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Author Topic: ADVENTURES IN SPECTRA  (Read 8260 times)

Online Dennis Adamisin

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ADVENTURES IN SPECTRA
« on: December 22, 2021, 10:29:00 AM »
If you follow the Stunt Hangar Chats (see “At the Bench”) hosted by Charles Carter on Mondays & Fridays, you have probably heard the ongoing discussions on how some of us have been proceeding with Spectra lines.  I will be switching everything over to Spectra, and wanted to share what I have learned, as well as reach out to others with who can share their experiences.

First, for background, here are the rated strengths of SS Cable we currently use.  Thank You to Brett Buck for posting this info in a thread in the Rules forum:

   Nominal Diameter (in.)    Const.                               Material Type                          Minimum Breaking Strength
           0.0120                     1 x 7                          Stainless Steel 302/304                                25 lbs
           0.0150                      1 x 7                          Stainless Steel 302/304                            40 lbs.
           0.0180                     1 x 7                          Stainless Steel 302/304                            55 lbs
           0.021                     1 x 7                          Stainless Steel 302/304                            80 lbs
           0.0240                     1 x 7                          Stainless Steel 302/304                          100 lbs

Spectra lines are not new to CL.  For several years the AMA General rules for Control Line included a chart suggesting sizes for Spectra lines.  However, Stunt event rules limited us to solid or SS Cables in specific minimum sizes.  Starting January 1, 2022, Stunt rules will allow any line material & construction which passes the 10G pull test.

The Combat guys have been using 100# Power Pro line not because of its strength, but because of its diameter; their thinking was that they wanted the same line drag for Spectra versus the normally mandated .018” cable.  The 1/2A Combat rules specified .012” cables, and the appropriate size Spectra line was 40# test.

The 1/2A flyers (except 1/2A Combat) have been using Spectra lines for a long time – it is the prohibitive choice, being way stronger than .008 cable, and far easier to handle.  I use 15# & 20# on my 1/2A's.

Of course, many of our forum members are also avid fishermen who hopefully have practical knowledge and experience with Spectra braids that I hope they can share here.

Spectra fiber is patented by Honeywell, there is another similar fiber called Dyneema that was patented in Europe. Power Pro was the “pioneer” introducing Spectra braided line for fisherman, and over the years there are several more brands available.  Braided lines are advertised as being the strongest, most durable and have “zero” stretch for maximum feel.  Spectra lines do not kink or curl like SS cable can, so they should be VERY user friendly for us.  Most producers have several product lines available, marketed to customers “hot buttons”; highest strength, smallest diameter, best castability – and of course price! Spectra is naturally bright white in color, but most lines come dyed in various colors.

How does it fly?:
Aside from the 1/2A’s, I first tried Suffix 832 65# x 60' on my Ringmaster a few years back. The 65# size (nominally .015”) is what is called out in the AMA General rules; but on a Ringer it is WAY overkill!  Before flying we pull tested to 40# to assure that my knots were secure.  In the first test flight I started off doing 5 inside loops then checked control response – no loss in feel due to lines binding together.  I did a second set of 5 then a third set, each time noting absolutely no loss in feel due to lines dragging on each other.  With 15 loops and no control loss I figured more loops were unnecessary. Later I used these same lines on an All-American Senior - after adding 1/2 oz inboard tip weight!  To those of you who have flown an AA Senior, the idea of inboard tip weight must seem really scarry!

Later I tied a set of Suffix 832 80# for my 55 oz Pathfinder to fly at Brodak the year they allowed Spectra.  Again, these lines are too big but on the PF, I took off 1/2 oz of tip weight and need to take more.
 
Although promising it was pointless to try Spectra on any of my PAMPA class airplanes because it could not be used in competition.  Then in late fall, after the rule passed, I flew my SV-11 (72 oz) back-to-back first with the .018” seven strand cables, then Power Pro 100# line. I noticed the Spectra lines had no discernable stretch or friction.  In fact, my pattern got much better because of the linearity of control I gained over cables – my round loops were finally round, I could go deeper into corners, and level flight was finally locked down.  The lack of line friction may be just what we have been looking for in electric!  Maybe that's why I noticed that here; might not have been as noticeable on a vibrating glow airplane?  Per my usual habit, I had some built-in tip weight, so I could only remove 1/4 oz from the tip weight box, so at the field I stuck on ½ oz weight to the inboard tip for a net ¾ oz reduction in tip weight.  Later, I weighed the outboard tip, then chopped it off to remove the weight I had built in plus the ½ oz stuck to the inboard side.  Finished by installing 3/4 oz in the weight box to achieve the same weight measured at the tip. I think I could have pulled pull another 1/4 oz., but the weather turned for the worse and I have not been able to try it again.  Next time out I will be switching to smaller/lighter Maxcuatro 80# so it is a foregone conclusion that I can remove more tip weight.  In fact, I will keep pulling weight out until it goes too far then put some back.

