ASG-29/ASW-27 wing refinish

[[email protected]]

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).

[Bob Kuykendall]

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...

[Mike the Strike]

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).

[[email protected]]

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]

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"

[HL Falbaum]

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"
>

[Eric Greenwell]

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

[Roger[_5_]]

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).

[Doug Haluza]

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).

[Stewart Kissel]

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?

[Udo]

Here is my hypothesis.
The SH lays up there spar cap into the wing skin, versus the
AS factory, which built there spar complete and separate from
the wing structure.
This requires a different joining technique and application
of epoxy slurry. In the later case the spar is set into the lower wing
skin in a controlled fashion, hence using less epoxy.
Before the top skin is set into place,
dams out of beaded foam are built, they are a bid higher then the
insight
of the skin when joint. The spar cap with the dams in place is now
filled
with an epoxy mixture. The shape of the mixture has a little inverted
V shape like a roof but shallower. This allows for the epoxy to make
contact in the centre first and pushes it out ward. At the same time
the foam dam gets pushed out of the way to allow for a bead to be form.
Due to the tolerances between the height of the spar cap and
the inner wing skin, there is more epoxy used then at the bottom joint,

hence more shrinking of the top skin occurs.

That does not explain the fact I did not have shrinkage on my
ASW24 wing in 16 years, unless, I venture to say, after 1999 a lot of
experience workers retired. I must assume that the tolerance were
also better before that time and better epoxies were used.
There is always a drive to keep the cost down.
I always like the idea of building the spar separate.
They got it right once they should get it right again.
Udo

Stewart Kissel wrote:
> 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?

[Greg Arnold]

Udo:

The DG website has a diagram of 4 different spar construction methods:

http://www.dg-flugzeugbau.de/holm-aufbau-e.html

Do I understand you to say that SH uses #3, and AS uses #1? DG says
that they use #4, so that would mean that each of the major
manufacturers uses a different method.



Udo wrote:
> Here is my hypothesis.
> The SH lays up there spar cap into the wing skin, versus the
> AS factory, which built there spar complete and separate from
> the wing structure.
> This requires a different joining technique and application
> of epoxy slurry. In the later case the spar is set into the lower wing
> skin in a controlled fashion, hence using less epoxy.
> Before the top skin is set into place,
> dams out of beaded foam are built, they are a bid higher then the
> insight
> of the skin when joint. The spar cap with the dams in place is now
> filled
> with an epoxy mixture. The shape of the mixture has a little inverted
> V shape like a roof but shallower. This allows for the epoxy to make
> contact in the centre first and pushes it out ward. At the same time
> the foam dam gets pushed out of the way to allow for a bead to be form.
> Due to the tolerances between the height of the spar cap and
> the inner wing skin, there is more epoxy used then at the bottom joint,
>
> hence more shrinking of the top skin occurs.
>
>

[Udo]

Greg ,
# 3 is a simplified version of the SH approach. The web has a pocket
along the spar
in which the web slides upon closure.The total amount of epoxy is
reduced,
and the shrinking acts in a different direction, hence less shrinking
in the vertical.
In any case that is my take on it.
http://www.alexander-schleicher.de/englisch/e_main.htm
Udo

Greg Arnold wrote:
> Udo:
>
> The DG website has a diagram of 4 different spar construction methods:
>
> http://www.dg-flugzeugbau.de/holm-aufbau-e.html
>
> Do I understand you to say that SH uses #3, and AS uses #1? DG says
> that they use #4, so that would mean that each of the major
> manufacturers uses a different method.
>
>
>
> Udo wrote:
> > Here is my hypothesis.
> > The SH lays up there spar cap into the wing skin, versus the
> > AS factory, which built there spar complete and separate from
> > the wing structure.
> > This requires a different joining technique and application
> > of epoxy slurry. In the later case the spar is set into the lower wing
> > skin in a controlled fashion, hence using less epoxy.
> > Before the top skin is set into place,
> > dams out of beaded foam are built, they are a bid higher then the
> > insight
> > of the skin when joint. The spar cap with the dams in place is now
> > filled
> > with an epoxy mixture. The shape of the mixture has a little inverted
> > V shape like a roof but shallower. This allows for the epoxy to make
> > contact in the centre first and pushes it out ward. At the same time
> > the foam dam gets pushed out of the way to allow for a bead to be form.
> > Due to the tolerances between the height of the spar cap and
> > the inner wing skin, there is more epoxy used then at the bottom joint,
> >
> > hence more shrinking of the top skin occurs.
> >
> >

