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Sawyer Oubre

(Older) rig slipping out of balance

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Question about rig accuracy and balance:

 
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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Could be that your gimbal is in need of servicing. Do a 180 test, get static balance, rotate 180 degrees. Does it go off, even by a hair? Robert Luna services gimbals out in LA. I had the pleasure of having him fix mine up. I had a similar issue, I felt I was always trimming. Now it's pure butter.

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Hi Sawyer,

i use to own a clipper 24. Do you get a tick when you tilt 90 degrees down and when you tilt back up you find the fore and aft balance is out? That use to happen to me. It took a long time to track down how ever we finally discovered what it was. I do not fully understand what I am writing but maybe the tiffen  people will. The “blocks” in the top stage had a 1/10000 inch of compression that was causing the problem. It really only showed up with longer camera set ups. The weight block they used at the shop was not re-creating the problem however when you had a Sony F900 with all the stuff on the problem was there. They eventually replaced the blocks with a new metal for me. This was in 2008 I’m no longer flying that sled. 

 

Hope me that helps. Feel free to call me if you have any more questions. 

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7 hours ago, Kevin Jacobsen said:

Could be that your gimbal is in need of servicing. Do a 180 test, get static balance, rotate 180 degrees. Does it go off, even by a hair? Robert Luna services gimbals out in LA. I had the pleasure of having him fix mine up. I had a similar issue, I felt I was always trimming. Now it's pure butter.

AAHHA! So she failed the 180 test big time! (great news! im just so glad ive finally found something)

However, im curious how this (having a out of tune gimbal) is throwing the rig off balance when doing something like a drop time test, or resting it up on your shoulder..? 

Do you think I still have something slipping like Philip brought up OR can it all be chocked up to the gimbal..? 

i suppose in both those actions are panning and tilting the gimbal.. even though it ultimately returns to its original position. 

(Thanks so much for the help!)

Cheers! 

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Hi Sawyer

First of all we find that 90% of the time we see balance issues they are something other than the gimbal ie something moving. Yours does sound like the stage F/A adjustment moving, have a look at page 8.3 of the M-1 manual as this explains how to take slack out of the trims (they should be similar but the F/A located on the back). If you over-tighten the adjuster it may make the adjusting knob difficult to turn.

Also, grab the yoke and see if there is any slack in the side bearings, vertical slack won't really matter but any clicks may be a tell tale sign that something is wrong.

I am located in the UK so not much use to physically look at the sled but feel free to mail me on robin.thwaites@tiffen.com.

Robin

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4 hours ago, RobinThwaites said:

Hi Sawyer

First of all we find that 90% of the time we see balance issues they are something other than the gimbal ie something moving. Yours does sound like the stage F/A adjustment moving, have a look at page 8.3 of the M-1 manual as this explains how to take slack out of the trims (they should be similar but the F/A located on the back). If you over-tighten the adjuster it may make the adjusting knob difficult to turn.

Also, grab the yoke and see if there is any slack in the side bearings, vertical slack won't really matter but any clicks may be a tell tale sign that something is wrong.

I am located in the UK so not much use to physically look at the sled but feel free to mail me on robin.thwaites@tiffen.com.

Robin

Super helpful thank you Robin! 

Ill give that a try tonight. 

As for the gimbal, yes unfortunately I do feel a very slight amount of play side to side.

so perhaps this whole thing is a combination of both! (Gimbal and top stage)

S

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14 hours ago, Philip J. Martinez SOC said:

Hi Sawyer,

i use to own a clipper 24. Do you get a tick when you tilt 90 degrees down and when you tilt back up you find the fore and aft balance is out? That use to happen to me. It took a long time to track down how ever we finally discovered what it was. I do not fully understand what I am writing but maybe the tiffen  people will. The “blocks” in the top stage had a 1/10000 inch of compression that was causing the problem. It really only showed up with longer camera set ups. The weight block they used at the shop was not re-creating the problem however when you had a Sony F900 with all the stuff on the problem was there. They eventually replaced the blocks with a new metal for me. This was in 2008 I’m no longer flying that sled. 

 

Hope me that helps. Feel free to call me if you have any more questions. 

Hi Philip! 

Yes that seems like my problem. However I don’t feel a tick.. in fact I can’t precieve and movement at all.. but yes tilting forward 90 and then bringing it back up I find it is out of trim. I have actually checked the top stage with dial calipers before and after tilting and can’t find any evidence of movement.. perhaps it’s just too minute to precieve even with calipers.

going to try tightening the adjustment stage down and go from there.

thanks again! 

S

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I had this problem with a different sled.  The problem turned out to be a post clamp that seemed tight but was loosening ever so slightly and making the sled go off level.  Drove me nuts trying to figure it out.  

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On 1/9/2019 at 6:04 AM, RobinThwaites said:

Hi Sawyer

First of all we find that 90% of the time we see balance issues they are something other than the gimbal ie something moving. Yours does sound like the stage F/A adjustment moving, have a look at page 8.3 of the M-1 manual as this explains how to take slack out of the trims (they should be similar but the F/A located on the back). If you over-tighten the adjuster it may make the adjusting knob difficult to turn.

Also, grab the yoke and see if there is any slack in the side bearings, vertical slack won't really matter but any clicks may be a tell tale sign that something is wrong.

I am located in the UK so not much use to physically look at the sled but feel free to mail me on robin.thwaites@tiffen.com.

Robin

After some more testing im confident the entire problem is stemming from the gimbal being out of tune.

I am hoping to send it off to Luna for a retune. Wondered if you had any advice for detaching the gimbal?

Im assuming this isnt possible without a complete rewire of the electrical thought the topstage. Would love to find someone in Atlanta GA who does electrical so im not shipping the entire sled to Terry in LA first. 

Thanks,

S

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