ADVENTURES IN SPECTRA

[Dennis Adamisin]

No kidding!  Now that you mention it, I think the plane was fishtailing where it should have been locking.  I blew that off as crappy piloting having not flown in a month or so.  Thanks for giving me an excuse to blame the plane!  Next time out I will divest it of some tip weight and add a few RPM's to keep the lines tight.  Funny you should mention rudder.   It has a cam for just the reason you stated.  Best whisper (shhh), because admitting to using rudder might get you cancelled. 

I was quite proud of how this profile flies.  It appears to fly like a real PA, but after a few months flying the canard, I was shocked at the difference in turning.  My first pullout on the RWO caused several worms to have heart attacks.

Ken

Ken
Switching to Spectra of course required at least a little re-trimming on existing airplanes. Not stopping there, whenever I pick up something haven't flown for awhile I end up with some kind of trim tweak to get a little  better feel, a little better performance.  Works both ways too; go back to the main bird and as often as not I'll get another idea to try to squeeze a little more out of it too!

[Ara Dedekian]

      Used my 100# dark green Spectra to lash the brass hinge barrels to the elevator of a well used, unknown combat plane destined for Brodaks. It looks suspiciously like Phil's Rugged Stunt Trainer modified from its former life to fly combat.

      Ara

[kiwibrit]

I am trying out my first set of Spectra type lines (actually Shimano Kairiki).  Pre stretching went fine.  I have used the modified surgeons knot to form the loops. Very pleased that my 60' lines are of identical length (beginners luck)? and just 1/4" short of the intended 60' length.

Question: do the free ends of line have to be sealed?  In his video, Mike didn't seal his.  I attempted to seal the ends using the flame from a match - but it didn't work well, and I have fraying as far as the knot.  My guess is that it can't go further, since the knot itself will stop any further progression, so all is well.  But I would be grateful if experienced users can confirm.

[Colin McRae]

I am trying out my first set of Spectra type lines (actually Shimano Kairiki).  Pre stretching went fine.  I have used the modified surgeons knot to form the loops. Very pleased that my 60' lines are of identical length (beginners luck)? and just 1/4" short of the intended 60' length.

Question: do the free ends of line have to be sealed?  In his video, Mike didn't seal his.  I attempted to seal the ends using the flame from a match - but it didn't work well, and I have fraying as far as the knot.  My guess is that it can't go further, since the knot itself will stop any further progression, so all is well.  But I would be grateful if experienced users can confirm.

I have never 'sealed' the free ends. Never had any issues.

[Dennis Nunes]

Question: do the free ends of line have to be sealed?  In his video, Mike didn't seal his.  I attempted to seal the ends using the flame from a match - but it didn't work well, and I have fraying as far as the knot.  My guess is that it can't go further, since the knot itself will stop any further progression, so all is well.  But I would be grateful if experienced users can confirm.

I've had some ends fray. I've used a Berkley Hot Line Cutter. I purchased mine at https://sportco.com/berkley-hot-line-cutter/ for under $12. This cutter uses two AA batteries and heats a retractable wire element that cuts or melts the Spectra line. The benefit of this is that it cauterizes the ends of the lines and keeps them from fraying.

Dennis

[Colin McRae]

I have various sets of Spectra lines that have many flights on them. Mine were cut with a simple wire cutter.

The free ends on mine are around 3/8" long away from the knot and show no signs of fraying. I have only used the PowerPro brand. Maybe the brand used has something do with possible fraying.

[kiwibrit]

Dennis Nunes, thanks.  That looks a very practical solution - I'll buy one.

Colin McRae, thanks.  I'll try Spectra next reel - I have started with Shimano Kairiki because my first flights with this sort of line were with it - courtesy of a kind New Zealand modeller who let me fly a couple of his models ... and I was impressed. I think using a hot wire cutter is a good idea and will probably use it on all future line sets I make with Spectra type line.

Meantime, I shall use the lines I have made up.  The knots are so tight, I don't think there will be trouble, but I shall do frequent line pull checks.

[Dan McEntee]

   I am on my second season of learning and flying with Spectra lines. So far, the biggest improvement I have seen on the airplanes I have tried it on, is vertical and overhead maneuvers have better tension and feel. I pretty much use the knot that Mike Stinson shows in the video, with a single loop for small models and a double loop for larger airplanes. The experiment continues.