[Roger[_5_]]

I sure am impressed with DG as a company! Many safety products, GREAT
web site, newsletters...etc. No, I do not own a DG glider, nor do I
have one on order. However, as soon as they make a competive glider
that I fit into (i.e., LS 10 with new cockpit I will buy it!). I just
wish the other manufacturers would make NOAH's, something to keep
spoilers from opening, and stall warning like DG does.

On Nov 5, 6:43 pm, Greg Arnold > wrote:
> Udo:
>
> The DG website has a diagram of 4 different spar construction methods:
>
> http://www.dg-flugzeugbau.de/holm-aufbau-e.html
>
> Do I understand you to say that SH uses #3, and AS uses #1? DG says
> that they use #4, so that would mean that each of the major
> manufacturers uses a different method.
>
> Udo wrote:
> > Here is my hypothesis.
> > The SH lays up there spar cap into the wing skin, versus the
> > AS factory, which built there spar complete and separate from
> > the wing structure.
> > This requires a different joining technique and application
> > of epoxy slurry. In the later case the spar is set into the lower wing
> > skin in a controlled fashion, hence using less epoxy.
> > Before the top skin is set into place,
> > dams out of beaded foam are built, they are a bid higher then the
> > insight
> > of the skin when joint. The spar cap with the dams in place is now
> > filled
> > with an epoxy mixture. The shape of the mixture has a little inverted
> > V shape like a roof but shallower. This allows for the epoxy to make
> > contact in the centre first and pushes it out ward. At the same time
> > the foam dam gets pushed out of the way to allow for a bead to be form.
> > Due to the tolerances between the height of the spar cap and
> > the inner wing skin, there is more epoxy used then at the bottom joint,
>
> > hence more shrinking of the top skin occurs.

[Eric Greenwell]

Roger wrote:
> I sure am impressed with DG as a company! Many safety products, GREAT
> web site, newsletters...etc. No, I do not own a DG glider, nor do I
> have one on order. However, as soon as they make a competive glider
> that I fit into (i.e., LS 10 with new cockpit I will buy it!). I just
> wish the other manufacturers would make NOAH's, something to keep
> spoilers from opening, and stall warning like DG does.

Schleicher does some nice things, too:

Starting with the ASW 27, the caps on unlocked spoilers tip up in back,
preventing the airflow from sucking open the spoilers.

They lead the way to safer cockpit construction, and still have a more
crash resistant cockpit than the DG models. For me, that is more
important than the better visibility the lower sidewalls of the DG
provide, and the availability of the NOAH system. My belief is I will be
more likely to crash into the ground than have a mid-air collision where
G loads pin me inside the glider, or to avoid the collision because of
the better visibility.

Ever since the ASW 20, their flapped gliders have had a landing flap
position that puts the flaps at 40 degrees positive, while raisig the
ailerons to a slight negative angle. This gives a high drag, high lift
configuration with no tendency to stall the tips, allowing a steeper,
slower approach and landing than gliders where the landing flap is more
like 20 degrees.

I do like the idea of DG's stall warning, and hope owners with it will
report on it's usefulness. Their web site is very good, and I visit it
more often than Schleicher's.

