Winch problem

We recently re-commissioned a winch that had been operated successfully
for years using armored tow-target cable. That being difficult to find
these days, we are using regular stranded cable and are having trouble with
the cable piling up at the center (width-wise)of the drum, then slipping off
to the side causing slack loops of cable that eventually grow enough to whip
out beyond the circumference of the drum, impacting adjacent structure. The
winch has never had a level-wind mechanism.
It would seem that the stranded cable has less tendency than the smooth,
armored cable to slip off of the high spot at the center of the drum and lay
into the lower, edge areas of the drum, which would result in a more level
winding of the cable on the drum.
It looks like a level-wind will be necessary, or a return to the old
armored cable.
Any suggestions?

Lach Ohman

Lach --

We're having excellent results with Plasma/Dyneema/Spectra hollow braid
5 mm rope. Our drum is 48 inch by 6 inch with 63 inch end plates. No
line breaks, kinks, pile-ups or tangles in 75 plus tows to around 1700
ft.

With well-designed pay-on sheaves there is absolutely no need for a
level wind. Rope is forty plus cents a foot, but have you priced a tug
and pilot plus their care and feeding lately?

BJ

Lach and JoAnn Ohman wrote:

We recently re-commissioned a winch that had been operated successfully
for years using armored tow-target cable. That being difficult to find
these days, we are using regular stranded cable and are having trouble with
the cable piling up at the center (width-wise)of the drum, then slipping off
to the side causing slack loops of cable that eventually grow enough to whip
out beyond the circumference of the drum, impacting adjacent structure. The
winch has never had a level-wind mechanism.
It would seem that the stranded cable has less tendency than the smooth,
armored cable to slip off of the high spot at the center of the drum and lay
into the lower, edge areas of the drum, which would result in a more level
winding of the cable on the drum.
It looks like a level-wind will be necessary, or a return to the old
armored cable.
Any suggestions?

Lach Ohman

Our club operate several two drum winches and use stranded
steel cable.

Two Tost winches have smaller, wide drums with 'pay
on' rollers that reciprocate across the width to lay
the cable flat like a cotton reel.

The 'Skylaunch' has large diameter and very narrow
drums with no 'pay on' gear, but has high sides and
raised guides on the sides of the drum to ensure it
goes onto the body.

The smaller wide drum Tost drum have the problem you
describe if the pay on gear fails or sticks. The cable
either throws large loops, goes over the side, or burys
itself and then jams on pay out.

The large narrow drums with no pay on gear work well.
The narrow width prevents the bunching and burying
problems.

With the smaller wide drums perhaps by raising the
sides and ensuring the cable goes to the centre of
the drum will solve the initial problems.

There are several ways of adding pay on rollers, but
it depends on what space you have round the cable drums
for modification.

There are some good photos of various winches on http://www.skylau
nch.de/album/d.html
these may give you some ideas on how to modify your
drums or add pay on gear.

Another possible alternative is to look at 'Plasma'
type ropes, this had been discussed at length on RAS
and URAS and a few clubs in America are using it.
It is expensive and has its own problems, but that
is another story.

Dave Martin wrote in message ...
Our club operate several two drum winches and use stranded
steel cable.

Two Tost winches have smaller, wide drums with 'pay
on' rollers that reciprocate across the width to lay
the cable flat like a cotton reel.

The 'Skylaunch' has large diameter and very narrow
drums with no 'pay on' gear, but has high sides and
raised guides on the sides of the drum to ensure it
goes onto the body.

The smaller wide drum Tost drum have the problem you
describe if the pay on gear fails or sticks. The cable
either throws large loops, goes over the side, or burys
itself and then jams on pay out.

The large narrow drums with no pay on gear work well.
The narrow width prevents the bunching and burying
problems.

With the smaller wide drums perhaps by raising the
sides and ensuring the cable goes to the centre of
the drum will solve the initial problems.

There are several ways of adding pay on rollers, but
it depends on what space you have round the cable drums
for modification.

There are some good photos of various winches on http://www.skylau
nch.de/album/d.html
these may give you some ideas on how to modify your
drums or add pay on gear.

Another possible alternative is to look at 'Plasma'
type ropes, this had been discussed at length on RAS
and URAS and a few clubs in America are using it.

