Cable vs rope pulling glider from field

[Auxvache]

I'd like to make a stout wire cable or rope with proper TOST ring, to
have on hand should I have to tow my 15m glider from mud/soft dirt/
guano.
Is a metal cable necessary/preferable, or would high breaking-strength
rope be sufficient?
My only experience here (Chester loam, Pegase, and stick-shift BMW)
did not end well.
Thanks in advance,
Erik

[jcarlyle]

Erik,

I don't think pulling your glider out of such a situation via its tow
hook is advisable. The drag from the landing gear and fuselage could
easily exceed the tow hook's structural mounting (read, expensive
repairs).

The one time I landed in a soft field we got the plane out by
disassembling it where it stopped, and carrying the pieces to the
trailer. Messy, and hard work, but I flew the next day (after washing
off the mud).

-John

On Oct 12, 11:34 am, Auxvache > wrote:
> I'd like to make a stout wire cable or rope with proper TOST ring, to
> have on hand should I have to tow my 15m glider from mud/soft dirt/
> guano.
> Is a metal cable necessary/preferable, or would high breaking-strength
> rope be sufficient?
> My only experience here (Chester loam, Pegase, and stick-shift BMW)
> did not end well.
> Thanks in advance,
> Erik

[Bill D]

On Oct 12, 9:34*am, Auxvache > wrote:
> I'd like to make a stout wire cable or rope with proper TOST ring, to
> have on hand should I have to tow my 15m glider from mud/soft dirt/
> guano.
> Is a metal cable necessary/preferable, or would high breaking-strength
> rope be sufficient?
> My only experience here (Chester loam, Pegase, and stick-shift BMW)
> did not end well.
> Thanks in advance,
> Erik

Steel cable is nasty - use Dyneema rope instead so it can be neatly
rolled up. Use the Tost weak link called out in your glider's manual
to protect the hook and glider from overloads. If that won't get you
out, you're REALLY stuck.

If this is a regular occurrence, consider a small portable 12V
electric winch from a vendor like Warn temporarily fitted to the
receiver hitch on your BMW so the glider can be slowly and gently
pulled out of the muck without stressing the car's clutch. Replace
the steel cable with Dyneema rope.
http://www.amazon.com/Warn-68531-WARN-Hitch-Adapter/dp/B000CQBMMW
http://www.warn.com/truck/winches/VR8000_winch.shtml

[kirk.stant]

On Oct 12, 10:34*am, Auxvache > wrote:
> I'd like to make a stout wire cable or rope with proper TOST ring, to
> have on hand should I have to tow my 15m glider from mud/soft dirt/
> guano.
> Is a metal cable necessary/preferable, or would high breaking-strength
> rope be sufficient?
> My only experience here (Chester loam, Pegase, and stick-shift BMW)
> did not end well.
> Thanks in advance,
> Erik

You might consider keeping a Tost ring set in your glider, as part of
your landout kit. Nice to have when you want a local to help move
your glider to a different location for derigging, etc. Rope of some
sort is almost always available, but trying to use a rope loop in a
Tost release is an exercise in futility!

Kirk

[Ben Watkins]

At 17:43 12 October 2011, kirk.stant wrote:
>On Oct 12, 10:34=A0am, Auxvache wrote:
>> I'd like to make a stout wire cable or rope with proper TOST ring, to
>> have on hand should I have to tow my 15m glider from mud/soft dirt/
>> guano.
>> Is a metal cable necessary/preferable, or would high breaking-strength
>> rope be sufficient?
>> My only experience here (Chester loam, Pegase, and stick-shift BMW)
>> did not end well.
>> Thanks in advance,
>> Erik
>
>You might consider keeping a Tost ring set in your glider, as part of
>your landout kit. Nice to have when you want a local to help move
>your glider to a different location for derigging, etc. Rope of some
>sort is almost always available, but trying to use a rope loop in a
>Tost release is an exercise in futility!
>
>Kirk
>

If you are putting strain on the tow rope make sure you lay something
reasonably heavy (coat, car rug etc.) over the rope more than half from the
car to the glider. That way if the rope does break the rings, weak link
etc. won't end up flying through your back window!

