Tying the Spider lines for Combat use.

[Doug Burright]

Guys around here are using the fishing line for their Combat planes. Whether it is even what the AMA supports in the "Competition Regulations" is even the stuff they're using, is up for some discussion. Firstly, they debate the approved knot, and remark "I have a better knot than that." Second, after tying a reasonable facsimile of the approved knot, one guy ties it to the connectors in a way that looks as how you join two rubber band loops together, to make a figure 8 shape-THAT KNOT! There went any strength in that rig! Another guy says we're all wet- because all you have to do is go around once, and tie any old knot. Says: "That's how the 'REAL' combat guys are doing it.

Well, AMA shows ONE approved method to tie a knot on that kind of line, and that it may only be used for sport flying, not in competition, IF I AM INTERPRETING THE RULES CORRECTLY! Combat may allow it in contests, but it should still be the correct knot, right?

I fly Stunt, and some 1/2A stuff, so I don't have much bearing on the issue, other than I don't want to get whacked by one of their 80 mph planes, if something went totally wrong. This could turn into a big deal, if they don't get on the same page, and a serious accident were to occur. They don't listen to me...I fly stunt-safely, and to the best of my ability,

[kenneth cook]

           The AMA currently allows this line assuming it's the proper # test and the required knot is tied. It's also my understanding that this line can be used for stunt in competition provided the CD allows it. I would think that if 80 mph is the speed the combat guys are flying, they should also be using some form of shutoff which would immensely deter a fly away. Ken

[Paul Smith]

Combat needs to maintain a policy of forcing everyone in each event to use exactly the same lines.  Otherwise one line will cut the other and cause even more flyaways.

If we're going the fish line, let it be.  But steel has consistant and predictable metallurgical properties.  We would need to find an acceptable way to define exactly which plastic fish line we will allow.   When I tried to check this out at Bass Pro Shop I saw a wall with at least a thousand different fish lines, of which many had names like people mention here.

.018" 7-strand steel is what it is.

[mike londke]

I think part of the problem is that AMA only mentions Spectra line. That is a trademarked name for an oriented-strand gel spun fiber. There are other trademarked gel-spun lines like Dyneema, Spiderwire and so on. The only line I have found that is %100 Spectra is PowerPro brand. So the way I read it only Spectra line is approved. Also I think many who want to use gel-spun line don't know the difference between the types of line either. Hopefully Phil Cartier will chime in on this he knows more about it than anyone.  As far as defining an acceptable fishing line AMA has already done that. They quite specifically call out Spectra.

[Jim Carter]

May I offer my experience as part of the discussion?  Because of the toughness of the line and past experience I opted to set up the lines with the use of a metal crimp shown on page CLG-7, figure 4, for multi strand cable.  I've found it to be very secure and strong enough that I have been able to loop one end to a secure point on the fence and using my fishing scale exceeded the rated test by at least 20% with each set i.e.  15# test pulled to 18#.  Has anyone else experienced similar results?  I'd love to test my 80# SpiderWire lines to their failure rate but my scale only goes to 50# so all I can say is I know I physically haven't been able to snap them, by pulling on them, with all my might and weight!!

Jim

[FLAMER & Combat Smasher]

 
Recent updates that I have received from a very reliable source ( It think it was Spider Man or Superman or one of those 'Super Hero's ) reiterated that the 'Knot' in question was shown to the AMA coordinator for contol line tying for competition is acceptable.  However, the above noted Super Hero's noted above mentioned that the only true 'Spider Knot' belongs to this guy.  His Knots will live through a Cat 19 Hurricane.   
http://www.fcps.edu/islandcreekes/ecology/Arthropods/Black%20and%20Yellow%20Garden%20Spider/byargiope8m1.jpg

 Best Regards,
    And Happy Smashing   

[mike londke]

Recent updates that I have received from a very reliable source ( It think it was Spider Man or Superman or one of those 'Super Hero's ) reiterated that the 'Knot' in question was shown to the AMA coordinator for contol line tying for competition is acceptable.  However, the above noted Super Hero's noted above mentioned that the only true 'Spider Knot' belongs to this guy.  His Knots will live through a Cat 19 Hurricane.   
http://www.fcps.edu/islandcreekes/ecology/Arthropods/Black%20and%20Yellow%20Garden%20Spider/byargiope8m1.jpg

 Best Regards,
    And Happy Smashing   

LAME!