--
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

[Gary Evans[_1_]]

At 03:54 08 November 2006, Eric Greenwell wrote:
>Roger wrote:
>> I sure am impressed with DG as a company! Many safety
>>products, GREAT
>> web site, newsletters...etc. No, I do not own a DG
>>glider, nor do I
>> have one on order. However, as soon as they make
>>a competive glider
>> that I fit into (i.e., LS 10 with new cockpit I will
>>buy it!). I just
>> wish the other manufacturers would make NOAH's, something
>>to keep
>> spoilers from opening, and stall warning like DG does.
>
>Schleicher does some nice things, too:
>
>Starting with the ASW 27, the caps on unlocked spoilers
>tip up in back,
>preventing the airflow from sucking open the spoilers.
>
>They lead the way to safer cockpit construction, and
>still have a more
>crash resistant cockpit than the DG models. For me,
>that is more
>important than the better visibility the lower sidewalls
>of the DG
>provide, and the availability of the NOAH system. My
>belief is I will be
>more likely to crash into the ground than have a mid-air
>collision where
>G loads pin me inside the glider, or to avoid the collision
>because of
>the better visibility.
>
>Ever since the ASW 20, their flapped gliders have had
>a landing flap
>position that puts the flaps at 40 degrees positive,
>while raisig the
>ailerons to a slight negative angle. This gives a high
>drag, high lift
>configuration with no tendency to stall the tips, allowing
>a steeper,
>slower approach and landing than gliders where the
>landing flap is more
>like 20 degrees.
>
>I do like the idea of DG's stall warning, and hope
>owners with it will
>report on it's usefulness. Their web site is very good,
>and I visit it
>more often than Schleicher's.
>
>--
>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
>

In your many trips to our DG web site you may have
missed this section that deals with their extensive
work on a better safety cockpit.
http://www.dg-flugzeugbau.de/index-e.html
While other manufactures have been content with building
what looks strong enough DG has actually participated
in crash testing. As a result of this testing they
offer the consummate safety cockpit as an option on
the 800 series and as standard on the 1000.

If you counting on higher frame rails for protection
you may also want to read this.
http://www.dg-flugzeugbau.de/index-e.html

[Gary Evans[_1_]]

At 13:42 08 November 2006, Gary Evans wrote:
>At 03:54 08 November 2006, Eric Greenwell wrote:
>>Roger wrote:
>>> I sure am impressed with DG as a company! Many safety
>>>products, GREAT
>>> web site, newsletters...etc. No, I do not own a DG
>>>glider, nor do I
>>> have one on order. However, as soon as they make
>>>a competive glider
>>> that I fit into (i.e., LS 10 with new cockpit I will
>>>buy it!). I just
>>> wish the other manufacturers would make NOAH's, something
>>>to keep
>>> spoilers from opening, and stall warning like DG does.
>>
>>Schleicher does some nice things, too:
>>
>>Starting with the ASW 27, the caps on unlocked spoilers
>>tip up in back,
>>preventing the airflow from sucking open the spoilers.
>>
>>They lead the way to safer cockpit construction, and
>>still have a more
>>crash resistant cockpit than the DG models. For me,
>>that is more
>>important than the better visibility the lower sidewalls
>>of the DG
>>provide, and the availability of the NOAH system. My
>>belief is I will be
>>more likely to crash into the ground than have a mid-air
>>collision where
>>G loads pin me inside the glider, or to avoid the collision
>>because of
>>the better visibility.
>>
>>Ever since the ASW 20, their flapped gliders have had
>>a landing flap
>>position that puts the flaps at 40 degrees positive,
>>while raisig the
>>ailerons to a slight negative angle. This gives a high
>>drag, high lift
>>configuration with no tendency to stall the tips, allowing
>>a steeper,
>>slower approach and landing than gliders where the
>>landing flap is more
>>like 20 degrees.
>>
>>I do like the idea of DG's stall warning, and hope
>>owners with it will
>>report on it's usefulness. Their web site is very good,
>>and I visit it
>>more often than Schleicher's.
>>
>>--
>>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
>>
>
>In your many trips to our DG web site you may have
>missed this section that deals with their extensive
>work on a better safety cockpit.
>http://www.dg-flugzeugbau.de/index-e.html
>While other manufactures have been content with building
>what looks strong enough DG has actually participated
>in crash testing. As a result of this testing they
>offer the consummate safety cockpit as an option on
>the 800 series and as standard on the 1000.
>
>If you counting on higher frame rails for protection
>you may also want to read this.
>http://www.dg-flugzeugbau.de/index-e.html
>
>
>
>
>
>
>

