Cutting plasma rope

There is considerable interest in the UK in using
plasma/dyneema rope for winch launching. However,
the main obstacle appears to be finding an efficient
method of cutting the rope in event of an emergency.
Has anyone ot there found the definitive method???

Hot wire/blade seems to be *the* method.

Perhaps a blade heated by the engine exhaust since an electrical system
might be subject to 'system bugs'. Actually its not such a stupid idea cone
to think of it. The blade/cutter mechanism needs to be on the glider side of
the winch and therefore downwind of the winch driver.

The only other solution I can think of is a blade that completes a circuit
across a primary battery when it is in the cutting position but that would
take a few seconds to heat up to the plasma melting point.

Has anyone contacted Marlow ropes in E. Sussex to find out what they
recommend? They manufacture Dynema cores sailing lines I think.

Ian

"Robert Makin" wrote in message
...
There is considerable interest in the UK in using
plasma/dyneema rope for winch launching. However,
the main obstacle appears to be finding an efficient
method of cutting the rope in event of an emergency.
Has anyone ot there found the definitive method???

On Sun, 02 Nov 2003 09:27:15 +0000, tango4 wrote:

Perhaps a blade heated by the engine exhaust

Maybe in an emergency the winch driver could climb out of the cab, grab
hold of the (hopefully stationery) plasma rope and pull it over a hot
exhaust pipe to cut it. Worth thinking about if you fortunate enough to
winch with plasma.

We have a set of bolt cutters mounted in the winch cab to function as a
backup to cut our steel cable in the unlikely event that the winch
guillotine fails to function in an emergency. It is part of the equipment
that must be present on the winch before launching commences. (Normally
they only get used for cutting off scrap cable after a tangle on the
drum).

Cheers

Ian

"Robert Makin" wrote in message
...
There is considerable interest in the UK in using
plasma/dyneema rope for winch launching. However,
the main obstacle appears to be finding an efficient
method of cutting the rope in event of an emergency.
Has anyone ot there found the definitive method???

I saw this message in another trhead named "Winch way is up":



You may want to have a look at
http://www.aec-landau.de/projekte/PE-Seil/vortrag.htm

They have modified their winch to cut their PE cable. You find the email
address of the author at the end of that page.
Eggert

Cutting Plasma rope

Skylaunch UK HAVE developed equipment that will cut
plasma rope succesfully.

A number of UK clubs have expressed interest in the
use of this rope which has reportedly many benefits
over steel, except perhaps on cost.

What is required is some proving tests in the UK to
ensure that not only are the claims valid BUT that
it can be used safely within the terms of UK Health
and Safety Legislation AND that is benefits are cost
effective.

Offers are on the table for a winch to be made available
to be modified to take the cutting gear and for a reduce
cost rope for the tests. Less than £1000 at the last
enquiry.

The UK research appears to have gone as far as it can
without someone forking out some cash for it to continue.

The equipment and offers of free help and involvement
are at present on the table.

If UK clubs, who want the benefits but not the cost,
want this to progress then someone has to dig into
their pocket. If several clubs pool their resources
the work can progress

Sadly at present no UK clubs want to part with a few
hundred quid to support the research.

That is where it stands in the UK.

Dave Martin

Hi Dave --

Thanks for the heads up. One question: Does the UK guillotine
specification include the necessity for cutting a moving synthetic line,
or would cutting a stationary line be satisfactory?

Thanks.

Bob Johnson

Dave Martin wrote:

Cutting Plasma rope

Skylaunch UK HAVE developed equipment that will cut
plasma rope succesfully.

A number of UK clubs have expressed interest in the
use of this rope which has reportedly many benefits
over steel, except perhaps on cost.

What is required is some proving tests in the UK to
ensure that not only are the claims valid BUT that
it can be used safely within the terms of UK Health
and Safety Legislation AND that is benefits are cost
effective.