Given that test I decided to commit to Power Pro Maxcuatro 80# (.016" dia) in place of .018” cable.  Power Pro’s “Maxcuatro” brand is their tightest woven and smallest diameter line for a given rating.  It is conceivable that 65# line would be adequate but seems like that would hit diminishing returns.  Similar logic led me to look at 50# in place of .015" cable. Maxcuatro 50# is .012", thus yielding 20% smaller line than the cable that is also 25% stronger and lighter - not a bad trade!  My main criteria will be stretch, I am not worried (too much!) about strength.

Lighter line weight and less tip weight for Spectra is a given, smaller line diameters will show up as less drag, possibly a lower RPM setting, and lower battery usage.  Will less line drag affect lead-out position too?  Seems like it should, but that will be easy enough to find out

Last week I tied 8 sets of lines including 4 sets for flying buddies.  I tied Maxcuatro, 40# Power Pro "Super Slick 8", Suffix 832 (65# & 80#), and FINS XS 50# because it is slippery and because I liked the colors! 
* The Maxcuatro 80# and Power Pro 40# were easy to handle & tie.  I am awaiting a spool of green Maxcuatro 50# to go with my yellow so I can tie dual color sets (green line up!)
* The Suffix 832 (65# & 80#) were the easiest to handle.  It has a real nice feel to it. These lines are larger in diameter than the Maxcuatro, about the same diameter as regular Power Pro.
* Did not like handling the FINS XS.  I do not think I will be using this long term.
* I tied 3 sets with eyelets using the Palomar knot and 5 sets with Modified Surgeon's knot that the Combat guys prefer.  The ones with eyelets should be easier to use with hardpoint handles.
* Crochet needle (with the hook on the end) & magnifiers HELP!
* Mine are close but NOT exact in length like the Tom Morris & Okie Air cables I have been buying.
* Instead of eyelets I think I am going to try small solid (NOT split!) rings and tie to those when not using the loop.
* I wrote the material, test, and length on each reel to keep them all straight.

A couple Links & Attachments:
* Do a SEARCH on Spectra posts SH, there are a lot of good post going way back to before when Combat adopted the lines.
* Dennis Toth found/posted a table of fishing line sizes on SH in the Combat section. I downloaded it and attached it below
* There are lots of vids on YouTube showing how to tie braid for fishing lines.  If you want to keep using eyelets on the line ends, it looks like the best knots for our use are the Uni tied with the line doubled, and the Palomar which naturally is tied with a doubled line. The trouble with these knots is that they are difficult to tie at an exact location.  I think our fishing buddies can help us here!  Ken Culbertson posted a sketch of a tying fixture here (see post #9) that looks like it could help: https://stunthanger.com/smf/combat/spectra-lines-braided-or-solid/
* Michael Stinson has updated & expanded his YouTube video again as of 6-January on tying the Modified Surgeons knot, that the Combat guys have settled on.  He also added a couple of do's & don'ts, including a really slick idea for keeping the loops in place on scissors style clips:



That is just about everything I know on the subject, pending the new flying season!  I seriously hope others will post their experiences and any guidelines they have on how to select and make up Spectra lines
« Last Edit: January 06, 2022, 04:54:55 PM by Dennis Adamisin »
Denny Adamisin
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Online Dennis Nunes

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Re: ADVENTURES IN SPECTRA
« Reply #1 on: December 22, 2021, 11:18:27 AM »
Good morning,

Great information Denny! There was something that was brought up during the Hangout that caught my attention. It was mentioned that the color lines tend to fade with time due to UV rays, which is no big deal. But I don't recall if anything was mentioned if this affects the integrity of lines.

My main concern is how these lines will hold up when temperatures reach the 90-100 degrees range on an asphalt or concrete surface? These surfaces can get extremely hot in the summertime. I've been in situations where my lines laid in the sun for hours. Any reasons to be concerned or will we learn the hard way through trial and error?

I know that the combat guys have been using these lines for some time now, but they fly on grass areas which don't get nearly as hot as asphalt or concrete surfaces. Should we get into the habit of replacing these lines every couple of years?


Stay safe,
Dennis

Online Dennis Adamisin

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Re: ADVENTURES IN SPECTRA
« Reply #2 on: December 22, 2021, 01:02:40 PM »
Hello Dennis N!

From what I can tell Spectra is considered UV resistant, especially when coated.  I found a reference to an accelerated UV test standard which showed Dyneema (considered by most sources to be equivalent to Spectra) to have excellent UV resistance.  Spectra is used in sailcloth, which would seem to be a high-UV application.

Melting point is 300F degrees, that's even hotter than Muncie in July!

Some fosherman claim the see line fade starting on the first day, sounds like it happens faster in sailt water than in fresh, does not seem to affect anything else tho.  Spectra is naturally a bright white, the dye is added on and not a factor of the forming of the Spectra material.

One of the kite line sites says Spectra is 40% stronger than Kevlar for the same weight.  So probably no surprise that other uses for Spectra cloth include ballistics clothing and cut proof gloves.


