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DG-300/303 owners...



 
 
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  #1  
Old April 19th 07, 02:31 AM posted to rec.aviation.soaring
Bob Kuykendall
external usenet poster
 
Posts: 1,345
Default DG-300/303 owners...

Earlier, Steve Davis wrote:
You have described a $20K repair on a product
which might not be worth $20K right after the
repair.


I assume that you're replying to my post of 1:39 today - though it
doesn't appear so in the Google view of r.a.s. Please let me know if
otherwise.

Yes, in the right hands that might be a $20K repair - I know a lot of
folks who can manage that, and I'm sure they're salivating over the
fallout of this situation. But if there's lots of them to do, a
relatively modest investment in tooling can easily cut the costs down
to around a third of that, possibly less. For example, it's virtually
a no-brainer to build a scarf-router to precisely mill out the
required chunk of wing spar. And the pre-fabbed skin repair panels are
easy, the layup is dirt simple and takes about an hour to do four;
with cure cycles you could probably yield 8 per day from a single wing
mold set.

I remember when the G103 team was here fixing spar spigots. There was
a lot of hand-wringing and gnashing of teeth around a repair that
requires hacking huge chunks out of the spar stub. But in the end,
they just lined them up and churned them out, and when they were done
they all fit fine, looked like new, and no problems since.

And, yeah, if it was some dogmeat glider only worth $20K last month,
this might all be moot. But the fact is that DG300 have typically
commanded around twice that, sometimes much more for young and well-
equipped examples.

My suggestion for the rods was to try
a $2K or less repair which would allow current
users the peace of mind to continue flying their
gliders.
My understanding of the DG 300 is that
it has a very stiff wing, presumably even with
undulations in the spar caps.


A for effort, but I think that the modulii mismatch between the
Graphlite and the fiberglass is probably too big to make it work
practically, even if the DG is reputed to be "stiff." The axiom of
such things is that as much as you might prefer it otherwise, stresses
are transferred not to the strongest parts but to the stiffest. If you
put any Graphlite into the spar, its stiffer modulus will make it try
to take on all of the stress, or fail its glue bond trying. So you'd
basically have to put in enough Graphlite to take all of the load, and
scarf it in shallow enough to yield enough bond area to get all the
load out of the fiberglass into it. And when you're done with that,
the surgery is likely no less traumatic than if you'd just done a
repair-manual scarf.

Another thing to consider is that if you execute an innovative repair,
you are probably on the hook to validate it with test it to
destruction, or at least to the somewhat-draconian EASA standard of
6.3*1.725. Whereas with a textbook repair, you may be justified in
only testing to design load or not testing at all.

Since Graphlite
ships in two and three ft. dia. spools it must be
plenty flexible and it is far stronger than the
equivalent amount of fiberglass rovings.


Yes, that's the way we've been buying Graphlite ribbon (not rod) for
the HP-24 and Glidair projects. Its flexibility is relative, though;
with a Young's Modulus of about 23 million it is much stiffer than the
equivalent profiles of pultruded fiberglass and is in fact 15% to 20%
stiffer than the equivalent hand-laid carbon tape or roving. For new
glider wing spar designs I think it is certainly the greatest thing
since sliced cheese, but it doesn't always play nice with others.

My
suggestion would be to saw several kerfs of
varying lengths and depths through the undulation
area extending for some length on either side of
the area possibly to the end of the spar stubs.
Graphlite rods could be epoxied into the kerfs,
like rebar in concrete, and they would take the
load from the rovings they butt up against.
I suppose fiberglass cloth could be wrapped and
epoxied around the spar butt to prevent the rods
from popping out, if that could happen, but I think
you would have a much stronger than designed spar
with a very stiff wing.


As I wrote, that might work, but it inflicts trauma on the same order
as the textbook repair, involves a pretty big modulus mismatch, and
has no track record. I'd like to see it tried, though, it'd be an
interesting experiment.

I have heard of someone cutting
a kerf in wooden spars and putting in the Graphlite
rods
to improve the strength.


Yes, I've heard of that too - I think it was on a Bowlus Baby
Albatross.

Thanks, and best regards to all

Bob K.

