ASG-29/ASW-27 wing refinish

I have heard that the new ASG-29 and many of the ASW-27's have had a
noticeable spar cap shrinkage problem. I am looking for an unbiassed
discussion of this problem, the extent of the problem and possible
solutions (other than a wing refinish).

Earlier, wrote:

I have heard that the new ASG-29 ... have had a
noticeable spar cap shrinkage problem....

The last time I saw pictures of a bare ASG-29 spar, it had shrunk
considerably since takeoff...

One of the reasons I switched to Schemmp-Hirth from Schleicher was the
latter's recent problems with wings, especially the ASW-27, which was
my intended new ship. I have several colleagues with ASW-27s of both
old and newer production and they all have suffered from this problem
to a greater or lesser degree. I know of a couple that have needed two
refinishes since new, although this seems to be less common. I've seen
ASW-27 wings that look really ugly and that are well beyond the point
that performance is compromised.

There is no solution other than to refinish the wings, unless you're
happy to pay $100,000 plus for a ship that performs like an old ASW-20.

The ASW-28 does not seem to have suffered from this problems from the
few examples I have seen.

I have no personal knowledge of the 29, but plenty of rumors, which
I'll leave to others.

Mike

On Nov 2, 3:15 pm, wrote:
I have heard that the new ASG-29 and many of the ASW-27's have had a
noticeable spar cap shrinkage problem. I am looking for an unbiassed
discussion of this problem, the extent of the problem and possible
solutions (other than a wing refinish).

Mike the Strike wrote:
One of the reasons I switched to Schemmp-Hirth from Schleicher was the
latter's recent problems with wings, especially the ASW-27, which was
my intended new ship.

Any thoughts on why this is happening? Based on my experience and that
of others, the ASW 24 has one of the most stable composite wings
around. I hope to get around to sanding mine this winter but it's still
in great shape--even under the dial gauge--and it's nearly 15 years
old. I'm told the '26 is similar. Yet the '27 and now the '29 are said
to be much less so. Did changing to hard tanks from ballast bags
trigger this? Different wing design? Different materials? Is it
happening to every glider out there or just intermittantly?

Chip Bearden
ASW 24 "JB"

This is just a WAG............but from reading the Specs on the -27
from Schleichers website, they mention making use of new materials. One
notably is the Carbon/Polyethelyne hybrid. I've used "this" material
and find it noticably less robust than regular carbon cloth.

Brad


wrote:
Mike the Strike wrote:
One of the reasons I switched to Schemmp-Hirth from Schleicher was the
latter's recent problems with wings, especially the ASW-27, which was
my intended new ship.

Any thoughts on why this is happening? Based on my experience and that
of others, the ASW 24 has one of the most stable composite wings
around. I hope to get around to sanding mine this winter but it's still
in great shape--even under the dial gauge--and it's nearly 15 years
old. I'm told the '26 is similar. Yet the '27 and now the '29 are said
to be much less so. Did changing to hard tanks from ballast bags
trigger this? Different wing design? Different materials? Is it
happening to every glider out there or just intermittantly?

Chip Bearden
ASW 24 "JB"

I know of '27s with waterbags that have had significant problems with this.
My '27 sn 27119 is the first production "B" model---I got it new in Dec
1999. It has flown mostly in contests with water and I have not flown it but
1 hr in the last year. Until then it had 249 hr. It has lived in my air
conditioned basement in its trailer its whole life--certainly "archival
storage".

Last year I measured the wings--out of interest, after talking to other '27
owners. Mine measures 0.002" or less everywhere except one small section,
about 6" long spanwise, just outboard of the right spoiler box, which was
0.003-0.004".

It has been tied out a few nites at contests in very benign weather.

I have only flown 120 kt or more a few minutes, and never over 135.

I don't know if any of this makes any difference, just adding to the data
pool.

--
Hartley Falbaum
ASW27B "KF"
wrote in message
oups.com...
Mike the Strike wrote:
One of the reasons I switched to Schemmp-Hirth from Schleicher was the
latter's recent problems with wings, especially the ASW-27, which was
my intended new ship.

Any thoughts on why this is happening? Based on my experience and that
of others, the ASW 24 has one of the most stable composite wings
around. I hope to get around to sanding mine this winter but it's still
in great shape--even under the dial gauge--and it's nearly 15 years
old. I'm told the '26 is similar. Yet the '27 and now the '29 are said
to be much less so. Did changing to hard tanks from ballast bags
trigger this? Different wing design? Different materials? Is it
happening to every glider out there or just intermittantly?

