PA Ultimate AMR setup

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donskills
Posts: 52
Joined: Fri 22. Aug 2014 16:57:03

Just maidened a PA Ultimate AMR with a uSpirit 1.3 in it. Amazing! The ailerons are said to be really effective and I noticed it directly with a oscillation on only aileron at 50% gain. First I turned the gain down in the tx until it was almost gone. It then struck me that I should turn down aileron in the sensor tab and lowered it to 40%. When I hooked up to the computer and checked I had turned down the main gain to 38% and aileron to 40% in the sensor tab.
I decided to up the main gain back to 50% in the diagnostic tab (58% in the tx) and lower aileron to 30% in the sensor tab as a starting point.
I am running BMS-385DMAX Digital Servo (Metal Gear) 4.2kg / .15sec and the whole airframe, ailerons included is stiff as hell, and with 4 of them I can see where the oscillation can come from. I am wondering if this is a good starting point? Any input to save me some trimming flights is welcome.
donskills
Posts: 52
Joined: Fri 22. Aug 2014 16:57:03

What if flies like in great hands!
https://www.youtube.com/watch?v=oB6jcBAjOiQ&t=101s
ZeXx86
Site Admin
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Joined: Mon 29. Apr 2013 16:06:44
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Hi,

if ailerons are too effective it can be fixed either by making servo arms shorter (one hole) - preffered.
Or by decreasing Gain for Aileron. I think that your procedure is correct but adjusting it mechanically can lead to a better result.
On the other hand if you will loose a required travel, then this is not good way.
Spirit System developer
donskills
Posts: 52
Joined: Fri 22. Aug 2014 16:57:03

The servo arms are specially made for the model and needed for ful travel. I will proceed to trim!


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donskills
Posts: 52
Joined: Fri 22. Aug 2014 16:57:03

The Ultimate, when set up correctly and balanced perfectly needs a little down elevator to fly level. This is apperently standard trimming for this model with basically everyone flying it (been reading since its snowing outside!). I only managed two flights before my esc gave up but notice that it settled naturally into a Harrier attitude when slowed down a bit. I thought to acheive this in the sub trim menu in the spirit. Will this work as intended?
ZeXx86
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If the model is flying straight without a corrections, then where it settled is exactly position which is needed to fly it straight. So any correction will actually make it very likely bad. Alternatively the compensation will move it back to the position where it was to maintain straight flight.

It is also very dependent on speed. When you will fly slowly needed correction could be different.

But usually the unit will take care of it. Alternatively Trim Flight can do this as well.
Spirit System developer
donskills
Posts: 52
Joined: Fri 22. Aug 2014 16:57:03

I will leave it without trim and see first. I suspect the Spirit will apply needed trim depending on speed!
ZeXx86
Site Admin
Posts: 12750
Joined: Mon 29. Apr 2013 16:06:44
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Yes, you are right. When head-lock mode is enabled it is trying to hold even with imprecisely trimmed model.
Spirit System developer
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