Winch rope 1/4 inch poly

There is talk of trying a hybrid to eliminate line sag for longer runs,have
to
wait and see on that one.
The point about the rope storing energy equal to a bigger engine, well we
are
already using a 5.7 ltr V8 with performance mods to get high output,to get
more pull is going to cost a lot in terms of the engine verses $250US for
1000 metres of poly.
The second part of this is the club 1.5hrs drive south of us had their winch
motor
stolen because it was very highly tweaked up and a prize worth stealing
gary

"Bill Daniels" wrote in message
hlink.net...
Actually, I'm not sure the economic effect would be positive. The rope
that
winds onto the drum first doesn't see much wear so the effect of using
cheap
rope might not be significant. Looking at the big picture, the cost
difference per launch for cable replacement might not be worth the hassle
of
using two kinds of rope. The price of high-strength synthetics is coming
down anyway.

All the engineering data I have says Spectra will outlast lesser
synthetics
by a factor of 10 or more. Nothing wrong with experimenting with cheaper
materials though. If you want a "bungee effect", then nylon would be a
better material than poly.

The bungee effect is a way to store engine power and then release it at
the
point of peak power demand with the result that a smaller engine can do
the
work for a larger one. My gut reaction is that it would be better to use
a
larger engine and no bungee effect - an engine is controllable and the
bungee effect is not. A stretchy rope is a step away from precise control
of the launch.

In my experience, most problems that arise in winch operations come from
poorly thought out efforts to save money up front. The best way to save
money is to do the thing right the first time.

Bill Daniels

"F.L. Whiteley" wrote in message
...
1. with a hybrid solution on a LONG (=5000ft) run, you still get
2500ft
of
bungee effect at the beginning of the launch (not sure that 5000ft of
bungee
effect is wanted)
2. then ELIMINATE the sag as the launch gets higher using the lighter
and
thinner and more expensive rope

I'm not suggesting this for launch runs of 1000m, but those about 1400m
length or greater where someone has already demonstrated that 10mm poly
has
issues of weight and drag.

Frank

"goneill" wrote in message
...
Big point ,the bungee effect is VERY DESIRABLE at the initial
acceleration
and rotation into the full climb,this is where the extra height is
coming
from ,
no wasted field length ,the penalty for the bungee effect is at the
top
of
the
launch where the the winch needs to have the release with no tension
so the rope does not catapult at the winch and snag in the feed
guide.
A number of single seaters are requesting 70 knots on the winch and
dipping the nose for release then pulling up with the residual speed
often
getting 1600-1700ft.
Overall the good effects outweigh the few minor problems created
,these
problems are negated by operational changes
gary
"F.L. Whiteley" wrote in message
...

"goneill" wrote in message
...
Other info now obtained
poly is 10 millimetres diameter and with use shrinks to 8ml
Durability is 1000-1500 launches on grass field being dragged out
by 4wd from stationary winch
Our local cost is $245US for 1000metres of rope.DO THE MATH.ITS
CHEAP
We charge round $8US per launch this to help fund another winch
The winch motor is a 5.7ltr V8 petrol driving through an auto box
to
an
old truck axle with diff modified to drive one side at time (your
common
winch)
The difference is the drums.The drums have a centre core cut from
the
old
front wheel
of a road roller 12ml thick hardened steel (we got it for free)and
the
side
plates
10ml thick with a welded on bevel at the top to act as a guide.
All this to stop the crushing effects.of the stretched rope
I have the email of one of the main members who helped in the
experimentation stage
and is on the instructor,s panel so can explain the changes to
the
flight
training on
winch launching with our style of winch.
Another club has also switched to this method and is having the
same
success
as we are on a similar strip length.Most single seaters are
getting
close
to
or +50% of
rope length in height.
Trials at another club with 5400ft of runway found that the sag in
the
rope
with longer
lengths tended to get premature releases in top third of launch as
angle
of
the rope
into the release was not as flat.
This was a limited number of launches.
gary

Gary,

Thanks for the information. Now, if the poly could be spliced
~50/50
or
so
with something like 1/8" Validator 12
http://www.samsonrope.com/admin/data...dator12_LR.pdf ,
(Vectran) http://www.pelicanrope.com/peli05c.htm both the bungee and
sag
effects could be reduced with some cost benefits. This could be a
solution
for long runs. When we launched with 1000ft of Spectra on the end
of
the
wire rope, we didn't pull the Spectra through the rollers. Two
synthetics
with a reasonable join might work well as a hybrid solution.