[Martin Gregorie[_5_]]

On Wed, 12 Oct 2011 19:38:24 +0000, Ben Watkins wrote:

> At 17:43 12 October 2011, kirk.stant wrote:
>>On Oct 12, 10:34=A0am, Auxvache wrote:
>>> I'd like to make a stout wire cable or rope with proper TOST ring, to
>>> have on hand should I have to tow my 15m glider from mud/soft dirt/
>>> guano.
>>> Is a metal cable necessary/preferable, or would high breaking-strength
>>> rope be sufficient?
>>> My only experience here (Chester loam, Pegase, and stick-shift BMW)
>>> did not end well.
>>> Thanks in advance,
>>> Erik
>>
>>You might consider keeping a Tost ring set in your glider, as part of
>>your landout kit. Nice to have when you want a local to help move your
>>glider to a different location for derigging, etc. Rope of some sort is
>>almost always available, but trying to use a rope loop in a Tost release
>>is an exercise in futility!
>>
>>Kirk
>>
>>
> If you are putting strain on the tow rope make sure you lay something
> reasonably heavy (coat, car rug etc.) over the rope more than half from
> the car to the glider. That way if the rope does break the rings, weak
> link etc. won't end up flying through your back window!
>
....and use a rope with as little stretch, which means energy storage, as
possible. A light weight cable is good too for the same reason.

Steel cable is about the worst thing you could use because of the way it
lashed round if it or a fixing breaks under load and, and is harder to
wind up and store than it needs to be. OTOH plastic rope rope,
particularly Dyneema or good quality climbing rope, both have minimal
energy storage and are easy to handle.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Bill D]

On Oct 12, 2:18*pm, Martin Gregorie >
wrote:
> On Wed, 12 Oct 2011 19:38:24 +0000, Ben Watkins wrote:
> > At 17:43 12 October 2011, kirk.stant wrote:
> >>On Oct 12, 10:34=A0am, Auxvache *wrote:
> >>> I'd like to make a stout wire cable or rope with proper TOST ring, to
> >>> have on hand should I have to tow my 15m glider from mud/soft dirt/
> >>> guano.
> >>> Is a metal cable necessary/preferable, or would high breaking-strength
> >>> rope be sufficient?
> >>> My only experience here (Chester loam, Pegase, and stick-shift BMW)
> >>> did not end well.
> >>> Thanks in advance,
> >>> Erik
>
> >>You might consider keeping a Tost ring set in your glider, as part of
> >>your landout kit. *Nice to have when you want a local to help move your
> >>glider to a different location for derigging, etc. *Rope of some sort is
> >>almost always available, but trying to use a rope loop in a Tost release
> >>is an exercise in futility!
>
> >>Kirk
>
> > If you are putting strain on the tow rope make sure you lay something
> > reasonably heavy (coat, car rug etc.) over the rope more than half from
> > the car to the glider. That way if the rope does break the rings, weak
> > link etc. won't end up flying through your back window!
>
> ...and use a rope with as little stretch, which means energy storage, as
> possible. A light weight cable is good too for the same reason.
>
> Steel cable is about the worst thing you could use because of the way it
> lashed round if it or a fixing breaks under load and, and is harder to
> wind up and store than it needs to be. OTOH plastic rope rope,
> particularly Dyneema or good quality climbing rope, both have minimal
> energy storage and are easy to handle.
>
> --
> martin@ * | Martin Gregorie
> gregorie. | Essex, UK
> org * * * |

Actually for the force required, < 2mm Dyneema would be strong
enough. The 12V winch linked above would likely hold 2000 feet or
so. If you landed in a boggy field which wouldn't support a car and
needed to get the glider to its trailer, this would be just the
trick. Mount the winch at the front of a trailer and it could help
get the glider onto its fuselage dolly, then pull the fuselage into
the trailer.

