United Technologies Corporation

Charles E Carlson

John A Violette

Edward A Rothman

A composite axial flow rotary machine blade (50) and method of blade construction is disclosed. A partial-length, spanwisely-disposed hollow spar (20) partially captures a shaped foam core (30) which extends from within the spar's cavity (26) along a substantial length of the blade (50) in a spanwise fashion. A resin-impregnated high strength, high modulus cloth (34) and graphite (32) composition overlays the spar-core assembly (36) and forms the casing (50) with airfoil regions (52, 54) of the propeller blade (10). This construction results in a rotor blade (50) with enhanced natural frequencies thereby providing for an enhanced operational speed range.

Composite blade with partial length spar

A composite axial flow rotary machine blade (10) and method of blade construction is disclosed. A substantially full length composite spar (30) is spanwisely disposed within an airfoil planform (18) which supports an airfoil surface (11a). A pad of reinforcing fibers (40) is sandwiched between the spar's periphery and the airfoil surfaces' proximate inner surfaces (24a, b) corresponding to the pressure (22) and suction (24) sides of the airfoil planform in a spanwise distribution. A quantity of structural foam filler (50) is disposed through the balance of the blade's cavity (16).

Reinforced full-spar composite rotor blade

A fan blade having a breakaway leading edge positioned on the spar and shell that constitute the main structure of the blade, the leading edge being adapted to break away, in part at least, upon being struck by a large foreign object, with the shell providing an acceptable leading edge after the breakaway.

Growing community of inventors

North Shallott, NC, United States of America

Charles E Carlson