| KAREM AIRCRAFT, INC. Patent applications |
| Patent application number | Title | Published |
|---|
| 20110024552 | Anhedral Tip Blades for Tiltrotor Aircraft - A tiltrotor aircraft having a fixed wing and tilting rotors has a rotor blade with a shaped tip portion that provides improved hover performance. The shaped tip portion preferably has a terminal anhedral of at least 20° with respect to its stacking line, and the blade has an overall twist from root to tip of at least 20°, and a thickness ratio between 19% and 30% at a radial station of 10%. These features advantageously conspire to provide a hover figure of merit of at least 0.84 and a cruise propulsive efficiency of at least 0.85. A controller preferably limits the rotor speed in sustained airplane-mode forward flight cruise of at most 40% of a hover maximum rotor speed, and alternatively or additionally limits a rotor edgewise advance ratio to at most 0.20. | 02-03-2011 |
| 20100127119 | ROTORCRAFT ENGINE AND ROTOR SPEED SYNCHRONIZATION - Systems and methods are provided in which an electrical control system independently effects acceleration of both driven and driving elements of a clutch to engage each other. In preferred embodiments the clutch is not a friction clutch, but a dog clutch, and forms part of a drive drain of a rotorcraft. A second clutch can be used, along with a mechanical interlock to prevent simultaneous engagement of the clutches. Speeds of the driven and driving elements can be sensed, and altered using at least one of a rotor, a brake, a generator, an electric motor, and a combustion motor. In rotorcraft embodiments, the gearbox can have a neutral condition in which no power is transmitted from the engine to the rotor | 05-27-2010 |
| 20090256026 | Tilt Actuation for a Rotorcraft - An aircraft is equipped with hingeless rotors on tilting nacelles, and the tilt angles of the nacelles are controlled using either or both of an actuator and a mast moment generated by a hingeless rotor. An aircraft with two or more rotors on tilting nacelles can achieve control of yaw orientation by differential tilt of its nacelles or masts. Hingeless rotors can be manipulated to control a tilt angle of a mast by changing the rotor blade pitch to produce a mast moment. The rotor and nacelle tilt of a tiltrotor rotorcraft can be controlled and effected in order to manipulate the yaw orientation and flight mode of a rotorcraft such as a tiltrotor. The use of mast moment to control nacelle tilt angle can reduce tilt actuator loads and allows for the control of nacelle tilt even in the event of an actuator failure. | 10-15-2009 |