Here's a chart on Dyneema UV performance:
https://assets.ctfassets.net/q6qgec8ud5tq/2F2XxEQuIxhQnlD9435Ddz/7413e91d3f25447a8f000f94f06aea7d/CIS_YA102_Ultraviolet_exposure_of_UHMWPE_fiber_from_DSM_Dyneema.pdf


Denny Adamisin
Fort Wayne, IN

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Offline Tom Luciano

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Re: ADVENTURES IN SPECTRA
« Reply #3 on: December 22, 2021, 01:13:50 PM »
Great thread Dennis!!!

Below is a quote from back in '07 it might be worth reviewing as Phil C was answering questions.

742
Open Forum / Re: Rules Proposal for Spectra(tm) Lines
« on: August 17, 2007, 12:28:58 PM »
Hey Guys,
   As I was reading along, my first thought was the effects of sunlight on the spectra lines, and Pat did address that. Then I thought what about a set of lines that has been sitting on the tarmac for 5 minutes or so when your getting ready for a flight. Obviously on a 95 degree day sun gleaming those lines could get pretty hot. Is there any research on these materials possibly softening and becoming weak or even stretching in this case.

Tom
https://stunthanger.com/smf/open-forum/rules-proposal-for-spectra(tm)-lines/msg51033/#msg51033

« Last Edit: December 23, 2021, 11:07:10 AM by Tom Luciano »
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Offline Perry Rose

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Re: ADVENTURES IN SPECTRA
« Reply #4 on: December 22, 2021, 01:35:48 PM »
If the line is insulated you can use a granny knot. 30# fly line backing is used to insulate the line.
I may be wrong but I doubt it.
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Online Dave_Trible

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Re: ADVENTURES IN SPECTRA
« Reply #5 on: December 22, 2021, 02:08:50 PM »
Denny thanks for great material here.  I did buy some stuff for these lines but haven’t tried them yet.  I’m interested to see how they go with the .76.... one question though:  I’m an incessant line cleaner,  wiping the gunk off after every flight with alcohol.  How is that going to work with these lines?  Do they absorb moisture?  How are they in wet grass?  Just asking.

Carry on.

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Online Dennis Nunes

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Re: ADVENTURES IN SPECTRA
« Reply #6 on: December 22, 2021, 02:39:38 PM »
Melting point is 300F degrees, that's even hotter than Muncie in July!

Not by much!   LL~

Dennis

Online Dennis Toth

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Re: ADVENTURES IN SPECTRA
« Reply #7 on: December 22, 2021, 04:27:19 PM »
This is great information and useful for the new line rules coming in January, 2022. One thing I think we need to develop is a consistent method for tying off the ends to get equal line length on the last line clip. If there is a knot that allows tightening by pulling the tag line (lose end) we could mark the line to be on the clip then tie the knot with the mark in place and tighten the tag. I have looked at all kinds of fishing line and kite line sites looking for this kind of approach and we are the only ones that need the lines that close in equal length. Anyone got a simple jig (not involving using your teeth)?

For the ends I came across what they use on cable called a "Cable Thimble" these are tear drop shaped open guides that the line rests in (like an eyelet) and you could knot at the bottom. They use this with swage ferrules (crimps to us) not sure if this could work with Spectra type line. I have seen some small thimbles for 1/16" line, even 1/32" line but not sure what would work with light thin 0.012" Spectra. The fishing guys want fast and cheap so no one tried this as far as I can find. Maybe Robert Zambelli (are CL swage/crimp SME) can try this and do some tests, would be much simpler than a knot.

Best,    DennisT

Offline john e. holliday

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Re: ADVENTURES IN SPECTRA
« Reply #8 on: December 22, 2021, 04:36:32 PM »
Well this is a great post Dennis.  I started way last year to try and get used to the Spectra lines.   Got maybe a dozen flights, but daughter took back her vehicle and this year the family took my car keys.  The back has not been much help either. D>K
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Online Dennis Toth

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Re: ADVENTURES IN SPECTRA
« Reply #9 on: December 22, 2021, 05:28:14 PM »
Doc,
Need to either get your daughter into flying or the grand kids. Maybe a take-a-part "flat plate winger" like the Aussie "Yardstick". The Spectra lines would make teaching them easier not needing to worry about learners stepping on lines or get kinks from walking them out to fast getting bends.

Best,     DennisT

Online Dennis Adamisin

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Re: ADVENTURES IN SPECTRA
« Reply #10 on: December 22, 2021, 07:44:30 PM »
Hottest NATs runway I ever encountered was in Lake Charles in '74  Was said to be 130 degrees.  All I remember is I couldn't stand still because it burned my feet.  Melting temp for Spectra is 300, that seems like a pretty good margin.  However, if the runway is hot maybe it would be enough to elevatethe lines, or for a long spell just reel them in.

Trib:
I have not had to clean my Spectra lines yet.  Spectra does not absorb water and it is extremely resistant to acids and bases. Sure sounds like a regular alcohol wipe will do the deed.  However, the dye may not be as resistant!
« Last Edit: January 03, 2022, 02:46:43 PM by Dennis Adamisin »
Denny Adamisin
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Offline Steve Hines

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Re: ADVENTURES IN SPECTRA
« Reply #11 on: December 22, 2021, 08:07:58 PM »
If you are worried about the temp of asphalt you could build a handle stand that was weighted and hold the lines up off the surface and then only have to deal with ambient temp. This would be no more than any other material on or in your plane. After takeoff and level laps lines should be down to ambient temp. At this time you are pulling on both lines. Even on a 70oz plane and 50 pound lines you would have about a 60lbs of safety.

