Spectrum analizer x-y-z meaning

[velocity90]

Can someone please explain me which is which axis? I don't understand the ail ele and Rudder labels in vibration axis relation.

Which is:

-Sideways (left to right)
-Forward /back (nose to tail)
-Up /down (in the extension of the mainshaft)

Tnx

[W.W.]

I don't know, maybe this depends on the orientation or is this fixed (changed by the orientation Settings)?

[ZeXx86]

Directions that you have mentioned are not correct with respect to the measurement.

Directions of Aileron, Elevator and Rudder are correct that are used in the analysis.
By selecting X, Y, Z you can see how the vibrations are affecting sensor, respectively how they are transferred to the unit.

[velocity90]

Please explain it, this is the first time im hearing that. A little more info please so we can actually use it.

Which axis would indicate a failing tail bearing (vertical) which axis a failing mainshaft bearing (horisontal)

[ZeXx86]

Sensors are sensing in 3 directions (axes).
Vibration analysis can show you vibrations in each one separately.
With this you will for example immediately know where you can observe impact of the vibrations.
If there are the biggest vibrations on the Z axis, you will know that the rudder is the most affected and its performance can be degraded in the highest extent.

Actually I dont understand what is not understandable on this.

[velocity90]

Because there's no explanation. So why is a faulty motorbearing on the ail axis and not on the ele axis? Is there any more info or a guide like skookum made for it?

[ZeXx86]

This is because the main frame allows to transfer vibrations to the axis easily, while vibrations in other axes from this same source are blocked or attenuated.
Each helicopter has different construction, but aileron axis is very often affected to the highest extent.

There is description in the manual and some descriptions in the forum.

Steps are quite easy:
1. determine frequency/RPM and amplitudes of the spikes (for each axis).
2. find out which spike belongs to which part of the model. Rotor head RPM should be known and you should see some spike at this RPM/frequency nearly always. Everything that is vibrating at this frequency is rotating with the mainshaft.
Head Spead RPM * 4.5 should be RPM of the tail rotor. If you will see such spike, than you know what it is.
The highest spike is coming from the motor.
3. try to reduce all spikes with 50%+ amplitude. Dismount rotating part one by one and perform analysis to find out which part is wrong.

Depending on the model there might be more spikes and from the gear ratios you can calculate its frequencies quite precisely.

[velocity90]

Then ail would be lateral, ele would be fore/aft and Rudder would be up/down? If not, im lost...

[Ben M]

x - elevator is front to back direction
y - aileron is side to side direction
z - yaw is rotation about the main shaft axis

Hope this helps.

[velocity90]

Yes it does, tnx but it still is unclear to me why tail vibrations would be on the z axis, should be on x axis?