How Do The Tail Rotors of Helicopters Function?
While the main rotor of a helicopter is paramount for flight, the tail rotor is also an assembly that is crucial for safely operating the rotorcraft. Aircraft tail rotors are part of the single rotor design of helicopters, and they are the type that most are familiar with. Consisting of small rotor blades vertically attached to the tail of the helicopter, the assembly ensures that reactional torque created by the main rotors does not have a major detrimental effect on performance and safety.
During the standard operation of a helicopter, the main rotor will revolve at high speeds to create sufficient lift for flight. This process causes a torque imbalance to occur which can be hazardous if not combated as the helicopter will naturally begin to spin in the opposite direction. With the use of the tail rotor blade assembly, torque imbalance is counteracted so that the orientation of the helicopter is maintained. Due to the role that the tail rotor plays for balance, it can also be used for adjusting the direction of the helicopter nose. During hovering procedures, a pilot may increase or decrease the speed of the tail rotor in order to create an imbalance that allows the rotorcraft to adjust itself on the vertical axis without banking. Due to that fact that helicopter rotor drive system parts may serve both the tail rotor and central rotor at the same time, both assemblies can be synced up as needed. Depending on the helicopter, tail rotors may be an assembly that is built onto the tail structure or may serve as a part of the tail such as is seen in fan-type assemblies such as the fan-tail or fenestron design.
When the first helicopter designs came about, many experimented with multiple rotors that would revolve in opposite directions such as is seen in various coaxial designs. While this method of balancing torque is quite efficient, it can be more complicated in design. After Igor Sikorsky developed the single tail configuration in 1939, the design quickly took off and became the primary style for most rotorcraft as subsequent developments and refinements were made over the following decades.
While the single tail rotor configuration is the most popular, it is not without its disadvantages as compared to other types. In order for the tail rotor to provide its functionality, it requires approximately 30% of the engine's power. Furthermore, the tail rotor blades are often fragile and can be broken upon striking an object. As the tail rotor is paramount for balance and for avoiding spinning out, protecting helicopter rotor components is very crucial. Nevertheless, there are many designs for the tail rotor of an aircraft, and some variations may bring increased rigidity for protection. With most tail rotors, however, changes in wind velocity and direction may cause control of the helicopter to become more difficult. In order to maintain steady flight during such conditions, the pilot may have to monitor and adjust tail rotor speed precisely.
Despite their shortcomings, the single rotor configuration does bring numerous advantages that can make it a clear choice for varying applications. For one, tail-rotors highly benefit the ability to hover and turn a helicopter which is critical for certain applications. Furthermore, the design of aircraft tail rotors also permits the increased size of rotor blades for slower revolutions and less energy consumption. With the addition of increased payload capabilities and optimal performance characteristics, tail rotors can allow many helicopters to excel in diverse applications.
With top quality helicopter rotor components and helicopter rotor drive system parts, you can ensure that your rotorcraft operates efficiently and reliably. At NSN Purchasing, we serve as an online distributor of aircraft parts with over 2 billion new, used, and obsolete items readily available for purchase through our website. If you are facing a time constraint or AOG situation, we offer same-day and expedited shipping on a number of items that we carry. To receive a competitive quote on parts you are interested in, send us a completed RFQ form and a dedicated account manager will reach out to you in 15 minutes or less to provide a personalized quote based on your individual needs.
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