[Auxvache]

Thanks very much for your answers--sounds like Dyneema with a weak
link and Tost ring would be a good set-up.
And, forewarned, I promise not to dehisce the nose of the glider with
Farmer Brown's tractor.
Or shatter the back window of mum's grocery-getter.

And if it gets to be a regular occurrence, I'll find another hobby.

Erik

[Tony[_5_]]

> And if it gets to be a regular occurrence, I'll find another hobby.

A landout every now and then isn't too bad. Luckily I've never gotten
into such a muddy field that I couldn't get the glider moved out.
Benefit of flying mostly in fairly dry climates I guess. There was
one time where I avoided a very muddy mucky mess by landing on a clear
unobstructed stretch of paved county road. I've only got 30ish
landouts though and a mere 6 or 7 this season.

[Martin Gregorie[_5_]]

On Thu, 13 Oct 2011 06:39:38 -0700, Auxvache wrote:

> Thanks very much for your answers--sounds like Dyneema with a weak link
> and Tost ring would be a good set-up.
>
Yes, I'd agree, but with one warning I should have mentioned: a naked
Dyneema cord is not a good idea because the slightest handling abrasion
tends to fluff it up into an unusable woolly caterpillar-like thing. I
discovered this when trying to use a thin woven Dyneema (80 lb) line to
control the VIT stop on a free flight power model - even expecting it to
handle a 90 degree bend by sliding round a 3mm brass tube was too rough
and caused it to fluff up and become unusable.

What I've found to be excellent is a core of unwoven Dyneema inside a
woven Dacron casing. I've used 100 lb kite bridle (about 0.7mm diameter)
as model glider towline. This was very easy to handle and almost totally
abrasion resistant. I believe you can get this type of line in up to at
least 3mm diameter.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Bill D]

On Oct 13, 7:31*pm, Martin Gregorie >
wrote:
> On Thu, 13 Oct 2011 06:39:38 -0700, Auxvache wrote:
> > Thanks very much for your answers--sounds like Dyneema with a weak link
> > and Tost ring would be a good set-up.
>
> Yes, I'd agree, but with one warning I should have mentioned: a naked
> Dyneema cord is not a good idea because the slightest handling abrasion
> tends to fluff it up into an unusable woolly caterpillar-like thing. I
> discovered this when trying to use a thin woven Dyneema (80 lb) line to
> control the VIT stop on a free flight power model - even expecting it to
> handle a 90 degree bend by sliding round a 3mm brass tube was too rough
> and caused it to fluff up and become unusable.
>
> What I've found to be excellent is a core of unwoven Dyneema inside a
> woven Dacron casing. I've used 100 lb kite bridle (about 0.7mm diameter)
> as model glider towline. This was very easy to handle and almost totally
> abrasion resistant. I believe you can get this type of line in up to at
> least 3mm diameter.
>
> --
> martin@ * | Martin Gregorie
> gregorie. | Essex, UK
> org * * * |

Martin, you must have had some really crappy rope mislabeled as
Dyneema . The 12 strand hollow braid we use has 15x the abrasion
resistance of steel. The off road 4x4 guys use it on their bumper
winches with it going over sharp rocks and trees. I've never seen the
problems you describe.

[Bob Kuykendall]

On Oct 13, 7:18*pm, Bill D > wrote:

> Martin, you must have had some really crappy rope mislabeled as
> Dyneema . *The 12 strand hollow braid we use has 15x the abrasion
> resistance of steel. *The off road 4x4 guys use it on their bumper
> winches with it going over sharp rocks and trees. *I've never seen the
> problems you describe.

Yes, that sounds more like aramid (such as Kevlar (tm)) behavior.

Thanks, Bob K.

[Martin Gregorie[_5_]]

On Thu, 13 Oct 2011 19:18:12 -0700, Bill D wrote:

> Martin, you must have had some really crappy rope mislabeled as Dyneema
> . The 12 strand hollow braid we use has 15x the abrasion resistance of
> steel.
>
Well, it looked and felt like Dyneema/Spectra/whatever brand you prefer,
i.e. dead slippery to handle. As I said it was naked - just a fairly
loosely woven braid with a circular cross section that was sold as 80 lb
fishing line - I've seen the same sort of line and thickness in Dacron
but then, of course, it would have been around 18-20 lb line, say
somewhere between 0.3 to 0.5mm in diameter.