Hmmm, sorry for some reason my original links only
take you to the DG web site opening page. If I paste
the link it works but it doesn't from clicking in the
post. Anyone know what I'm doing wrong?
From the opening page click on DG-808 and under DG-808
General find 'The Consummate Safety Cockpit'.

[01-- Zero One]

Gary,



Depending on your newsreader and computer, at, for instance, the DG808
page, hover your mouse over the "The Consummate Safety Cockpit" and
right-click or option-click the link. Choose "Copy Link Location" or
some such from the options. Then you can paste that link into the
email.



Larry

"01" USA









> >
> >
>
> Hmmm, sorry for some reason my original links only
> take you to the DG web site opening page. If I paste
> the link it works but it doesn't from clicking in the
> post. Anyone know what I'm doing wrong?
> From the opening page click on DG-808 and under DG-808
> General find 'The Consummate Safety Cockpit'.

[Glidingstuff]

The Safety cockpit is now standard in the DG 808 as well. They where
amazed that not many new owners where taking the safety cockpit option.
One reason given ( apart from the cost ) was the width of the seatpan
was narrower when it was installed.They improved the design and also
made it part of the base glider price.

So same sized cockpit as before and stronger to boot.

Paul

[Eric Greenwell]

Gary Evans wrote:

> While other manufactures have been content with building
> what looks strong enough DG has actually participated
> in crash testing.

This is not correct. Gerhard Waibel won an OSTIV prize for his work in
cockpit safety about 20 years ago. Gerhard's ideas, and the ASW 24
cockpit (the first of the really crashworthy cockpits) was based on
extensive testing by a group at MIT, and others. In the years since
then, Schleicher continues to monitor the performance of their designs
by examining their gliders that are involved in crashes, either when
they are brought to their shop for repair, or using pictures sent to
them by the mechanics repairing the glider elsewhere. An advantage of
this approach is it shows what happens in an actual crash.

> As a result of this testing they
> offer the consummate safety cockpit as an option on
> the 800 series and as standard on the 1000.

I have been impressed with DG's improvements in safety over the years,
but their single seaters cockpits still do not match what Schleicher has
done. This page on the DG website shows that this view is shared by
others (go to the "Safety Cockpit" row):

http://www.dgflugzeugbau.de/ash-dg-ventus-e.html

These differences are not surprising. The low sides and open nose of the
DG single seater cockpit pose a difficult engineering problem for the
designer, compared to the greater enclosure of the Schleicher cockpits.

I'm not suggesting that the DG cockpit is unsafe or inadequate, but only
that it does not match what Schleicher has done. A prospective owner
should consider the value of that protection along with the other
features of the gliders he is considering; for example, the lower sides
of the DG cockpit (particularly if the NOAH option is selected) should
make baling out easier than from a Schleicher cockpit.

>
> If you counting on higher frame rails for protection
> you may also want to read this.
> http://www.dg-flugzeugbau.de/index-e.html

I was unable to find this reference, but I would like to read it.

