![]() ![]() The moment can be calculated using the following formula: Step 3: Calculate the moment (M) caused by the 15-kip load. The distance from the neutral axis to point a is 0.65 - 0.3 = 0.35 in, and the distance to point b is 0.65 in. The neutral axis is located at the center of the square tube, which is 0.65 in from the top and bottom edges. Step 2: Calculate the distance from the neutral axis to points a and b. Where a is the outer side length and b is the inner side length. The moment of inertia for a square tube can be calculated using the following formula: The structural tube has a square cross-section with side length 1.3 in and wall thickness 0.3 in. They are holes, typically one-fourth the diameter of the original tube, drilled in the outer splice and welded around the circumference for attachment to the inner replacement tube or original tube structure.Step 1: Calculate the moment of inertia (I) of the structural tube. Rosette WeldingRosette welds are used on many of the type repairs that were previously discussed. If the manufacturer stress relieved the engine mount after welding, the engine mount should again be stress relieved after weld repairs are made. Engine mount rings that are extensively damaged must not be repaired unless the method of repair is specifically approved by FAA Engineering, a Designated Engineering Representative (DAR), or the repair is accomplished in accordance with FAA-approved instructions. Minor damage, such as a crack adjacent to an engine attachment lug, can be repaired by rewelding the ring and extending a gusset or a mounting lug past the damaged area. If all members of the mount are out of alignment, the mount should be replaced with one supplied by the manufacturer or with one built to conform to the manufacturer’s drawings and specifications. Streamline tubing, used for some light aircraft landing gear, may be repaired using a round insert tube of the same material and having a wall thickness of one gauge thicker than the original streamline tube and inserting and welding as shown in Figure 7.Īll cracked welds should be ground out and only high-grade filler rod of the appropriate material should be used. The spring-steel part is, in general, nonrepairable, should not be welded on, and should be replaced when it is excessively sprung or otherwise damaged. The spring-steel leaf, shown as type E, is a component of a standard main landing gear on many light aircraft. These parts would be distorted by any welding repair and should be replaced if damaged to ensure the part was airworthy. During manufacture, the upper oleo section of the assembly is heat treated and machined to close tolerances to assure proper functioning of the shock absorber.The lower axle stub is usually made from a highly heat-treated nickel alloy steel and machined to close tolerances. ![]() The landing gear assembly type D is generally nonrepairable for the following reasons: Remove all burrs from the edges of the replacement tube, sleeves, and the original tube stubs. Use the fish mouth sleeve wherever possible. From this outer sleeve tube material, either cut diagonally or fishmouth two sections of tubing, each of such a length that the nearest end of the outer sleeve is a minimum distance of 1½ tube diameters from the end of the cut on the original tube. ![]() The clearance between the inside diameter of the sleeve and the outside diameter of the original tube may not exceed 1⁄16-inch. The material selected for the outer sleeve must be of the same material and at least the same wall thickness as the original tube. ![]() The replacement tube must bear against the stubs of the original tube with a tolerance of ☑⁄64-inch. Cut a replacement steel tube of the same material, diameter, and at least the same wall thickness to match the length of the removed portion of the damaged tube. To perform the outer sleeve repair, remove the damaged section of the tube, utilizing a 90° cut at either end. ![]()
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