Offline GERALD WIMMER

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Re: ADVENTURES IN SPECTRA
« Reply #12 on: December 23, 2021, 03:51:04 AM »
Hello

I have been using Spectra for a few years now for combat (65lb for most on 52 ft and 100 for the faster stuff on 60ft) and 80lb for most bigger stunt models. Me and the whole family prefer the feel and convenience of Spectra over steel and only use steel lines where the rules require it like team race or to avoid mixed line types in combat. Has proven very durable and can be cleaned with detergent if you get fuel on them as that makes them feel sticky. Even faded to white with many years use they still pass the pull tests . They do abrade on sharp edges and will melt when wrapped around a crankshaft but endure the rigors of combat much better then 'stainless steel line and with less stretch then stainless.
Getting them in blue where possible or yellow makes it easier to see over grass and I normally mark the up line red with a red felt pen .

Regards Gerald

Offline frank mccune

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Re: ADVENTURES IN SPECTRA
« Reply #13 on: December 23, 2021, 01:12:26 PM »
      I changed to fishing lines last year, and have not seen any reason to go back to steel lines!


      Stay well,

      Frank

Online Dan McEntee

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Re: ADVENTURES IN SPECTRA
« Reply #14 on: December 23, 2021, 01:58:51 PM »
    When the lines are laying on the ground, the actual contact area of the line to the pavement is very , very small. I think you would have to have something laying on the line to get any heat transfer. If there is any breeze blowing that will mitigate any temperature also, even on the ground. If it were a problem, I think some one would have experienced it by now.
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Offline GERALD WIMMER

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Re: ADVENTURES IN SPECTRA
« Reply #15 on: December 24, 2021, 03:28:40 AM »
Hello As for Spectra getting wet it works better then steel when wet, its more slippery when its wet not clingy like steel lines tend to do. But glow fuel oil does make them sticky (do not roll them out with oil soaked hands to avoid this) but I have cleaned them by squirting detergent on them then rinsing off then drying them. They still pass a pull tests when faded to white or almost clear too.

Regards Gerald

Online Dennis Toth

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Re: ADVENTURES IN SPECTRA
« Reply #16 on: December 24, 2021, 05:05:45 PM »
While browsing on the Barton site I came across an idea for tying knots with a Fly-Fishing tool. I did a little search and found the "Knot Needle" (https://theknotkneedle.com/?msclkid=e9d3623ef56a19b044ed03f8af4d3a8a&utm_source=bing&utm_medium=cpc&utm_campaign=DSA&utm_term=theknotkneedle&utm_content=All%20Webpages)

Looking at the videos they claim it will do 20 different knots including the Uni and Palomar. It seems this could work well with Spectra lines to maybe make it easier to get them the same length. Anyone try any kind of fly-fishing tool like this?

Update: I decided to get one so will report once I get a chance to try it once it gets here in a week or so.

Best,      DennisT
« Last Edit: December 24, 2021, 05:42:57 PM by Dennis Toth »

Offline phil c

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Re: ADVENTURES IN SPECTRA
« Reply #17 on: December 28, 2021, 06:01:10 PM »
Denny thanks for great material here.  I did buy some stuff for these lines but haven’t tried them yet.  I’m interested to see how they go with the .76.... one question though:  I’m an incessant line cleaner,  wiping the gunk off after every flight with alcohol.  How is that going to work with these lines?  Do they absorb moisture?  How are they in wet grass?  Just asking.

Carry on.

Dave
Good questions, Dave.  No, polyethylene in any form including Spectra type lines does not absorb any significant amount of moisture.  They really don't need to be cleaned, but if you want alcohol, acetone etc. will wipe off any dust they may accumulate.  There are no problems at all on grass.  They might, since they are more flexible than steel, not catch as easily on clumps of grass.  We've locally not had any troubles.
phil Cartier

Online Dennis Adamisin

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Re: ADVENTURES IN SPECTRA
« Reply #18 on: December 29, 2021, 08:27:20 AM »
In the Chat last Monday, there was a discussion about tying "NEAT" loop ends in the modified surgeon's knot shown in Mike Stinson's excellent YouTube video.  The discussion centered around tying small loops as a measure of "neatness" - that is misguided.  While beauty is in the eye of the beholder, lets make it clear that a properly tied knot is secure whether the final loops are small or large.  In my case I am trying to make the ends consistent but I typically get the final loops roughly the size of my finger.

Instead of obsessing over the size of the loops, instead concentrate on pulling all of the tags secure.  Lubricate the line (spit on it!) and pull each tag until the knot is completely tight.  Mike's video shows that pretty clearly.  THAT is how the knots get excellent!

