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Voodoo 700 servo arms bend on servo
https://www.spirit-system.com/phpBB3/viewtopic.php?f=24&t=2528		 Page 1 of 1
Author:  delta peak [ Fri 20. Apr 2018 11:32:32 ]
Post subject:  Voodoo 700 servo arms bend on servo
I have changed from AC3X V3 to Spirit red. Firstly, i used the already attached servo horns, but with Spirit the linkages of the Roll servos bend on the servo horn.
Then i changed to Mikado horns. Now the linkage screw bend on the servo case in the upper direction. I could get rid off that by setting cyclic ring to 105 but then i were unable to reach the cyclic rates.
With AC3X it was not a problem, since there is a travel limit for each servo to set. It may be the only system that can do that.
I have considered going back to the original Voodoo horns and grind something off the horns, it may work then.
There i have 16mm, with Mikado 17mm or 17.5mm distance on the horns.

Here´s the not finished setup. It´s important to me to get rid of that bending issue.

Attachments:
spirit setup 20.4-b2.4ds [255 Bytes]
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spirit setup 20.4-b1.4ds [255 Bytes]
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spirit setup 20.4-b0.4ds [255 Bytes]
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Author:  ZeXx86 [ Fri 20. Apr 2018 11:57:00 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
Hello,

servo arms should be always be so that push rods are perpendicular to the swashplate in all axes.

If you will limit one servo differently than other, then this will result in an inequal rates for some sides. So all servos should be limited in the same way. If there will be limitation for bigger angles, then you will feel kind of "stalling" in a pirouetting maneuvers as there will be low angles.

If you can observe a difference in limits for each servo, maybe the problem is in the Subtrims - all servo arms should be at the center when you tick Subtrim (tuning). Can you confirm it is in this way?

For Spirit you can limit Cyclic angles and Pitch angles.
Author:  delta peak [ Fri 20. Apr 2018 12:30:33 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
The mechanics are set correctly. Servo arms 90° to linkages at 0° Pitch as mentioned in Voodoo´s manual. Max min Pitch is at 12°.
As i said, i´m going to grind off a bit to make it work.

Do you see any odd things in the setup?
Author:  ZeXx86 [ Fri 20. Apr 2018 12:45:45 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
Yes,

I would decrease Cyclic Ring to maybe 70%.
Then Pirouette Consistency seems to be very high. Normally helicopters have no more than 190. So high values could cause big oscillations in fast forward flight. But it depends on servo arm length. Your Rudder End-points are quite small (default values) - are these correct?

Elevator Filter should be 3 - 4 for your helicopter.

Cyclic Feed Forward could be too low, but can be still good. The most people like it between 4 - 6.

Flight Style - there higher value could be better for you - lower delay (higher confidence). You can use value of 5 - 8 with no problem.

Were you measuring the angles by Pitch gauge? - especially for Cyclic Ring and Collective pitch range
Author:  delta peak [ Fri 20. Apr 2018 13:07:44 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
The Rudder end points are around 190. This value is not global? The current rudder gains are not to high, as i have flown it today (BLS 251 and BLS 452 for cyclic).
Still i need to redo the setup and tweak the settings :) Did it just quick and dirty.

Quote:
Were you measuring the angles by Pitch gauge? - especially for Cyclic Ring and Collective pitch range

What do you mean? I don´t understand.

edit: Oh sorry, i meant binding not bending for the previuos posts.
Author:  delta peak [ Sun 22. Apr 2018 19:38:20 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
Now i´m using SAB arms on 17mm. I get 12° pitch and 10° cyclic at 0° pitch. But it seems that this is still too small. With AC3X I was capable of having 14° pitch and 15° cyclic without binding because of servo travel limit. It seems Voodoo is only made for AC3X :shock:

With today´s flying I was not very pleased at all. At fast forward flying elevator behaves not very precise. Maybe Flight Style to high (6)?
Also in 3d maneuvres the swash wasn´t precise as well. It won´t follow as I wan´t and it was not that stable. Also Flight Style?
Feed Forward is on 7.

When I switch from high to low rpm the tail oscillates noticeable.
Author:  ZeXx86 [ Sun 22. Apr 2018 20:07:00 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
Hello,

please send me your current settings. Then I can help you more.

In any case there are at least few pilots with Voodoo 700 and Spirit and they are very satisfied as far as we know and no one reported a problem with configuring the limits. In any way 12° for pitch and 10° for cyclic are very normal and the most people are flying with no troubles with this. Usage of 14° is really not good idea until you fly like Tareq :)

Very likely you will need to set Elevator Filter as high as possible for this model.
Flight Style should not cause any troubles.

Also please let me know what servos you are using, then it will be easier to suggest a correct values.
Author:  delta peak [ Sun 22. Apr 2018 20:16:48 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
Here are the settings.
14° are needed for lower rpm even with the 6s setup I have. I´m still happy with that. I hope getting the Voodoo to fly such like AC3X.


I have found new servo arm configuration which I want to test in the next time.

Attachments:
voodoo2.4ds [255 Bytes]
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voodoo1.4ds [255 Bytes]
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voodoo.4ds [255 Bytes]
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Author:  delta peak [ Tue 24. Apr 2018 20:09:16 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
Ok, now I got 13° pitch with 12° cyclic. It flies a bit better, it seems he really needs much cyclic. I´m using the Mikado arms with the Mikado ball links with phillips screws.
Attachment:
DSC00289.JPG
DSC00289.JPG [ 1.71 MiB | Viewed 1341 times ]

This is the mounting of the Wifi module. It seems to interfere with the radio. I wanted to open the log, suddenly the motor starts spinning.
Servos are BLS 251 and 452. Voodoo is about 4,8 kg with 12s. Also DH 711 Flybar are used.
Attachment:
IMG_20180424_170619.jpg
IMG_20180424_170619.jpg [ 487.86 KiB | Viewed 1341 times ]
Author:  ZeXx86 [ Wed 25. Apr 2018 7:20:07 ]
Post subject:  Re: Voodoo 700 servo arms bend on servo
Thank you for the details.

For better tail performance, I recommend to make the servo arm longer.
At the moment you have too high servo resolution.
So changing it will make it more optimal. Your rudder end-points will be also smaller.

Pirouette Consistency value is probably still too high. But probably should not be less than 190.

Please note, that changing Servo arms will result in different Geometry 6° which has impact on the cyclic performance/behavior.
So this value should be updated when changing servo arms.
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