What are Types of Helicopter Rotor Systems?
To take flight, helicopters utilize a combination of specialized components to achieve such capabilities. While most modern helicopters come in a variety of sizes and shapes, the critical apparatuses that comprise the aircraft remain fundamentally the same. To achieve flight, primary components of a helicopter consist of the airframe, fuselage, landing gear, powerplant, transmission, main rotor, and anti-torque system. While all of these parts are needed and contribute to flight, the rotor system in particular is a major section that separates helicopters from other aircraft types. Without these correlating sections of the rotorcraft, flight would be compromised and unsafe for pilots.
Specifically for the use of generating upward momentum, main rotor systems like the fully articulated rotor, semirigid rotor, and rigid rotor are used to propel helicopters. The main rotor consists of a mast, hub, and rotor blades which are assembled together to provide a single functioning unit. Joined together, these items are mounted atop the airframe of the vehicle. To better understand these parts and how they operate, we will discuss the main rotor structures used for many rotorcraft, and how each provides a helicopter with lift.
Fully Articulated Rotors
Invented in the 1920s, the fully articulated rotor is the oldest and most often used type to this day. Providing the ability to modify lift, fully articulated rotors primarily consist of three independent rotor blades that rotate along a pitch axis which is affixed to an articulated rotor head. Capable of flap movements, revolving back and forth, and feathering, the blades are attached to a central rotor hub that enables the components to function individually of one another. To inhibit overextension of the blades during changes in lead forces, damper or drag hinges can be used.
Rigid Rotors
Tested and developed for a series of helicopters during the 1960s and 1970s, rigid rotors eliminate the threat of mast bumping, a common characteristic of semi-rigid rotors. The effect of mast bumping causes a helicopter's blade to extend beyond its capability, leading to the detachment of the blade from the hub and various other potential hazards. To mitigate the forces associated with flapping, lead, and lag times, the blades affixed to the rotor encompass a hingeless rotor system. Least often used, these rotors are mechanically simple, but structurally complex.
Semi-rigid Rotors
A semi-rigid rotor, commonly known as a teetering or seesaw rotor, is typically composed of two blades rigidly attached to a main rotor hub. Like its name, the blades attached to the rotor allow for movement in two directions, executing a seesaw-like motion in return. This is achieved through multiple factors, including the blades coning angle design, a feathering hinge which attaches the blade to the rotor shaft, and the rotors underslung mounting which helps to regulate geometric imbalances. This also improves flexibility and minimizes the bouncing of rotor blades.
Ensuring your aircraft meets all maintenance and safety requirements needed for safe flight requires regular and thorough inspections. For faulty or aging items that are in need of replacement, look no further than NSN Purchasing, a trusted supplier of aircraft equipment, rotor assemblies, and their parts and components. Whether for helicopter rotor part kits or rotor drive systems, we provide qualifying certifications or manufacturing trace documentation for every purchase as applicable. Due to our quality control and export compliance, we operate with AS9120B, ISO 9001:2015, and FAA AC 00-56B certification and accreditation. If you would like to request a quote for your comparisons, you can submit an RFQ form as provided on our website. Upon receipt, a dedicated account manager will quickly review and respond with a personalized solution to your needs in just 15 minutes or less, 24/7x365.
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