is blade tracking? If you look at the rotor disk from the
side you should see a thin line. This means that both
blades rotate around to the same position the other blade
was in. If the blades do not align right then you will
see a thick line or if bad enough you will see two lines.
Some examples are shown in the picture on the right. The
top image is of the blades in track. The middle is of
just one side out indicating the flybar is bent, paddle
not aligned, etc. The bottom is a typical out of track
do I adjust to get the blades tracked?
So why do blades need to be tracked? Most of the time if the two blades are manufactured with close tolerances then they will not need additional alignment. However if one blade flexes more then the other or the blade has a warp in it then the purpose of tracking is to bring that blade in the same path as the other one.
First step: Before tracking the blades you need to have one side of the rotor head marked so your adjustments will be consistent. I usually scrap an 'X' on the top of one blade grip and also on top of the blade near the grip. In addition to using this so you can keep up with the link you are adjusting, you can also use this so if you take the blades off you can then get the blade back on the same grip and not have to re-track the blades.
step: Static tracking: this is the process of adjusting
the pitch of each blade so they are the same on the bench.
Almost all of the time this is the only tracking you will
need to do. If it is wrong in the air then one of the
blades must be flexing differently then the other and you
will need to adjust the links to compensate. Start the
process by sighting down the end of the blade and move
the collective to a position that the tip of the leading
edge and tip of the trailing edge are aligned with the
flybar. Next I rotate the rotor head 180 degrees and
sight down the end of the other blade. I adjust the long
link attached to it so that that blade is also aligned
with the flybar. This will now have both blades at the
same pitch settings.
Third step: Hover the helicopter and look at the edge of the rotor disk. Do not get to close to yourself. While looking at the blades it is easy to not pay attention to the helicopters position. It is a good idea to let a friend look at the tracking while you concentrate on hovering still. If the blades are out of track then land and look for the blade you marked. Adjust the link one turn, snap it back on, and check the tracking again. If it is worse then land and find the marked blade again and adjust the link two turns in the opposite direction. If one turn is not enough then go to the unmarked blade and adjust one turn the opposite direction. By rotating between one blade to the other you will keep your pitch range closer to the original range.
Troubleshooting: If you see the blades go out of track sometimes or you see one side of the disk is in track but the other side is not then you need to go to my troubleshooting page <here>.