Lightening holes | Lightening holes in aircraft, Purpose & Process

Lightning Holes

Lightening holes are often used for manufacturing of aircraft or its parts in aviation industry. The aircraft can be made as light as feasible thanks to the lightening holes while still maintaining the structural integrity and airworthiness of the aircraft.

In order to make equipment and buildings lighter, many engineering professions incorporate "lightning holes" in their structural components. To improve the component's rigidity and strength, the edges of the hole could be flanged. To prevent the risk of stress risers, the holes must never have sharp corners and can be circular, triangular, elliptical, or rectangular. They must also not be too close to the edge of a structural component.

To reduce weight, rib sections, fuselage frames, and other structural components have lightning holes punched into them. Flanges are frequently pushed around the holes to strengthen the region from which the material was withdrawn in order to prevent weakening the member by removing the material. Any structural item should never have lightning holes cut into it without permission. Design parameters define the size of the lightning hole and the width of the flange that is produced around it. The specs take safety margins into account so that the part's weight can be reduced while maintaining the required strength. With a hole saw, a punch, or a fly cutter, lightning holes can be made. For the purpose of preventing tearing or cracking, the edges are filed smooth.

Flanging Lightning Holes

A flanging die, wooden or metal form blocks, or both can be used to create the flange. A female and a male die are the two pieces that make up a flanging die. Hardwoods like maple can be used for the dies when flanging soft metal. Steel should be used if working with hard metal or for longer-term applications. The shoulder and pilot guide should match the desired flange's width and angle. The pilot guide should be the same size as the hole to be flanged.

The simple process for flanging lightning holes is to place the material between the die's matching portions and produce the lightning hole by hammering or pressing the dies together in a vise or an arbour press (a small hand-operated press). If the dies are coated in light machine oil, they will operate more smoothly.