--
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

[Markus[_1_]]

The page he is refering to can be found here:

http://www.dg-flugzeugbau.de/sicherheitscockpit-e.html

Hope this helps,

Markus

Eric Greenwell wrote:
> Gary Evans wrote:
>
> > While other manufactures have been content with building
> > what looks strong enough DG has actually participated
> > in crash testing.
>
> This is not correct. Gerhard Waibel won an OSTIV prize for his work in
> cockpit safety about 20 years ago. Gerhard's ideas, and the ASW 24
> cockpit (the first of the really crashworthy cockpits) was based on
> extensive testing by a group at MIT, and others. In the years since
> then, Schleicher continues to monitor the performance of their designs
> by examining their gliders that are involved in crashes, either when
> they are brought to their shop for repair, or using pictures sent to
> them by the mechanics repairing the glider elsewhere. An advantage of
> this approach is it shows what happens in an actual crash.
>
> > As a result of this testing they
> > offer the consummate safety cockpit as an option on
> > the 800 series and as standard on the 1000.
>
> I have been impressed with DG's improvements in safety over the years,
> but their single seaters cockpits still do not match what Schleicher has
> done. This page on the DG website shows that this view is shared by
> others (go to the "Safety Cockpit" row):
>
> http://www.dgflugzeugbau.de/ash-dg-ventus-e.html
>
> These differences are not surprising. The low sides and open nose of the
> DG single seater cockpit pose a difficult engineering problem for the
> designer, compared to the greater enclosure of the Schleicher cockpits.
>
> I'm not suggesting that the DG cockpit is unsafe or inadequate, but only
> that it does not match what Schleicher has done. A prospective owner
> should consider the value of that protection along with the other
> features of the gliders he is considering; for example, the lower sides
> of the DG cockpit (particularly if the NOAH option is selected) should
> make baling out easier than from a Schleicher cockpit.
>
> >
> > If you counting on higher frame rails for protection
> > you may also want to read this.
> > http://www.dg-flugzeugbau.de/index-e.html
>
> I was unable to find this reference, but I would like to read it.
>
> --
> 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

[Gary Evans[_1_]]

At 16:12 11 November 2006, Eric Greenwell wrote:
>Gary Evans wrote:
>
>> While other manufactures have been content with building
>> what looks strong enough DG has actually participated
>> in crash testing.
>
>This is not correct. Gerhard Waibel won an OSTIV prize
>for his work in
>cockpit safety about 20 years ago.

20 years ago, wasn't Chicago still a swamp? A lot has
happened in the past 20 years. The crash tests I referenced
that DG participated in were done in 1994. This is
the correct link.

http://www.dg-flugzeugbau.de/sicherheitscockpit-e.html

Gerhard's ideas, and the ASW 24
>cockpit (the first of the really crashworthy cockpits)
>was based on
>extensive testing by a group at MIT,

DG claims that the DG100 from the late 70's was the
first to use a double wall construction that is commonly
referred to as a safety cockpit. Was the 24 done before
or after that advancement?

> and others. In the years since
>then, Schleicher continues to monitor the performance
>of their designs
>by examining their gliders that are involved in crashes,
>either when
>they are brought to their shop for repair, or using
>pictures sent to
>them by the mechanics repairing the glider elsewhere.
>An advantage of
>this approach is it shows what happens in an actual
>crash.

I suppose looking at the damage after the fact is worth
doing if that’s all you have but actual crash testing
will reveal more information as explained in the previously
referenced test. The car manufactures don't use crash
testing just because if costs a lot of money. They
gave up just looking at a crashed car a long time ago.
It is however expensive but what is safety worth?

>
>> As a result of this testing they
>> offer the consummate safety cockpit as an option on
>> the 800 series and as standard on the 1000.
>
>I have been impressed with DG's improvements in safety
>over the years,
>but their single seaters cockpits still do not match
>what Schleicher has
>done.

That could be termed a matter of opinion unless there
is factual data available to prove that advantage.
If so post it up.

>This page on the DG website shows that this view is
>shared by
>others (go to the 'Safety Cockpit' row):

What your referring to is the old original safety cockpit.
As I stated before the term safety cockpit refers to
the double wall construction but DG has gone way beyond
that as a result of the crash test data. What they
now offer is termed a Consummate safety cockpit, which
is described in the article.

