Removing Bladders in a J wing and reinstalling.

[jezzie]

I have fuel weeping in my left wing. It's time for a complete strip and reseal on my 77J. I own a salvage wing from a 78J that has bladders. Is it worth trying to move from one to the other? I am on a waiting list for fixing the weeping tanks. I expect my first call would be to the STC holder to see if the STC is transferrable? Any thoughts from the pros??

[1980Mooney]

52 minutes ago, jezzie said:

I have fuel weeping in my left wing. It's time for a complete strip and reseal on my 77J. I own a salvage wing from a 78J that has bladders. Is it worth trying to move from one to the other? I am on a waiting list for fixing the weeping tanks. I expect my first call would be to the STC holder to see if the STC is transferrable? Any thoughts from the pros??

An STC is assigned to a specific airframe serial number.  As long as the STC is still supported (which it is - Griggs/O&N) then you need the consent of the STC Holder (Griggs/O&N) in order to transfer it to a new airframe/serial number.  I have a hunch that they won't do it for liability reasons.

Griggs Aircraft Refinishing | Mooney bladders

 KNR, Inc., wrote a review of bladder application/installation in Mooney's back in 2009.  They said it took 55-60 manhours to install the latest 64 gallon 8 bag (4/wing) installation. (includes cutting additional hole for an access panel in each wing in order to instal the 4th bag).   If your salvage bags are  the 54 gallon 6 bag (3/wing) system then the installation would be 45 hours.  However you need to add more hours to remove the bags from the salvage wing. 

200910 Ribs Wet or Dry? (knr-inc.com)

There was a topic here on MS pirepping the installation. That topic had plenty of pictures of the job in process but sadly they are gone with the switch to the current server/host.  If you Google the subject and select "images" some of the pictures remain on Google

The last thing is how do you know the condition of the bladder?.  Also I don't know how they plumb the separate bags together inside the wing - possible damage on removal?

If your salvage bladders are the 6 bag (54 gallon) system you can buy 2 add on bladders to get up to the full 64 gallon "8 bag system".  It sounds like that costs about another $3,000 and 15 manhours.  They have to cut another access hole in each wing.

Installing a new bladder system with a 7 year warranty is one thing - it has plenty of positives.

Installing a salvage bladder system - more man hours than a new system, unknown condition and most likely reduced life. - I see a lot of labor expense with questionable life/quality - 

• The only "positive" is the free used bags. - and I am not sure that is a positive.

 

Edited November 19, 2023 by 1980Mooney