[phil c]

It's a little more complicated than Paul makes out.  A lot of the ".018" stainless wire comes in under .018, sometimes as small as .017, due to the way it is made.  Stainless steel is not as strong as many other steels or music wire.  The .018 stuff usually breaks at the termination with a pull of 50-55lbs. Some of  the F2D lines mike out at .0175 and will take 65+ lbs.

The Power Pro 100 lb. test Spectra will break at 50lbs, like stainless steel with even a simple overhand knot tied on a bight- fold the line over and tie an overhand knot on the doubled line to leave a loop.  The 5 turn Uni knot in the rulebook is usually stronger, but it needs an overhand stop knot in the tag end.  Unless the knot is pulled down smoothly and carefully with some spit for lubrication the fishing line is slippery enough to pull right through the knot. It also has to be tied to a clip of some kind and is very difficult to tie to an exact length. Other knots such as a figure eight knot tied on a bight or a figure knot on a bight(see picture) can't slip, are easy to tie to fixed lengths,  and will pull over 50 lbs if they are pulled down smoothly.

Some folks have gotten cheap stuff from China that isn't nearly as strong and stiff.  If you make up a 60ft. line and it stretches more than 1.5 inches with a 35lb. pull test it's not the right stuff.  Spectra is as strong as or stronger than stainless steel and stretches about the same amount.  I used 100lb test Spectra on F2D planes at the NATS and Team Trials.  It stretched exactly the same amount as the 4 strand brass-coated F2D line-  1.5in. the 44lb pull test.

Jim Carter's suggestion of using standard crimps is a good that I'll give a try.  A knot is very easy but if the crimp is stronger that is a plus.

A couple of thing to watch out for.  If you run the lines directly to the bellcrank the lines may start to wear at the leadout guide.  It doesn't seem to make much difference what you use for a guide- brass eyelets, nylon eyelets, even glass beads- will all wear.  Depending on how it is braided you may just see little black nubbins or a bit of fraying.  If you see actual loose ends of fiber frayed the length of the line travel it is probably time to either pull test the lines individually, or just throw them out.  Wrapping the lines up from the plane and switching them end for end after every use evens out any wear and will double the useful life.  Unlike stainless where you can't see the fatigue in the wire or a broken wire in the crimp or wrapping the Spectra lets you see when it is getting tired.

Some F2D models have very rough wire for the leadout fittings.  Polish out any visible roughness.

Most brands of Spectra line are a little draggier than stainless lines.  If you have to go as fast as possible(dumb idea) don't switch.  Makes no difference in the speed limited events.



A couple of things to watch out flr

[Jim Carter]

Jim Carter's suggestion of using standard crimps is a good that I'll give a try.  A knot is very easy but if the crimp is stronger that is a plus.

Hi Phil, just as a side note, I (knock on wood) still have yet to experience a failure (not that I want to, but if it happens, Lord knows I've gotten my moneys worth).  The single set of 80# SpiderWire lines that I've been using for my .35, .40 and .60 sized planes have been used well over well over 250 flights (almost 300 as I've been keeping a daily flight log) over the past 20 months with no obvious, noticeable signs of wear or fraying.  Yes, they may be a bit more draggy now than when I first used them because they definitely are fuel residue, oil covered and even saturated but they're still working quite well for me.  I thought the crimps might cut through the points where the lines pass through but there's no obvious, visible evidence of wear at those points either!!  I'm really very pleased!!  I'm thinking about making up a set of 50# just to see if they hold up as well  .

Jim

[Phil Krankowski]

I fly 1/2a on spectra, and nearly have 1 set per plane.  A sharpie marker goes a long ways to making lines equal.  Include the mark inside the turns of the knot.

I did pull some doubled 5-turn uni-knots to failure and they all broke at or over the rated weight in 20# test Power Pro.  (Doubled means take the end foot of line and fold it over on itself, then treat this section as one strand)  I was pulling by hand on a luggage scale.

Phil