Hi, I have been trying for some time to work out why the vibration logs on my heli are so high for the main rotor. The heli is my old t rex 450 se converted to a copter x black angel head, non dfc.
The aileron vibrations are very high or off the scale, but reduce to about 60 or so if I pick the heli up by the boom. Without the head installed they are very low, but I have checked the head many times and nothing seems to be wrong ( all bearings installed correctly, no wobbles when spooled up etc ).
I was wondering if the gorrila gear landing gear was contributing as it is very soft and flexible?
Also the swash follower arms are not level at 0 degree pitch as the main shaft from the flybarless head does not fit the heli, so I am using the t rex main shaft which means the head is a bit higher than it was designed for, so I was wondering if this was the problem?
Eric.

Hi,

could you please send the plot from Y axis? (You can save it directly in the software).
This can tell us more, especially if your landing gear is reason for this - mostly it is not, because these vibrations are at very low frequencies (filtered in the plot).

Often the problems are coming from some assymetry in the rotor head - for example some bearing is not fitted correctly in the blade holder or there are different washers in each sides.

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Spirit System developer

Hi, thanks for your reply. Upon further examination I have noticed that the head block has a very small wobble in it which I had failed to spot initially. It is less than 1mm but I imagine that this is the problem, as the logs show this high vibration at main rotor speed, about 3000 rpm.
It is just as well that the Spirit has this feature actually.
Eric.

Hi,

that is great. I believe that it will improve vibration level.
Unit must be mounted pretty hard without any movement.

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Spirit System developer