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

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.

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.

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

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

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.

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

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'

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


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Dan, 5J

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'

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Dan, 5J