Cable vs rope pulling glider from field

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

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 |