Wing Launch - Can it pull your wings off?

Originally Posted by Derek C

On Aug 18, 11:47*am, John Smith wrote:
Derek C wrote:
Does anybody know the runway length at Magdeburg?

Plenty.http://eddh.de/info/landeinfo-ergebnisb.php?ueicao=EDBM

If the runway length is 1000m as claimed, from 80 metres high (260ft)
it should have been possible to just open the airbrakes and land
straight ahead, especially as the windsock in the crash video is
showing a reasonably stiff headwind. In the UK we always encourage
pilots to land ahead as the primary option, if reasonably possible, as
no low turns with a risk of spinning are involved. My club also
charges a much reduced winch launch fee for landing straight ahead as
a futher incentive.

Derek C

At the Auckland Gliding Club, New Zealand, there is no charge levied against a launch failure thereby trying to take a way the temptation of low level heroics that turn out bad. Having said that, poor airmanship is still displayed with some insanely low circuits when a straight ahead landing would have been more appropriate.

It seems that it is just too inconvenient for some people to have to tow their glider back to the launch point!!

Colin

On Aug 18, 11:32*pm, bildan wrote:
On Aug 18, 5:54*am, Andreas Maurer wrote:

On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott

wrote:
I see, abrasion and low density blow down. Perhaps a little drogue and
post partum pull back - or is that the way it is?

That's the way it is, unfortunately.

Generally we found that Dyneema is simply much less fault-tolerant
than a steel cable - small handling errors (like using a little too
much power to pull it out of the wood) often result in a really
expensive damage.

Andreas

And yet there are many user finding Dyneema is far, far more tolerant
than steel. *Go to a manufacturer's spec sheet and look at the
numbers. *It has 15x the abrasion resistance of steel and absolutely
no tendency to twist or kink. *It handles shock loads much better than
steel. *It has only three weaknesses - chlorine bleach, heat and sharp
edges.

Users with excellent rope handling winches see no breaks until it
wears out. *If it's breaking before it's worn out, it's getting
damaged - most likely by the winch. *Undamaged Dyneema just doesn't
suffer random breaks like steel.

Poor fairlead design is the biggest culprit. *Allowing the rope to
contact sharp edges somewhere in the rope path runs a close second.
Airfield surfaces, even really rough ones, do little damage.

Fairleads must use sheaves, not rollers. *The grooves in the sheaves
must have a very specific cross section called out by the rope
manufacturer. *Industrial studies have shown this is critical to long
life. *On every winch I've seen without a Dyneema-specific sheave,
I've been able to pull strips of melted Dyneema off the fairlead.

Drums must be boxed. *It's not unusual for a loop to form on the drum
for a fraction of a second and whip the rope against a sharp edge on
the winch frame before it gets pulled tight on the drum again. *One
winch operator declared this couldn't happen or he would have seen
it. *I pointed to bits of torn rope on a frame bracket 8 feet behind
the drum as evidence it was happening.

Dyneema is wonderful stuff and it will last up to 15x steel but it
needs a different rope path design and handling protocol.

At our somewhat abrasive airfield at Lasham (UK) we normally get about
1900 launches from a steel cable and the one trial Spectra UHMWPE
cable we tried lasted 2500 launches. The winch we used for this trial
was a modified Tost fitted with what Bill calls sheaves, level wind
paying on gear and specially reinforced drums to prevent drum-
crushing. All the parts that came into contact with the cable had been
highly polished as recommended. According to Bill that cable should
have lasted for 28,500 launches, which is over ten times what was
actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
have reported similar results to what we found. I wonder how many
launches Bill's 'American Superwinch' has carried out so far?

I believe that Bill has put the cause of winch launching in the US
back by at least 5 years by insisting that only fancy and very
expensive computer controlled diesel hydraulic or electric winches
fitted with Dyneema are capable of giving safe launches. This is in a
country where there are many potential donor vehicles fitted with
suitably large powerful engines and good automatic gearboxes that
could be used as a basis for good and low cost conventional winches.


Derek C

On Aug 19, 9:23*am, Derek C wrote:
On Aug 18, 11:32*pm, bildan wrote:

On Aug 18, 5:54*am, Andreas Maurer wrote:

On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott

wrote:
I see, abrasion and low density blow down. Perhaps a little drogue and
post partum pull back - or is that the way it is?