Since it felt so slick I was sure it would slide round the outside of
something as relatively large and smooth as 3mm brass tube, but nooo -
the stuff had fluffed up before I even got the model out of my workshop,
so I replaced it immediately with Dacron, which worked as I'd expected
the Dyneema to do.

> but The off road 4x4 guys use it on their bumper winches with it
> going over sharp rocks and trees. I've never seen the problems you
> describe.
>
But is that stuff naked or has it got a woven Dacron tube as its outer
layer? Obviously some of the stuff that was used as winch cable had such
an outer shell or the splicing method I saw described (threading one end
in and out of the casing with a big needle for 50cm or so) would never
have worked.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Bill D]

On Oct 14, 2:22Â*pm, Martin Gregorie >
wrote:
> On Thu, 13 Oct 2011 19:18:12 -0700, Bill D wrote:
> > Martin, you must have had some really crappy rope mislabeled as Dyneema
> > . Â*The 12 strand hollow braid we use has 15x the abrasion resistance of
> > steel.
>
> Well, it looked and felt like Dyneema/Spectra/whatever brand you prefer,
> i.e. dead slippery to handle. As I said it was naked - just a fairly
> loosely woven braid with a circular cross section that was sold as 80 lb
> fishing line - I've seen the same sort of line and thickness in Dacron
> but then, of course, it would have been around 18-20 lb line, say
> somewhere between 0.3 to 0.5mm in diameter.
>
> Since it felt so slick I was sure it would slide round the outside of
> something as relatively large and smooth as 3mm brass tube, but nooo Â*-
> the stuff had fluffed up before I even got the model out of my workshop,
> so I replaced it immediately with Dacron, which worked as I'd expected
> the Dyneema to do.
>
> > but Â* The off road 4x4 guys use it on their bumper winches with it
> > going over sharp rocks and trees. Â*I've never seen the problems you
> > describe.
>
> But is that stuff naked or has it got a woven Dacron tube as its outer
> layer? Obviously some of the stuff that was used as winch cable had such
> an outer shell or the splicing method I saw described (threading one end
> in and out of the casing with a big needle for 50cm or so) would never
> have worked.
>
> --
> martin@ Â* | Martin Gregorie
> gregorie. | Essex, UK
> org Â* Â* Â* |

This is the stuff the 4x4 guys use - it has no sheath.
http://www.okoffroad.com/stuff-winchrope-atv.htm

Dyneema/Spectra/UHMWPE rope or whatever you call it has 15x steels
abrasion resistance, 10x steel's strength per weight and a friction
coefficient lower than Teflon plus a lot of other engineering
superlatives. It simply can't be beat as winch rope for 4x4's or
gliders. It does "fuzz up" as it wears but the fuzz actually protects
the rest of the rope.

Even this miracle material is being significantly improved.

"Abstract:
This paper reports the use of multiwalled carbon nanotubes (MWCNT) to
reinforce and toughen gel-spun ultra high molecular weight
polyethylene (UHMWPE) fibers. By adding 5 wt% MWCNT, ultra strong
fibers with tensile strengths of 4.2 GPa and strain at break of ∼5%
can be produced. In comparison with the pure UHMWPE fiber at the same
draw ratios, these values represent increases of 18.8% in tensile
strength and 15.4% in ductility. In addition, a 44.2% increase in
energy to fracture has also been observed. The mechanism of
reinforcement has been studied using a combination of high resolution
scanning electron microscopy (SEM) and micro-Raman spectroscopy.
Carbon nanotube alignment along the tensile draw direction has been
observed at high elongation ratios. Such alignment induces strong
interfacial load transfer both at small and large strains to enhance
the stiffness and tensile strength of the composite fiber.
Consequently, the mechanical properties of the composite fiber follow
closely with the rule of mixtures. Our work also reveals potential for
positive deviation from rule of mixtures if the CNT alignment can be
further optimized."

