An Overview of Helicopter Rotor Hub Components

A helicopter is able to hover and maneuver mainly through the employment of a rotor hub, a mechanism that combines various components to transmit torque from the engine to the blades to generate lift. More than that, the items in the rotor hub also adjust blade pitch for controlled movement, as well as absorb aerodynamic or mechanical stresses. In this blog, we will discuss the most essential components that make up the rotor hub assembly, laying out how they function together to create safe and responsive helicopter movement.

The Rotor Mast

The rotor mast, also referred to as the main shaft, serves as the axis around which the rotor blades spin. Placed at the center of the rotor system, it transmits rotational energy generated by the engine to the rotor hub and blades, all while facilitating consistent load distribution.

Blade Grips 

Radiating outward from the central hub or yoke, blade grips are forked housings that secure each rotor blade to the rotor hub while allowing for any pitch movement. Internally, blade grips often contain bearings that reduce friction and wear, enabling smoother and more precise adjustments driven by the swashplate assembly.

The Swashplate Assembly 

The swashplate assembly translates pilot inputs into blade movement, consisting of a stationary swashplate directly linked to the helicopter's control systems and a rotating swashplate mechanically coupled to the rotor shaft.

Pitch Links and Pitch Horns 

Pitch links and pitch horns are intermediary components that assist in adjusting blade pitch by connecting the swashplate assembly to the rotor blades. Pitch links are rigid rods that extend vertically from the rotating swashplate to each blade’s pitch horn. The pitch horns, mounted directly onto the blade grips, are levers that transmit motion from the pitch links to the blades themselves. When the pilot inputs collective or cyclic commands, the swashplate tilts or moves vertically, causing the pitch links to push or pull on the pitch horns, altering the angle of attack of each rotor blade for lateral movement.

Dampers 

Dampers are cylindrical components mounted between the rotor hub and blade grips to handle lead-lag and flapping motions that arise from aerodynamic loading and blade inertia. By reducing the amplitude of these movements, dampers help preserve the structural integrity of the rotor system and improve helicopter stability. Depending on the design preferences of the model they are on, helicopter dampers generally fall into one of the following categories:

• Elastomeric Dampers: Made from rubber-like materials that flex under load, elastomeric dampers offer moderate responsiveness with minimal maintenance.
• Hydraulic Dampers: Hydraulic dampers utilize fluid-filled chambers to provide adjustable resistance, being highly responsive but requiring regular maintenance.
• Friction-Based Dampers: Relying on resistance between moving surfaces, friction-based dampers are simple and durable, though less precise in performance.

The Hub Center and Yoke 

Interconnecting all blade grips, dampers, and associated hardware around the rotor mast, the hub center and yoke provide the mechanical foundation for transmitting torque and bearing the loads generated during flight. The yoke’s configuration determines how each blade moves relative to the hub, influencing rotor flexibility and control responsiveness. Configurations include:

• Fully Articulated Yokes: This design incorporates flapping, feathering, and lead-lag hinges at each blade grip, allowing all blades to move independently in response to aerodynamic forces.
• Semi-Rigid Yokes: This type uses a teetering hinge that permits the blades to flap as a unit while still allowing for limited feathering motion, offering a balance between mechanical simplicity and flexibility.
• Rigid Yokes: Rigid yoke variations reduce complexity by having no hinges, instead relying on the elastic properties of composite materials to accommodate necessary blade movement.

Source All the Rotor Hub Components You Need on NSN Stream 

As the rotor hub assembly is responsible for facilitating safe and controlled helicopter movement, sourcing all associated components with quality and compliance in mind is non-negotiable. When you need to do upkeep or replace aspects of a rotor hub assembly, turn to NSN Stream. As an ASAP Semiconductor owned and operated website, our inventory includes a comprehensive selection of rotor hub assembly components and various other helicopter parts sourced from leading manufacturers.

We understand the necessity for high-caliber aviation products, which is why we have several quality-assurance measures in place that allow us to confirm authenticity and screen for potential issues before shipping items to customers. Moreover, our expert team is always prepared to accommodate certain requirements or restrictions our customers may be facing without sacrificing reliability, competitive pricing, or timely fulfillment. Bearing this in mind, we encourage you to explore our database and connect with our specialists at your earliest chance.