Material Strength in Multirotor Component Construction

Many factors contribute to your choice of multirotor components. Material strength plays a large role in the quality, durability and dependability of multirotor components. Strength takes into consideration factors that relate to the behavior of the material when subjected to stresses and strains. From density to fatigue strength, there are specifications critical to the material strength and success of multirotor components. At KDE Direct, we engineer components made from strong materials that minimize failure from the mechanical design of our products and allow for safe operation.

Multirotor Component Material Strength

Material strength is defined by various parameters, all of which are typically summarized for a specific material.

Critical items include:

• Density – The mass of the material per a volume of material (grams per cubic centimeter, g/cc)
• Ultimate Tensile Strength – The strength of the material before it breaks under tension (pulling on both sides similar to a rubber band)
• Tensile Yield Strength – The strength of the material before it permanently stretches/bends (this is reached before the Ultimate Tensile Strength)
• Fatigue Strength – The amount of stress the material can handle for a high amount of cycles (aka, push/pull, for 500,000,000 cycles)
• Shear Strength – The amount of stress the material can handle under shear (the forces are perpendicular to the material, trying to tear the material)

All of these critical parameters are used in Finite Element Analysis (FEA) studies, where the computer uses the material properties to define the strength of the material and where it is calculated to break. From there, as mechanical engineers, we can then optimize the part to add material where strength is needed and remove excess material where the forces are minimal – overall, optimizing the design.

Aluminum for Propeller Adapters

Take, for example, the high-strength material we use for our propeller adapters – AL7075-T6 (aluminum). 

In the case of the provided FEA report (FEA Study of the Heavy-Lift Hex-Blade Propeller Adapter), a total of 15 pounds is applied to the mounting arms of the propellers (simulating a thrust scenario of 15 pounds), and the bending that occurs. The bending is heavily exaggerated, as the Deformation Scale is 1113.35 times what the actual deformation of the part would witness, so it’s purely for demonstration. Looking at the right of the image, this part has a FOS (factor of safety) of 61.4779 times the material strength. It is approximately 61 times stronger than it needs to be in order to protect against breaking at this load scenario.

In all of the KDE Direct designs, we shoot for a FOS >10, so that the parts are extremely strong and safe for operation to minimize failures from the mechanical design of our products.

Material Strength | A Professional Advantage

Choosing multirotor components with the best material strength allows you to create systems with the highest performance capabilities. By increasing performance, you’re setting yourself up for success. From humanitarian relief efforts to aerial cinematography for major motion pictures, performance and material strength matter in multirotor applications.

KDE Direct uses FEA reports to optimize the geometry, strength and durability of our aerospace-grade multirotor components. By using this method, we’re able to understand the physical behaviors of a material, including strength, heat transfer capability, fluid flow and more. We can predict the performance and behavior of the design, calculate the safety margin and identify weaknesses within the design. At KDE Direct, FEA reports allow us to accurately identify the optimal design with confidence.

New production versions of KDE Direct products, from propeller adapters to brushless motors, include these materials for increased strength and durability. As with all of our components, we take material strength and the various parameters that define it very seriously. In addition to FEA reports to evaluate the geometry, all KDE Direct components undergo strenuous quality assurance testing. Through these efforts, we’re able to engineer best-in-class, aerospace-grade multirotor components.