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HelicopterFlybarless Rotor Head SystemsAlign 3G › Crappy tail; Gain vs. Delay and nose pitch up in FFF and Vibrations
06-06-2010 06:22 PM  7 years agoPost 1
Turbonator

rrNovice

Randfontein,Gauteng, South Africa

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Dudes, I could really use some advice here:

I’ve set up my G3 as per manual and must say that it’s really easy to do. I’ve mounted the sensor on the “traditional” spot and had a crappy tail. I then moved it to the Rx tray and got on better results.

My problem: On a steady hover it hunts. I reduce the gain until it doesn’t hunt any more. The problem is that the gain is like 5 percent (very low). When I do pirouette and stop, the tail has a lazy bounce.

The manual recons that this is due to a slow servo and some delay must be added. I was skeptical as I’m using Align’s 520. Amazingly it worked very well! I could increase the gain somewhat, and the bouncing pirouette is less.

My issue is that it’s not nearly what I expected. I come from old school and am used to the GY401. I was lead to believe that the GP780 is superior compared to the GY401, but till now its other way round.

What am I doing wrong?

HHH

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06-06-2010 09:30 PM  7 years agoPost 2
jsenicka

rrProfessor

Eagle River, WI

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What heli?
What power system?
I started with a 3G on a T500 and it wagged and hunted till I turned gain down so low it would not stop well, and would blow out on any backwards flight. As soon as I disabled my governor on the ESC, I was back to 50% gain and holds perfectly

Jim Senicka
Team Manager, GrandRC Flight Team

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06-07-2010 06:21 AM  7 years agoPost 3
Turbonator

rrNovice

Randfontein,Gauteng, South Africa

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Trex 500.

Scorp 1400Kv, stock Align ESC, Torqe tube.

The ESC is not in governor mode.

HHH

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06-08-2010 07:06 AM  7 years agoPost 4
Turbonator

rrNovice

Randfontein,Gauteng, South Africa

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Ball link

I’ve moved the ball link on the tail servo to the most inner hole. Gain is up from 5% to 48% and tail is now steady on a hover!

Pirouetting anti clockwise + stop = virtually no bounce.
Pirouetting clockwise + stop = bounce.

Why towards one side, but not the other? The 520 seems to be in perfect order. Slop?

Another problem I have is constant pitching up of the nose. Elevator gain at max & low makes no dif. Could incorrect CG do this?

HHH

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06-08-2010 08:35 PM  7 years agoPost 5
scotty3

rrApprentice

houston, texas - united states

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Your getting vibration on your heli somewhere, mine did the same thing until I fixed the vibration issues. Also it stops better on one side because when u let go of the stick the tail goes to center and then tries to stop. If you set it up in default mode first then it should stop both ways just fine.

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06-08-2010 08:39 PM  7 years agoPost 6
504Rone

rrKey Veteran

New Orleans, LA.

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Turn your gain down.

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06-09-2010 11:03 AM  7 years agoPost 7
HiroboFreak

rrVeteran

Central Coast, NSW, Australia

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Put the sensor on the base plate (yes the bottom plate) using a stiff tape, ideally 3M #4010.
Reset gains back to default & try again.

The Rx mount is too flimsy & you'll pick up too many vibes if you mount it on the boom case, especially if you're running the Torque Tube.

Upgrading to V2.1 will help with the tail.

T-rex700n VBar 5.3 Pro | T-rex700e DFC VBar 5.3 Pro | JR DSX9
Team RCBits | Team Lynx

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06-09-2010 09:25 PM  7 years agoPost 8
scotty3

rrApprentice

houston, texas - united states

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I have mine on the tt and it has the least vibration on my entire heli? I checked it by removing the blades and feeling the vibrations in different spots with my finger.

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06-09-2010 10:28 PM  7 years agoPost 9
HiroboFreak

rrVeteran

Central Coast, NSW, Australia

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Really?
With bearings & gears in close vicinity it's a decent source of vibes.
My sensor didn't like it on the boom case at all.

The manual states the sensor should be mounted away from vibration sources.

The best place for me was the base plate.
Quite a few guys running the sensor there with good results.

T-rex700n VBar 5.3 Pro | T-rex700e DFC VBar 5.3 Pro | JR DSX9
Team RCBits | Team Lynx

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06-10-2010 06:58 AM  7 years agoPost 10
Turbonator

rrNovice

Randfontein,Gauteng, South Africa

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Vibrations eliminated!

The base plate makes sense. I’ll give it a go. BTW, I’ve discovered a major source of vibration on my heli: Tight meshing gears! I paper meshed the pin gear but still had something happening in the TT. I discovered the following:

The horizontal white gear in the TT gearbox has got 2 bearings. The one bearing closest to the collar of the gear did not push right against the collar! This resulted in a tight mesh with the vertical shaft gear.

I fixed this and spooled her up. The 500 sounds and feel very happy. The sensor is now on the TT gearbox. I noticed the swash moving rapidly in forward and backwards motion. This to me is a clear indication of vibration feedback. I think that ideally, with blades removed, and motor at operational speed, the swash should remain absolutely still, and only respond to actual movements of the heli itself. This way one will know for sure that the sensors are responding purely on movement, rather than vibration feedback.

Next I’ll try the base plate…

Agree?

HHH

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06-10-2010 07:31 AM  7 years agoPost 11
scotty3

rrApprentice

houston, texas - united states

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Sounds good

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HelicopterFlybarless Rotor Head SystemsAlign 3G › Crappy tail; Gain vs. Delay and nose pitch up in FFF and Vibrations
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