Cold Spray Landing Gear Repair

In by Chris Garville

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COC Aerospace - Proprietary and Confidential Company Information

AS9100D

COC Aerospace has developed a repair for F-5 landing gear components

F-5 landing gears have tight tolerances with regards to repairs.

Example is the Main Landing Gear Cylinder and Nose Landing Gear Cylinder.

  • Tight tolerances for the main upper cylinder bore diameter are from 3.000 to 3.004.
  • Scratches and gouges need to be removed.
  • Some gouges exceed 3.004 requiring the cylinder honed until it is oversized.
  • Hard anodizing with will not provide enough build-up to achieve a bore of 3.004 or less.
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Cold Spray Defined

Is an Additive Manufacturing Process.

Does not induce thermal stresses into the parent or deposited material.

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Metallurgical testing the Cold Spray of Main Landing Gear Cylinder; P/N 14-40602

Test coupon of main landing gear cylinder gun-drilled, cold sprayed, cut into sections and tested every 2-3 inches for molecular adhesion, hardness, macro-micro inspections.

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Preparing cylinder for Cold Spray.

Cylinder is gun drilled (honed) .005 – 008” to remove all damage to inside walls.

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Cold Spraying inside of MLG Cylinder

Using COC-developed long-reach nozzle and ‘turntable’ that rotates the cylinder at the correct speed for the Cold Spray application.

The powder has a bond strength of 6,000 psi (ASTM-C633). Porosity >1% (MIL-STD-3021, Hardness: 91 HR-15Y, AI02 content 8-16%.

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Inner bore of MLG Cylinder is then re-honed back to the newly manufactured tolerances

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Nickel-based Spraying

Cylinders are sprayed with a nickel-based material that is more durable than the 7075 aluminum.

Surface finish of the cylinder walls are 12-14, twice as smooth as T.O. requirement of 32.

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Cylinders are honed after cold spray to 3.000-3.001”, back to original specifications

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Inspection and Preparation

Cylinders are penetrant inspected, anodized and prepared for painting.

Dimensions are checked with digital bore gauge.

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Outer Surface Finish

Outer cylinder Cold Spray is used to repair damage to outer surfaces of MLG Cylinder.

The areas are blended back to original dimensions.

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COC’s Cold Spray MLG Cylinder Repair saves over 70% of new production and turn-around is as short as 90 days.

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Thank You

The COC F-5 Team

EXPERIENCE - OVER 5 DECADES YEARS SUPPORTING LEGACY AIRCRAFT
CUSTOMER SERVICE - OVER 50 YEARS SUPPORTING THE SAME CUSTOMERS
TRUST - ABOVE ALL, WE ALWAYS DO THE RIGHT THING

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COC Aerospace - Proprietary and Confidential Company Information

AS9100D