  #2  
Old April 19th 07, 03:30 AM posted to rec.aviation.soaring
Steve Davis
external usenet poster
 
Posts: 36
Default DG-300/303 owners...

Yes Bob, I was responding to your earlier post.
Thanks for your reply; there seems to be a lot
more going on in the spar than I had realized.
I was just guesstimating at the value of a DG 300
now vs. after a repair. With the current 'fix'
from DG I suspect a lot of them will just sit in
trailers not getting flown, or bought.
Also, is this a problem with both the top and
bottom spar caps of the wings or just one cap?
Thanks for your information.
Steve

You have described a $20K repair on a product
which might not be worth $20K right after the
repair.


I assume that you're replying to my post of 1:39 today
- though it
doesn't appear so in the Google view of r.a.s. Please
let me know if
otherwise.

Yes, in the right hands that might be a $20K repair
- I know a lot of
folks who can manage that, and I'm sure they're salivating
over the
fallout of this situation. But if there's lots of them
to do, a
relatively modest investment in tooling can easily
cut the costs down
to around a third of that, possibly less. For example,
it's virtually
a no-brainer to build a scarf-router to precisely mill
out the
required chunk of wing spar. And the pre-fabbed skin
repair panels are
easy, the layup is dirt simple and takes about an hour
to do four;
with cure cycles you could probably yield 8 per day
from a single wing
mold set.




  #3  
Old April 19th 07, 03:30 AM posted to rec.aviation.soaring
Steve Davis
external usenet poster
 
Posts: 36
Default DG-300/303 owners...

Yes Bob, I was responding to your earlier post.
Thanks for your reply; there seems to be a lot
more going on in the spar than I had realized.
I was just guesstimating at the value of a DG 300
now vs. after a repair. With the current 'fix'
from DG I suspect a lot of them will just sit in
trailers not getting flown, or bought.
Also, is this a problem with both the top and
bottom spar caps of the wings or just one cap?
Thanks for your information.
Steve

You have described a $20K repair on a product
which might not be worth $20K right after the
repair.


I assume that you're replying to my post of 1:39 today
- though it
doesn't appear so in the Google view of r.a.s. Please
let me know if
otherwise.

Yes, in the right hands that might be a $20K repair
- I know a lot of
folks who can manage that, and I'm sure they're salivating
over the
fallout of this situation. But if there's lots of them
to do, a
relatively modest investment in tooling can easily
cut the costs down
to around a third of that, possibly less. For example,
it's virtually
a no-brainer to build a scarf-router to precisely mill
out the
required chunk of wing spar. And the pre-fabbed skin
repair panels are
easy, the layup is dirt simple and takes about an hour
to do four;
with cure cycles you could probably yield 8 per day
from a single wing
mold set.




  #4  
Old April 19th 07, 09:49 AM
bagmaker bagmaker is offline
Senior Member
 
First recorded activity by AviationBanter: Aug 2005
Location: Melbourne Australia
Posts: 167
Default

just wondering how much a NEW set of wings, 808 profile with butt adaption and tongue/fork width to suit 300/303 series would be worth.
Mr DG would be tooled up already, the new specs could be added to the manual and the glider is upgraded.
You Americans could then buy up the old 303 wings and bolt them to your beloved tinships for training!


There is always an outside to the square.

Bagger
(diving for flamesuit, as usual)
  #5  
Old April 19th 07, 04:51 AM posted to rec.aviation.soaring
brianDG303
external usenet poster
 
Posts: 44
Default DG-300/303 owners...

On Apr 18, 6:30 pm, Steve Davis
wrote:
.. With the current 'fix'
from DG I suspect a lot of them will just sit in
trailers not getting flown, or bought.


Steve, this all came out about ten days ago. Last weekend at the field
there was quite a bit of chatter about it, and I had to answer a lot
of questions about how I was planning on dealing with my 303. And the
answer is, I'm so happy with the glider I just don't really care.
Andreas is correct, this will not affect me until I decide to sell it,
and that is some years down the line. The focus in this thread is on
how to fix the problem; my interest is on how to test at the lowest
cost. Let's say 50% of the gliders are affected, that means that the
cost to fix half the gliders is exactly nothing. While the testing
process is being worked out I'll be flying, and having fun.

