yet another A2 toilet bowl question

[Spirevision]

Hey all, now before everyone tells me to use the "search" button for my answer...believe me I have tried. I now need some specialized help!

The goods:

Arris M680 Hex
Arris motors, gimbal, I think ESC's too
A2 flight control with GPS
Futaba T8fg controller

The Problem:

On Yaw left, the hex toilet bowls in one direction (either CW, or CWW, I can't remember specifically which)
On Yaw right, the hex toilet bowls in the opposite direction
In both instances, as soon as the stick is released, it returns to the proper position in the sky it should have remained in.

While hovering, it is ROCK STEADY. no movement what-so-ever

I am at Magnetic Declination of 13, and have adjusted the GPS to meet this. I have also experimented with +- 5 degrees, all the way to +-45 degrees. The toilet bowl effect is smallest at 13, but still there

I have calibrated compass (several times)

Does anyone have anything else I can check? It is flyable right now...but this toilet bowl thing needs to go.

 

[jbrumberg]

The toilet bowl effect as I understand it is by "definition" a ground effect event caused by air turbulence created by the props. This should not be a concern at eye level elevation or higher.

 

[Scott Drysdale]

Other possibilities that contribute toilet bowl effect...
1) Horizontal center of gravity is not positioned in the center of the MR hub
2) The x/y position of the FC relative to c of g of the MR was not accurately entered in to the FC via Assistant software.
3) The position coordinates of the GPS puck was not accurately entered via Assistant software in to the FC
4) Magnetic compass re-calibration may be required.

Hey all, now before everyone tells me to use the "search" button for my answer...believe me I have tried. I now need some specialized help!

The goods:

Arris M680 Hex
Arris motors, gimbal, I think ESC's too
A2 flight control with GPS
Futaba T8fg controller

The Problem:

On Yaw left, the hex toilet bowls in one direction (either CW, or CWW, I can't remember specifically which)
On Yaw right, the hex toilet bowls in the opposite direction
In both instances, as soon as the stick is released, it returns to the proper position in the sky it should have remained in.

While hovering, it is ROCK STEADY. no movement what-so-ever

I am at Magnetic Declination of 13, and have adjusted the GPS to meet this. I have also experimented with +- 5 degrees, all the way to +-45 degrees. The toilet bowl effect is smallest at 13, but still there

I have calibrated compass (several times)

Does anyone have anything else I can check? It is flyable right now...but this toilet bowl thing needs to go.

 

[jbrumberg]

Scott- Thanks for this information and the enhanced definition of and correction for toilet bowl effect as it relates to multicopters and advanced FCB's.

There is always something new to learn with this hobby

 

[Spirevision]

Scott, thanks for the help. I will check all of these things and go from there.

 

[Spirevision]

Dumb follow up question. Which is the horizontal cg on a hex? If the hex is sitting on a N,S,E,W axis, Do I pick it up by the East arm and the West arm to see if it is balanced? and is this with or without the battery?

 

[SoCal Blur]

I'm not familiar with A2 programming/setup but the wrong Magnetic-Declination can also cause the toilet bowl effect. Not sure if you have to enter that info into the A2 or adjust your GPS pucks direction relative to the FC.

 

[Tahoe Ed]

Look at this:

http://www.rcgroups.com/forums/showthread.php?t=2123178

It will explain it.

 

[gtranquilla]

Z is the vertical plane, x and y are the horizontal planes..... +x is the righthand side of the MR when the front of the MR is pointing away from you. +Y is the front of the MR etc.

Dumb follow up question. Which is the horizontal cg on a hex? If the hex is sitting on a N,S,E,W axis, Do I pick it up by the East arm and the West arm to see if it is balanced? and is this with or without the battery?