In the world of aviation, nothing is left to chance. Even simple mistakes often lead to catastrophic accidents, and this is why even the smallest details are checked thoroughly. An example of this is the process required in the selection and choice of engine mountings.
On the surface, mounting an engine on the wing of a plane might seem straightforward. Most people assume that just any bolt or nut would do. However, there is a lot of thought that has to go into the process of designing and selecting the fasteners to be used in just one part of the plane. Some of these include:
Issues to do with weight
During plane design, weight has to be kept as low as possible. This has a direct influence on the amount of energy needed to keep the plane airborne. In addition to that, light planes are generally easier to handle than very heavy ones, so this is a very good incentive to keep weight down as well. The fasteners used to mount the engine contribute a small amount of weight to the overall weight of the plane, but it’s still important to keep them as light as possible. Titanium hex head cap screws and bolts are the preferred option since they are strong and light.
During normal operations, plane engines tend to vibrate a great deal. In some cases, they have to do this for extended periods of time, such as for more than 12 hours when doing intercontinental flying. For this reason, the fasteners normally used to mount the engines are usually selected based on their ability to withstand this. Fortunately, titanium hex lag bolts are also effective at withstanding vibration, and so can be used in this setting.
The torque values
During installation of plane engines, the fasteners are not simply put in place to be as tight as possible. A number of concessions have to be made to ensure that the engine is solidly in place, but to also ensure that it’s safe. In the event of the engine becoming damaged due to an explosion within it, for instance, it should fall back in such a manner that it will not cause any damage to the fuselage. To facilitate this, the fasteners used for the front of the engine are usually not tightened as much as the ones at the back, so that they can give earlier. However, this does not necessarily mean that they are loose enough to be unsafe.
Plane engine fasteners are usually exposed to a lot of heat both from the plane engine and from the air rushing over them. For the sake of safety, the ones chosen for use are usually designed to have a thermal tolerance limit that is significantly above the operating temperatures in this region of the plane. This way, even if the engines become hotter than usual, they will still be held in place.
These are just some of the concepts that guide the mounting of plane engines.
Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.