That's the way it is, unfortunately.

Generally we found that Dyneema is simply much less fault-tolerant
than a steel cable - small handling errors (like using a little too
much power to pull it out of the wood) often result in a really
expensive damage.

Andreas

And yet there are many user finding Dyneema is far, far more tolerant
than steel. *Go to a manufacturer's spec sheet and look at the
numbers. *It has 15x the abrasion resistance of steel and absolutely
no tendency to twist or kink. *It handles shock loads much better than
steel. *It has only three weaknesses - chlorine bleach, heat and sharp
edges.

Users with excellent rope handling winches see no breaks until it
wears out. *If it's breaking before it's worn out, it's getting
damaged - most likely by the winch. *Undamaged Dyneema just doesn't
suffer random breaks like steel.

Poor fairlead design is the biggest culprit. *Allowing the rope to
contact sharp edges somewhere in the rope path runs a close second.
Airfield surfaces, even really rough ones, do little damage.

Fairleads must use sheaves, not rollers. *The grooves in the sheaves
must have a very specific cross section called out by the rope
manufacturer. *Industrial studies have shown this is critical to long
life. *On every winch I've seen without a Dyneema-specific sheave,
I've been able to pull strips of melted Dyneema off the fairlead.

Drums must be boxed. *It's not unusual for a loop to form on the drum
for a fraction of a second and whip the rope against a sharp edge on
the winch frame before it gets pulled tight on the drum again. *One
winch operator declared this couldn't happen or he would have seen
it. *I pointed to bits of torn rope on a frame bracket 8 feet behind
the drum as evidence it was happening.

Dyneema is wonderful stuff and it will last up to 15x steel but it
needs a different rope path design and handling protocol.

At our somewhat abrasive airfield at Lasham (UK) we normally get about
1900 launches from a steel cable and the one trial Spectra UHMWPE
cable we tried lasted 2500 launches. The winch we used for this trial
was a modified Tost fitted with what Bill calls sheaves, level wind
paying on gear and specially reinforced drums to prevent drum-
crushing. All the parts that came into contact with the cable had been
highly polished as recommended. According to Bill that cable should
have lasted for 28,500 launches, which is over ten times what was
actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
have reported similar results to what we found. I wonder how many
launches Bill's 'American Superwinch' has carried out so far?

I believe that Bill has put the cause of winch launching in the US
back by at least 5 years by insisting that only fancy and very
expensive computer controlled diesel hydraulic or electric winches
fitted with Dyneema are capable of giving safe launches. This is in a
country where there are many potential donor vehicles fitted with
suitably large powerful engines and good automatic gearboxes that
could be used as a basis for good and low cost conventional winches.

Derek C- Hide quoted text -

- Show quoted text -

The other thing about Bill Daniels and the Yanks in general, is that
they are trying to re-invent the winch launching wheel and ignore any
advice from the other side of the pond from people who have been winch
launching for years and have a lot of experience in that technique. In
Germany, Holland and the UK about two-thirds of all glider launches
are done by winch.

Derek C

On Aug 17, 6:16*pm, bildan wrote:

Andreas, Derek, your posts reveal, in great detail and in ways you
obviously don't realize, just how screwed up many UK winch operations
are. *The real danger for US operations is if they take your posts as
"normal" operations - they aren't. *I hope they will ignore the UK and
study Continental, *specifically German operations instead.


For the record I have found out that Andreas Maurer flies at Landau,
which is situated about 100 kilometres south of Frankfurt in GERMANY,
yet we seem to agree on most issues related to winch launching,
despite me being a Brit! There is quite a lot of interchange of
information between the European countries that practice winch
launching. A link to his club is:

http://www.djk-landau.de/

It's in German but Google will translate it into English if you need
it.

Derek C

On Aug 12, 10:16*pm, ContestID67 wrote:
I was sent this link from a UK soaring friend of mine about a death
when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/arti...lunged-death-b...

