SAFE Winch Launching

Has anybody in the good old US of A developed a printed, available,
specification for the pay-on gear for Dyneema etc. rope – like low
weight (aluminum? - note USA spelling!) rollers, low friction and low
inertia bearings, anything special needed for the drum , etc.?

I suspect that there is scope for saving inventing too many wheels
twice over.

(And for the avoidance of doubt, I am NOT going to get into the Bildan/
DC/DJ etc. spats – you are all welcome to keep those among
yourselves.)

Chris N.

On Jul 22, 4:50*pm, Chris Nicholas wrote:
Has anybody in the good old US of A developed a printed, available,
specification for the pay-on gear for Dyneema etc. rope – like low
weight (aluminum? - note USA spelling!) rollers, low friction and low
inertia bearings, anything special needed for the drum , etc.?

I suspect that there is scope for saving inventing too many wheels
twice over.

(And for the avoidance of doubt, I am NOT going to get into the Bildan/
DC/DJ etc. spats – you are all welcome to keep those among
yourselves.)

Chris N.

While I'm sure there *are such documents handy, if your goal is
'saving wheels' one can (and is better off...) doing away with the
level wind mechanism altogether, which is itself a source of
additional hassle in most operations. The trick is to use a high
enough aspect drum and have a long enough run between the fairlead
assy and the drum, somewhere around 1:18 I believe, comparing drum
width to run length between the two mechanisms according to German
DAeC.

Assuming a bigblock/TH400/truck rearend setup is what you're leaning
towards, final drive gearing needs to be selected based on drum
diameter, since larger diameter drums call for higher gear ratios in
the rearends... a small price to pay considering. There are
spreadsheets and other files covering all this on winchdesign BTW

-Paul

PS. join the winchdesign group and comb the postings and files there
as well as keeping up on new ones...
http://groups.yahoo.com/group/winchdesign/ -that is if you can
handle more episodes of the Derek/Bill show

On Jul 22, 6:38*pm, sisu1a wrote:
On Jul 22, 4:50*pm, Chris Nicholas wrote:

Has anybody in the good old US of A developed a printed, available,
specification for the pay-on gear for Dyneema etc. rope – like low
weight (aluminum? - note USA spelling!) rollers, low friction and low
inertia bearings, anything special needed for the drum , etc.?

I suspect that there is scope for saving inventing too many wheels
twice over.

(And for the avoidance of doubt, I am NOT going to get into the Bildan/
DC/DJ etc. spats – you are all welcome to keep those among
yourselves.)

Chris N.

While I'm sure there *are such documents handy, if your goal is
'saving wheels' one can (and is better off...) doing away with the
level wind mechanism altogether, which is itself a source of
additional hassle in most operations. The trick is to use a high
enough aspect drum and have a long enough run between the fairlead
assy and the drum, somewhere around 1:18 I believe, comparing drum
width to run length between the two mechanisms according to German
DAeC.

Assuming a bigblock/TH400/truck rearend setup is what you're leaning
towards, final drive gearing needs to be selected based on drum
diameter, since larger diameter drums call for higher gear ratios in
the rearends... a small price to pay considering. There are
spreadsheets and other files covering all this on winchdesign BTW

-Paul

PS. join the winchdesign group and comb the postings and files there
as well as keeping up on new ones...http://groups.yahoo.com/group/winchdesign/* -that is if you can
handle more episodes of the Derek/Bill show *

The ratio of drum width to feed is 10:1 for unassisted level winding.
So an 8-inch wide drum needs 80 inches. The Gehrlein Model 62
distance is about 88 inches from axle to rollers. The drum I had
built is 8.5 inches wide. A high ratio can only make it more
effective.

That said, the winch at Littlefield, TX, uses a simple level wind that
is easy to maintain and works very well on their wide drum. The wide
drum advantage is the there is a small shift in the torque arm as the
drum loads.

Frank Whiteley

On Jul 22, 11:16*pm, Frank Whiteley wrote:
On Jul 22, 6:38*pm, sisu1a wrote:



On Jul 22, 4:50*pm, Chris Nicholas wrote:

Has anybody in the good old US of A developed a printed, available,
specification for the pay-on gear for Dyneema etc. rope – like low
weight (aluminum? - note USA spelling!) rollers, low friction and low
inertia bearings, anything special needed for the drum , etc.?