Vectran is stronger than Spectra with a higher critical temperature,
but
with somewhat less abrasion resistence.

There are some interesting 1/4" vectran sheathed products
http://www.pelicanrope.com/new04.htm
for improved abrasion resistence.

And Plasma 12
http://www.cortlandcable.com/psrope/...PlasmaRev9.pdf
Spectra in a variety of sizes.

Frank Whiteley
Colorado

I have nothing against cheap rope, if the long term economics work. But, if
you reduce the question to how much extra it costs for each launch, an all
spectra rope would likely add less than $1 US per launch and return an extra
25% in height achieved, at least on long (5000 feet+) winch runs. (Don't
expect to see that much extra height on short runs.)

For me, adding $1 to the launch costs for a higher, sweeter, more reliable
launch is well worth it.

Tweaking an ex-automobile engine for more output is an expensive way to go
in the long run since it tends to make for a peaky torque curve and less
reliability. What seems to work best for a winch is an engine with a flat
power curve and a huge torque reserve. Every automobile power train that I
have seen used in glider winch had problems of one kind or another - usually
inadequate control of the launch because of the transmission shifting to
accommodate the peaky torque curve.

Getting an engine stolen is a security issue, not a winch design issue.
But, if the engine had been a 3000 pound diesel, the bandits would have
probably left it alone.

Bill Daniels

"goneill" wrote in message
...
There is talk of trying a hybrid to eliminate line sag for longer
runs,have
to
wait and see on that one.
The point about the rope storing energy equal to a bigger engine, well we
are
already using a 5.7 ltr V8 with performance mods to get high output,to get
more pull is going to cost a lot in terms of the engine verses $250US for
1000 metres of poly.
The second part of this is the club 1.5hrs drive south of us had their
winch
motor
stolen because it was very highly tweaked up and a prize worth stealing
gary

"Bill Daniels" wrote in message
hlink.net...
Actually, I'm not sure the economic effect would be positive. The rope
that
winds onto the drum first doesn't see much wear so the effect of using
cheap
rope might not be significant. Looking at the big picture, the cost
difference per launch for cable replacement might not be worth the
hassle
of
using two kinds of rope. The price of high-strength synthetics is
coming
down anyway.

All the engineering data I have says Spectra will outlast lesser
synthetics
by a factor of 10 or more. Nothing wrong with experimenting with
cheaper
materials though. If you want a "bungee effect", then nylon would be a
better material than poly.

The bungee effect is a way to store engine power and then release it at
the
point of peak power demand with the result that a smaller engine can do
the
work for a larger one. My gut reaction is that it would be better to
use
a
larger engine and no bungee effect - an engine is controllable and the
bungee effect is not. A stretchy rope is a step away from precise
control
of the launch.

In my experience, most problems that arise in winch operations come from
poorly thought out efforts to save money up front. The best way to save
money is to do the thing right the first time.

Bill Daniels

"F.L. Whiteley" wrote in message
...
1. with a hybrid solution on a LONG (=5000ft) run, you still get
2500ft
of
bungee effect at the beginning of the launch (not sure that 5000ft of
bungee
effect is wanted)
2. then ELIMINATE the sag as the launch gets higher using the lighter
and
thinner and more expensive rope

I'm not suggesting this for launch runs of 1000m, but those about
1400m
length or greater where someone has already demonstrated that 10mm
poly
has
issues of weight and drag.

