General Electric Company

Edwin K Miller

Petr Hora

David L Joyce

Thomas G Wakeman

David Edward Bulman

John Stephen Mears

William R Spencer

Thomas C Hermans

Robert L Roberts

A butterfly valve comprises a butterfly vane including a radial notch. A seal groove is situated in the vane and a seal including tabs is disposed within the seal groove wherein the tabs are adapted to fit within the notch. The tabs are designed to bear against the sides of the notch. The notch is located on the high pressure side of the butterfly vane and in a position such that the butterfly housing limits the radial motion of the tabs when the valve is in the open position.

Butterfly valve seal retainer

A system for changing pitch in aircraft propfans is disclosed, in which a motor, located at a stationary position, changes pitch of the blades by of a gear train. Three features of the system are that a feather brake can override the motor and drive the blades toward feather; a unison brake can prevent pitch from undergoing excursions toward fine pitch when propeller speed exceeds a limit; and the motor is non-rotating in the absence of pitch change. A pair of such systems can be used in a counterrotating propfan system, in order to independently change pitch of the propfans.

Aircraft pitch change mechanism

The invention concerns a system for controlling an aircraft propeller. A hydraulic motor controls pitch of the propeller blades. The propeller blades are characterized by the absence of feather-inducing counterweights. An overspeed governor senses when propeller speed exceeds a limit, and, in response, assumes control of the hydraulic motor and drives the blades toward a coarsened pitch position, which reduces the propeller speed. In another form of the invention, a mechanical brake can override the hydraulic motor and mechanically retard a rotating gear, which causes the propeller blades to move toward a coarsened pitch.

Propeller pitch control

The invention concerns a pitch change mechanism for an aircraft propeller in which a common ring gear (51) changes pitch of all propeller blades on a given rotor simultaneously. Motion of the ring gear (51) is induced by a planet (40)-and-carrier (101) system driven by a pinion (110). Acceleration of the pinion causes a change toward flat pitch. Deceleration of the pinion causes change toward feathered pitch. If the motor driving the pinion fails, a large deceleration occurs, driving the blades to a safe, feathered position.

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West Chester, OH, United States of America

Edwin K Miller