I suspect that there is scope for saving inventing too many wheels
twice over.

(And for the avoidance of doubt, I am NOT going to get into the Bildan/
DC/DJ etc. spats – you are all welcome to keep those among
yourselves.)

Chris N.

While I'm sure there *are such documents handy, if your goal is
'saving wheels' one can (and is better off...) doing away with the
level wind mechanism altogether, which is itself a source of
additional hassle in most operations. The trick is to use a high
enough aspect drum and have a long enough run between the fairlead
assy and the drum, somewhere around 1:18 I believe, comparing drum
width to run length between the two mechanisms according to German
DAeC.

Assuming a bigblock/TH400/truck rearend setup is what you're leaning
towards, final drive gearing needs to be selected based on drum
diameter, since larger diameter drums call for higher gear ratios in
the rearends... a small price to pay considering. There are
spreadsheets and other files covering all this on winchdesign BTW

-Paul

PS. join the winchdesign group and comb the postings and files there
as well as keeping up on new ones...http://groups.yahoo.com/group/winchdesign/*-that is if you can
handle more episodes of the Derek/Bill show *

The ratio of drum width to feed is 10:1 for unassisted level winding.
So an 8-inch wide drum needs 80 inches. *The Gehrlein Model 62
distance is about 88 inches from axle to rollers. *The drum I had
built is 8.5 inches wide. *A high ratio can only make it more
effective.

That said, the winch at Littlefield, TX, uses a simple level wind that
is easy to maintain and works very well on their wide drum. *The wide
drum advantage is the there is a small shift in the torque arm as the
drum loads.

Frank Whiteley

The German DAeC winch recommendation calls for an 18:1 ratio between
fairlead pulleys and the drum width. However, that's for steel
cable. "Plastic Rope" seems to spread out nicely so even 8:1 seems to
work.

On Jul 22, 5:50*pm, Chris Nicholas wrote:
Has anybody in the good old US of A developed a printed, available,
specification for the pay-on gear for Dyneema etc. rope – like low
weight (aluminum? - note USA spelling!) rollers, low friction and low
inertia bearings, anything special needed for the drum , etc.?

I suspect that there is scope for saving inventing too many wheels
twice over.

(And for the avoidance of doubt, I am NOT going to get into the Bildan/
DC/DJ etc. spats – you are all welcome to keep those among
yourselves.)

Chris N.

The hydrowinch feed is a single sheave approximately 8inches in
diameter, perhaps an 1.25" wide with a tapering v-notch. Aluminum and
powder coated. I suspect a common bearing type. Close enough
tolerance in the fairlead to avoid problems.

The original drum has been reinforced at the center, but has a u-
shaped cross section. About 36" at inner core.

See my other post about the drum I recently had built. Worked fine
though the axle shaft align is slightly off leading to a slight
tendancy to load the rope to one side. A bit of cutting and welding
needed to correct this. Images in winchdesign Yahoo group.

Frank Whiteley

Chris,

Nothing special required, except that the rollers or pulleys should be
smoothed out and polished if they have been used for steel cable. Some
types of drum may need to be reinforced as Dyneema can slip and tighten on
the drum to the extent that it get crushed.

What type of winch do you have?

Derek Copeland


At 23:50 22 July 2009, Chris Nicholas wrote:
Has anybody in the good old US of A developed a printed, available,
specification for the pay-on gear for Dyneema etc. rope =96 like low
weight (aluminum? - note USA spelling!) rollers, low friction and low
inertia bearings, anything special needed for the drum , etc.?

I suspect that there is scope for saving inventing too many wheels
twice over.

(And for the avoidance of doubt, I am NOT going to get into the Bildan/
DC/DJ etc. spats =96 you are all welcome to keep those among
yourselves.)

Chris N.

Thanks for answers so far.

Derek, we have two ex-ATC winches (Eagle or Wild – not sure which), re-
equipped with USA-made V8’s and auto gearboxes. Both run on LPG or
similar. One has a completely new cab, the other a modified cab.

