Mylar replacement

[Bojack J4]

How often should the mylar be redone on a horizontal stab/elevator?
The glider is always stored indoors in its trailer,and
everything looks fine with the factory installed tapes, etc.
There is sometimes a quiet air sound that changes pitch with elevator deflection especially when cold.

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From what I've heard, and don't hold me to this because I am no expert..

Is that it all depends on how the glider is stored, how often it is flown, and how well they were installed previously.

My advice: ask someone at the glider club who also privately owned sailplane and get their opinion, or even more than one opinion.and especially ask a A&P or IA that is local to the glider port.

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On Tuesday, April 25, 2017 at 11:06:03 PM UTC-4, Bojack J4 wrote:
> How often should the mylar be redone on a horizontal stab/elevator?
> The glider is always stored indoors in its trailer,and
> everything looks fine with the factory installed tapes, etc.
> There is sometimes a quiet air sound that changes pitch with elevator deflection especially when cold.

If you are starting to get noises you did not have before, and the bond of the seal to the stabilizer is good, it is likely to be time to replace the seals. Over time the seal material slowly loses the curve that is formed and made "stable" by heat. Likely it is the bottom seal making the noise as it is on the low pressure side.
A quick check of curve loss is to deflect the elevator(tail off the ship), and see where the seal stops having solid contact with the elevator. We just did this on a local ship and "new" noise went away.
Good luck
UH

[Bojack J4]

Thanks, Hank. J4

[Charlie M. (UH & 002 owner/pilot)]

To help keep seals longer, it pays to store the glider such that the controls are "neutral". Horizontal tail is usually covered by the mount/holder for it when disassembled.
Flaps and ailerons can be covered by small trailing edge "cuffs" that center the control relative to the fixed wing trailing edge on "most" gliders. The cuffs are thin sheetmetal bent almost in half that just slip on. A layer of tape, etc. inside prevents scuffing the gelcoat when installed.
Make the cuffs as cheap or fancy as you want.