Frank

"goneill" wrote in message
...
Big point ,the bungee effect is VERY DESIRABLE at the initial
acceleration
and rotation into the full climb,this is where the extra height is
coming
from ,
no wasted field length ,the penalty for the bungee effect is at the
top
of
the
launch where the the winch needs to have the release with no
tension
so the rope does not catapult at the winch and snag in the feed
guide.
A number of single seaters are requesting 70 knots on the winch and
dipping the nose for release then pulling up with the residual speed
often
getting 1600-1700ft.
Overall the good effects outweigh the few minor problems created
,these
problems are negated by operational changes
gary
"F.L. Whiteley" wrote in message
...

"goneill" wrote in message
...
Other info now obtained
poly is 10 millimetres diameter and with use shrinks to 8ml
Durability is 1000-1500 launches on grass field being dragged
out
by 4wd from stationary winch
Our local cost is $245US for 1000metres of rope.DO THE MATH.ITS
CHEAP
We charge round $8US per launch this to help fund another winch
The winch motor is a 5.7ltr V8 petrol driving through an auto
box
to
an
old truck axle with diff modified to drive one side at time
(your
common
winch)
The difference is the drums.The drums have a centre core cut
from
the
old
front wheel
of a road roller 12ml thick hardened steel (we got it for
free)and
the
side
plates
10ml thick with a welded on bevel at the top to act as a guide.
All this to stop the crushing effects.of the stretched rope
I have the email of one of the main members who helped in the
experimentation stage
and is on the instructor,s panel so can explain the changes to
the
flight
training on
winch launching with our style of winch.
Another club has also switched to this method and is having the
same
success
as we are on a similar strip length.Most single seaters are
getting
close
to
or +50% of
rope length in height.
Trials at another club with 5400ft of runway found that the sag
in
the
rope
with longer
lengths tended to get premature releases in top third of launch
as
angle
of
the rope
into the release was not as flat.
This was a limited number of launches.
gary

Gary,

Thanks for the information. Now, if the poly could be spliced
~50/50
or
so
with something like 1/8" Validator 12
http://www.samsonrope.com/admin/data...dator12_LR.pdf
,
(Vectran) http://www.pelicanrope.com/peli05c.htm both the bungee
and
sag
effects could be reduced with some cost benefits. This could be a
solution
for long runs. When we launched with 1000ft of Spectra on the end
of
the
wire rope, we didn't pull the Spectra through the rollers. Two
synthetics
with a reasonable join might work well as a hybrid solution.

Vectran is stronger than Spectra with a higher critical
temperature,
but
with somewhat less abrasion resistence.

There are some interesting 1/4" vectran sheathed products
http://www.pelicanrope.com/new04.htm
for improved abrasion resistence.

And Plasma 12
http://www.cortlandcable.com/psrope/...PlasmaRev9.pdf
Spectra in a variety of sizes.

Frank Whiteley
Colorado

Vectran would not be a very suitable winch rope. It tends to fatigue
relatively rapidly with bending. It is useful as standing rigging on
sailboats but isn't used for running rigging. Technora is about the
same tensile strength and modulus (both have very high modulus)
without the fatigue problem. I don't have any proof of this but was
told this by someone who appeared to know quite a lot about all the
various new fibers being used in rope.


Gary,

Thanks for the information. Now, if the poly could be spliced ~50/50 or so
with something like 1/8" Validator 12
http://www.samsonrope.com/admin/data...dator12_LR.pdf ,
(Vectran) http://www.pelicanrope.com/peli05c.htm both the bungee and sag
effects could be reduced with some cost benefits. This could be a solution
for long runs. When we launched with 1000ft of Spectra on the end of the
wire rope, we didn't pull the Spectra through the rollers. Two synthetics
with a reasonable join might work well as a hybrid solution.

Vectran is stronger than Spectra with a higher critical temperature, but
with somewhat less abrasion resistence.

There are some interesting 1/4" vectran sheathed products
http://www.pelicanrope.com/new04.htm
for improved abrasion resistence.

And Plasma 12
http://www.cortlandcable.com/psrope/...PlasmaRev9.pdf
Spectra in a variety of sizes.