>
>http://www.dgflugzeugbau.de/ash-dg-ventus-e.html
>
>These differences are not surprising. The low sides
>and open nose of the
>DG single seater cockpit pose a difficult engineering
>problem for the
>designer, compared to the greater enclosure of the
>Schleicher cockpits.
>
>I'm not suggesting that the DG cockpit is unsafe or
>inadequate, but only
>that it does not match what Schleicher has done. A
>prospective owner
>should consider the value of that protection along
>with the other
>features of the gliders he is considering; for example,
>the lower sides
>of the DG cockpit (particularly if the NOAH option
>is selected) should
>make baling out easier than from a Schleicher cockpit.

I almost forgot NOAH another big safety step forward.
Wonder who developed that? It wasn't DG was it? I think
DG may have made the design available to other manufactures
so it may be possible for the older guys to actually
be able to get out of the high 26 side rails in an
emergency. Maybe not though as some seem to believe
that whatever Schleicher has done is good enough and
anything more is, to steal anothers line, unnecessary
like the Lexis auto park option.

>
>>
>> If you counting on higher frame rails for protection
>> you may also want to read this.
>> http://www.dg-flugzeugbau.de/index-e.html
>
>I was unable to find this reference, but I would like
>to read it.

Here it is.

http://www.dg-flugzeugbau.de/cockpit-e.html

The point is that in a crash there is a G force beyond
which survival is unlikely due to the lack of a crush
zone. When the cockpit has been strengthened to the
point it will not deform and kill the occupant below
that force then design improvements are best turned
to what else can be done to prevent fatalities(like
the better visibility brought by DG style canopies
and the NOAH system) rather than just adding more strength
to the cockpit. DG's new Consummate safety cockpit,
which another poster advised is now standard equipment
on the 800/808 and 1000, was designed to prevent the
temporary cockpit deformation that occured during crash
testing. If DG had only been following Schleicher's
method of looking at damage after the fact this safety
advantage would never have occurred.

>
>--
>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

[Eric Greenwell]

Gary Evans wrote:
> At 16:12 11 November 2006, Eric Greenwell wrote:
>> Gary Evans wrote:
>>
>>> While other manufactures have been content with building
>>> what looks strong enough DG has actually participated
>>> in crash testing.
>> This is not correct. Gerhard Waibel won an OSTIV prize
>> for his work in
>> cockpit safety about 20 years ago.
>
> 20 years ago, wasn't Chicago still a swamp? A lot has
> happened in the past 20 years.

That was to support my claim Schleicher lead the way to a significant
improvement in cockpit crash protection. Of course, Schleicher's work
did not stop with the prize or the 24.

snip

> DG claims that the DG100 from the late 70's was the
> first to use a double wall construction that is commonly
> referred to as a safety cockpit. Was the 24 done before
> or after that advancement?

The 24 first appeared 1988. It uses a very strong, straight, and stiff
cockpit sill to maintain the integrity of the cockpit near the pilot and
to absorb the loads from the fuselage and wings. The cockpit itself is
single wall construction of at least three materials (some carbon, but
primarily fiberglass and synthetic fabrics, including some hybrid
fabrics) selected and fabricated to crush progressively to absorb energy
in a controlled fashion. As I recall Waibel's explanation, the strong
sill and mixed materials made it easier to achieve the desired crash
protection than a double-walled cockpit.

For pictures and more explanation, unfortunately only in German, go to
the Schleicher website:

http://tinyurl.com/y3pk9m
http://tinyurl.com/tufw6

Google language tools did an almost adequate job of translating.

snip

>
>> This page on the DG website shows that this view is
>> shared by
>> others (go to the 'Safety Cockpit' row):
>
> What your referring to is the old original safety cockpit.
> As I stated before the term safety cockpit refers to
> the double wall construction but DG has gone way beyond
> that as a result of the crash test data.

The table I referenced at

http://www.dgflugzeugbau.de/ash-dg-ventus-e.html

is labeled "ASH26E / DG-808C / Ventus 2cM - The Differences", so I
believe it refers to current production.

