A system comprising an aerial vehicle or an unmanned aerial vehicle (UAV) configured to control pitch, roll, and/or yaw via airfoils having resiliently mounted trailing edges opposed by fuselage-house deflecting actuator horns. Embodiments include one or more rudder elements which may be rotatably attached and actuated by an effector member disposed within the fuselage housing and extendible in part to engage the one or more rudder elements.

A system comprising an aerial vehicle or an unmanned aerial vehicle (UAV) configured to control pitch, roll, and/or yaw via airfoils having resiliently mounted trailing edges opposed by fuselage-house deflecting actuator horns. Embodiments include one or more rudder elements which may be rotatably attached and actuated by an effector member disposed within the fuselage housing and extendible in part to engage the one or more rudder elements.

A vibration attenuator for a rotor of an aircraft has a first ring with an eccentric weight, a coaxial second ring with an eccentric weight, and a central ring coaxial with the first and second rings and located therebetween. A first post extends from the first ring toward the central ring and is received in a first arcuate groove formed on the central ring, whereas a second post extends from the second ring toward the central ring and is received in a second groove formed on the central ring. A motor is configured for driving the central ring in rotation about the axis relative to the motor. The grooves are equal in length, and a center of the first groove is located on an opposite side from a center of the second groove. Rotation of the central ring by the motor causes rotation of the first and second rings.

An aircraft propulsion system comprises a propulsor an electric motor coupled to the propulsor. The electric motor comprises a surface mounted permanent magnet electric machine comprising a rotor mounted radially inward of a stator. A Motor Diameter Ratio (MDR) is defined as an inner diameter (D.sub.stator,in) of the motor stator in metres divided by an outer diameter (D.sub.stator,out) of the motor stator in metres. The MDR of the electric motor stator is within 10% of the value given by the equation:

[00001]${\mathrm{MDR}=0.83\times (\frac{\mathrm{Torq}ue}{L_{active}}\times \frac{1}{U_{\mathrm{fan},\mathrm{tip}}})}^{0.08}$ where: T is the maximum torque rating of the electric motor in kilonewton metres; L.sub.active is the active length of the motor stator in metres; and U.sub.tip is the tip speed of the propulsor at the maximum rated torque of the electric motor in metres per second.

In the described embodiments, the MDR is less than 1.

A ducted propulsion assembly for an aircraft includes a duct and a plurality of stators. The distal ends of the stators are coupled to the duct. The ducted propulsion assembly includes a line replaceable centerbody assembly isostatically coupled to the proximal ends of the stators. The line replaceable centerbody assembly includes one or more electric motors driving an output driveshaft. The ducted propulsion assembly also includes a proprotor assembly interchangeably coupled to and rotatable with the output driveshaft of the line replaceable centerbody assembly. The proprotor assembly is rotatable in a rotational plane to generate thrust.

A ducted fan of an aircraft includes a rotor-side fan and a stator-side duct that surrounds the rotor-side fan radially at the outside and that defines a flow channel for air flowing via the fan. The stator-side duct has an inner wall facing toward the fan, an outer wall averted from the fan, and at least one stiffening strut that runs within the flow channel. The stiffening strut, at one respective end, extends through the duct and protrudes radially relative to the outer wall of the duct. At the respective end of the stiffening strut, a fastening device is formed. The fastening device is configured to mount the ducted fan on a structural component of the aircraft. The fastening device has an insert composed of a fiber-reinforced plastic and laminated into the respective end of the stiffening strut.

A ducted fan of an aircraft includes a rotor-side fan and a stator-side duct that surrounds the rotor-side fan radially at the outside and that defines a flow channel for air flowing via the fan. The stator-side duct has an inner wall facing toward the fan, an outer wall averted from the fan, and at least one stiffening strut that runs within the flow channel. The stiffening strut, at one respective end, extends through the duct and protrudes radially relative to the outer wall of the duct. At the respective end of the stiffening strut, a fastening device is formed. The fastening device is configured to mount the ducted fan on a structural component of the aircraft. The fastening device has an insert composed of a fiber-reinforced plastic and laminated into the respective end of the stiffening strut.

A convertible ducted fan engine and mounting system. The convertible ducted fan engine has a shroud encircling a mechanical fan. The convertible ducted fan engine includes a fluid-propulsion configuration in which the mechanical fan rotates freely with respect to the shroud to produce thrust through fluid flow, and a drive-wheel configuration in which the shroud rotates about the rotational axis.

An ice protection system includes an aircraft surface and a gutter defined in the aircraft surface between raised rails. The gutter includes a mouth that narrows into a trailing portion of the gutter. The mouth is configured to channel water runback rivulets into the trailing portion of the gutter. The gutter can be a first gutter of a plurality of side by side gutters, each including a respective mouth narrowing into a respective trailing portion, wherein the gutters are separated from one another by respective rails.

An ice protection system includes an aircraft surface and a gutter defined in the aircraft surface between raised rails. The gutter includes a mouth that narrows into a trailing portion of the gutter. The mouth is configured to channel water runback rivulets into the trailing portion of the gutter. The gutter can be a first gutter of a plurality of side by side gutters, each including a respective mouth narrowing into a respective trailing portion, wherein the gutters are separated from one another by respective rails.