What Are Helicopter Stabilizer Systems?
Helicopters are robust vehicles, expertly engineered to achieve sustained heavier-than-air flight with their blade assemblies while also withstanding the various forces exerted upon them during typical operations. To maintain safe and balanced flight under various stressors and upsetting forces, helicopters rely on a number of stabilizer systems. From structural components to tracking systems, various components and technologies are implemented on helicopters to improve their ability to maintain uniform flight paths.
With a structural component known as a bell stabilizer bar system, the stability of helicopters can be greatly improved upon. Installed perpendicularly to the rotor blades, the stabilizer bar introduces weighted ends that maintain balance for the plane of rotation. With its linkage to the swash plate assembly, the pitch rate of the helicopter may also be reduced. With the implementation of such a stabilizer system, the rotor blades may operate together without the need for lag-lead hinges.
During flight and hover procedures, helicopters can be further stabilized with a stability augmentation system (SAS). In their most basic configurations, stability augmentation systems are a type of force trim system that utilizes a magnetic clutch and springs to maintain set cyclic control. In more robust variations, electric actuators may be used to relay inputs to hydraulic servos. With the detection of altitude alongside informational inputs such as speed, heading, and navigation, such systems can allow for autopilot capabilities. With either basic or advanced SAS implementation, however, pilots can have some of their workload alleviated to allow them to focus on other duties or operations such as search and rescue or transportation. When a pilot does not want to rely on the SAS, they may simply disable the system at any time.
With aircraft hinges such as the offset flapping hinge located at the rotor hub, force may be produced to stabilize flight during various procedures. With a greater offset between the hub and the hinge, a more powerful moment can be produced. As balance is shifted constantly between inertial, lift, and centrifugal forces, a flapping motion may result. As such, many often compare the flapping of the blades to that of a bird.
As the rotor blade assembly operates, blade tracking is used to find the relative position of rotor blades to one another. With a blade tracker, the pilot can better ensure that all rotor blades are kept within safe tolerances through corrections. As there are various blade tracking systems available, each will provide their own characteristics and functionality to maintain tip path.
With the flag and pole blade tracker, the tips of blades are marked with either chalk or a grease pencil. As each rotor blade is marked with a unique color, observing the relative positioning of each blade is much easier. Generally, flag and pole blade trackers are most often used for models that do not utilize jet propulsion for their blades.
Electronic blade tracking systems are also commonplace, and they will typically include a Strobex blade tracker, Vibrex tester, and a Balancer/Phazor. With the use of the blade tracker, tracking may be conducted in or out of the helicopter while it is either grounded or in flight. With the use of concentrated light beams that flash in relation to the main rotor blades, blades can efficiently be tracked and monitored.
Tail rotor tracking is also useful for stability, and marking and electronic methods may be used similarly to rotor blades. When one utilizes the marking method, a device is used to mark the near blade while the engine is running before stopping the system. Once the rotor is stopped, the procedures of running the engine and marking near blades is continued until the tracking mark crosses to the other blade. At this point, the unmarked blade may have its pitch control link extended by one half turn. With the electronic method, vibration is measured with a Vibrex balancing and tracking kit and vibration amplitude and clock angle is charted.
With the use of various stabilizer systems, helicopters can maintain set flight paths and operate more efficiently and safely. At Aviation Parts Online, we are a leading distributor for aerospace components and items that have been sourced from top global manufacturers. As the only independent distributor with a no China sourcing pledge, we ship every item alongside its qualifying certifications or manufacturing trace documentation as applicable. Initiate the purchasing process today when you fill out and submit an Instant RFQ form and experience how Aviation Parts Online can serve your operational needs with ease.
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