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Question about rig accuracy and balance:

Howdy! 
I fly an older Clipper 24 with tilt stage, ultrabrite monitor and V mount battery hanger. I’ve grown to really like flying with a very slow drop time, sometimes almost neutral. 
 
Recently I’ve run into a problem:
After trimming the rig it flys fine but after resting in on my shoulder or doing a larger tilt move I find it is thrown out of balance. It’s not drastic but enough that I have to retrim every time. Sometimes something as gentle as a drop time test will throw it off. It’s consistently in the direction that it tilt (tilt forward and the rig becomes front heavy). 
I have combed through every inch of the rig looking for a loose part and have found nothing. I’ve also tried balancing without the monitor or batteries and it still won’t hold balance. (Just to be clear I’m using a weight plate as a camera, which I have also checked thoroughly so it’s not a loose camera part.. it’s gotta be something on the rig). Top stage is tight, the plate isn’t slipping, monitor and batteries aren’t moving.. 
 
After pulling the entire rig apart and feeling very certain I’ve checked everything that could possible be moving,
I raise the question: am I just asking too much of my (older) rig? Is flying with such a neutral drop time just not practice with an older rig? 
 
Wondering if anyone has any ideas or has run into anything like this before. 
Anything helps.. I’m stumped! 
Thanks!
Sawyer 
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Hi Sawyer,

I'm often flying a Clipper 2 that I rent from another operator and I experience the same thing often working at 4 to 8s drop time

Going past 45° on any tilt direction will modify the rig balance and it will still hold a slight tilt.

I also checked that everything was tight. I have sometime noticed a small noise when doing the tilts.

I didn't disasembled the sled to check if it was that but my idea was that it could come from the cable moving in the post, if it is not a coiled cable like in most modern sleds.

If you have a way to check if that can be because of the cable I assume the solution would be to either replace it with a coiled one or to find anything to keep the cable in place without losing the ability to extend the post.

Maybe I'm totally wrong about the reason.

Let me know if you find out!

Cédric

 

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Sound like all the classic symptoms an Asymmetrical Gimbal.   Gimbal needs to be calibrated, because it is NOT centered.

Call me at 1-781-585-7900 if you need further details on this.  Thanks!

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It’s your gimbal.  Staticly balance the rig with whatever drop time you use with rig nose pointed toward one side of the gimbal yoke.  Make it perfectly staticly balance front to back and side to side.  Use a very accurate bubble level for both directions directly over the center of the post.  Rotate the rig 180 degrees and let it come to rest.  If it goes off from perfect balance then your gimbal is out of alignment.  Send it in to be corrected.  If it passes this test but then goes out when you tilt, then something is shifting ever so slightly in the gimbal usually around the side bearing area.  Either way you should send it to Tiffen for realignment and possibly needing to be shimmed to take out the shifting.  It is not something you want to do yourself.  The Ultra2 rigs could be field adjusted but it was a terrible thing to try and do yourself.

Grayson Grant Austin, SOC

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My two cents. It is not the gimbal.
It is the fore/aft travel adjustment machine screw/ nut combination.

Unless you've already resolved this, send me a PM and I can talk you through working it out. Takes about 3 minutes but a bit of prep to make a custom tool.

Best,

Peter Abraham, S.O.C.

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Could be either the gimbal or top stage shift. Do the static 180 degree test Grayson describes. If it fails this (without tilting), its the gimbal. If it passes this, but fails once the sled is tilted,  it could still be the gimbal but I tend to think it is something moving slightly within the top stage (or post connectors). I've never owned this sled so I'd look at the parts Peter suggests. I used to get this on occasion with my PRO/XCS hybrid. On that sled it was always the quick release on the top of the post. Taking it off, cleaning and reattaching with a tad bit of lithium grease on the threads and then a good tighten with the "post wrench" would get rid of it.

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My response was based on what Sawyer said but there is nothing wrong with double checking the topstage fore-aft but he did state that the topstage was tight and nothing is slipping and he wrote that he checked everything he could think to check so i have gone with the information he gave.  If there were a slight shift or slop in the fore-aft, you should be able to feel it if you try to shift by hand and pay close attention to how it feels. The Clipper 24 has essentially the same gimbal (and topstage) as the Ultra2 which i owned and had this same exact issue with the gimbal which needed to be sent in to Tiffen for realignment, especially with a long drop time which i also use. It was not a problem with the topstage although i did check it to be sure since that was something i could do myself.  Gimbal alignment is much trickier.  That gimbal can be field adjusted but it really is a pain in the ass and it can “go out” again later down the road even if you get it right. Tiffen will tell you that they do their alignments to a three to three and a half second drop time.  At that time (years ago) i had them do a “special” alignment for me that was more accurate than they tend to normally do and required more precise shimming and then they sealed the covers for me to prevent them from loosening from vibration/etc.  They may not want to go this deep anymore so if you want to use a very long drop time, it may never be as perfect as you want it to be.  Good luck and report back with how it ends up getting resolved.

Grayson Grant Austin, SOC

Edited by Grayson Austin

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