It is expensive and has its own problems,

Name one problem-

"Lach and JoAnn Ohman" wrote in message ...
We recently re-commissioned a winch that had been operated successfully
for years using armored tow-target cable. That being difficult to find
these days, we are using regular stranded cable and are having trouble with
the cable piling up at the center (width-wise)of the drum, then slipping off
to the side causing slack loops of cable that eventually grow enough to whip
out beyond the circumference of the drum, impacting adjacent structure. The
winch has never had a level-wind mechanism.
It would seem that the stranded cable has less tendency than the smooth,
armored cable to slip off of the high spot at the center of the drum and lay
into the lower, edge areas of the drum, which would result in a more level
winding of the cable on the drum.
It looks like a level-wind will be necessary, or a return to the old
armored cable.
Any suggestions?

Lach Ohman


Lach,

I found the following reference in the German Aeroclub's (DAeC)rules
and regulations regarding the technical aspects of building a winch:

"Hinweis: Eine Spulvorrichtung ist erforderlich, wenn das Verhältnis
von Trommelbreite zum Abstand zwischen Trommel und Rollen kleiner als
1:18 ist."

Translation:
Note: A level winding mechanism is required if the ratio between the
drum's width and the distance between the drum and fair-lead rollers
is less than 1:18.

This may sound complicated but makes sense: if you have a wide drum
and a short distance, the cable will pile up in the center. It will
not deflect to the sides by itself. On the other hand, if you have a
narrow drum and a long distance, the cable will fill up the available
space more evenly.

I don't know if using the Dyneema type rope will change your situation
or not.

Hope this helps

Ulrich Neumann
Libelle 'GM'

Dave Martin wrote

Another possible alternative is to look at 'Plasma'
type ropes, this had been discussed at length on RAS
and URAS and a few clubs in America are using it.


It is expensive and has its own problems,

At 00:06 24 December 2003, Craig Freeman wrote:

Name one problem-

Problem 1 Cutting it in an emergency

Problem 2 Pursuading UK clubs and the BGA to support
trials to evaluate its claimed advantages.

Problem 3 Pursuading UK clubs that the extra expense
may be saved by the higher launches, easier handling,
longer life.

Dave Martin wrote in message ...
Dave Martin


It is expensive and has its own problems,

At 00:06 24 December 2003, Craig Freeman wrote:

Name one problem-

Problem 1 Cutting it in an emergency

Problem 2 Pursuading UK clubs and the BGA to support
trials to evaluate its claimed advantages.

Problem 3 Pursuading UK clubs that the extra expense
may be saved by the higher launches, easier handling,
longer life.

Problem 1. Skylaunch has a cutter available
Problem 2,3 I understand your situation but this is not a
problem with the rope. I would liked to have
seen some real test data too before purchasing,
but after using it I am glad I did not wait. I
would not go back to wire for any reason ever
period. Unfortunatly we don't fly enough to put
the time on the rope which could help you out with
pursuading UK clubs. Someday clubs will wish they
had switched sooner.

And problem 4, which explains why I don't agree that my club should do
trials: we would have to pioneer modifications to the pay-on pulleys,
possibly the scroll gear that ensures even winding onto the drum, and
possibly the guillotines, at considerable trouble and expense with no
certainty that it would be successful. All that is on top of the expense
of at least one drum of the new cable. Having worked for years to
develop know-how and a system that ain't broke, with low cost per launch
and almost no cable breaks, I see no reason to try to fix it. We have
better uses for our resources.

My fears about the redevelopment costs come from having heard that the
fibre cable can burn if it rubs. Knowing that our pulleys are heavy,
need considerable pressure to accelerate them, and are deeply scored
from steel cable use, I doubt if it is worth the cost and effort.

Chris N.

At 12:42 24 December 2003, Chris Nicholas wrote:
And problem 4, which explains why I don't agree that
my club should do
trials: we would have to pioneer modifications to
the pay-on pulleys,
possibly the scroll gear that ensures even winding
onto the drum, and
possibly the guillotines, at considerable trouble and
expense with no
certainty that it would be successful. All that is
on top of the expense
of at least one drum of the new cable. Having worked
for years to
develop know-how and a system that ain't broke, with
low cost per launch
and almost no cable breaks, I see no reason to try
to fix it. We have
better uses for our resources.

My fears about the redevelopment costs come from having
heard that the
fibre cable can burn if it rubs. Knowing that our
pulleys are heavy,
need considerable pressure to accelerate them, and
are deeply scored
from steel cable use, I doubt if it is worth the cost
and effort.

Chris N.

Chris

I accept all your arguments apart from the last line,
if we never try we will never know!

Dave