Sad story. *A few things;

- My friend's thought was that the wing pins were left out. *Howerver,
this was the second flight of the day. *Both winch launches. *So I
would think that the wing pins were installed but the wings failed
under a winch load. *Which glider was it? *Older? *Wooden spars?
Never having had a winch launch, what happens if you don't release
back pressure at the top? *Can you pull your wings off? *Maybe
safeties on the pins were missed and the pins wiggled out on the
second flight after staying in for the first.

- I was under the impression that the BGA required parachutes for all
pilots. *Wrong? *1000 ft should have been enough to get out in time
but who knows what was happening in the cockpit or if she was 1000 MSL
or AGL at the time.

Thanks.

- John DeRosa

Getting back to the original subject, many Polish gliders have a
rigging system which consists of vertical tapered mainpins that expand
outwards on a screw to engage with the wing root fittings. This is
basically a good system because the pins stay as part of the
structure, so there is no separate mainpin that can be lost, and if
correctly assembled gives a positive, secure and play free joint. I
understand that the problem comes when the bushing that keeps the
expanding pins central becomes worn. Then it is possible that one half
of the pin may not fully engage in one the wing root fitting, even if
the jack screw is fully tightened. I have a share in an elderly Polish
two-seater glider with two such taper mainpins. We are always careful
to check that these are fully and equally engaged in the wing root
fittings when rigging it, but it is easier to see this than in the
single seaters with a single pin. See:
http://www.sylacaugasoaring.com/SZD%...%20WARNING.htm

On the subject of bailing out, it is not compulsory to wear parachutes
in gliders in the UK, but it is normal practice to do so if the design
of the glider permits. We don't know exactly at what height the wings
fell off the crash glider (but probably less than 1000ft) and the
fuselage would have dropped like a stone without them. I doubt if the
pilot could have got out in time.

Derek C

On Aug 12, 10:16*pm, ContestID67 wrote:
I was sent this link from a UK soaring friend of mine about a death
when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/arti...lunged-death-b...

Sad story. *A few things;

- My friend's thought was that the wing pins were left out. *Howerver,
this was the second flight of the day. *Both winch launches. *So I
would think that the wing pins were installed but the wings failed
under a winch load. *Which glider was it? *Older? *Wooden spars?
Never having had a winch launch, what happens if you don't release
back pressure at the top? *Can you pull your wings off? *Maybe
safeties on the pins were missed and the pins wiggled out on the
second flight after staying in for the first.

- I was under the impression that the BGA required parachutes for all
pilots. *Wrong? *1000 ft should have been enough to get out in time
but who knows what was happening in the cockpit or if she was 1000 MSL
or AGL at the time.

Thanks.

- John DeRosa

Getting back to the original subject, many Polish gliders have a
rigging system which consists of vertical tapered mainpins that expand
outwards on a screw to engage with the wing root fittings. This is
basically a good system because the pins stay as part of the
structure, so there is no separate mainpin that can be lost, and if
correctly assembled gives a positive, secure and play free joint. I
understand that the problem comes when the bushing that keeps the
expanding pins central becomes worn. Then it is possible that one half
of the pin may not fully engage in one of the wing root fitting, even
if the jack screw is fully tightened. I have a share in an elderly
Polish two-seater glider with two such taper mainpins. We are always
careful to check that these are fully and equally engaged in the wing
root fittings when rigging it, but it is easier to see this than in
the single seaters with a single pin. See:
http://www.sylacaugasoaring.com/SZD%...%20WARNING.htm

On the subject of bailing out, it is not compulsory to wear parachutes
in gliders in the UK, but it is normal practice to do so if the design
of the glider permits. We don't know exactly at what height the wings
fell off the crash glider (but probably less than 1000ft) and the
fuselage would have dropped like a stone without them. I doubt if the
pilot could have got out in time.

Derek C

On Aug 12, 10:16*pm, ContestID67 wrote:
I was sent this link from a UK soaring friend of mine about a death
when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/arti...lunged-death-b...

Sad story. *A few things;

- My friend's thought was that the wing pins were left out. *Howerver,
this was the second flight of the day. *Both winch launches. *So I
would think that the wing pins were installed but the wings failed
under a winch load. *Which glider was it? *Older? *Wooden spars?
Never having had a winch launch, what happens if you don't release
back pressure at the top? *Can you pull your wings off? *Maybe
safeties on the pins were missed and the pins wiggled out on the
second flight after staying in for the first.