[Martin Gregorie[_5_]]

On Fri, 14 Oct 2011 14:05:13 -0700, Bill D wrote:

> This is the stuff the 4x4 guys use - it has no sheath.
> http://www.okoffroad.com/stuff-winchrope-atv.htm
>
Actually it does have a short section of sheath. There is explicit
mention of a 5 foot length of anti-abrasion tube on the winch cable so it
can be slid to where its needed, and you'll have noted the warning about
using the winch's payout brake, so the stuff may not be as bullet-proof
as you think. There's also a comment, alongside the storage bag they sell
for it, of the need for careful storage.

That said, those products look like a good, if relatively expensive,
thing to have in your glider landout retrieval kit, but a section cut
from a discarded aero-tow rope would be a lot cheaper!


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Fred Weir]

On Oct 14, 3:36*pm, Martin Gregorie >
wrote:
> On Fri, 14 Oct 2011 14:05:13 -0700, Bill D wrote:
> > This is the stuff the 4x4 guys use - it has no sheath.
> >http://www.okoffroad.com/stuff-winchrope-atv.htm
>
> Actually it does have a short section of sheath. There is explicit
> mention of a 5 foot length of anti-abrasion tube on the winch cable so it
> can be slid to where its needed, and you'll have noted the warning about
> using the winch's payout brake, so the stuff may not be as bullet-proof
> as you think. There's also a comment, alongside the storage bag they sell
> for it, of the need for careful storage.
>
> That said, those products look like a good, if relatively expensive,
> thing to have in your glider landout retrieval kit, but a section cut
> from a discarded aero-tow rope would be a lot cheaper!
>
> --
> martin@ * | Martin Gregorie
> gregorie. | Essex, UK
> org * * * |

For what it's worth, energy storage is not necessarily bad due to the
fact such storage results in reduced shock loading. As a practical
example, the yachting community will usually moor/anchor their vessels
with a nylon rode or dock line in order to minimize shock damage due
to wind/wave loading. Larger boats using a chain rode depend on the
catenary and weight of the chain to provide cushioning. Three strand
nylon is inexpensive, abrasion resistant and readily available.
Experienced boat folk will also recommend using smaller rather than
larger line in order to maximize "springiness". Obviously, the chosen
line has to be strong enough to do the job though. I think you'll find
most primary climbing ropes contain a parallel strand nylon core for
the same reason.

Fred Weir
Deming, WA

[Martin Gregorie[_5_]]

On Sat, 15 Oct 2011 16:35:08 -0700, Fred Weir wrote:

> For what it's worth, energy storage is not necessarily bad due to the
> fact such storage results in reduced shock loading. As a practical
> example, the yachting community will usually moor/anchor their vessels
> with a nylon rode or dock line in order to minimize shock damage due to
> wind/wave loading. Larger boats using a chain rode depend on the
> catenary and weight of the chain to provide cushioning. Three strand
> nylon is inexpensive, abrasion resistant and readily available.
> Experienced boat folk will also recommend using smaller rather than
> larger line in order to maximize "springiness". Obviously, the chosen
> line has to be strong enough to do the job though. I think you'll find
> most primary climbing ropes contain a parallel strand nylon core for the
> same reason.
>
Understood, and a good point when you're dealing with that sort of
situation.

I use something very similar to the climbing rope you describe on my tie-
downs: I bought a set of those super-cute Claw tiedowns, which came with
exactly that type of rope. Its nice and soft, so can't damage the gel
coat if its kept clean.

However, for ground handling I'd rather use a non-springy rope:
personally I prefer the glider to not catapult itself forward as the
wheel comes out of a mud hole, something I've experienced when moving
club gliders with a golf buggy and a thin, stretchy bit of rope. Thanks
to that infinitely variable transmission a buggy can put out a surprising
amount of torque in those circumstances, really stretching that rope,
with the result that the glider pops out of the hole much faster than
you'd expect.

YMMV of course!


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |