A power electronics cooling system includes a ram air fan with one or more blades and a ram air fan motor connected via an output shaft. The ram air fan draws in air and passes it across a heat exchanger to cool one or more cooling liquids. One or more pumps pressurize and pump the cooling liquids to various electronic components, including one or more motor controllers. The pumps may be mechanically or electrically coupled to the output shaft of the ram air fan, such that the motor of the ram air fan provides energy to the pumps.

A locking mechanism for releasably locking a lock bolt against axial movement includes: a locking mechanism for releasably locking a lock bolt against axial movement, and: an elongate member 1 axially moveable relative to a housing and, in use, in moveable engagement with a lock bolt. The mechanism also includes a flap assembly 2 moveable between a first, closed position, located between the elongate member and the housing so as to prevent axial movement of the elongate member towards the housing, and a second, open position allowing the elongate member to move axially towards the housing.

An aircraft starting and generating system includes a starter/generator and an inverter/converter/controller (200) that is connected to the starter/generator and that generates AC power to drive the starter/generator in a start mode for starting a prime mover of the aircraft, and that converts AC power, obtained from the starter/generator after the prime mover have been started, to DC power in a generate mode of the starter/generator. A four leg inverter is coupled with a DC power output (452) of the starter/generator and has an inverter/converter/controller (ICC) (580) with a four leg MOSFET-based bridge configuration that drives the starter/generator in a start mode for starting a prime mover of the aircraft, and converts DC power to AC power in a generate mode of the starter/generator. A four leg bridge gate driver (560) is configured to drive the four leg MOSFET-based bridge (580) during start and generate mode using bi-polar pulse width modulation (PWM).

A ram air turbine is provided that utilizes a hybrid design. The ram air turbine includes a hydraulic power conversion device directly coupled to a turbine shaft and an electric power conversion device coupled to a drive shaft. A gearbox is used to couple the turbine shaft to the drive shaft.

An actuator release mechanism includes an axially moveable member biased in a first axial position by a bias spring and driven to a second axial position by an actuation means such as a solenoid arranged in substantially the same axis as the axially moveable member. The axially moveable member can be a piston.

A speed sensing adapter plate is provided and includes an adapter housing having a perimeter and a central portion and including a body having first and second opposite sides, mounting features disposed in the perimeter to extend from the first side to the second side, a shaft, bearings and a speed sensor. The shaft is disposed in the central portion and includes first and second splines at the first and second sides, respectively, and a flange. The flange is axially interposed between the first and second splines such that input rotational energy is transmittable from the first spline to the second spline via the flange. The bearings are disposed to rotatably support the shaft within the adapter housing. The speed sensor is coupled to the perimeter of the adapter housing and is configured to measure a rotational speed of the shaft from rotational energy driven rotations of the flange.

A driveshaft for an aircraft ram air turbine, the driveshaft including a cylindrical body having an outer surface, an inner surface, a longitudinal axis, a first end section, a second end section opposite the first end section, and an elongated intermediate section connecting the first end section and the second end section. The outer surfaces of the elongated intermediate section includes at least three separate grooves initiating at a location proximate to the first end section and extending parallel to the longitudinal axis across the outer surface to a location proximate to the second end section, the grooves being separated equidistantly around a circumference of the outer surface. The grooves provide a high lateral bending stiffness and low torsional stiffness such that a drivetrain operates at a frequency below an operating range frequency and the driveshaft at a critical speed above an operating speed.

An electric system of an aircraft includes a power stabilizing device connected to a primary AC bus and a secondary battery. The secondary battery has a rated voltage which allows the secondary battery to absorb regenerative power from a control surface actuator. Based on a voltage and a frequency in the primary AC bus, charging/discharging of the secondary battery is controlled to stabilize the electric system.

An aircraft tailcone comprising a tailcone fuselage, a turbomachine, for example an APU, housed inside the tailcone, a ram air intake on the tailcone fuselage for the ingestion of ram air towards the interior of the turbomachine compartment, an inlet flap operable reciprocately from an open position in which ingestion of ram air is allowed, and a closed position in which ram air ingestion is prevented. The ram air intake extends annularly along a perimeter of the tailcone fuselage, and the inlet flap is configured such in its closed position that a surface of the inlet flap is substantially flush with the tailcone fuselage.

A locking mechanism comprising a linkage assembly comprising a first link and a second link joined at a pivot point; a linkage assembly spring to bias the linkage assembly into a first, locked, position; a cam assembly having a cam 1 with a cam surface in engagement with the linkage assembly; a cam biasing member such as a spring arranged to bias the cam surface to press against the linkage assembly sufficiently to overcome the linkage assembly spring and to force the linkage assembly into a second, unlocked position; and a solenoid assembly arranged to engage the cam in a locked position in which the cam is prevented from forcing the linkage assembly into the unlocked position.