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IP.com Disclosure Number: IPCOM000249631D
Publication Date: 2017-Mar-09
Document File: 6 page(s) / 115K

Publishing Venue

The IP.com Prior Art Database


A metal leading edge guard for a composite airfoil incorporates scallops to reduce its stiffness and preserve the adhesive bond between the leading edge guard and the airfoil.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 40% of the total text.

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[0001] A metal leading edge guard for a composite airfoil incorporates scallops to reduce

its stiffness and preserve the adhesive bond between the leading edge guard and the



[0002] A typical aircraft engine includes numerous components which have a leading

edge facing a high-velocity air flow. Some of these components are made from

nonmetallic materials such as carbon fiber composites. While these materials are strong,

stiff, and have good strength-to-weight ratios, they can require protection from impacts of

foreign objects entrained in the airflow.

[0003] One particular example of this type of component is an outlet guide vane. In a

turbofan engine, outlet guide vanes are a ring of airfoils that are disposed immediately

downstream of the fan blades and serve the purpose of straightening the flow exiting the

fan. To protect the outlet guide vanes, a metal leading edge guard is bonded to the

composite outlet guide vane using an adhesive.

[0004] In operation, the outlet guide vanes vibrate because of aeromechanical effects.

They vibrate in multiple modes, resulting in leading edge deflection side-to-side and, to a

lesser extent, forward and aft.

[0005] One problem with existing leading edge guards is that the deflection of the

outlet guide vane drives the metal leading edge to deflect, but because of the metal

leading edge guard's internal stiffness, strain develops in the thin layer of adhesive. This

can lead to dis-bonding (delamination) and subsequent cracking and loss of metal leading

edge guard material.

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[0006] Described herein is a leading edge guard configured to have reduced bending

moment of inertia (i.e. bending stiffness), for the purpose of protecting the integrity of the

adhesive bond between the leading edge guard in the composite structure.


[0007] The concept may be best understood by reference to the following description

taken in conjunction with the accompanying drawing figures in which:

[0008] FIG. 1 is a schematic half-sectional view of a gas turbine engine;

[0009] FIG. 2 is a schematic side elevational view of an exemplary outlet guide vane

with a leading edge guard attached thereto;

[0010] FIG. 3 is an end view of the guide vane of FIG. 2;

[0011] FIG. 4 is an end view of the leading edge guard shown in FIG. 2 ; and

[0012] FIG. 5 is front elevational view of the leading edge guard of FIG 4.


[0013] Referring to the drawings wherein identical reference numerals denote the same

elements throughout the various views, FIG. 1 depicts an exemplary gas turbine engine

10. While the illustrated example is a high-bypass turbofan engine, the principles of the

present invention are also applicable to other types of engines, such as low-bypass

turbofans, turbojets, turboprops, etc. The engine 10 includes a fan 12, booster 14,

compressor 16, combustor 18, high pressure turbine 20, and low pressure turb...