- I was under the impression that the BGA required parachutes for all
pilots. *Wrong? *1000 ft should have been enough to get out in time
but who knows what was happening in the cockpit or if she was 1000 MSL
or AGL at the time.

Thanks.

- John DeRosa

Getting back to the original subject, many Polish gliders have a
rigging system which consists of vertical tapered mainpins that expand
outwards on a screw to engage with the wing root fittings. This is
basically a good system because the pins stay as part of the
structure, so there is no separate mainpin that can be lost, and if
correctly assembled gives a positive, secure and play free joint. I
understand that the problem comes when the bushing that keeps the
expanding pins central becomes worn. Then it is possible that one half
of the pin may not fully engage in one of the wing root fitting, even
if the jack screw is fully tightened. I have a share in an elderly
Polish two-seater glider with two such taper mainpins. We are always
careful to check that these are fully and equally engaged in the wing
root fittings when rigging it, but it is easier to see this than in
the single seaters with a single pin. See:
http://www.sylacaugasoaring.com/SZD%...%20WARNING.htm

On the subject of bailing out, it is not compulsory to wear parachutes
in gliders in the UK, but it is normal practice to do so if the design
of the glider permits. We don't know exactly at what height the wings
fell off the crash glider (but probably less than 1000ft) and the
fuselage would have dropped like a stone without them. I doubt if the
pilot could have got out in time.

Derek C

We had a Foka 4 at my club in the 1970s, with this sort of expanding
bolt.

My recollection is that the owners used to count the number of turns
to get the full expansion. If the number of turns was correct, and the
top bolt was visible in the right place, then the invisible lower one
must also have fully engaged with the lower lugs.

Might be a useful check in the absence of a visible sign.

(I'm not saying that this had anything to do with the recent accident
- the latter may have been caused by something different.)

Chris N

On Aug 19, 2:23*am, Derek C wrote:
On Aug 18, 11:32*pm, bildan wrote:



On Aug 18, 5:54*am, Andreas Maurer wrote:

On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott

wrote:
I see, abrasion and low density blow down. Perhaps a little drogue and
post partum pull back - or is that the way it is?

That's the way it is, unfortunately.

Generally we found that Dyneema is simply much less fault-tolerant
than a steel cable - small handling errors (like using a little too
much power to pull it out of the wood) often result in a really
expensive damage.

Andreas

And yet there are many user finding Dyneema is far, far more tolerant
than steel. *Go to a manufacturer's spec sheet and look at the
numbers. *It has 15x the abrasion resistance of steel and absolutely
no tendency to twist or kink. *It handles shock loads much better than
steel. *It has only three weaknesses - chlorine bleach, heat and sharp
edges.

Users with excellent rope handling winches see no breaks until it
wears out. *If it's breaking before it's worn out, it's getting
damaged - most likely by the winch. *Undamaged Dyneema just doesn't
suffer random breaks like steel.

Poor fairlead design is the biggest culprit. *Allowing the rope to
contact sharp edges somewhere in the rope path runs a close second.
Airfield surfaces, even really rough ones, do little damage.

Fairleads must use sheaves, not rollers. *The grooves in the sheaves
must have a very specific cross section called out by the rope
manufacturer. *Industrial studies have shown this is critical to long
life. *On every winch I've seen without a Dyneema-specific sheave,
I've been able to pull strips of melted Dyneema off the fairlead.

Drums must be boxed. *It's not unusual for a loop to form on the drum
for a fraction of a second and whip the rope against a sharp edge on
the winch frame before it gets pulled tight on the drum again. *One
winch operator declared this couldn't happen or he would have seen
it. *I pointed to bits of torn rope on a frame bracket 8 feet behind
the drum as evidence it was happening.

Dyneema is wonderful stuff and it will last up to 15x steel but it
needs a different rope path design and handling protocol.