Best way to learn how to tie excellent knots is practice.  I used the line I bought for safety thongs for teaching myself - its easy to see how the knot comes together.  You could also use various sizes of rope, twine or string for practice.  Next I practiced with actual Spectra line - wasted some line but learned what was important.

Mike's video did not show it, but especially when tying smaller lines, it helps to have a leather glove to protect your hand when you are pulling the tags to tighten the knot.  Many of the many of the fishing line videos on YouTube recommend this too.  I have to wear magnifiers to more clearly see the knot snug up.  Large & light color line is easier to see...

 
Denny Adamisin
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Online Dennis Nunes

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Re: ADVENTURES IN SPECTRA
« Reply #19 on: December 29, 2021, 10:50:11 AM »
Thanks Denny for the great information.

Questions: What do you do with the tag ends when done pulling on them? I’m assuming that you cut the off. But how much should you let stick out pass the knot?

Dennis


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Online Ken Culbertson

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Re: ADVENTURES IN SPECTRA
« Reply #20 on: December 29, 2021, 12:58:37 PM »
Thanks Denny for the great information.

Questions: What do you do with the tag ends when done pulling on them? I’m assuming that you cut the off. But how much should you let stick out pass the knot?

Dennis


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Leave as much as you can.  No matter how good you are at tying them they are going to slip some.  In fact they need to to finally lock in place.  It is part of the process, and you simply need to allow for it.  On my Spectra sets I left an inch.  Half that will probably do but, other than looking a bit unfinished, nothing is lost by having a little extra.  It is super important to wet the knot before the last pull.

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Online Dennis Adamisin

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Re: ADVENTURES IN SPECTRA
« Reply #21 on: December 29, 2021, 09:55:38 PM »
Thanks Denny for the great information.

Questions: What do you do with the tag ends when done pulling on them? I’m assuming that you cut the off. But how much should you let stick out pass the knot?

Dennis


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Hi Dennis,

Good question.  After cinching up all the tag ends as secure as possible, I have been clipping pretty close; about 1/16" or so from the knot.  However, what Ken C said about leaving a little longer tag makes sense; at least until you get more comfortable with your process.

HEY COMBAT GUYS, KITE FLYERS & FISHERMEN: how about some input here???
Denny Adamisin
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Online Dennis Toth

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Re: ADVENTURES IN SPECTRA
« Reply #22 on: December 30, 2021, 06:51:19 AM »
One thing I was thinking about was to leave a little more tag line but slip on heat shrink tubing over the cinch end, you could leave like 1/4" and maybe 1/16" out the back of the heat shrink so you could see if it moves?

Best,    DennisT

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Re: ADVENTURES IN SPECTRA
« Reply #23 on: December 31, 2021, 09:21:44 AM »
I ordered a package of 1/64" thimbles from McMaster to try as a smooth loop end for the Spectra lines. Seems the weakest part of the connection is at the knot so having it smooth into the knot area might help. This might be overkill and fixing a problem that doesn't present a significant problem.

Best,   DennisT

Online Ken Culbertson

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Re: ADVENTURES IN SPECTRA
« Reply #24 on: December 31, 2021, 09:45:51 AM »
I ordered a package of 1/64" thimbles from McMaster to try as a smooth loop end for the Spectra lines. Seems the weakest part of the connection is at the knot so having it smooth into the knot area might help. This might be overkill and fixing a problem that doesn't present a significant problem.

Best,   DennisT
My major experience with knots on fishing line is fishing.  You are absolutely correct, that the weakest point is the knot by as much as 50% if not tied so that it can gradually tighten around the eyelet.  If the angle created by wrapping around the eyelet is too great the knot will pressure the line and prevent it from slipping.  Others may disagree but IMHO the smaller the object you are wrapping around is (up to a point, perhaps 2-3x the diameter of the line) the more the knot can slip under pressure and not break.   Slippage, although microscopic is what keeps the line from breaking.  Just as an example, for our deep water rigs we cut the hooks off after each session about an inch above the knot and retied them next time out. We are not trying to lift a 100 pound fish either so I don't recommend this for our lines except to illustrate that a knot that cannot tighten any more is going to break.  99.9% of line breakage is at the knot.

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Online Dennis Adamisin

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Re: ADVENTURES IN SPECTRA
« Reply #25 on: January 01, 2022, 07:22:48 AM »
One thing I was thinking about was to leave a little more tag line but slip on heat shrink tubing over the cinch end, you could leave like 1/4" and maybe 1/16" out the back of the heat shrink so you could see if it moves?

Best,    DennisT

Dennis T:
Careful if you do this, DO NOT heat shrink the tube.  Too hard to control the heat, too easy to burn the line.  if you want, slip the tubing on as just a sleeve, but no heat or glue.

Did you receive that knot-tying tool and have you tried it out?
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Online Dennis Toth

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Re: ADVENTURES IN SPECTRA
« Reply #26 on: January 01, 2022, 10:18:44 AM »
Dennis A,
The Knot Needle arrived yesterday, haven't had a chance to work with it yet. What type of knot have you been using? With all the options about this it is hard to find setups that you can trust. I was thinking of doubling over the line no matter what knot just to give more surface to spread the force over.

