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CG Trimming after Tail Boom Repair



 
 
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  #1  
Old November 23rd 17, 08:20 PM posted to rec.aviation.soaring
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Default CG Trimming after Tail Boom Repair

A new weight and balance, after a tail boom repair, shows that several tens of pounds of trim weight needs to be added to a forward location in order to move the CG back into acceptable range. This fixes CG issue, but are there other concerns with doing this? Would be interested in experience of others.
Tom A
  #2  
Old November 23rd 17, 08:28 PM posted to rec.aviation.soaring
Tim Taylor
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Default CG Trimming after Tail Boom Repair

On Thursday, November 23, 2017 at 12:20:04 PM UTC-7, wrote:
A new weight and balance, after a tail boom repair, shows that several tens of pounds of trim weight needs to be added to a forward location in order to move the CG back into acceptable range. This fixes CG issue, but are there other concerns with doing this? Would be interested in experience of others.
Tom A


Please specify the glider type. We assume you mean that the c.g. needs to be moved forward into the correct range.

Some gliders have ballast weights that can be placed in the nose or near the front bulkheads, others will have lead epoxied into the nose.


  #3  
Old November 23rd 17, 08:42 PM posted to rec.aviation.soaring
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Default CG Trimming after Tail Boom Repair

You should investigate the potential of some ballast hidden somewhere in the tail. Or perhaps your CG calc's and/or measurements. A boom repair should not require that much ballast in the nose to get the empty airframe in CG range.
  #4  
Old November 23rd 17, 10:02 PM posted to rec.aviation.soaring
Mike C
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Default CG Trimming after Tail Boom Repair

On Thursday, November 23, 2017 at 12:20:04 PM UTC-7, wrote:
A new weight and balance, after a tail boom repair, shows that several tens of pounds of trim weight needs to be added to a forward location in order to move the CG back into acceptable range. This fixes CG issue, but are there other concerns with doing this? Would be interested in experience of others.
Tom A


Other than the max allowable weight of non lifting parts there should not be any other issues if the repair was solid. Added weight in a tail boom repair (long tail moment) takes several times the added weight when added to the shorter nose moment. Having to add so much weight forward of the cg though shows that a sloppy and probably excessive repair was made.

Mike

  #5  
Old November 23rd 17, 11:06 PM posted to rec.aviation.soaring
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Default CG Trimming after Tail Boom Repair

On Thursday, November 23, 2017 at 2:20:04 PM UTC-5, wrote:
A new weight and balance, after a tail boom repair, shows that several tens of pounds of trim weight needs to be added to a forward location in order to move the CG back into acceptable range. This fixes CG issue, but are there other concerns with doing this? Would be interested in experience of others.
Tom A


A properly done repair should not add more than 2 or 3 pounds at the tail skid. That would need about 10 in the nose. Many ships have some fixed ballast aft that can be removed to get back in range without lots of nose ballast.
What type of ship and where was it broken?
UH
  #6  
Old November 24th 17, 05:32 AM posted to rec.aviation.soaring
George Haeh
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Default CG Trimming after Tail Boom Repair

The factory can add tail ballast to suit the first owner's weight and CG
preference. The factory documents will show how much, if any, ballast was
added.

  #7  
Old November 24th 17, 08:01 AM posted to rec.aviation.soaring
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Default CG Trimming after Tail Boom Repair

On Thursday, November 23, 2017 at 11:20:04 AM UTC-8, wrote:
A new weight and balance, after a tail boom repair, shows that several tens of pounds of trim weight needs to be added to a forward location in order to move the CG back into acceptable range. This fixes CG issue, but are there other concerns with doing this? Would be interested in experience of others.
Tom A


Thanks for suggestions. The repair (and the weight and balance measurement) was done some time ago. The concern arises because of a new pilot with different weight and preferred CG location. Sounds like a reweighing is in order and also a check to see if there is already trim installed.
Tom
  #8  
Old November 24th 17, 03:32 PM posted to rec.aviation.soaring
AS
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Default CG Trimming after Tail Boom Repair

A boom repair should not require that much ballast in the nose to get the empty airframe in CG range.

I have seen boom repairs just short of having 2x4s inside, so if it is one of those, that much lead in the nose may be indeed required.

Uli
'AS'
  #9  
Old November 25th 17, 02:04 AM posted to rec.aviation.soaring
Dan Marotta
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Default CG Trimming after Tail Boom Repair

I think I see the problem...
https://www.dropbox.com/s/gy3qkujmyy...26.49.jpg?dl=0

On 11/23/2017 2:02 PM, Mike C wrote:
On Thursday, November 23, 2017 at 12:20:04 PM UTC-7, wrote:
A new weight and balance, after a tail boom repair, shows that several tens of pounds of trim weight needs to be added to a forward location in order to move the CG back into acceptable range. This fixes CG issue, but are there other concerns with doing this? Would be interested in experience of others.
Tom A

Other than the max allowable weight of non lifting parts there should not be any other issues if the repair was solid. Added weight in a tail boom repair (long tail moment) takes several times the added weight when added to the shorter nose moment. Having to add so much weight forward of the cg though shows that a sloppy and probably excessive repair was made.

Mike


--
Dan, 5J
  #10  
Old November 25th 17, 04:19 PM posted to rec.aviation.soaring
Dan Marotta
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Default CG Trimming after Tail Boom Repair

You mean like this?

https://www.dropbox.com/s/gy3qkujmyy...26.49.jpg?dl=0

On 11/24/2017 7:32 AM, AS wrote:
A boom repair should not require that much ballast in the nose to get the empty airframe in CG range.

I have seen boom repairs just short of having 2x4s inside, so if it is one of those, that much lead in the nose may be indeed required.

Uli
'AS'


--
Dan, 5J
 




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