We bought the basic winches in about 1991 at auction, cost less than
£1000 (say $1600) each. First was modified by ourselves at very low
cost, with an ex-Ford Tow truck 5.6L V8 and associated auto
transmission. The second we used a winch-builder at another gliding
club who had built their Tost winch, and he modified ours including
new big V8 and auto transmission, and the completely new cab. I think
we spent about £14000 on the conversion, and completed a bit ourselves
at very modest extra cost.

Chris N.

Chris Nicholas wrote:
Thanks for answers so far.

Derek, we have two ex-ATC winches (Eagle or Wild – not sure which), re-
equipped with USA-made V8’s and auto gearboxes. Both run on LPG or
similar. One has a completely new cab, the other a modified cab.

We bought the basic winches in about 1991 at auction, cost less than
£1000 (say $1600) each. First was modified by ourselves at very low
cost, with an ex-Ford Tow truck 5.6L V8 and associated auto
transmission. The second we used a winch-builder at another gliding
club who had built their Tost winch, and he modified ours including
new big V8 and auto transmission, and the completely new cab. I think
we spent about £14000 on the conversion, and completed a bit ourselves
at very modest extra cost.

Chris N.


I can add that I've launched from at least one of those winches, and had
very nice launches. Probably down to the driver, though there's clearly
nothing wrong with the winch(es).

Hint for US clubs who go for a winch - pilots should always thank the
winch driver for good launches, and explain what went wrong if a launch
is not satisfactory. This feedback helps the driver to improve, and also
means that your own foibles might be catered for in future launches!
Poor launches are often the pilot's own fault, and winch drivers like to
know that it wasn't their poor driving.

On Jul 23, 12:45*am, Derek Copeland wrote:
Chris,

Nothing special required, except that the rollers or pulleys should be
smoothed out and polished if they have been used for steel cable. Some
types of drum may need to be reinforced as Dyneema can slip and tighten on
the drum to the extent that it get crushed.


More spectacularly bad advice from Del C.

Smoothing and polishing rollers will NOT work since the rope slides in
a helical path on the roller if the wrap angle is not exactly at right
angles to the roller. All roller designs used with 'plastic rope'
show rings of melted plastic when used with Plasma Rope. The rope
itself shows severe damage from melting. Using rollers with Plasma
Rope is an expensive mistake

Plasma Rope (Spectra/Dyneema) should have swiveling pulleys with
specific pulley groove geometry. I have a tested design for fairlead
pulleys with a Plasma specific guillotine that I'll let anybody use to
make their own. E-mail me and I'll send the drawings.

I assume that Bill's comment is intended to be yet another thinly veiled
attack on Skylaunch, who make an excellent winch! There is no hard
evidence that rollers are any less Dyneema friendly, and in any case
Skylaunch can supply and fit swivelling pulleys if you think they are
better. Our new Skylaunch winches at Lasham are so fitted.

Again the rollers he is talking about are as fitted to antiquated US
Gerhlein winches, and his Ford Model T analogy is about right.

The guillotine issue is more relevant. For some reason hardened steel
blades that will chop steel cable many times are instantly blunted when
used on any type of UHMWPE synthetic cable. I believe the fix is to
replace the anvil with a bronze component. So much for modern materials
and technology!

Derek Copeland

At 23:39 23 July 2009, bildan wrote:
On Jul 23, 12:45=A0am, Derek Copeland wrote:
Chris,

Nothing special required, except that the rollers or pulleys should be
smoothed out and polished if they have been used for steel cable. Some
types of drum may need to be reinforced as Dyneema can slip and
tighten
o=
n
the drum to the extent that it get crushed.


More spectacularly bad advice from Del C.

Smoothing and polishing rollers will NOT work since the rope slides in
a helical path on the roller if the wrap angle is not exactly at right
angles to the roller. All roller designs used with 'plastic rope'
show rings of melted plastic when used with Plasma Rope. The rope
itself shows severe damage from melting. Using rollers with Plasma
Rope is an expensive mistake

Plasma Rope (Spectra/Dyneema) should have swiveling pulleys with
specific pulley groove geometry. I have a tested design for fairlead
pulleys with a Plasma specific guillotine that I'll let anybody use to
make their own. E-mail me and I'll send the drawings.