At our somewhat abrasive airfield at Lasham (UK) we normally get about
1900 launches from a steel cable and the one trial Spectra UHMWPE
cable we tried lasted 2500 launches. The winch we used for this trial
was a modified Tost fitted with what Bill calls sheaves, level wind
paying on gear and specially reinforced drums to prevent drum-
crushing. All the parts that came into contact with the cable had been
highly polished as recommended. According to Bill that cable should
have lasted for 28,500 launches, which is over ten times what was
actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
have reported similar results to what we found. I wonder how many
launches Bill's 'American Superwinch' has carried out so far?

I believe that Bill has put the cause of winch launching in the US
back by at least 5 years by insisting that only fancy and very
expensive computer controlled diesel hydraulic or electric winches
fitted with Dyneema are capable of giving safe launches. This is in a
country where there are many potential donor vehicles fitted with
suitably large powerful engines and good automatic gearboxes that
could be used as a basis for good and low cost conventional winches.

Derek C

This is yet another in a long list of your gross fabrications and
lies. Can you point to any source where i wrote 28,500 launches on
one rope?

The only "re-invention" is your adoption of our 50 year old technology
using big V8's and automatic transmissions and claiming it as your
idea. We knew it was a bad idea long before you even heard of it.

Yes, I emphatically do not want the US to adopt UK methods or winch
designs. They are extremely uninformed and dangerous - as your
accident record proves. Geez, you guys still use steel cable!

On Aug 23, 2:28*am, bildan wrote:
On Aug 19, 2:23*am, Derek C wrote:


Dyneema is wonderful stuff and it will last up to 15x steel but it
needs a different rope path design and handling protocol.

At our somewhat abrasive airfield at Lasham (UK) we normally get about
1900 launches from a steel cable and the one trial Spectra UHMWPE
cable we tried lasted 2500 launches. The winch we used for this trial
was a modified Tost fitted with what Bill calls sheaves, level wind
paying on gear and specially reinforced drums to prevent drum-
crushing. All the parts that came into contact with the cable had been
highly polished as recommended. According to Bill that cable should
have lasted for 28,500 launches, which is over ten times what was
actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
have reported similar results to what we found. I wonder how many
launches Bill's 'American Superwinch' has carried out so far?

I believe that Bill has put the cause of winch launching in the US
back by at least 5 years by insisting that only fancy and very
expensive computer controlled diesel hydraulic or electric winches
fitted with Dyneema are capable of giving safe launches. This is in a
country where there are many potential donor vehicles fitted with
suitably large powerful engines and good automatic gearboxes that
could be used as a basis for good and low cost conventional winches.

Derek C

This is yet another in a long list of your gross fabrications and
lies. *Can you point to any source where i wrote 28,500 launches on
one rope?

To quote your posting on 18th August at 11.32:

"Dyneema is wonderful stuff and it will last up to 15x steel but it
needs a different rope path design and handling protocol."

Our steel cables last about 1900 launches on an airfield where you
always have to run over two 50 yard wide concrete or asphalt runways,
so I multiplied 1900 x 15 which makes 28,500.

The only "re-invention" is your adoption of our 50 year old technology
using big V8's and automatic transmissions and claiming it as your
idea. *We knew it was a bad idea long before you even heard of it.

Well you need a big powerful engine to power a winch and big gas or
turbo-diesel V8s are ideal for this. We are using modern engines and
gearboxes, not 50 year old ones.

Yes, I emphatically do not want the US to adopt UK methods or winch
designs. *They are extremely uninformed and dangerous - as your
accident record proves. *Geez, you guys still use steel cable!- Hide quoted text -

Strange therefore that German winches are generally very similar in
design to UK winches, and indeed quite a few British Skylaunch winches
have been sold to German and French gliding clubs. The trend at the
moment is to use polyrope cable, which is stronger and lighter than
steel, and costs slightly less. We have nothing against Dyneema apart
from the fact it costs 6 times more than steel cable (but doesn't last
6 times longer) and can cause handling difficulties, as described by
Andreas Maurer from the Laudau club in Germany. The UK winch
launching safety record has recently been very good, although we had
one fatality last year when a pilot rotated too quickly. I seem to
remember that you were recommending very rapid ground run
accelerations and rotations at one time, which are dangerous for a
number of reasons. The Germans call these 'Kavalierstarts' and have
stopped doing them after a number of fatal flick spin accidents.

Derek C