Common Uses for Pulleys in Aircraft

Aircraft are complex pieces of machinery, often featuring retractable landing gear assemblies, adjustable flight surfaces, and much more. In order to move various components on an aircraft from the cockpit, pulleys and other mechanical solutions are relied on. Pulleys are fairly simplistic machines, featuring a wheel mounted on a fixed axis and a rope that settles within the wheel’s groove. With the use of a pulley, cables can be guided for the means of adjusting flight surfaces and other components.

In order for a load to be efficiently raised and lowered, the pulley system utilizes the wheel and rope assembly in a way that a force smaller than the weight of the load will be enough to adjust it. With the addition of machinery, the speed at which loads can be moved is much faster. For a standard set-up, pulley wheels are typically placed within a supportive frame known as a block, and a block and tackle is simply a pair of blocks. Depending on the needs of particular aircraft equipment, there are also numerous types of pulleys that one may take advantage of.

Fixed pulleys are a fairly simplistic type, often compared to first class levers with equal arms. Having equal arms means that the force enacted on the rope will need to be equivalent to the load that is being carried. As a result, such pulleys are only used when the direction of a force needs to be changed, or the rope will be pulled in a simplistic manner. Single movable pulleys allow for the force exerted on the rope to be magnified, and this is done by having both ropes extend upward from the pulley so that the support of the weight is shared. Single movable pulleys have a diameter that is twice the size of the radius, meaning that 50 lbs of force moving the rope four feet would cause a 100 lbs load to lift two feet.

Bolt and tackle assemblies are a bit more complex, featuring multiple pulleys that may be a mix of fixed and movable types. The amount of weights that are supporting the ropes will determine the advantage of such an assembly, and the ratio of exerted weight to lifting force is similar to movable pulleys. For example, if an assembly featured four pulleys, a 200 lbs load would only necessitate 50 lbs of exerted force to lift the object from the ground.

To help facilitate the movement of various components without having deterrence from friction, pulley bearing components are commonly used. Pulley bearing components are sealed elements, and they do not need any additional lubrication outside of what was applied during the manufacturing process. While bearings facilitate the motion of the pulley, guards serve the important role of guiding cables so that they do not slack, slip, or otherwise move from their intended position.

If you are in the midst of outfitting a plane and require top-quality pulleys, pulley bearing components, and other aviation parts, there is no better alternative to NSN Sphere. NSN Sphere is a premier purchasing platform owned and operated by ASAP Semiconductor, and we are unmatched in our ability to save customers time and money while fulfilling even the most hard-to-find part requirements. If you find particular items on our website that you are interested in, please fill out and submit an RFQ form at your earliest convenience, and a dedicated account manager will reach out to you in 15 minutes or less to continue the purchasing process. Connect with an NSN Sphere representative today and learn more about our ability to serve as your strategic sourcing partner for all your operational needs. 


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