Airframe leading edge

Patent metadata

Field	Value
Publication number	US-10131415-B2
Application number	US-201214646028-A
Country	US
Kind code	B2
Filing date	Nov 20, 2012
Priority date	Nov 20, 2012
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

An airframe leading edge part designed to be replaceable fixed to a structural portion which during use moves through the air. The airframe leading edge part includes first and second longitudinal joint edges adapted to fit the structural portion. At least one joint is provided between the structural portion and at least one of the longitudinal joint edges. The joint is adapted to break in the event of a object strikes and deforms the airframe leading edge part during use. The joint is designed to break at beforehand determined maximum joint strength of the joint. Also a repair method for exchanging a damaged leading edge.

First claim

The invention claimed is:

1. An airframe leading edge part designed to be replaceable fixed to a structural portion which during use moves through the air, the airframe leading edge part comprising:
a first longitudinal joint edge and a second longitudinal joint edge adapted to fit the structural portion;
at least one joint between the structural portion and at least one of the longitudinal joint edges, wherein the joint comprises adhesive;
the joint being configured to break in the event of an eventual object strikes and deforms the airframe leading edge part during said use,
the airframe leading edge part being configured to transfer impact energy into a breakaway force, to break away the airframe leading edge part from the structural portion in order to protect the structural portion; and
the joint being designed to break at beforehand determined maximum joint strength of the joint,
whereby the joint is designed to break apart when an impact force is so high that, even though deformation of the airframe leading edge part has occurred due to absorption of the impact energy, the maximum joint strength of the joint is reached span wise.

2. The airframe leading edge part according to claim 1 , wherein a further joint oriented in chordwise direction is designed to break at a joint strength higher than said maximum joint strength.

3. The airframe leading edge part according to claim 1 , wherein the joint is an inclined scarf joint, a butt joint, or a butt strap joint.

4. The airframe leading edge part according to claim 1 , wherein the joint comprises a resin rich zone.

5. The airframe leading edge part according to claim 1 , wherein the joint comprises electrically conductive adhesive or electrically isolating adhesive.

6. The airframe leading edge part according to claim 1 , wherein the joint comprises an additional plastic layer being sanded for achieving a smooth aerodynamic surface also within the area of the joint.

7. The airframe leading edge part according to claim 1 , wherein the airframe leading edge part is one of a plurality of parts joined together via cord wise joints, wherein the parts are made of metal and the structural portion being made of plastic.

8. The airframe leading edge part according to claim 1 , wherein the structural portion comprises an outer skin, the edge of which is adapted to fit the longitudinal joint edge.

9. The airframe leading edge part according to claim 8 , wherein the structural portion is a wing box.

10. The airframe leading edge part according to claim 1 , wherein both the longitudinal joint edges are adapted to break away from the structural portion.

11. The airframe leading edge part according to further comprising:
a first transverse joint edge and a second transverse joint edge adapted to fit a transverse joint edge of an adjacent airframe leading edge part.

12. The airframe leading edge part according to claim 11 , wherein one of the transverse joint edges has longer extension in the transverse direction than another transverse joint edge.

13. The airframe leading edge part according to claim 11 , wherein the airframe leading edge parts are designed to fit a certain type of aircraft, and each airframe leading edge part has an individual design for a certain position of the aircraft.

14. The airframe leading edge part according to claim 1 , wherein the structural portion comprises a wing box and/or an outer wing skin and/or spar cap and/or stiffener, and a thickness of the leading edge part is such that the leading edge part is thicker at a section first meeting the air stream than other sections.

15. The airframe leading edge part according to claim 1 , wherein the airframe leading edge part and the structural portion are made of plastic comprising reinforcing fibres.

16. The airframe leading edge part according to claim 1 ,
wherein the joint indicates a cut-off-line between the airframe leading edge part and the structural portion.

Assignees

• Saab Ab

Inventors

• Nordin Pontus
• Strindberg Göte

Classifications

• B64D2045/0095

  Devices specially adapted to avoid bird strike · CPC title

• B64C3/28 Primary

  Leading or trailing edges attached to primary structures, e.g. forming fixed slots · CPC title

• B64C1/12

  Construction or attachment of skin panels · CPC title

• B64C1/062 Primary

  specially adapted to absorb crash loads · CPC title