I found some 1/64" cable thimbles from McMaster that are teardrop shaped and will see how they work. I think because of the smooth shape it should put less stress on the knot, just need to make sure there are smooth edges. What do you think?

I want to set up a hanging weight test rig to see how the various knots will hold with different amounts of weight or maybe a simple pull scale.

Best,    DennisT

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Re: ADVENTURES IN SPECTRA
« Reply #27 on: January 01, 2022, 02:45:03 PM »
Dennis A,
The Knot Needle arrived yesterday, haven't had a chance to work with it yet. What type of knot have you been using? With all the options about this it is hard to find setups that you can trust. I was thinking of doubling over the line no matter what knot just to give more surface to spread the force over.

I found some 1/64" cable thimbles from McMaster that are teardrop shaped and will see how they work. I think because of the smooth shape it should put less stress on the knot, just need to make sure there are smooth edges. What do you think?

I want to set up a hanging weight test rig to see how the various knots will hold with different amounts of weight or maybe a simple pull scale.

Best,    DennisT

Hoping the Knot Needle makes it easier to handle the line while you tie whatever knot you want to use.

CONGRATS on finding those teardrop thimbles!  I can almost never find anything in M-C because they list so many things!  The normal brass eyelets we used for SS cable lines have a 1/8" ID.  It looks like the teardrop you found is 3/16" x 1/4" so it is a bit larger - does that matter to you?

I found the YouTube on how to tie the doubled-line Uni knot as recommended by AMA.    I have tied this directly to clips on one end of the line and to round brass eyelets on the other end heck it out here:
 

The more I think about it the more I think my best plan is to use the Modified Surgeons knot developed by Phil Cartier, as used by the Combat guys, and as shown in the Mike Stinson video in the first post of this thread
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Offline phil c

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Re: ADVENTURES IN SPECTRA
« Reply #28 on: January 01, 2022, 04:23:06 PM »
The reason we stayed with the modified Surgeons knot is because  wrapping the line around both sides of the loop better spreads the load and increases the ultimate pull test.  The first tests with the standard Surgeon's knot were no better than steel lines, about 50-55lb.
Revising the know to lock both sides of the loop made it good up to 75lbs or so, per line.
The AMA rules require the knot to be tied by first doubling it over.  This wasn't done just to make it harder.  I don't see it as much use in ordinary flying, but the extra strength probably did wonders for the  Insurance side of the business.
Don't tell anyone but I used the original set of 60ft. until last year!  Must have been around 1000 flights.  I've still got about 1000 ft of the original reel I bought from Australia.
The only real problem was that eventually that line tends to "fluff up" a bit where they went through the plastic lead out guides.  A couple of guys used steel eyelets and had some trouble.  A line broke several times when it sawed through the eyelet and frayed.

Another interesting thing during the testing-I used a shorter set for F2D at the NATS.  The Mears brothers made a slick "auto" pull tester out of 2x4s.  A bent bracket on one end and two weight attachment pins for F2D and AMA  made the operation simple.  Just lay the handle in the bracket and pull on the plane until the lines lifted the beam.
The most popular F2D lines come from Europe-usually 4 single brass-coated lines of music wire twisted with a fairly long "twist".  It is way stronger than the 44 pound pulltest.  In side by side pull tests both types of line easily did the pull and in the process they both stretched almost 2 1/4 inches.  I don't think there is much to worry about as far as long term strength and durability.
« Last Edit: January 10, 2022, 05:45:00 PM by phil c »
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Offline Tom Luciano

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Re: ADVENTURES IN SPECTRA
« Reply #29 on: January 02, 2022, 05:49:38 AM »
I successfully tied  the modified surgeons knot around a thimble. I did this for the guys that were concerned about fatigue  at a line clip. Ill do some testing on break strength today. I think it also satisfies the comments  about neat terminations for stunt.

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Re: ADVENTURES IN SPECTRA
« Reply #30 on: January 02, 2022, 07:22:23 AM »
Using 100# test maxcuatro . I picked 70#'s of weight and the line broke twice after a few seconds. The termination held even bending the eyelet/thimble.

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Re: ADVENTURES IN SPECTRA
« Reply #31 on: January 02, 2022, 07:26:01 AM »
Although not enough data. I would say maxcuatro is 70% of rated claims. I would also say, that real world data wiuld need to be done as to how the termination will react to vibration over time during flight.  I will try this setup on a IC beater I have. I will keep inspecting for fraying and report my findings. I think this is promising!
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Online Ken Culbertson

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Re: ADVENTURES IN SPECTRA
« Reply #32 on: January 02, 2022, 09:27:26 AM »
Although not enough data. I would say maxcuatro is 70% of rated claims. I would also say, that real world data wiuld need to be done as to how the termination will react to vibration over time during flight.  I will try this setup on a IC beater I have. I will keep inspecting for fraying and report my findings. I think this is promising!
Tom
I like what I see here.  Did you say that the line broke before the knot on one of your posts?  How close to the knot? That is not a good thing.  Where did that thimble come from, it could work for more that "Spectra".

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Offline Perry Rose

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Re: ADVENTURES IN SPECTRA
« Reply #33 on: January 02, 2022, 10:04:50 AM »

several years ago I was doing strength tests with the braided line and it broke before the rated number. I called the mfg. and spoke to a quality control person about the way they do the pull test. He said they use (I forget the brand name) a force gauge. I have used the same brand in the past and I'm quite familiar with it's operation. Chatillon Force Guage, there I remembered it. It runs very slow, about an inch a minute, and very steady.  But the way we are testing is more accurate for the way it's being used.
I may be wrong but I doubt it.
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Re: ADVENTURES IN SPECTRA
« Reply #34 on: January 02, 2022, 11:24:29 AM »
Tom,
I like the circle thimble as I feel it spreads the load evenly. I found some small teardrop thimbles (McMaster) that I feel will spread the load even better. 

Since you are doing strength testing it would be good if you could describe the test rig and way the load was applied. I would also like to see how the double Uni and double Palomar knot compare.

Another interesting test would be to do a simple ferrule crimp just to see how it compares.

Best,   DennisT

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Re: ADVENTURES IN SPECTRA
« Reply #35 on: January 02, 2022, 12:19:23 PM »
My test was simple. I put 2 35lb. Plates on my pulley system. They did not break near the termination.  They both broke about mid span between the cable and the plate mount.
Tom

Maybe I should explain the picture. Im holding yhe thimble between my fingers. The two lines heading up to the spring clip are .027 cable. The two broken lines are on the lower clip. Neither the modified surgeons knot(combat way)or the modified surgeons knot on the thimble failed. The actual line broke. I will repeat the maxcuatro may be not as strong as the standard. Regardless, it broke at 70lbs. Which gives you 140 lb pull test.
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Re: ADVENTURES IN SPECTRA
« Reply #36 on: January 02, 2022, 05:47:02 PM »
Tom - NICE work! Thanks for sharing.

First off, congrats on the beautifully tied small Modified Surgeons knot. great demo showing the brass eyelets are the failure point! The teardrop eyelets Dennis T found look to be an improvement over the round brass eyelet, but then again, I noticed the knot at the other end of your test line was also the Modified Surgeons knot, tied to a "normal" size, without an eyelet, and no drama at that end!
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Re: ADVENTURES IN SPECTRA
« Reply #37 on: January 02, 2022, 06:14:28 PM »
Tom - NICE work! Thanks for sharing.

First off, congrats on the beautifully tied small Modified Surgeons knot. great demo showing the brass eyelets are the failure point! The teardrop eyelets Dennis T found look to be an improvement over the round brass eyelet, but then again, I noticed the knot at the other end of your test line was also the Modified Surgeons knot, tied to a "normal" size, without an eyelet, and no drama at that end!
I am really interested to see how they do with the teardrop eyelet.  Our old "truth" was that the more you had to bend the line at the point it met the knot the weaker it would be. A round eyelet makes for a pretty sharp bend at the knot.  Remember,  these knots were originally designed to hold fish hooks.  I would think that small rings are a better choice.  I don't use either.  I tie to the smooth end of the line clip.

Ken
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Online Mike Alimov

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Re: ADVENTURES IN SPECTRA
« Reply #38 on: January 02, 2022, 07:01:10 PM »
Gabe and I just did a few quick tests, similar to what Tom did.

The 20lb PowerPro failed right at 20 lbs.
The 65lb PowerPro Maxcuatro failed at 42-45 lbs.
The regular 65lb PowerPro failed at even smaller values, but the exact number was hard to register.

I'm starting to believe that the PowerPro (and possibly other brands too) has to be de-rated to about 70% of its nominal value for the purposes of estimating its actual breaking strength. 

By the way, it looks like the link to the modified surgeons knot video posted in the original post is corrupted?

P.S. None of the failures were at the knot; they were in the middle of the line.

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Re: ADVENTURES IN SPECTRA
« Reply #39 on: January 02, 2022, 07:04:52 PM »
What happen to Mike’s video?? It’s no longer available. 😖

Also why use a thimble? Would it not be better to just tie right to the line clip?

For fishing we tie right to the swivel or hook. K.I.S.S.

Double Uni knot on line clips??????
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Re: ADVENTURES IN SPECTRA
« Reply #40 on: January 02, 2022, 07:21:33 PM »
What about this knot.

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Online Dennis Adamisin

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Re: ADVENTURES IN SPECTRA
« Reply #41 on: January 02, 2022, 10:04:33 PM »
Hi Paul

I sent a note to Mike Stinson about his video, hopefully we can restore access somehow.

In the video you posted the line goes through the hook twice (probably improves that interface) but the Uni knot is tied with the single line strand.  In the AMA rulebook , it shows the Uni knot tied with the thread doubled over on itself.  That makes the knot much stronger, than just going through the loop twice.

No problem tying the doubled line Uni directly to a line clip.  However it makes it difficult to change clips if you are using a hardpoint handle and using different size clips to get your neutral.  If you are using a cable handle then no worries...
Denny Adamisin
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Re: ADVENTURES IN SPECTRA
« Reply #42 on: January 03, 2022, 07:26:07 AM »
Thanks Dennis. 👍🏼👍🏼
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Re: ADVENTURES IN SPECTRA
« Reply #43 on: January 03, 2022, 07:56:33 AM »
Dennis T:
Careful if you do this, DO NOT heat shrink the tube.  Too hard to control the heat, too easy to burn the line.  if you want, slip the tubing on as just a sleeve, but no heat or glue.
Question: will acetone or cellulose thinners harm Spectra in any way?  If so, what follows is of no use: if not, then I wonder how many people know an old trick I discovered by accident some sixty years ago - immerse ordinary PVC tubing (e.g. the insulation stripped from electrical wiring) in cellulose thinners or acetone for a couple of hours, and it swells and becomes very soft and stretchy (and also rather weak, needing gentle handling).  Slip this over whatever you want to slip it over, and leave it.  In 12-24 hours, it shrinks back to its original size, feeling a bit harder and stiffer than it was originally.  I use this all the time for propeller hooks on my rubber-powered models.  Apologies if this is something everybody already knows!

John
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Offline Tom Luciano

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Re: ADVENTURES IN SPECTRA
« Reply #44 on: January 03, 2022, 08:24:14 AM »
[quote

Also why use a thimble? Would it not be better to just tie right to the line clip?

[/quote]
 Some guys have concern about securing to a line clip because of the tight radius. The thimble will spread the load.  So far in combat the only area of concern has been where the line passes thru the leadout guide. In time chaffing has occurred,  which will cause an eventual failure.
  Phil C is really the authority on the knot. He says modified surgeons,  thats alright by me!

Tom
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Re: ADVENTURES IN SPECTRA
« Reply #45 on: January 03, 2022, 03:05:52 PM »
I will have to say, it's about time. 

 I did some tests 2 winters ago, I made up many 1 foot sections with different knots as termination.  I loaded them statically, out of 10 test sections with uni, double uni, granny and Palomar, and granny, none failed at the knot.  I was seeing well over 2x the rating on the line. 

I do statically pull on a new set pretty hard to set the knot.  I clip the tag end after setting the know to 1/16

I only had a line break after a line tangle and the airplane went slack over my head and jerked pretty hard.  but the bellcrank pulled out as well
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Re: ADVENTURES IN SPECTRA
« Reply #46 on: January 04, 2022, 09:56:12 AM »
Interesting link to factoids on spectra and kevlar fibers.

https://www.everprogloves.com/kevlar-vs-dyneema/
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Online Ken Culbertson

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Re: ADVENTURES IN SPECTRA
« Reply #47 on: January 04, 2022, 11:27:08 AM »
I have been doing a bunch of reading on this.  Mostly from the Kite flyers.  One problem seems to be fake line.  Seems some of the Chinese stuff actually comes in identical packaging as the real.  Is there a surefire way to know you are not getting the fake line?   ~^

Secondly, since my decision matrix is between Spectra and the Ukraine lines, has anybody done a stretch comparison between the two?   My anecdotal experience is that spectra stretches more but the literature says less.  It also seems to have more rake but, my ability to do my usual video analysis is grounded.   Anybody have any thoughts? D>K

It is hard to pass on something that is lighter, thinner and 15 times stronger but putting your pride and joy out there in a 15mph wind on fishing line sort of bothers me still.  Help me get over it! LL~

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Re: ADVENTURES IN SPECTRA
« Reply #48 on: January 04, 2022, 12:57:51 PM »

It is hard to pass on something that is lighter, thinner and 15 times stronger but putting your pride and joy out there in a 15mph wind on fishing line sort of bothers me still.  Help me get over it! LL~

Ken

I would say the decade of the fast combat guys reliably flying thier Nelson 36 ships at 110-120mph on Power-Pro Spectra should answer the questions on fragility, durability, longevity, ect.  That is a really harsh testing environment compared to stunt.  Even with the weight differences between a 65oz stunt ship and a Nelson or TWA 36 combat, that 120mph combat ship pulls quite hard. 

The drag through the air and amount of perceivable stretch in flight are probably the factors that would dictate choice between traditional .018 stainless,  Spectra and the Ukrainian lines for highest level stunt competition.
« Last Edit: January 04, 2022, 03:11:41 PM by Brent Williams »
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Online Ken Culbertson

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Re: ADVENTURES IN SPECTRA
« Reply #49 on: January 04, 2022, 03:17:13 PM »
The drag through the air and amount of perceivable stretch in flight are probably the factors that would dictate choice between Spectra and the Ukrainian lines for highest level stunt competition.
I have slipped down the ladder of success a bit so I am not exactly at the highest level of stunt competition anymore BUT I like to think that the ladder still goes both ways!  I have a couple of sets of the latest Ukrainian lines that I am using now so I guess the next step is make up a set of same size Spectra, have a few beers and give it a shot.   ~^

Glad you used "perceived".  So mush of trim is wishful thinking.  That is why it is nice to have someone less likely to screw up than you are fly your plane every now and then while you take a trip to the port-a-potty so you don't have to watch! LL~

Ken
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