Chip Bearden
ASW 24 "JB"

Brad wrote:
This is just a WAG............but from reading the Specs on the -27
from Schleichers website, they mention making use of new materials. One
notably is the Carbon/Polyethelyne hybrid. I've used "this" material
and find it noticably less robust than regular carbon cloth.

I believe this material is used in the cockpit area (where pure carbon
is not a good choice), but don't have the reference for it. It would be
easy enough to ask the dealer about, or someone that has repaired ASW 27
wing.

--
Eric Greenwell - Washington State, USA
Change "netto" to "net" to email me directly

"Transponders in Sailplanes" on the Soaring Safety Foundation website
www.soaringsafety.org/prevention/articles.html

"A Guide to Self-launching Sailplane Operation" at www.motorglider.org

Anyone know what the factory is doing to correct this problem? Has it
affected the buying decisions of those who bought ASW-27's or were
thinking of buying an ASG-29?

On Nov 2, 3:22 pm, "Mike the Strike" wrote:
One of the reasons I switched to Schemmp-Hirth from Schleicher was the
latter's recent problems with wings, especially the ASW-27, which was
my intended new ship. I have several colleagues with ASW-27s of both
old and newer production and they all have suffered from this problem
to a greater or lesser degree. I know of a couple that have needed two
refinishes since new, although this seems to be less common. I've seen
ASW-27 wings that look really ugly and that are well beyond the point
that performance is compromised.

There is no solution other than to refinish the wings, unless you're
happy to pay $100,000 plus for a ship that performs like an old ASW-20.

The ASW-28 does not seem to have suffered from this problems from the
few examples I have seen.

I have no personal knowledge of the 29, but plenty of rumors, which
I'll leave to others.

Mike

On Nov 2, 3:15 pm, wrote:

I have heard that the new ASG-29 and many of the ASW-27's have had a
noticeable spar cap shrinkage problem. I am looking for an unbiassed
discussion of this problem, the extent of the problem and possible
solutions (other than a wing refinish).

I was at the Schleicher factory last week, and asked about this. They
did purchase new higher temperature curing ovens to try to solve this
problem, but it has not helped much. It seems that it just has to run
its course over time. They did say that the shrinkage seems to be a
one-time thing, and it is complete after about 4 years. So if you wait
until then to refinish, you should not have to do it again.

Roger wrote:
Anyone know what the factory is doing to correct this problem? Has it
affected the buying decisions of those who bought ASW-27's or were
thinking of buying an ASG-29?

On Nov 2, 3:22 pm, "Mike the Strike" wrote:
One of the reasons I switched to Schemmp-Hirth from Schleicher was the
latter's recent problems with wings, especially the ASW-27, which was
my intended new ship. I have several colleagues with ASW-27s of both
old and newer production and they all have suffered from this problem
to a greater or lesser degree. I know of a couple that have needed two
refinishes since new, although this seems to be less common. I've seen
ASW-27 wings that look really ugly and that are well beyond the point
that performance is compromised.

There is no solution other than to refinish the wings, unless you're
happy to pay $100,000 plus for a ship that performs like an old ASW-20.

The ASW-28 does not seem to have suffered from this problems from the
few examples I have seen.

I have no personal knowledge of the 29, but plenty of rumors, which
I'll leave to others.

Mike

On Nov 2, 3:15 pm, wrote:

I have heard that the new ASG-29 and many of the ASW-27's have had a
noticeable spar cap shrinkage problem. I am looking for an unbiassed
discussion of this problem, the extent of the problem and possible
solutions (other than a wing refinish).

At 20:31 05 November 2006, Doug Haluza wrote:
I was at the Schleicher factory last week, and asked
about this. They did purchase new higher temperature
curing ovens to try to solve this problem, but it has
not helped much. It seems that it just has to run its
course over time. They did say that the shrinkage seems
to be a one-time thing, and it is complete after about
4 years.

Hmmm, I take it they have examined the construction
of this wing vs other wings that don't shrink and get
spar bumps. Far be it for me to question Teutonic
marketing rationale...but spending $100k+ on a glider
that is going to have its performance suffer as the
wing shrinks, then get to spend another $20k+ on reprofile
and refinish....am I missing something here?