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Old Aug 25, 2007, 10:05 AM
The Future is Here Today
Kansas City
Joined Jan 2007
306 Posts
Discussion
Left - Right nose swing on my BCX2

I bought a completly bligned out CX2, folding blades and all CNC from another member. I can't seem to get it trimmed out right. This is my 3rd CX2 so I'm pretty confident that I have tried all the normal stuff but the nose still wants to swing left or right and I can't get it into a stable hover. I have it bound to my DX7 Tx. The only thing I haven't tried yet is to adjust my Tx to make the throw less sensitive. Any other idea's.
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Old Aug 25, 2007, 12:15 PM
The Shadows are coming!
Sirion's Avatar
Glen Forrest, Western Australia
Joined Dec 2006
1,373 Posts
Try releveling the swash plate - use the Klondikes PDF; check the gyro gain & the proportional trimmer pots - that at least will get you back to Square One. Good luck.
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Old Aug 25, 2007, 01:02 PM
Crashin' n learnin'
klondikes's Avatar
Hopkinsville, KY
Joined Dec 2006
807 Posts
jdunn9,

I would try adjusting the proportional and gain pots first. Here is a link on how I do it: http://www.rcgroups.com/forums/showt...37#post7720218.

If there ends up being some horizontal movement (forward, backward, left or right or a combination) then go for the swash plate adjustment. Here is how I do that: http://www.rcgroups.com/forums/showthread.php?t=642401.

Good luck and happy flying. Hope all that bling doesn't make the heli unflyable.

klondikes
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Old Aug 26, 2007, 01:43 PM
The Future is Here Today
Kansas City
Joined Jan 2007
306 Posts
Quote:
Originally Posted by klondikes
jdunn9,

I would try adjusting the proportional and gain pots first. Here is a link on how I do it: http://www.rcgroups.com/forums/showt...37#post7720218.

If there ends up being some horizontal movement (forward, backward, left or right or a combination) then go for the swash plate adjustment. Here is how I do that: http://www.rcgroups.com/forums/showthread.php?t=642401.

Good luck and happy flying. Hope all that bling doesn't make the heli unflyable.

klondikes
The first thing I did when I got it was to set the gain and pot and adjust the swash using your guide. At first all it wanted to do was roll over on its left side so I knew adjustments were in order. I did tweak it some more and have pretty much got it to where it will hover. Now my problem is that while it doesn't nose left or right anymore, it just wants to fly big circles by itself. What I mean is that when I use left stick only to control altitude it will hover and the nose stays straight, but the entire heli goes into about a 4 foot radius circle by itself, and mind you, the nose doesn't turn. It's not toilet bowl or ground effect, I know how to fix those, just can't figure out this one. After already having two of these you would think I have seen everything that could go wrong, guess not Any idea's on this???
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Old Aug 26, 2007, 04:31 PM
Crashin' n learnin'
klondikes's Avatar
Hopkinsville, KY
Joined Dec 2006
807 Posts
Quote:
Originally Posted by jdunn9
What I mean is that when I use left stick only to control altitude it will hover and the nose stays straight, but the entire heli goes into about a 4 foot radius circle by itself, and mind you, the nose doesn't turn.
jdunn9,

I don't know what to advise. Sounds like you have covered all of the bases. The description you give of the problem, although you say it is not TBE, sounds just like TBE. I would make sure the flybar and the top rotor movement system are ultra free working. It should teeter toter just by looking at it.

When my heli acts up and nothing is easily evident, I take it all apart and rebuild it looking very closely at each part and making sure bearings, end plays, and part locations are as perfect as possible.

Good luck.

klondikes
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Old Aug 26, 2007, 04:54 PM
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kansas city
Joined Feb 2007
12,642 Posts
jdunn9,

How's it going? I have read a lot about people who put the aluminum blade holders on who can't get it to fly correctly. You might try changing it back to cx blades. I'll be around Metcalf and 435 all day tomorrow Maybe I could take a look. PM me If your in the area I have a great indoor test area. If not I'm in the Raytown Independance area after 4.
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Old Aug 28, 2007, 07:02 PM
The Future is Here Today
Kansas City
Joined Jan 2007
306 Posts
Quote:
Originally Posted by mhills51
jdunn9,

How's it going? I have read a lot about people who put the aluminum blade holders on who can't get it to fly correctly. You might try changing it back to cx blades. I'll be around Metcalf and 435 all day tomorrow Maybe I could take a look. PM me If your in the area I have a great indoor test area. If not I'm in the Raytown Independance area after 4.
mhills - as you know I PM'd you. For the rest; I trimmed and trimmed some more, three packs worth to be exact. I went into my DX7 Tx and made sure nothing in there was set incorrectly. I got it finally into a mostly controlled hover, the tail still has a slight wag but no amount of gain seems to correct that. I am thinking it maybe the boom causing that. Time to order another one from Jamie. For grins I bound it back to the original Tx and tried to lift off. It went immediately hard right, looking at the tail, and rolled over after skidding for about a foot on the floor. Bound it back to my DX7, and no problem. This implies something is very different in the two Tx's. Any thoughts on this latest development.
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Old Aug 28, 2007, 07:18 PM
Lou
Registered User
United States, VA, Waynesboro
Joined Dec 2005
5,643 Posts
For some reason the word flybar keeps popping into my noodle when I ponder this problem. I did have a Lama at one time that when in ground effect ( about 4 inches off the floor ) it would do as your is doing. I seem to recall it was a combination of flybar and ground effect.

It seems that the heli is level and stable, not dancing all over the place; just flying a gentle 360 degree path. Balance the blades and check the flybar, see if that helps.
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Old Aug 28, 2007, 09:38 PM
Born again newbie
dmulligan's Avatar
Calgary, Canada
Joined Jul 2007
994 Posts
You said that you have two other CX2's. You may want to try swapping out the bling parts one at a time to see if you can narrow it down that way.
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Old Aug 29, 2007, 06:35 PM
Genius or Madness?
Necron Xen's Avatar
The Evergreen State
Joined Jul 2007
873 Posts
If your heli is goin in 4-foot circles without rotating the nose at all, it has to be your flybar. I modified my flybar just recently cutting it down to make it shorter. My heli was doing the same thing. With further investigation, I discovered my flybar weights weren't balanced perfectly, one seemed slightly heavier than the other. I took out the inner shaft and the upper blades, and stood the shaft up on its own to see whether or not the weights were balanced. The problem was that one of the bars were a millimeter longer than the other, I jus didn't cut them right. I fixed that problem with a spare flybar that I measured and cut to the precise length.
Sometimes its not always the length, the weights themselves could also be unbalanced. I tested the weights with the stock CX2 flybar attached to the inner shaft, still vertically standing, the weights were not in balance. I took the weights from a spare stock CX2 flybar that I had and replaced those weights. Apparently these weights were in balance to each other. I stuck these weights on my chopper and the 4-foot circles stopped

Though, I'm not sure what kind of solution I can provide you, perhaps you can list all the mods that are on the heli? If it has an adjustable flybar, then you can immediately fix that problem. What I've mentioned earlier was with a stock flybar that I cut down to size
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Old Aug 29, 2007, 07:09 PM
Born again newbie
dmulligan's Avatar
Calgary, Canada
Joined Jul 2007
994 Posts
Necron Xen: I assume that your upper blade tracking was way off. If so that is a good way to see if it is the flybar.
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Old Aug 31, 2007, 07:18 PM
Genius or Madness?
Necron Xen's Avatar
The Evergreen State
Joined Jul 2007
873 Posts
I might of failed to mention both of my blades were perfectly in track when I was doing that. Sorry, thanks for pointing that out =3
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