Use of weak links

Paul wrote:
Currently the club that I am part of don't seem to be too concerned about
the safety aspects of using the correct weak links for winch launching
and I'd like to know how safe it is.

Currently I see two issues with the winch launching:

1. Sometimes a weak link is not used at all. The gliders are attached
directly to the winch cable (via drogue chute and various connectors).

2. When a weak link is included in the cable (only a primary link - no
reserve link) it is used for all glider types (G102 Astir, G103 Twin II,
ASW20, LS4) and I'm not even sure what the breaking strain is. My guess
is it's a Tost #1 black (1000 daN) weak link but that's hard to tell
because its weathered and the protective sleeve obscures the Tost number.
The weak link is never changed between glider types.

According to what I have read (glider manuals and Tost manual) the
maximum winch load that should be exerted on most of the single seaters
is 500 daN and on the G103 Twin II it's 750 daN.

Am I being paranoid about safety? Are weak links not that important for
safe winch launching?

I took the matter up with the safety officer who said I need to take it
up with the CFI but I'd like to get some advice and input before I engage
with the CFI over the matter.
I'm new to soaring so I don't know it all.

Thanks

The FARs have a rule for it. If I recall: 80 to 200% of ...(forget which
weight/force...)
Darn it!

Brian W

On Jun 2, 8:31*pm, brian whatcott wrote:
Paul wrote:
Currently the club that I am part of don't seem to be too concerned about
the safety aspects of using the correct weak links for winch launching
and I'd like to know how safe it is.

Currently I see two issues with the winch launching:

1. Sometimes a weak link is not used at all. The gliders are attached
directly to the winch cable (via drogue chute and various connectors).

2. When a weak link is included in the cable (only a primary link - no
reserve link) it is used for all glider types (G102 Astir, G103 Twin II,
ASW20, LS4) and I'm not even sure what the breaking strain is. My guess
is it's a Tost #1 black (1000 daN) weak link but that's hard to tell
because its weathered and the protective sleeve obscures the Tost number.

I took the matter up with the safety officer who said I need to take it
up with the CFI but I'd like to get some advice and input before I engage
with the CFI over the matter.
I'm new to soaring so I don't know it all.

Thanks

And exactly why is some CFIG the last word on what is OK or safe?

Winching without a weak link is right up there on the suppidity list
with downwind ground launches or tail-scrapping vaults into the air
instead of gradual rotations. All of which we have observed by so-
called "experienced" CFI's some of whom have turned out to have
relatively little experience or worse have practiced bad habits for
years.

Interesting that a newbe has to come on the field, point out the
emperor has no clothes to the soaring sages and bring it to light on a
dicussion group for common sense and support.

BTW. See the preliminary findings on Sandhill Soaring's winch mishap
that took a life a year ago.

Winch cables can be too strong and break things inside the aircraft,
long before the wings come off; or way too fragile and introduce an
unexpected surprise.

http://www.livingstondaily.com/artic...lider+accident

Michael

On Jun 2, 6:31*pm, brian whatcott wrote:
Paul wrote:
Currently the club that I am part of don't seem to be too concerned about
the safety aspects of using the correct weak links for winch launching
and I'd like to know how safe it is.

Currently I see two issues with the winch launching:

1. Sometimes a weak link is not used at all. The gliders are attached
directly to the winch cable (via drogue chute and various connectors).

2. When a weak link is included in the cable (only a primary link - no
reserve link) it is used for all glider types (G102 Astir, G103 Twin II,
ASW20, LS4) and I'm not even sure what the breaking strain is. My guess
is it's a Tost #1 black (1000 daN) weak link but that's hard to tell
because its weathered and the protective sleeve obscures the Tost number.

On Jun 2, 2:43*am, Paul wrote:
Currently the club that I am part of don't seem to be too concerned about
the safety aspects of using the correct weak links for winch launching
and I'd like to know how safe it is.

Currently I see two issues with the winch launching:

1. Sometimes a weak link is not used at all. The gliders are attached
directly to the winch cable (via drogue chute and various connectors).

2. When a weak link is included in the cable (only a primary link - no
reserve link) it is used for all glider types (G102 Astir, G103 Twin II,
ASW20, LS4) and I'm not even sure what the breaking strain is. My guess
is it's a Tost #1 black (1000 daN) weak link but that's hard to tell
because its weathered and the protective sleeve obscures the Tost number.
The weak link is never changed between glider types.