Frank Whiteley
Colorado

I was not present at the original trials but I believe the extra height from
Spectra
type rope was about the same as the poly.
The one other effect of poly is its memory seems to be only to shrink into
its own
length and if released under tension pulls away from the glider and only
throws
loops towards the winch but they do not reach the winch if the drum is
stopped
no tendency for the ends to whip .
I saw a suggestion about nylon earlier in the thread to create the bungee
effect
but correct me if I am wrong but nylon does tend to whip out
gary
"Bill Daniels" wrote in message
link.net...
I have nothing against cheap rope, if the long term economics work. But,
if
you reduce the question to how much extra it costs for each launch, an all
spectra rope would likely add less than $1 US per launch and return an
extra
25% in height achieved, at least on long (5000 feet+) winch runs. (Don't
expect to see that much extra height on short runs.)

For me, adding $1 to the launch costs for a higher, sweeter, more reliable
launch is well worth it.

Tweaking an ex-automobile engine for more output is an expensive way to go
in the long run since it tends to make for a peaky torque curve and less
reliability. What seems to work best for a winch is an engine with a flat
power curve and a huge torque reserve. Every automobile power train that
I
have seen used in glider winch had problems of one kind or another -
usually
inadequate control of the launch because of the transmission shifting to
accommodate the peaky torque curve.

Getting an engine stolen is a security issue, not a winch design issue.
But, if the engine had been a 3000 pound diesel, the bandits would have
probably left it alone.

Bill Daniels

"goneill" wrote in message
...
There is talk of trying a hybrid to eliminate line sag for longer
runs,have
to
wait and see on that one.
The point about the rope storing energy equal to a bigger engine, well
we
are
already using a 5.7 ltr V8 with performance mods to get high output,to
get
more pull is going to cost a lot in terms of the engine verses $250US
for
1000 metres of poly.
The second part of this is the club 1.5hrs drive south of us had their
winch
motor
stolen because it was very highly tweaked up and a prize worth stealing
gary

"Bill Daniels" wrote in message
hlink.net...
Actually, I'm not sure the economic effect would be positive. The
rope
that
winds onto the drum first doesn't see much wear so the effect of using
cheap
rope might not be significant. Looking at the big picture, the cost
difference per launch for cable replacement might not be worth the
hassle
of
using two kinds of rope. The price of high-strength synthetics is
coming
down anyway.

All the engineering data I have says Spectra will outlast lesser
synthetics
by a factor of 10 or more. Nothing wrong with experimenting with
cheaper
materials though. If you want a "bungee effect", then nylon would be
a
better material than poly.

The bungee effect is a way to store engine power and then release it
at
the
point of peak power demand with the result that a smaller engine can
do
the
work for a larger one. My gut reaction is that it would be better to
use
a
larger engine and no bungee effect - an engine is controllable and the
bungee effect is not. A stretchy rope is a step away from precise
control
of the launch.

In my experience, most problems that arise in winch operations come
from
poorly thought out efforts to save money up front. The best way to
save
money is to do the thing right the first time.

Bill Daniels

"F.L. Whiteley" wrote in message
...
1. with a hybrid solution on a LONG (=5000ft) run, you still get
2500ft
of
bungee effect at the beginning of the launch (not sure that 5000ft
of
bungee
effect is wanted)
2. then ELIMINATE the sag as the launch gets higher using the
lighter
and
thinner and more expensive rope

I'm not suggesting this for launch runs of 1000m, but those about
1400m
length or greater where someone has already demonstrated that 10mm
poly
has
issues of weight and drag.

Frank

"goneill" wrote in message
...
Big point ,the bungee effect is VERY DESIRABLE at the initial
acceleration
and rotation into the full climb,this is where the extra height is
coming
from ,
no wasted field length ,the penalty for the bungee effect is at
the
top
of
the
launch where the the winch needs to have the release with no
tension
so the rope does not catapult at the winch and snag in the feed
guide.
A number of single seaters are requesting 70 knots on the winch
and
dipping the nose for release then pulling up with the residual
speed
often
getting 1600-1700ft.
Overall the good effects outweigh the few minor problems created
,these
problems are negated by operational changes
gary
"F.L. Whiteley" wrote in message
...

