installing mylar

On Sun, 29 Jul 2007 17:41:26 +0000, mmartin via AviationKB.com wrote:

I've read all the posts, several times, regarding mylar seal replacemate. My
LS3-A needs the seals replaced and am considering doing the job myself. Is
this something a reasonabley compitent person can do on his own, or should
this be left to a pro? Your input would be appreciated.

Our LS3a has internal seals, which will need replacing soon, and no mylar.

Which is the best way to go, internal seals or mylar (or both) and why?

My gut feel is that the airfoil wont benefit much from mylar provided that
the hinge gap is sealed to prevent air leakage from the lower to upper
surface - as is the case with internal seals.

We also use a textured duct tape on the lower (hinge) side of the joint. I
presume with mylar, the hinge tape would fall away.

There is currently some "raised bump" (zig-zag like) tape just upwind of
the joint on the underside. I doubt this helps and if it does, the
textured hing tape should have the same effect. We will probably take off
the bump tape when we do the hing seals again.

But how much work is install internal seals verses mylar?

Thanks


Ian

Ian,
It is my humble opinion that all you need is mylar!
I believe this because my Nimbus 3 was exactly the
same as another local Nimbus 3, I mean exactly the
same...........same climb, same cruise. I could even
tell the difference in a couple of extra gallons of
water. My internal seals were wearing out, so I just
pulled them out without removing the controls and replaced
them with mylar. Guess what? No change in the ships
performance!!!

I'd cover the hinge gaps on your LS-3 with little pieces
of mylar on the flaps and ailerons (look at a ASW-27)
they did a meticulous job installing mylar. Then select
mylar that just touches the control surface and doesn't
go any further. If the mylar is lifted when control
in moved, you will get increased stick pressure and
it would be a shame to lose the light stick your LS-3
has.

I have seen teflon tape that covers the lower gap with
mylar over the teflon. I don't believe it is necessary.


Don't know if zig-zag works on the LS-3, anybody got
performance feedback on that?
JJ



At 10:06 08 August 2007, Ian wrote:
On Sun, 29 Jul 2007 17:41:26 +0000, mmartin via AviationKB.com
wrote:

I've read all the posts, several times, regarding
mylar seal replacemate. My
LS3-A needs the seals replaced and am considering
doing the job myself. Is
this something a reasonabley compitent person can
do on his own, or should
this be left to a pro? Your input would be appreciated.

Our LS3a has internal seals, which will need replacing
soon, and no mylar.

Which is the best way to go, internal seals or mylar
(or both) and why?

My gut feel is that the airfoil wont benefit much from
mylar provided that
the hinge gap is sealed to prevent air leakage from
the lower to upper
surface - as is the case with internal seals.

We also use a textured duct tape on the lower (hinge)
side of the joint. I
presume with mylar, the hinge tape would fall away.

There is currently some 'raised bump' (zig-zag like)
tape just upwind of
the joint on the underside. I doubt this helps and
if it does, the
textured hing tape should have the same effect. We
will probably take off
the bump tape when we do the hing seals again.

But how much work is install internal seals verses
mylar?

Thanks


Ian

Hi JJ

Thanks for your input.

On Wed, 08 Aug 2007 13:29:26 +0000, John Sinclair wrote:

I'd cover the hinge gaps on your LS-3 with little pieces
of mylar on the flaps and ailerons (look at a ASW-27)
they did a meticulous job installing mylar. Then select
mylar that just touches the control surface and doesn't
go any further. If the mylar is lifted when control
in moved, you will get increased stick pressure and
it would be a shame to lose the light stick your LS-3
has.

This sounds tricky, I must have a good look at a 27. I am not sure how to
get mylar to cover the gap but not bend when the surfaces are moved. And
as you point out, while the LS3a has not got the best performance it has
got lightest controls! I am sure it would be much easier to mess up the
control feel with mylar than it would be to increase the performance.

What is the relative work in fitting and maintaining mylar verses internal
seals?

Maybe we should just use hinge tape on its own. Lots of work to replace
every season, but possibly as effective as the other options.

Don't know if zig-zag works on the LS-3, anybody got performance
feedback on that?

Ours was fitted by the previous owner. I doubt it has any benefit.

Thanks


Ian

This sounds tricky, I must have a good look at a 27.
I am not sure how to
get mylar to cover the gap but not bend when the surfaces
are moved.

Short strips of mylar are secured to the control surface
in order to cover the hinge gaps, then the wing mounted
mylar rubs on the control mylar......look at a 27.

Maybe we should just use hinge tape on its own. Lots
of work to replace
every season, but possibly as effective as the other
options.

Teflon gap tape will last for several years. Be sure
to install with control in fully deflected position
+ a tad of a dimple into the hinge line or shrinkage
will restrict the movement.
Cheers,
JJ

Ray Lovinggood wrote:
I'm following this thread with interest. I've had
problems with mylar not sticking to the double sided
tape. The tape sticks quite well to the gel coat,
but the mylar doesn't want to stay stuck to the double
sided tape.

I've been accused of having an engine on my glider
as I pass over the airfield. But it's just that damned
loose mylar buzzing.

Of course, the hardest part of dealing with mylar is
getting the old stuff completely removed. The next
hardest is figuring out how to insure the mylar stays
stuck to the double sided tape.

I bought mylar from the sailplane dealer with the adhesive already on
the mylar, hoping the people supplying the product knew what they were
doing. So far, so good, after 6 months and 30 or so flights in a variety
of conditions - dry, humid, cold, hot.

--
Eric Greenwell - Washington State, USA
* Change "netto" to "net" to email me directly
* "Transponders in Sailplanes" http://tinyurl.com/y739x4
* "A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Don't know if zig-zag works on the LS-3, anybody got
performance feedback on that?
JJ

Sorry for the late response; just getting caught up after a long trip.

My experience with turbulator tape on my LS-3 back in the mid 80s was
favorable. Testing against XX's Ventus seemed to indicate improvement.
I tried several locations before finding one that worked (no, I don't
recall what the % of chord was). This was pre-mylar, with tape as the
external seal on the flaperon plus the internal teflon-coated fabric
seal.

Chip Bearden
ASW 24 "JB"
USA