According to what I have read (glider manuals and Tost manual) the
maximum winch load that should be exerted on most of the single seaters
is 500 daN and on the G103 Twin II it's 750 daN.

Am I being paranoid about safety? Are weak links not that important for
safe winch launching?

I took the matter up with the safety officer who said I need to take it
up with the CFI but I'd like to get some advice and input before I engage
with the CFI over the matter.
I'm new to soaring so I don't know it all.

Thanks

Paul, that you would question safety procedures in this way suggests
you will have a long and illustrious career as a glider pilot. I only
wish others would do the same.

I propose your club bring in outside experts for a winch clinic.

Bill D

80-200% for aero-towing *
100-200% for ground launching *
of max certificated gross weight *
tim
-
Please visit the Wings & Wheels website at www.wingsandwheels.com



wrote in message
...
On Jun 2, 8:31 pm, brian whatcott wrote:
Paul wrote:
Currently the club that I am part of don't seem to be too concerned
about
the safety aspects of using the correct weak links for winch launching
and I'd like to know how safe it is.

Currently I see two issues with the winch launching:

1. Sometimes a weak link is not used at all. The gliders are attached
directly to the winch cable (via drogue chute and various connectors).

2. When a weak link is included in the cable (only a primary link - no
reserve link) it is used for all glider types (G102 Astir, G103 Twin II,
ASW20, LS4) and I'm not even sure what the breaking strain is. My guess
is it's a Tost #1 black (1000 daN) weak link but that's hard to tell
because its weathered and the protective sleeve obscures the Tost
number.
The weak link is never changed between glider types.

According to what I have read (glider manuals and Tost manual) the
maximum winch load that should be exerted on most of the single seaters
is 500 daN and on the G103 Twin II it's 750 daN.

Am I being paranoid about safety? Are weak links not that important for
safe winch launching?

I took the matter up with the safety officer who said I need to take it
up with the CFI but I'd like to get some advice and input before I
engage
with the CFI over the matter.
I'm new to soaring so I don't know it all.

Thanks

The FARs have a rule for it. If I recall: 80 to 200% of ...(forget which
weight/force...)
Darn it!

Brian W- Hide quoted text -

- Show quoted text -

Check what that applies to. I predict you will see it relates to aero
towing.
UH

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Brian wrote:
/snip/
Specifically what I am saying is that unless you are exceeding the
Maximum Winch Launch speed of the glider it should be impossible to
overstress the wings as the wing will stall before exceeding maximum
structural load of the aircraft.

Brian


This is a perfectly sound argument in many phases of flight.
But a tow capable of exerting enough force on a stalled structure
will certainly break it. A winch need not relax when a wing stalls....
Visualize an airframe being hauled along at an AoA of 90 degrees,
to exaggerate this point...

Brian W

On Thu, 03 Jun 2010 19:43:46 -0500, brian whatcott
wrote:


Specifically what I am saying is that unless you are exceeding the
Maximum Winch Launch speed of the glider it should be impossible to
overstress the wings as the wing will stall before exceeding maximum
structural load of the aircraft.

Brian


This is a perfectly sound argument in many phases of flight.
But a tow capable of exerting enough force on a stalled structure
will certainly break it. A winch need not relax when a wing stalls....
Visualize an airframe being hauled along at an AoA of 90 degrees,
to exaggerate this point...

This won't break the wing spars either.

As long as the IAS is below VA (in other words: in the green range of
the airspeed indicator), no control input at all can damage the glider
- the definition of VA is that this is the speed under which a high
speed stall will prevent exceeding the maximum g-load. So, as long as
you are slower than VA, you are safe.

(Of course - combined control inputs can indeed break the structure
even below VA, usually by torsional load on the tail boom by a
deflected rudder at speeds close to VA combined with significant yaw
angle.)


The problem of exceeding the Maximum Winch Launch speed is not the
wing, but the attachment of the tow hook to the fuselage structure.
Pretty hard to explain why you landed with the belly hook missing...


Cheers
Andreas
Bye
Andreas

On Thu, 3 Jun 2010 14:38:51 -0400, "Tim Mara"
wrote:

80-200% for aero-towing *
100-200% for ground launching *
of max certificated gross weight *

Most amazing.
This violates the POHs of all the gliders I know.

Cheers
Andreas

Bye
Andreas

For clarity, did the original poster mean Chief Flying Instructor by
"CFI" (UK and some other countries' usage), or "some CFIG” as another
(USA?) poster thought?

Either way, what is the safety officer doing, not caring and deferring
to the the CFI whoever it is?

Chris N.