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PostPosted: Fri 19. Jan 2018 17:40:02 
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Joined: Mon 30. Oct 2017 19:18:22
Posts: 25
Hello

i have a Extra 330 with 1,6m wingspan Link. I never crashed with the maschine. The motor and the propeller are working normally. There is no unbalance. In my opinion there are low and normal vibrations as a plane on this dimension with a 17x8 Propeller have. I dont think there are less vibrations with a other propeller or motor. Now i want to upgrade my Extra with a Spirit Aero. But before i go to fly i have analyzed the vibrations.

The vibrations without propeller are between 0-1. Everything is ok.

The vibrations with the propeller are between 150 and 200 and up very high. In my opinion there vibrations are really less for a 17x8 propeller.

But the Spirit sayes the vibrations are too high.

Is the Spirit Aero more for gliders without motors? Can the Spirit Aero not handle motorplanes with motorsize propeller around 17x8?

I dont know what to do. I have analyzed the vibrations with two different Spirit Aeros on 2 different places on the plane. I also used different tapes to test. But there is always the same result.

:| :?:


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PostPosted: Fri 19. Jan 2018 18:24:43 
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Joined: Mon 29. Apr 2013 16:06:44
Posts: 7496
Hello,

the Spirit units can work with any motor and any model size.
The vibrations on the models are usually occugin when the unit is not mounted to a hard/stiff surface.
Then this surface is vibrating or flexing so much that the unit is basically jumping on it.
And then the unit is detecting it as a vibration, because physically the unit is vibrating.
So what you can try is to mount the unit on a surface that is as hard as possible.

We have a pilots that are flying Spirit Aero units with 5 meter wing-span gasser models that are vibrating so much that it is not safe to stay close to it...
But even with this the unit is working very nicely, if it is holding well. Some surfaces such as thin balsa wood could flex a lot in the middle.
So better area for mounting is close to the frame supports.

Technically it can work usually also with 400% vibration level and more.

On the plot you may see from where the vibrations are coming from. If among others you can see also very low frequency/rpm, then it is caused by the soft mounting as described above.

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PostPosted: Fri 19. Jan 2018 19:59:45 
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Joined: Mon 30. Oct 2017 19:18:22
Posts: 25
:lol:

after i eat 22 Chicken McNuggets to stress down i followed your instructions. I mounted the Spirit Aero next to the motor and used only the hard original tape. pic

Now i can give full gas and the vibrations are around 20-40 and ok. :lol:

thanks for help :mrgreen:


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PostPosted: Fri 19. Jan 2018 21:03:36 
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Joined: Mon 29. Apr 2013 16:06:44
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You are welcome.

Yes, you can mount it with supplied tape so it is mounted as hard as possible without a possibility to wobble on the surface.

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PostPosted: Wed 24. Jan 2018 20:35:18 
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Joined: Mon 30. Oct 2017 19:18:22
Posts: 25
Is it better to position the Spirit straight in the flight direction of the model or is it better to position the Spirit straight in the direction to the motor? The motor is the main vibration source but is not complete straight to the flight direction. Which position is the best for low vibration?

Image


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PostPosted: Thu 25. Jan 2018 8:55:49 
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Joined: Mon 29. Apr 2013 16:06:44
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To operate correctly it is always necessary to mount the unit paralelly to each axis of the model.
This mean always stright in the flight direction.

Any deflection has a negative impact on the performance, similarly as with helicopters.

By rotating the unit the vibrations are not lower, they are only distributed little bit differently regarding axes (sensors in the unit).

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