state. When the aircraft is in autorotation, the power generated by the propeller drives rotation of the main rotor assembly via the gearbox.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly and a lower rotor assembly. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A horizontal stabilizer with a left elevator and right elevator positioned at the extending tail. A flight control computer to independently control one or more of the main rotor assembly and the elevator through a fly-by-wire control system. The flight control computer is configured to mix a collective pitch of the main rotor assembly and a deflection of the elevator.

One example of a rotor assembly comprises: a rotor hub operable to rotate based on rotation of a mast; a first rotor blade pivotally attached to the rotor hub; a bracing member pivotally attached to the rotor hub at a first end and pivotally attached to the first rotor blade at a second end; and a linkage mechanism coupling the first rotor blade to a second rotor blade. The bracing member is operable to transfer a coning movement of the first rotor blade to a movement of the linkage mechanism and a corresponding coning movement of the second rotor blade.

An aircraft includes an airframe having an extending tail, a counter rotating, coaxial main rotor assembly disposed at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the extending tail and providing translational thrust to the airframe, the translational thrust system including a propeller. A gearbox system is operably connected to the main rotor assembly and the propeller to drive rotation of the main rotor assembly and the propeller. The gearbox is configured to maintain a main rotor assembly tip speed below Mach 0.9 and a propeller helical tip speed below Mach 0.88.

The present invention includes a passive hub flapping lock including stop wedges; frames coupled to the stop wedges; rods coupled to the frames, and each rod comprising a bracket; lever arms, each lever arm rotatably coupled to a pivot and coupled at a first lever arm end to one of the rods at the bracket of the rod; weight sets, each weight set coupled to a second lever arm end; and pivot torsion springs, each pivot torsion spring positioned at a pivot and biased to hold the flapping lock in an engaged position when stationary or at a rotational speed below a specified rotational speed; wherein the flapping lock is in an engaged position below the specified rotational speed and in a disengaged position above the specified rotational speed and the weight sets move outward, rotating the lever arms.

An aircraft is provided including an airframe, an extending tail, and a counter rotating, coaxial main rotor assembly including an upper rotor assembly composed of a plurality of blades and a lower rotor assembly composed of a plurality of blades. A translational thrust system positioned at the extending tail, the translational thrust system providing translational thrust to the airframe. A flight control system to control the upper rotor assembly and the lower rotor assembly, wherein the flight control system is configured to control lift offset of the upper rotor assembly and the lower rotor assembly.

An embodiment device includes a clamp body having a clamp opening, an extension opening and a traverse block having an internally threaded portion, a reaction plate having a recess in a first face at a first side of the reaction plate and one or more pins disposed in the recess extending away from the first face, and further having an extension extending along a long axis of the reaction plate through the extension opening, and bearing blocks disposed on a second side of the reaction plate opposite the first side, where the traverse block is disposed between the bearing blocks. An actuator is aligned parallel to the long axis of the reaction plate and extending through each of the bearing blocks and through the traverse block, and the actuator has an eternally threaded portion engaged with the internally threaded portion of the clamp body.