Composite Helicopter Skid Shoes Shear Force Distribution
Solution Overview
Problem
Traditional skid shoes used in helicopters are heavy, leading to reduced usable load capacity and increased friction-related damage to skid tubes during landings and ground transport.
Innovation Solution
A lightweight skid shoe assembly made from wear-resistant, non-metallic or partially metallic materials such as polyamide impregnated carbon fiber layup, with a coupling mechanism and shear-bearing mechanism to distribute shear forces, and a wear indicator for easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional metal skid shoes are used, then friction-related damage protection is effective, but weight increases reducing usable load capability
Solution Approach 1:
The skid shoe assembly uses composite materials consisting of a non-metallic body (polymer, carbon fiber reinforced polymer, or other lightweight composite) combined with a metallic insert or coating at the wear surface. This composite construction provides the lightweight advantage while maintaining the necessary wear resistance and friction-related damage protection through the metallic component.
Solution Approach 2:
The skid shoe assembly applies different material properties to different regions: the bulk body is made from lightweight non-metallic materials to reduce weight, while the contact surface or specific wear areas contain metallic inserts or coatings to provide localized wear resistance and friction protection where it is most needed.
2Weight of moving object
If lightweight non-metallic materials are used, then weight is reduced increasing usable load, but wear resistance may be insufficient
Solution Approach 1:
The skid shoe assembly combines lightweight non-metallic materials (polymer, carbon fiber reinforced polymer) for the bulk body to reduce weight, with metallic inserts or coatings at the wear surface to provide the necessary wear resistance and friction protection, creating a composite structure that achieves both lightweight and wear-resistant properties.
Solution Approach 2:
The skid shoe assembly uses lightweight non-metallic materials for the bulk body to minimize weight, while applying metallic inserts or coatings specifically at the contact surface and high-wear areas to provide localized wear resistance and friction-related damage protection where it is most critical.
3Object-affected harmful factors
If skid shoe material is made softer, then friction-related damage is reduced, but structural strength decreases
Solution Approach 1:
The skid shoe assembly uses composite construction with a non-metallic body (polymer or carbon fiber reinforced polymer) that provides adequate structural strength, combined with a metallic insert or coating at the wear surface that provides soft, friction-resistant material to protect the skid tube while maintaining overall structural integrity.
Solution Approach 2:
The skid shoe assembly applies different material properties locally: the bulk body is made from materials providing necessary structural strength, while the contact surface contains softer metallic materials or coatings that provide friction-related damage protection without compromising overall structural strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The lightweight skid shoe assembly effectively prevents friction-related damage to helicopter skid tubes while reducing the overall weight of the aircraft, allowing for increased useful load capacity and easier maintenance.
Implementation Method 1
the body withstands shear forces when frictionally engaging a contact surface
Data Source
AI summary
A lightweight skid shoe assembly comprises a body of wear resistant, non-metallic or partially metallic material; and a structure coupling mechanism; wherein the body prevents friction-related damage to the structure. Another lightweight skid shoe assembly comprises a body of wear resistant, non-metallic or partially metallic material selected from the group consisting of: a polyamide or polyimide impregnated carbon fiber layup, a peek or PEI injection mold with carbon fiber, compression molded carbon fiber or fiberglass, a resin infusion with carbon fiber preform fabric, a fiber reinforced thermoset, acetal resin, machined acetal or thermoplastic, thermosetting plastic, or a metal-matrix composite; wherein the body prevents friction-related damage to a structure. Another lightweight skid shoe assembly comprises a body of wear resistant, non-metallic or partially metallic material; and a shear-bearing mechanism; wherein the shear-bearing mechanism directs shear forces away from the body; and wherein the body prevents friction-related damage to the structure.