Blade track is the ability of one blade to follow the other in the same plane of rotation. If your propeller has been bumped or compromised, check the tracking. A change in tracking can be unnoticeable or cause severe vibrations.
How did helicopter tracking flags work?
With the helicopter running on the ground, the tracking flags were moved in toward the rotor blade tips. As the blade tips made contact with the flags, each left a mark corresponding to its assigned color. If the marks were vertically separated, a pitch-change adjustment was needed to move the blade tips closer together. If the marks overlapped one another, no adjustment was required. The downside to this method is that it was dangerous and could only be done on the ground.
What is static balance in helicopters?
In BC (before computers) times and the days of wooden rotor blades, helicopter manufacturers and mechanics used what was referred to as “static” balance equipment to achieve rotor system track and balance. This equipment was usually in the form of a balance-beam assembly with a bubble-type level and a set of tracking flags. The static balance device was used to adjust the main rotor span and chord-wise mass distribution. A long, vertically-held pole that had two horizontal arms protruding from it would have multiple pieces of tape (tracking flags) attached between the horizontal arms. The individual main rotor blade tips were coated with differently-colored grease pencil or chalk.
How to make a helicopter ride smoother?
You would think that to achieve the smoothest possible ride, the ideal goal would be to balance all the main rotor blades exactly the same and have all the blade tips pass through exactly the same point in the rotational plane. Well, the concept is true, but in reality, that does not always lead to the smoothest ride. It is not uncommon for some helicopters to have a smoother ride with what is called a “track split.” That is to say that not all the blade tips pass through the same point in the rotational plane. There is a split in position among the blades. However track and balance is achieved on your helicopter, when the job is done, the helicopter should have the smoothest ride possible.
How to correct rotor balance?
To correct the balance, either the blade is swiped and/or lead fishing shot is added as required. There is a paper chart to help determine how much weight or sweep is needed. The balance is then checked again.
What are the pros and cons of the 8500 helicopter?
The cons are that the Model 8500 comes with a pretty hefty price tag and takes longer to acquire that first run data. It does a lot more and to do more, it looks at more data and takes longer in doing so. This translates into more run time for the customer’s helicopter and that costs more money. I believe this is a small price to pay for the excellent results that are achieved from the Model 8500.
Why do we need to balance rotors?
That is why balance is performed first. In complex rotor systems, balance is also used to help control the lead and lag of the blade. If the system is out of balance, then the blade dampers have to work overtime to try to keep the rotor system in balance.
Where is Roger Sharkey's helicopter?
To get some sense of how track and balance techniques have evolved over time, I traveled to Sharkey’s Helicopters in Lebanon, NH. It specializes in Bell and Enstrom helicopters and provides service, parts, charter and flight instruction. Company president Roger Sharkey is well recognized in our industry in performing helicopter track-and-balance maintenance. Sharkey started operations on Oct. 24, 1973. The first aircraft he bought was an ex-army surplus Hiller 12 C. The second aircraft was a Bell 47G and they both had wooden rotor blades. As of this writing, he had eight helicopters for sale: one Bell 407, one Bell 206B3, four Enstrom model 480Bs, one Enstrom model 28F and one Enstrom model F28A. Sharkey and I sat down and he provided me with an interesting one-on-one tutorial on how the mechanics of helicopter rotor blade track-and-balance techniques have evolved over time.
How to check if RC helicopter is tracking?
You can check the blade tracking by simply hovering the helicopter in place at eye level and looking at the blades as it hovers. If you see a lot of shaking and vibrating, your RC helicopter is more than likely not tracking properly. If you're not sure if it's tracking properly, do this:
What to do when your helicopter blades stop spinning?
After the blades have stopped spinning, you can adjust the blade that is out of alignment. You'll need to have your RC helicopter manual handy so that you can look up the proper blade tracking information in it. Be sure that you adjust the correct linkages in what the manual says and not what someone says. This is the best way to be sure that ...
What is the main rotor in a helicopter?
The main rotor is the primary source of vibration in a helicopter. Each main rotor blade is an aero foil section, which produces lift. Aerodynamic conditions that change as the blade rotates generate dynamic loads. The frequencies of these loads relate to the number of blades and the speed of rotation (blade passing frequency).
Why do helicopters vibrate?
Air flow over the helicopter can result in vibration at frequencies which are not related to rotor speed. For example, tail planes, fins, loose fairings can vibrate at their natural frequencies because of aerodynamic turbulence. Helicopters can also vibrate at their fundamental natural frequency because of aerodynamic turbulence.
Why is the tail rotor unbalanced?
The unbalance caused due to weight scatter results in radial or in-plane unbalance of the rotor and vibration due to out of plane rotation causes the axial unbalance. There is also a cross sensitivity between the radial and axial unbalance. Pre-conditions before dynamic balancing of rotor:
