Author Topic: Spectra Lines (Read 3912 times)

Jerry Leuty · « **on:** August 10, 2011, 08:14:52 PM »

In Control Line World in the July issue and page 76 Tom Hampshire has written an article on using Spectra fishing line for control lines. I went to Cabelas today and purchased 150 yards of 50# test .012 Hi-Vis yellow fishing line. Price $16.99. Tonight I made up a 60' set of flying lines. This stuff is super tough but fairly easy to work with. I did not tie the traditional fishing knots as described in Tom's article. I did try the 5 wrap knot as described on page 79 and it did seem to be super tight. But I opted to make up the lines in the more traditional manner of copper tube with the line fed through it a couple of times then wrapped with copper wire and coated with medium CyA. This stuff is a lot lighter than the 7 strand .015 lines that we use normally. I will be trying these out possibly in the morning on a .40 size profile. A friend of mine purchased a set of Sullivan Dacron lines and I have tried them once. They seem to have extra line drag in the air and of course less feeling of the controls as compared with 7 strand stainless steel lines. The jury is still out on the Sullivan lines as I will try them one more time for comparison. The Spectra lines are approved for combat use but the stunt gurus have yet to do their study on them. So I will experiment with them myself.

Shultzie · « **Reply #1 on:** August 10, 2011, 10:43:08 PM »

Jerry and gang!
A FEW WORDS OF CAUTION... MOST FISH LINE SPECTRA..ESPECIALLY #50 LB. LINES....ARE NOT FACTORY PRE-STRETCHED!

go to:
www.chicokites.com or www.prismkites.com
and read about spectra lines on their forums

MOST HIGH QUALITY (AND EXPENSIVE) PROFESSIONAL SPORT KITE LINES ARE CAREFULLY PRE-STRETCHED BY RIGID FACTORY STANDARDS!

Jerry Leuty · « **Reply #2 on:** August 11, 2011, 09:27:12 AM »

Well more than anything I am cautious and concerned about safety. I witnessed lots of fly aways in combat back in the mid 70s. The last thing that I want to happen is for one of these planes to come loose and hit a hanger, passing by motorist, or God forbid a child. My next step is to make up a line about 6 feet long with the standard ends and do a pull test in my hobby shop. I will use a fish weighing scale to record the breaking point. Also I want to see how much stretch there is. This stuff seems plenty tough. But everything stretches to a breaking point. I certainly do not want to lose a plane due to a unproven set of flying lines let alone damaging property.

Jerry Leuty · « **Reply #3 on:** August 11, 2011, 10:51:19 AM »

The 6' line that I made up to test in the hobby shop broke at the end rather quickly and at around 16#s. I tried this twice and with equal results. That made me nervious. I unrolled the two set lines that I made up last night and did a pull test on them. Note that this test involved 2 lines instead of just one as in the shop testing. The two line set held and did not fail even at past 20 #s. I know that we pull around 35#s or more on the flight line. I will not be using these Spectrum lines for any contest use. In fact until I get some further confidence these may be relegated to .25 size Ring Master sport flying only or put on the g-kids fishing poles to catch the big Carp that hang out around my docks. After all it is fishing line............

Dick Pacini · « **Reply #4 on:** August 11, 2011, 01:22:32 PM »

Just something to think about...you will avoid contests with these lines because of the pull test. I believe the AMA requires that equipment be pull tested before flying. Now, I realize that this is pie-in-the-sky for most modelers and that thousands of flights are made on the sport field or park without the gear being pulled. I would always be concerned that, should a line fail and the plane get away, ultimately hitting someone or damaging property, what would the AMA's insurance position be?

Thirty-six years ago, I flew without pull testing except at contests. Re-entering the hobby today, I built a pull test device that I can use alone, since that is how I fly now. It is fail/fool proof and relatively easy to make for small money. I intend to publish an article about it in the future.

John Cralley · « **Reply #5 on:** August 11, 2011, 05:23:28 PM »

Quote from: Jerry Leuty on August 10, 2011, 08:14:52 PM

In Control Line World in the July issue and page 76 Tom Hampshire has written an article on using Spectra fishing line for control lines. I did try the 5 wrap knot as described on page 79 and it did seem to be super tight. But I opted to make up the lines in the more traditional manner of copper tube with the line fed through it a couple of times then wrapped with copper wire and coated with medium CyA.

You should use the knots described by Tom and not try to reinvent the wheel. The copper tube is used because the steel line looses significant strength when it is kinked but the spectra line is highly flexible and does not mind sharp bends. It ties into strong terminations using fishing knots. As noted above kite fliers have good information on terminating spectra lines.

john e. holliday · « **Reply #6 on:** August 12, 2011, 09:08:12 AM »

All lines should be pulled tested, even if just sport flying. There are posts already on this forum about the fishing lines and how they are done. I now have some that I plan on testing to the extreme before they go on a plane.

John Cralley · « **Reply #7 on:** August 12, 2011, 11:00:09 AM »

Here is a link to a good video for tying a doubled five turn uni-knot with spectra. This knot is supposed to retain a high degree of strength if it is tied properly.

http://video.search.yahoo.com/search/video?p=strongest+knots+for+spectra+line

Shultzie · « **Reply #8 on:** August 12, 2011, 11:14:12 AM »

For proper maintence...and conditioning specta lines...check out the discussion about keeping lines fresh and friction free as possible. Subject on the SPORT KITES forum heading.
www.gwtwkites.com/index.php?topic=2858.0

Jerry Leuty · « **Reply #9 on:** August 12, 2011, 03:32:52 PM »

I did change the line ends from the crimped tool wrapped in copper wire and CyA sealed. I tied all 4 ends as Tom described on page 79 of Control Line World---July 2011 issue and sealed them with medium CyA. I have pull tested them and they seem plenty strong. I know the 42" Ring Master with a .25 on it will be happy with these lines. But I am still a little leery of putting a .40 size plane on them. But I do have a profile that I might risk and on a lite breezy day with them. But with a 50# test, unless the knots give way I don't see a problem. My concern is how the controls feel with any stretch of the lines while in flight. I remember the first time I used solid 60' lines on a Ring Master some 50 years ago now and what a feeling to actually be able to feel the airplane respond to the hand controls as compared to the little Scientific .049 airplanes. That is my main concern. Only a flight will tell if I use these lines for sport flying or end up winding these lines on my fishing poles. My g-kids like to catch these big carp in my lake and it takes lines with this sort of strength to land those big fish. Of course once these carps are out of the water we are suppose to keep them. We do have a lot of large carp out back in the lake.

Lester Nicholson · « **Reply #10 on:** August 12, 2011, 03:45:02 PM »

Are we talking about Sectre Braid fishing line?

Jerry Leuty · « **Reply #11 on:** August 12, 2011, 04:10:03 PM »

Yes it is the fishing line that you can purchase at Cabelas or perhaps at Bass Pro Shop maybe even Academy. I never would of dreamed of using this stuff except for the article in Control Line World.

Bill Adair · « **Reply #12 on:** August 12, 2011, 06:41:09 PM »

Jerry,

Several of us have been using braided Spectra for a year or more, and the only failure we have seen was because one of the guys didn't trust the fishing knots, so he used CA to keep them from unraveling.

CA sets up like a rock, and then all of the line flex is concentrated at the edge of the CA hardened sleeve! I don't use it myself, and have had no failures. Also, I've seen some folks use Spectra for leadouts, with the bellcrank located outside the wings, right in the blast of Castor oil and exhaust from the engine! Think about what constant oil soaking might do to an otherwise nonslip knot!

If you don't trust the Palomar knot, I'd suggest sealing it with something that does not harden, like simple rubber cement, or possibly RTV. Another product that might work, is the rubber compound you can buy to dip tool handles into, to improve the grip and feel.

Bill

phil c · « **Reply #13 on:** August 13, 2011, 03:17:59 PM »

I worked with Tom Hampshire on the rules change(it only took 6 years!). The bottom line appears to be that the worst knot you can tie with Spectra line will give a breaking strength of 50% of the rated strength. Using the general rule and the combat rules the required sizes will give a set of lines that are comparable to 7 strand stainless cable or slightly stronger no matter what knot you use. The 5 turn Uni Knot Tom suggests does much better, but it does take some practice and it is nearly impossible to get two lines close to the same length. It is very important to get equal tension on all the strands as the knot is pulled tight and it must be pulled very tight or it can slip. If you look at it closely, there is nothing to prevent the line from simply sliding through the knot(it is very slippery), so add a single, overhand blocking knot in the tag end to prevent it from pulling through.

For matched length lines a figure eight knot or a surgeon's knot, works well and gives breaking strengths in the range of 60-80% of the rated strength. These knots can't slip through and come apart because pulling on the standing line clamps the line harder someplace inside the knot.

To check things out and set the lines pull test each line to about 40% of the rated breaking strength. This takes out any slight stretch and makes sure the knots are set.

You can get pretty accurate measurements of the line diameter by pulling the line tight by hand and measuring the diameter with a light touch on a set of calipers. If you aren't using a well-know brand this will make sure that the lines are large enough. If you don't have measuring instruments go by the manufacturer's monoline equivalent diameter and the breaking strength. For most brands 30 lb. test is .012 equivalent, 50lb test is .015 equivalent, and 80-100 lb. test is .018 equivalent.

Jim Morris · « **Reply #14 on:** August 13, 2011, 08:08:50 PM »

What rules have changed. Ive been out for almost 3 years. Is it still .015 for up to 40 and .018 for larger displacements? or is it different now?

Jerry Leuty · « **Reply #15 on:** August 14, 2011, 03:21:34 PM »

Welcome back even though being out 3 years is hardly considered coming back into the hobby. When you go flying it will still feel the same but you will be a bit out of touch with the pattern. As far as line size goes; about a year or so ago the aircraft are now being weighed and pulled tested to 10 times their weight. This is all due to electrics gaining interest in our other wise gas powered sport. I even have an electric set up in a scratch built profile. If all works well I will build a Legacy for electric.

Phil Spillman · « **Reply #16 on:** August 14, 2011, 07:30:20 PM »

I have used Spectra Lines over the past 6 years as described by Phil and Tom. Phil's original motion was signed in my home in Hermitage, PA prior to its submission! The improvement in flying performance due to these new fibers is amazing! BUT the ruling by the AMA Safety Committee mandates using the larger sizes for our present enjoyment; which is to say to add a multiple of safety margins I would not use anything less than .018 Spectra for any plane! Why worry or chance it afterall the improvement even using this thicker stuff will more than adequately reward the flyer for his efforts!

And just as an added extra for safety and peace of mind use the knots described in Tom's article and rest assured that they will stay. I would recommend against any CAing of any part of this procedure and in addition not used any hard metallic tubes against the fibres as their useage may set up stress ricers in the system.

Using this new science on a Ringmaster will doubler the user's pleasure in new performance heretofore never realized!

Phil Spillman

Bill Little · « **Reply #17 on:** August 15, 2011, 02:58:43 PM »

My 2 cents...

I love to use the stuff on small models. >049-.061 and it is so much easier to use for that than the .008 stranded steel lines which can kink in a heartbeat.

I have no doubt that they will work fine on larger models, just have to use the larger size lines!
Big Bear

Clancy Arnold · « **Reply #18 on:** August 15, 2011, 04:02:30 PM »

To answer the question of size and strength of the modern flying line material I asked the source!
Clancy

Thanks for your interest in Sullivan Products!

The diameter of the Kevlar is .021" without compressing.
Breaking strength is 142 lbs.

regards,

Alex
Sullivan Products

Shultzie · « **Reply #19 on:** August 15, 2011, 04:23:53 PM »

Any guess as to how many line twists can be performed on----------say an average 50 or 60 ounce CLPA stunt machine on 65 ft. .021 Kevlar lines....on a speed of about 5.5 sec. laps--before they begin to stick n' bind up?

Makes me go......HUMMMMMMMMMMMM?

??
At least Kevlar won't melt and part ways...from friction heat like Specta lines are infamously known to doing?
Spectra rules...as far as smooth and slippery over Kevlar which is considerable less smooooooooth n' slippery and tends to bind much more quickly when lines wrap.

Bill Little · « **Reply #20 on:** August 16, 2011, 11:22:08 PM »

Brother Donaldo,

From the one time I saw (flew) a plane with the Sullivan lines, they were heavy, stretched, and draggy. Really killed off performance. The model was a last series Veco Tomahawk with a Veco .19BB. Switching to .015 steel lines gave a very nice flying plane.

On the little planes the Spectra lines can build up a lot of twists and not seem to hang at all. Plus they do not need quite the same level of care the tiny .008 steel lines need. Never the less, I cannot bring myself to use them on anything bigger than the .061 size models.....

Big Bear

Shultzie · « **Reply #21 on:** August 17, 2011, 11:56:35 AM »

Quote from: Bill Little on August 16, 2011, 11:22:08 PM

Brother Donaldo,

From the one time I saw (flew) a plane with the Sullivan lines, they were heavy, stretched, and draggy. Really killed off performance. The model was a last series Veco Tomahawk with a Veco .19BB. Switching to .015 steel lines gave a very nice flying plane.

On the little planes the Spectra lines can build up a lot of twists and not seem to hang at all. Plus they do not need quite the same level of care the tiny .008 steel lines need. Never the less, I cannot bring myself to use them on anything bigger than the .061 size models.....

Big Bear

For an example of how spectra lines can rather easily and instantly "melt"----Cut off a short length of Spectra. Hold it taunt by both ends...
Quickly (holding the lines tight) Now quickly drag the spectra (especially the smaller guage sizes such as the 25lb. or 50 or even the 125 lb size piece) down a counter top edge or just about any obstruction just to see how heat build up from friction can melt and cut through these other wise Awesomely strong Spectra lines?
The results can be pretty sobering!!! One tool that our military special forces team members have been known to carry hidden in their personal clothing during special missions behind enemy lines...is a small length of KEVLAR line with two small wooden loops on each end of the string.
The results when Kevlar used on flesh also can be quite sobering!

In the early 90's at our Phantom Works at Boeing....and because I was an avid kite-kook I was assigned to a special project where we extended a very suspect object out the back end of our old chase plane....that was attached to a very long 1.5 mile long #150 lb. Kevlar line.
(Sadly this experiment ended with the "object" that was tied...started into "flutter mode", lost one vane of its flying surface and parted off the connector end of that line that I so carefully threaded a fiberglass cloth sleeving material over that Kevlar line.
(This object ended up....landing on the hood of a very beautiful old Pink Caddy convertible....a few miles south of McCord Airforce base.)

Long story short....
the Spectra line , and its sleeving held beautifully...after that long line back onto the spool.

phil c · « **Reply #22 on:** August 17, 2011, 08:17:24 PM »

before Spectra there was Kevlar. It also made its way into fishing lines and Sullivan lines, and bullet proof vests. For our use the problem with Kevlar is that it is pretty sensitive to sunlight. Ultraviolet light(sunburn), would greatly weaken fishing line in a season or less. So the fishing folks pretty quickly dropped Kevlar line. Kevlar still makes great bullet proof vest though.

All wires and ropes are very subject to abrasion when the lines are crossed and one line is pulled over the other at one spot. I've had .021 steel lines cut by .018 lines from just a couple of feet off sliding contact in a line tangle.

One test I ran was putting one line under load and making a bow with about 10 lb. of tension on it and dragging the bow across the test line where it passed over the edge of the workbench. 100 lb. Spectra lines took about 200 strokes before it sawed through. Stainless steel(.018) took about 50 strokes.

But there is no doubt Spectra is subject to melting, about 300degF will turn it into plain old polyethylene and it it will break easily. So don't snag the lines on the head of an overheated engine!

Jerry Leuty · « **Reply #23 on:** August 20, 2011, 09:15:37 PM »

Ok so this has been a great thread for discussion. I have a set of .012 X 60' lines made up with the 5 twist knot as discribed in the article. I am in Albuquerque this weekend for their contest and have as of yet to try these Sprectra lines out on any plane. After reading all of this about melting points and losing breaking strength due to line rubbing and so forth, I am wondering if I should just rewind the g-kids fishing poles with this stuff and stay with the stainless steel braided lines that I have been using for the past 50+ years now. It all sounds a little too complex to me.......I mean why reinvent the wheel when what we have been using is better in the long run?

Joseph Patterson · « **Reply #24 on:** August 21, 2011, 12:06:38 AM »

I'm with you Jerry on the change. I'm not willing to change to something that is not beneficial enough to warrant a wholesale change-over.
Doug