Wire Inserts in UAV's

The amount and type of fasteners (screws, nuts, bolts) in UAV’s varies widely depending on the size, frame material, design, and intended use, thus, playing an important role in the performance, reliability, and manufacturability of such crafts.

Designers and Engineers must use chassis and fastener materials designed for optimal performance and reliability without sacrificing speed and payload capability. Even small improvements in hardware -using lighter and stronger fasteners - can improve drone operation and dependability. This article will briefly discuss some of these areas that are affected by hardware and offer possible solutions.

• Weight and Flight Performance - Excess weight due to incorrect chassis material, having light weight chassis designs using more fasteners than needed, even a longer thread engagement between the screw and the chassis may impact flight time due to higher power consumption.
• Vibration Resistance - Drones generate significant vibration, especially multirotor types. Thread-locking compounds (e.g., Loctite) or nylon-insert locknuts are used to constrain joints and components. Connections secured with thread locking compounds can be difficult to remove, contain FOD on the screw and inside the tapped thread, leading to longer repair times since FOD must be removed from the hardware and chassis prior to reassembly.
• Aerodynamics - While less significant in large aircraft, fasteners can still impact airflow. Flush or low-profile fasteners reduce drag on fixed-wing or high-speed drones. Protruding screws or nuts create small turbulences that can impact efficiency in racing drones or micro fixed-wing crafts.
• Assembly, Repair, Manufacturing Efficiency - Fastener selection affects maintainability. Quick-release fasteners make field repairs easier. Standardizing on one or two sizes and types of fasteners simplifies maintenance and reduces tooling requirements. When possible, the use of self-tapping screws for plastic parts is preferred. If stronger joints are required, the use of wire inserts may be beneficial.

Over the years KATO has developed a wide range of Tangless sizes: 0-80 and M2 to 1/2” and M16. Sizes 0-80 (the world’s smallest Tangless insert), 1-64 and M2 are ideal for applications that are sensitive to weight. In applications where vibration is of concern, the use of locking inserts may be beneficial since the use of thread locking compounds is not recommended with helical coil inserts. Utilizing KATO’s Tangless inserts can optimize aerodynamics since wire inserts are a light-weight internal fastener which will be hidden within the chassis.

Designers and Engineers can also utilize the KATO Tensile Strength Wizard located in the KATOpedia section of the website to ensure the correct size and length are chosen for the application.