> What they
> now offer is termed a Consummate safety cockpit, which
> is described in the article.
>
>> http://www.dgflugzeugbau.de/ash-dg-ventus-e.html

Included in this article is a reference to another article
(http://www.dgflugzeugbau.de/sicherheitscockpit-e.html), which includes
this remark:

"The cockpit sides [of the other gliders] are higher than the DG
sailplanes. The large canopy is one of our "Trade Marks" and leads to,
we must admit, slightly less strength than the higher cockpits."

And from another article: "The more enclosed cockpit of the same
construction can certainly absorb a higher impact energy than one with a
large canopy."

So, I conclude the table I referred to accurately reflects DG's opinion.

snip

>>> If you counting on higher frame rails for protection
>>> you may also want to read this.
>>> http://www.dg-flugzeugbau.de/index-e.html
>> I was unable to find this reference, but I would like
>> to read it.
>
> Here it is.
>
> http://www.dg-flugzeugbau.de/cockpit-e.html
>
> The point is that in a crash there is a G force beyond
> which survival is unlikely due to the lack of a crush
> zone.

Quoting from the article you reference:

"The more enclosed cockpit of the same construction can certainly absorb
a higher impact energy than one with a large canopy."

That's all I'm trying to point out.

Prospective owners have to determine for themselves what particular
features of each glider are important to them and their situation. My
determination was, for me, a crash was more likely than a mid-air
collision where G forces pinned me in the cockpit, and that the extra
visibility afforded by the DG cockpit would not significantly reduce my
chances of a mid-air collision. So, for this safety aspect of the
glider, I prefer Schleicher's solution.

If the particular safety aspects of a glider are important to a
prospective owner, I urge you to talk directly to the designers (DG,
Schleicher, Schempp-Hirth, etc). I have found them to generally be
candid in person, pleased to speak to a pilot that is interested in
safety, and eager to describe how they chose their particular solution
to a difficult problem. A good place to meet them is at the SSA
conventions, but I also recommend getting on a plane and visiting the
factory. Flights are available in the $500 range, a cheap price for a
pilot contemplating a new glider.

Or, you could start with a phone call!

--
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

[[email protected]]

> If the particular safety aspects of a glider are important to a
> prospective owner, I urge you to talk directly to the designers (DG,
> Schleicher, Schempp-Hirth, etc). I have found them to generally be
> candid in person, pleased to speak to a pilot that is interested in
> safety, and eager to describe how they chose their particular solution
> to a difficult problem. A good place to meet them is at the SSA
> conventions, but I also recommend getting on a plane and visiting the
> factory. Flights are available in the $500 range, a cheap price for a
> pilot contemplating a new glider.
>
> Or, you could start with a phone call!

Eric,

I, too, had a great experience corresponding directly with the
factory...and with Gerhard Waibel himself when I was seeking
information about a new ASW 24 15 years ago. I would also encourage
anyone who has a question to do the same.

For example, I had a number of questions about the canopy wire
deflector bar that was then mandatory in Holland (and which I ordered
and still use): how did it affect visibility, would it stop a telephone
or powerline strike, was it a potential hazard to the pilot's head in a
crash, etc.? Herr Waibel answered each question in a fax and mailed me
a drawing of the bar with the suggestion to sit in a '24 after taping
up the canopy with black tape to simulate the bar positions to check
visibility. I cannot conceive of an American manufacturer being as
candid and straightforward and refreshingly free of "caution: flying
may be hazardous to your health" warnings. Similarly, anyone reading
the DG site must also be amazed at their candor on the subject of
safety.

FWIW, I "voted with my wallet" and paid a price premium for my '24 over
the other brands even though they were all said to have equivalent
performance simply because of the enhanced safety I thought the '24
offered at the time. That it's turned out to be a wonderful glider that
is still fully competitive is a bonus.

Chip Bearden
ASW 24 "JB"