As it happens, I have the last plane (DG303 # 486) ever made by ELAN,
and the 27th ACRO. It will be interesting to look back on this in a
year or two.

  #6  
Old April 19th 07, 05:57 AM posted to rec.aviation.soaring
Jack
external usenet poster
 
Posts: 86
Default DG-300/303 owners...

brianDG303 wrote:

As it happens, I have the last plane (DG303 # 486) ever made by ELAN,
and the 27th ACRO. It will be interesting to look back on this in a
year or two.


Who made the final 25 units, and what is the source of this information?


Jack
  #7  
Old April 19th 07, 06:12 AM posted to rec.aviation.soaring
Marc Ramsey
external usenet poster
 
Posts: 207
Default DG-300/303 owners...

Jack wrote:
brianDG303 wrote:

As it happens, I have the last plane (DG303 # 486) ever made by ELAN,
and the 27th ACRO. It will be interesting to look back on this in a
year or two.


Who made the final 25 units, and what is the source of this information?


AMS Flight made the last 25, after they bought out ELAN's aircraft
business and bought the production rights from DG Flugzeugbau...

Marc
  #8  
Old April 19th 07, 07:17 AM posted to rec.aviation.soaring
Jack
external usenet poster
 
Posts: 86
Default DG-300/303 owners...

Marc Ramsey wrote:

AMS Flight made the last 25, after they bought out ELAN's aircraft
business and bought the production rights from DG Flugzeugbau...


And they continued the defective construction techniques,
in the same facility, probably using the same personnel?

No wonder they are staying silent.


Jack
  #9  
Old April 21st 07, 07:34 AM posted to rec.aviation.soaring
Steve Davis
external usenet poster
 
Posts: 36
Default DG-300/303 owners...

I doubt that you stay liable through bankruptcy.
DG is not Glazer-Dirks nor is it Rolladin-Schneider
and when DG bought the assets of those bankrupt
companies it didn't buy the liability of them. The
liabilities, debts to suppliers, warranties, shareholders
rights, employee compensation issues, etc... all
were disposed of by the bankruptcy court.
By buying the company name, assets and tooling
etc...DG got the goodwill of the customer base and
may have taken on the obligation to monitor the
status of legacy product but it did not take on an
obligation to provide free repair.
Also, they seem to believe that the third option,
the wings are strong enough with reduced operating
limits is sufficient.

Bob K. mentioned 'Hmmm... I wonder who that
'someone' might be. Whoever they are, they're
pretty brave to get wrapped up in this mess.'

This could also be applied to DG. If they specify
an inspection and repair procedure for this mess
does it imply that they are accepting some liability
for payment and warranty if someone other than
DG does the work?

At 03:06 21 April 2007, Mart wrote:

I read the report on the DG website and it all looks
very nice except
the last words; end of discussion. That rubs me the
wrong way.
As far as I know this is not a warranty issue but a
building mistake
and I think you stay liable for that, no time expire.
It seems to me that some business will have an insurance
to cover the
loss for the pilots.
I was at the Elan factory a number of years ago. They
were building
there the very first DG 1000. So there was defenitely
a close business
contact.
If DG would have to pay they might go bankrupt.Due
the previous
bankrupty they might not be liable anyway.
But Elan is a very big ski-factory. The gliders were
made on the same
terrain,behind the same fence. After seeing the gliders
build I saw
them build ski's by the 1000's. There is money there
to compensate or
fix the gliders.
I think all the 300/303 pilots should put $100 in an
account and have
somebody find out who is liable.




--
mart




  #10  
Old April 21st 07, 02:34 PM posted to rec.aviation.soaring
JJ Sinclair
external usenet poster
 
Posts: 388
Default DG-300/303 owners...

I too believe the restrictions on the 300 will scarcely be noticed by
the average pilot, but if someone is concerened (acro) their ship can
easily be proof-loaded to 5.3 G's. Stan Hall wrote a good paper on
just how to go about it, published in Soaring. Basically you mount the
wing inverted on a sturdy test stand, secure it so it won't twist and
then sand-bag that puppy to the flight limits, usually 5.3 G's. Then
you know the wing is stong enough for anything it should see in flight
if the ship is flown within the flight envelope.
JJ

 




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