"goneill" wrote in message
...
Other info now obtained
poly is 10 millimetres diameter and with use shrinks to 8ml
Durability is 1000-1500 launches on grass field being dragged
out
by 4wd from stationary winch
Our local cost is $245US for 1000metres of rope.DO THE
MATH.ITS
CHEAP
We charge round $8US per launch this to help fund another
winch
The winch motor is a 5.7ltr V8 petrol driving through an auto
box
to
an
old truck axle with diff modified to drive one side at time
(your
common
winch)
The difference is the drums.The drums have a centre core cut
from
the
old
front wheel
of a road roller 12ml thick hardened steel (we got it for
free)and
the
side
plates
10ml thick with a welded on bevel at the top to act as a
guide.
All this to stop the crushing effects.of the stretched rope
I have the email of one of the main members who helped in the
experimentation stage
and is on the instructor,s panel so can explain the changes
to
the
flight
training on
winch launching with our style of winch.
Another club has also switched to this method and is having
the
same
success
as we are on a similar strip length.Most single seaters are
getting
close
to
or +50% of
rope length in height.
Trials at another club with 5400ft of runway found that the
sag
in
the
rope
with longer
lengths tended to get premature releases in top third of
launch
as
angle
of
the rope
into the release was not as flat.
This was a limited number of launches.
gary

Gary,

Thanks for the information. Now, if the poly could be spliced
~50/50
or
so
with something like 1/8" Validator 12

http://www.samsonrope.com/admin/data...dator12_LR.pdf
,
(Vectran) http://www.pelicanrope.com/peli05c.htm both the bungee
and
sag
effects could be reduced with some cost benefits. This could be
a
solution
for long runs. When we launched with 1000ft of Spectra on the
end
of
the
wire rope, we didn't pull the Spectra through the rollers. Two
synthetics
with a reasonable join might work well as a hybrid solution.

Vectran is stronger than Spectra with a higher critical
temperature,
but
with somewhat less abrasion resistence.

There are some interesting 1/4" vectran sheathed products
http://www.pelicanrope.com/new04.htm
for improved abrasion resistence.

And Plasma 12
http://www.cortlandcable.com/psrope/...PlasmaRev9.pdf
Spectra in a variety of sizes.

Frank Whiteley
Colorado

How about this "bungee effect" scenario:

You accelerate the glider smartly and stretch the rope. The glider lifts
off normally but encounters a strong headwind layer at 100 feet AGL. The
pilot frantically signals for less speed and the winch driver promptly
reduces power, but the "bungee effect" just keeps pulling the glider faster
until the stored energy is depleted. Then the glider airspeed sags as the
reduced winch engine power is felt. The pilot signals for more speed and
the winch engine throttle is again advanced, but the additional power is
absorbed in stretching the rope before the glider sees the additional speed.
Then repeat cycle.

I once tried auto tow with 3000 feet of 5mm nylon and this is what I
encountered. We never did tame the launch so we went back to steel wire.
_______

This is a very bad way to control a launch unless the winch power is set
very low so the glider pilot controls airspeed with pitch attitude. I don't
like the idea of winch rope that stretches any more than needed to damp
vibrations. I like the idea of instantaneous airspeed response to throttle
changes. Spectra stretches less than 1% at the failure point. Spectra is
pretty much a "drop in" replacement for steel wire except that it is 90%
lighter.

It's much better to have reserve power from a large, high torque engine and
a winch line with little stretch. My dream winch is a powerful one that has
a telemetry link to the glider. The winch pulls the glider to the desired
airspeed at the maximum safe acceleration and holds it precisely there while
the pilot pulls up to tension the rope to 80 - 90% of the weak-link breaking
point. That is the definition of an optimized launch.

