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Aug 28, 2016, 03:13 AM
supreme being of leisure
ZAGNUT's Avatar
i use 0.68mm braided dyneema, think it's rated for 70kg....way, way overkill but easier to see and handle.
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Aug 28, 2016, 12:39 PM
solastagia
kcaldwel's Avatar
The rules do say 100m of nylon line, with a minimum diameter of 0.7mm:

"b) is started with a rubber rope consisting of 15 0.5 meter rubber hose and 100 meters nylon rope with a minimum diameter of 0.7 mm with a knotted into flags."

Kevin
Aug 28, 2016, 02:24 PM
Registered User
0.7mm is ridiculous, weight of such line is half of the plane !
I am using 0.4 mm since the beginning and I don't see why switch to a bigger diameter...
Aug 28, 2016, 03:19 PM
supreme being of leisure
ZAGNUT's Avatar
more like 40g for 100m length. where i fly it is constantly getting caught on rocks and weeds so it's nice to be able to yank it around without worrying about damage.
Aug 28, 2016, 03:40 PM
solastagia
kcaldwel's Avatar
Quote:
Originally Posted by renatoa
0.7mm is ridiculous, weight of such line is half of the plane !
I am using 0.4 mm since the beginning and I don't see why switch to a bigger diameter...
35g for 100m of 0.7mm nylon line. You must have a very light airplane if 35g is half the weight.

http://fishingcampus.com/product/0-7...-tackle-clear/

Smaller diameter lines will have less drag, so will launch higher. I believe they are trying to stop people from using ultra thin line to gain an advantage, and head off another possible launching technology war like F3J.

Kevin
Aug 29, 2016, 02:17 AM
Registered User
If your field is so plagued by rocks and weeds, then I would rather worry about hook at launch, than resist to a serious yank...
Indeed I am launching on a fine field, a small aerodrome for ULMs, not golf class grass, but clear off any weed higher than ankle, and no rocks. As I know, this is the standard for all Germany and UK clubs I visited so far.

What is wrong to launch higher... You can't more than 100 meters anyway...
Aug 29, 2016, 02:19 AM
Registered User
Another related subject that I think could be covered here: methods to join line to elastic, elastic to elastic, elastic to ground hook...
I think the way how the stress apply in the point where elastic is joined to anything else is critical for the future health of the whole assembly.
Please, don't tell me you just made knots and nothing else...
Aug 29, 2016, 11:08 AM
Registered User
I think the rule is based on stopping guys using very thin line that will add stretch (mono) to the system. For all intensive purposes unless you are competing in the class it doesn't matter what you use. If you don't fly on grass mono will be a pain, well unless you like tying knots.

For connections I like to use swivels. Makes it way easier to manage the line. Between all the hard points I like to use heavy duty key rings. All stuff that you can find on Amazon.
Aug 29, 2016, 02:26 PM
Registered User
Swivels and rings all have metal edges, even not so sharp they will end cutting elastic.
I try to imagine a connector like a coaxial pinch, able to grip the whole mass of elastic from inside and outside, without bends over any kind of edges.
Aug 29, 2016, 03:25 PM
LJH
LJH
Moths do not fly inverted
LJH's Avatar
I will be trying out the red HK tubing combined with a .9MM braided Dyneema line that I sell. because the line is braided it is not terrible with becoming a rats nest but time will tell is that holds true.

In connecting the the line and rings to the tubing I have played around with a couple methods and wanted to get your thoughts. First I tried a short piece of wood dowel that fits inside the tubing with some contact cement. It holds but I am nervous that at some point it could let go....that could be a problem. My second meathod was to use the same dowel and chucked it up in my drill press and but grooves in it. I then inserted it into the tube and used a small cable tie and cinched the the tube down into the grooves. That feels much safer to me. The third idea was to tie a diamond knot in the line and shove it down the hole in the tubing and again use a cable tie to cinch down on the tubing. I tried it and it seems good but I worry that the cable tie may work its way off the tubing.

Cheers,
Jim
Aug 29, 2016, 05:28 PM
Registered User
Oh you mean to the high tubing?

I used a home depot 1/4-20 bolt with a loop threaded into a piece of plastic tubing. You stuff that in the tube and use a piece of heat shrink over it. There are a million different ways to do it. Honestly as prone to failure as you think it would be it's not.
Aug 29, 2016, 10:14 PM
Registered User
Roo2's Avatar
I've successfully used a type of self tightening "constrictor" knot to tie cord to rubber tubing in the past to launch other types of projectiles... Anyone else used this connection method?
Aug 30, 2016, 01:40 AM
Registered User
I own both red and blue elastic from HK, they don't compare... the red has no more than 2kg when stretched 4 times. I use it for my 990 mm 280 grams HLG only.
Aug 30, 2016, 07:02 AM
Mark LSF # 3792

Joining to High Start Rubber


I have used plastic tubing barbs. Here is a .Pdf from a manufacturer. Many sizes are available at my local real hardware store. They are light, can be modified and easily inserted with a little hairspray. Work like a Chinese finger puzzle.
Aug 30, 2016, 07:49 AM
Registered User
That is !
Add two zip ties each side, and this is the join I want !

For the line to rubber join I imagine the line passed through this tube, bent over the ribs, inserted into rubber and secured with zip tie. Perfectly collinear join and equal effort distributed around the rubber.


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