Offers are on the table for a winch to be made available
to be modified to take the cutting gear and for a reduce
cost rope for the tests. Less than £1000 at the last
enquiry.

The UK research appears to have gone as far as it can
without someone forking out some cash for it to continue.

The equipment and offers of free help and involvement
are at present on the table.

If UK clubs, who want the benefits but not the cost,
want this to progress then someone has to dig into
their pocket. If several clubs pool their resources
the work can progress

Sadly at present no UK clubs want to part with a few
hundred quid to support the research.

That is where it stands in the UK.

Dave Martin

At 16:30 03 November 2003, Bob Johnson wrote:
Hi Dave --

Thanks for the heads up. One question: Does the UK
guillotine
specification include the necessity for cutting a moving
synthetic line,
or would cutting a stationary line be satisfactory?

Thanks.

Bob Johnson

Hi Bob

Thanks for the interest.

Without getting the BGA winch manual out the answer
to your question is yes. In practice the guillotines
are required to cut both stationary and moving cables.


I have not seen the new Skylaunch equipment in action,
but I am told the cut is on a stationary rope. The
experts tell me this is the most difficult way to cut
rope and that a rope moving under tension is easier
to cut.

This is partly the reason we need to carry out load,
flight and cutting tests in a live situation. If only
to satisfy ourselves.

Dave Martin

Hello Dave --

Regarding the moving line, can you think of a situation where the winch
driver, upon becoming aware of an emergency situation, would want or
need to keep the line coming in?

You can see where this is leading: If the line can be stopped, why
couldn't the operator jump out of his cab and cut the synthetic line
with a sharp knife?

Or do you think this action would somehow place him in danger?

BJ

Dave Martin wrote:

At 16:30 03 November 2003, Bob Johnson wrote:
Hi Dave --

Thanks for the heads up. One question: Does the UK
guillotine
specification include the necessity for cutting a moving
synthetic line,
or would cutting a stationary line be satisfactory?

Thanks.

Bob Johnson

Hi Bob

Thanks for the interest.

Without getting the BGA winch manual out the answer
to your question is yes. In practice the guillotines
are required to cut both stationary and moving cables.

I have not seen the new Skylaunch equipment in action,
but I am told the cut is on a stationary rope. The
experts tell me this is the most difficult way to cut
rope and that a rope moving under tension is easier
to cut.

This is partly the reason we need to carry out load,
flight and cutting tests in a live situation. If only
to satisfy ourselves.

Dave Martin

Bob Johnson wrote in message ...
Hello Dave --

Regarding the moving line, can you think of a situation where the winch
driver, upon becoming aware of an emergency situation, would want or
need to keep the line coming in?

Can't really think of one. But we are talking about an emergency
situation here so anything can be possible.


You can see where this is leading: If the line can be stopped,...

Can it? Before you were talking about 'want to' and 'need to'. That's
not the same. I can imagine situations where the cable cannot be
stopped or starts moving again.

... why
couldn't the operator jump out of his cab and cut the synthetic line
with a sharp knife?

Again: Cutting the winch cable is an emergency. Why on earth would you
want to lose time jumping from the winch and looking for your cutting
tool?


Or do you think this action would somehow place him in danger?

Yes it could. See above.

BTW: In my 18 seasons of gliding I am not aware of the winch cable
ever been cut in an emergency. And that's in about 70'000 launches.

Regards
Marcel

BTW: In my 18 seasons of gliding I am not aware of the winch cable
ever been cut in an emergency. And that's in about 70'000 launches.

Regards
Marcel

Our club had an instance recently where it was required to cut the cable
but the pilot did some radical flying (75degree nose down in a ventus a
at 700 feet) he let go of the stick and used both hands on the release
and the cable came off.
This ventus had been backreleasing for some time and an "adjustment"
was done but the backrelease angle was now somewhere near the wheel
centre.
One shaken pilot and one big lesson .
One senior pilot of 45 yrs 11000hrs said he had never seen a hangup
in all his flying.