Oct 17, 2019 - How Rotor Track and Balance Reduces Your Helicopter’s Airframe Vibrations

As a helicopter owner, you’ve no doubt realized that your craft is an intricate assembly of rotating components that allow for unique flight patterns; flight patterns that are not possible with fixed-wing air crafts. For instance, with a copter, you can fly forwards, backwards and even vertically! It’s hard to imagine an airplane doing the same, isn’t it? 



When you experience undue vibrations in-flight, it can mostly be attributed to the wear-and-tear of the rotating components. The solution? Call in a professional to reduce the vibrations in the airframe and lend yourself a safe flight and your helicopter a long life.


Here at RotorLink, we’re all about in-flight safety! Our professionally trained technicians anticipate and prevent mechanical problems so that you’re never put out. If you need Bell helicopter parts in BC, we source parts from an extensive network of suppliers to get you what you need ASAP. 


We offer innovative solutions for all aspects of the rotor wing industry. Our team also provides Airbus helicopter rotor repairs in Vancouver so that you can return to the skies!


Without further ado, let’s delve into the importance of a rotor track and balance. 


Overview of Rotor Track and Balance

As you may be aware, rotor blades move at rapid speeds around a stationary point. While the copter is in the air, these rotors are very vulnerable to deterioration as they travel at different angles to achieve the proper lift. 


The rotors should be created well and categorized into matching sets. This enables them to function smoothly during their lifecycle. Sometimes, they might endure minor damage, depreciate or undergo erosion. At such time, the rotor becomes unbalanced. 


What is rotor tracking and balancing? This is a process by which airframe vibrations, typically caused by the primary rotor, are smoothened. The process also calibrates the movement of tail rotors, drive shafts and oil cooler fans. 


The tracking and balancing process makes sure that the rotors operate in the right manner. 


Vertical vs Lateral Vibrations

The primary rotor is able to produce two types of vibrations, namely vertical and lateral. 


A vertical vibration is caused by the uneven lift generated by the primary rotor blades. This unevenness, in turn, is due to the blade chord profile discrepancies from one blade to the other or the imprecise alignment of pitch change links and trims tabs. 


A lateral vibration arises when the mass in the primary rotor is unevenly distributed. This unevenness could be due to the manufacturing process wherein components or blades were incorrectly weighted. Imprecise alignments, shoddy assembly tactics, erosion of the rotor trunion and an array of other issues also give rise to this scenario. 


A common misconception is to have all the rotor blades balanced just so, so that they pass by the same point in the rotational plane. In reality, a smooth ride isn’t dependent on this. 


There are quite some copter models that have a track split, meaning not all the blade tips are aligned nor do they pass through that exact point in the rotational plane. This split amidst the blade position is what generates an equal lift in-flight. 


Measures Used to Correct Vibrations

When it comes to vertical vibrations, there are 2 key adjustments to correct them;


- Moving a blade up or down in order to lengthen or shorten the rotor pitch change links (PCL). The PCL is responsible for separately controlling the angle of each of the primary rotor blades. By adjusting these, the on-ground blade separation and in-hover vibration can be corrected.

- Moving the rotor trim tab up or down so as to enable the blade to achieve high or low flight patterns.


With lateral vibrations, the uneven lift can be corrected by placing weight on the primary rotor hub at a certain location. Additionally, you can also “sweep” the blades; sweeping consists of shifting the blade forward or aft from its angled location. It is recommended to go for aft sweeping as moving it forward may result in rendering the blade unstable. 


Bear in mind, both these types of adjustments are very sensitive in nature. If done imprecisely, they can do more harm than good. Don’t DIY! We strongly urge you to call in a professional to handle this job. 



Take Advantage of Our Rotor Tracking and Balancing Services in Vancouver

RotorLink has the expertise to support you through the full lifetime of your helicopter. We offer professional and affordable maintenance services in all aspects of the rotor wing industry. 


Your in-flight safety is so so important. Don’t jeopardize that. We’re available for a quick service call and can identify and fix mechanical issues quickly.


Contact us to set up a quick copter maintenance check!

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