Bill Daniels

First line of your reply is the wrong way round, the full power signal is
given and about 1-2 seconds stretching later the glider accelerates very
rapidly
and is airborne 1-2 fuse lengths, depending on which glider and winch
power setting has been used you have a very short initial climb phase
and have to rotate to full climb or you will overspeed ,the winch reduces
his
power setting as you rotate into the full climb arc.
We are not talking a huge effect here and your reference to your use of
nylon
as a launch rope ,if I am correct nylon has far more spring in it than poly.
Autotow we do here for fun every now and again and the acceleration is
slower
The other thing to remember is this club and other clubs have dialed up
many
thousands of launches on this poly rope and it has shown to be consistant
and predictable in the bungee effect
gary
"Bill Daniels" wrote in message
link.net...
How about this "bungee effect" scenario:

You accelerate the glider smartly and stretch the rope. The glider lifts
off normally but encounters a strong headwind layer at 100 feet AGL. The
pilot frantically signals for less speed and the winch driver promptly
reduces power, but the "bungee effect" just keeps pulling the glider
faster
until the stored energy is depleted. Then the glider airspeed sags as the
reduced winch engine power is felt. The pilot signals for more speed and
the winch engine throttle is again advanced, but the additional power is
absorbed in stretching the rope before the glider sees the additional
speed.
Then repeat cycle.

I once tried auto tow with 3000 feet of 5mm nylon and this is what I
encountered. We never did tame the launch so we went back to steel wire.
_______

This is a very bad way to control a launch unless the winch power is set
very low so the glider pilot controls airspeed with pitch attitude. I
don't
like the idea of winch rope that stretches any more than needed to damp
vibrations. I like the idea of instantaneous airspeed response to
throttle
changes. Spectra stretches less than 1% at the failure point. Spectra is
pretty much a "drop in" replacement for steel wire except that it is 90%
lighter.

It's much better to have reserve power from a large, high torque engine
and
a winch line with little stretch. My dream winch is a powerful one that
has
a telemetry link to the glider. The winch pulls the glider to the desired
airspeed at the maximum safe acceleration and holds it precisely there
while
the pilot pulls up to tension the rope to 80 - 90% of the weak-link
breaking
point. That is the definition of an optimized launch.

Bill Daniels

On Fri, 2 Jan 2004 17:39:28 +1300, "goneill"
wrote:

We are not talking a huge effect here

Agreed. I was watching launches at Auckland a few weeks ago and didn't
notice any gross bungee effects. All the launches I saw looked pretty
smooth.

One question: I saw that you were using a long plastic covered strop
between the drogue and glider, but could not see either a weak link or
a set of colour coded strops. Did I miss something?


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

The weak link is there between chute and strop
so when the pilot pulls the bung there is something
relatively large to find attached to the rings.
The strop seems to come down slower than just the rings
gary
"Martin Gregorie" wrote in message
...
On Fri, 2 Jan 2004 17:39:28 +1300, "goneill"
wrote:

We are not talking a huge effect here

Agreed. I was watching launches at Auckland a few weeks ago and didn't
notice any gross bungee effects. All the launches I saw looked pretty
smooth.

One question: I saw that you were using a long plastic covered strop
between the drogue and glider, but could not see either a weak link or
a set of colour coded strops. Did I miss something?


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

On Sat, 3 Jan 2004 08:36:59 +1300, "goneill"
wrote:

The weak link is there between chute and strop
so when the pilot pulls the bung there is something
relatively large to find attached to the rings.

.....makes sense


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

In article ,
Martin Gregorie wrote:

On Fri, 2 Jan 2004 17:39:28 +1300, "goneill"
wrote:

We are not talking a huge effect here

Agreed. I was watching launches at Auckland a few weeks ago and didn't
notice any gross bungee effects. All the launches I saw looked pretty
smooth.

I took a couple of winch launches at Puhipuhi in a Janus on I think poly
rope last week. Seemed pretty smooth, and I didn't notice bad effects
from stretching. Not that I got much height from my own pathetic
attempt (less than 1000 ft), but it was enough to get away...

-- Bruce