Winch Weak Link Strengths

[Kevin Neave[_2_]]

Does anyone out there know how German Glider Manufacturers calculate the
max weak link strength for winching?

Presumanbly this is also related to the max winch speed

For example in the UK the max winch speed of a K13 depends on which weak
link (Brown or Black) is being used

Regards

KN

[Dan Daly[_2_]]

On Thursday, December 7, 2017 at 9:30:08 AM UTC-5, Kevin Neave wrote:
> Does anyone out there know how German Glider Manufacturers calculate the
> max weak link strength for winching?
>
> Presumanbly this is also related to the max winch speed
>
> For example in the UK the max winch speed of a K13 depends on which weak
> link (Brown or Black) is being used
>
> Regards
>
> KN

Download CS22 (previously JAR22) and search for "weak link" using find function.
"CS 22.583 Winch-launching" describes the conditions.
TOST also has a table on weak link strength on p. 16 of their catalogue giving rated load (in decaNewton). Multiply by 2.2481 to get Pounds.
Gliding New Zealand has a useful "advisory circular weak links" with examples and a rule of thumb.

[Bob Kuykendall]

On Thursday, December 7, 2017 at 7:08:15 AM UTC-8, Dan Daly wrote:

>...Multiply by 2.2481 to get Pounds.

With Brexit and all, is there a formula to convert to Euros?

[WB]

On Thursday, December 7, 2017 at 12:32:03 PM UTC-6, Bob Kuykendall wrote:
> On Thursday, December 7, 2017 at 7:08:15 AM UTC-8, Dan Daly wrote:
>
> >...Multiply by 2.2481 to get Pounds.
>
> With Brexit and all, is there a formula to convert to Euros?

Sawzall.

[Kevin Neave[_2_]]

With Brexit and all they're heading for parity

Thanks Dan for the link to CS22.
I think the bit I wanted is CS 22.581 (b)(2)
The ultimate strength of the weak link must be not less than 1.3 x Max
weight.

So for a Max weight of 565kg weak link should be 735kg

Regards

KN

At 19:53 07 December 2017, WB wrote:
>On Thursday, December 7, 2017 at 12:32:03 PM UTC-6, Bob Kuykendall wrote:
>> On Thursday, December 7, 2017 at 7:08:15 AM UTC-8, Dan Daly wrote:
>>
>> >...Multiply by 2.2481 to get Pounds.
>>
>> With Brexit and all, is there a formula to convert to Euros?
>
>Sawzall.
>

[AS]

On Friday, December 8, 2017 at 4:00:08 AM UTC-5, Kevin Neave wrote:
> With Brexit and all they're heading for parity
>
> Thanks Dan for the link to CS22.
> I think the bit I wanted is CS 22.581 (b)(2)
> The ultimate strength of the weak link must be not less than 1.3 x Max
> weight.
>
> So for a Max weight of 565kg weak link should be 735kg
>
> Regards
>
> KN
>
>

So the glider will take off at 565kg plus 735kg = 1300kg?? Wow!
Sorry - I couldn't resist! I always cringe when I see mass and force happily mixed and used interchangeably. There is a reason why Tost calls out the weak links in daN.

Uli
'AS'

[Kevin Neave[_2_]]

Apologies for mixing the units.

At 13:04 08 December 2017, AS wrote:
>On Friday, December 8, 2017 at 4:00:08 AM UTC-5, Kevin Neave wrote:
>> With Brexit and all they're heading for parity
>>
>> Thanks Dan for the link to CS22.
>> I think the bit I wanted is CS 22.581 (b)(2)
>> The ultimate strength of the weak link must be not less than 1.3 x Max
>> weight.
>>
>> So for a Max weight of 565kg weak link should be 735kg
>>
>> Regards
>>
>> KN
>>
>>
>
>So the glider will take off at 565kg plus 735kg = 1300kg?? Wow!
>Sorry - I couldn't resist! I always cringe when I see mass and force
>happily mixed and used interchangeably. There is a reason why Tost calls
>out the weak links in daN.
>
>Uli
>'AS'
>

[Bruce Hoult]

On Friday, December 8, 2017 at 4:04:23 PM UTC+3, AS wrote:
> On Friday, December 8, 2017 at 4:00:08 AM UTC-5, Kevin Neave wrote:
> > With Brexit and all they're heading for parity
> >
> > Thanks Dan for the link to CS22.
> > I think the bit I wanted is CS 22.581 (b)(2)
> > The ultimate strength of the weak link must be not less than 1.3 x Max
> > weight.
> >
> > So for a Max weight of 565kg weak link should be 735kg
> >
> > Regards
> >
> > KN
> >
> >
>
> So the glider will take off at 565kg plus 735kg = 1300kg?? Wow!

Of course it would. Probably at around 65 - 70 knots. And keep your turns down to maybe 45 degrees of bank if you don't want to break it -- 60 degrees (2 G) absolute maximum.