Dimensional Restoration of Landing Gear Component Bores

When the internal diameter (ID) of an aluminum alloy landing gear outer cylinder bore is damaged or worn there is currently very little that can be done to facilitate a repair. The main cause for early condemnation of aluminum alloy outer cylinders is excessive wear on the bore. The aerospace industry condemns many aluminum strut outer cylinders at a high cost. The cost to the USAF due to early condemnations is approximately $3M per year. Hard anodize is a repair method often used to repair cylinder bores but if not done correctly will cause premature condemnations and has restorative thickness limitations. A coating repair for aluminum alloys, which builds up thickness and can be ground or machined to size, similar to chrome plating or High Velocity Oxygen Fuel (HVOF) coatings used to repair steel landing gear components, would be of great value to the United States Air Force (USAF). The coating would have to seal against hydraulic fluid as well as high pressure nitrogen and not spall at high loads. A dimensional restoration repair method of aluminum landing gear component bores would result in a considerable cost savings to the USAF as well as the Aerospace Industry as a whole. Rotary Plasma coating systems have the ability to apply thick (up to 0.030 inch per side) aluminum alloy coatings to the ID of outer cylinder bores. This will allow a greater range of damaged conditions to pre machined and then coated. These coatings can then be machined back to original dimensions and anodized to serviceable condition. In addition, Rotary Plasma coating systems have the ability to apply many coating chemistries other than pure aluminum. This provides the opportunity to apply hard, wear resistant coatings to landing gear bores, thus removing the need to anodize the surface after final machine. BENEFIT: Research conducted to develop Rotary Plasma Coating systems, which can restore IDs of worn or damaged land gear aluminum outer cylinders, focuses on military applications; however, benefits will be similar for all commercial & military landing gear that need IDs restored to original dimensions. ES3 expects the following benefits from Rotary Plasma System restoring the Inner Dimension of landing gear outer cylinders based on both industry and in-house research: • Outer cylinders with worn or damage IDs can be restored to serviceable condition • Increased supportability of aluminum landing gear parts for USAF and commercial industry • Reduction in ownership cost for the USAF and commercial industry • Rotary Plasma has the ability to apply hard material chemistries thus eliminating the need to anodize after final machine