    But I'll have to ask the question I have been looking for some one else to ask !! Has there been any kind of failures by anyone?? Just curious. After doing something one way for so many years, it's difficult to put all your faith in a new method in one big leap!!

   Type at you later,
     Dan McEntee

[Lauri Malila]

..

[kiwibrit]

Wow, once shipping and all the charges have been applied, one of those Berkley hot line tools costs $40 to arrive at my UK home. Times are tight;  I shall experiment to see if a small electric soldering iron will do the job!

[kenneth cook]

                 Dan, we were using them for combat but I fly all the sport stuff with the same lines. The only failures we ever encountered was at the line guide at the tip. We would flip our lines now and then because it would fray them were it rubbed on the bushing. It didn't matter what material we used because I was also using the ceramic tip guides used on fishing rods. I love the stuff and I never EVER had a knot fail. The lines always broke where it exited the plane. Most of my  early combat planes were using nylon bushings at the tip guide. It took quite a bit to fray the lines but eventually they would.

[Dave_Trible]

                 Dan, we were using them for combat but I fly all the sport stuff with the same lines. The only failures we ever encountered was at the line guide at the tip. We would flip our lines now and then because it would fray them were it rubbed on the bushing. It didn't matter what material we used because I was also using the ceramic tip guides used on fishing rods. I love the stuff and I never EVER had a knot fail. The lines always broke where it exited the plane. Most of my  early combat planes were using nylon bushings at the tip guide. It took quite a bit to fray the lines but eventually they would.

I think I would use cable to the bell crank and exit the lead out guide just like with steel lines and then attach the other line there.  That would eliminate the wear problem.  I'm just getting my first airplane intended for those lines ready to go and that's my method.  I can also go back to the steel quickly if I wanted.

Dave

[Colin McRae]

This is how I have been doing my PowerPro Spectra, very simple using Sullivan 80# clips. Never had a line failure or knot come loose. And no fraying.

I have been using 65# test Spectra lines, even on my heavy Vector 40 at 62 oz. Concerning overall strength, two 65# test lines to a model would total 130#. In level flight, my Vector probably has a pull of say 10# (5# per line). Or a safety factor of 13.

Some pilots are using 80# test. The only reason to do so that I can think of would be for lower stretch. But 80# is surely not needed for overall strength.

Also, lines can end up with slight damage over time (dragging lines on the ground, someone maybe stepping on them, etc.). I can make up a new set of lines for around $5. So, I have been replacing my lines that have lots of flights on them every couple of years. Just additional safety factor overkill for me.

[kenneth cook]

            Dave, I don't use a adjustable handle on my combat planes. My lines are exact length using a button style bellcrank. 60' center to center. Using leadouts to the tip would be consistently changing from plane to plane therefore I keep them all the same. We pull test prior to a match and inspect at the designated area. Unfortunately, more than once the failure I mentioned only happened in the area subjected to wear.

[Jim Hoffman]

I see some discussion of Spectra failures.  Perhaps this empirical data will be helpful

I’ve done a bit of destructive testing on Spectra materials. I pull test samples to destruction to allow me to make decisions on lines material for a given weight airplane.  Based on testing, my rule of thumb is to plan on failure at 50% of manufacturers rated capacity.  I then size and validate my flying lines to withstand a 15G pull test knowing they will see a 10G pull test at contests.  A proof test of 150% max normal operating load is an aerospace standard.

TESTING
•   I make the test sample ends exactly the way I make my flight lines.
•   Test samples are  1 to 2 foot in length.
•   I generally make 5 test samples of any product under test.
•   I tie the knots per the Mike Stinson You Tube video and use weld rings at the ends.
•   I use a luggage spring scale with a max load indicator dial.
•   I work my way up to failure in 5# increments and dwell at each load maybe 5-10 seconds.

RESULT:
•   I have found that the material fails at about 50% of the rated strength, although there is certainly some variation.
•   Failure occurs where the line exits the knot.
•   I have tried knitted overbraid per the kite community and found no improvement.

My test samples included:
•   Macuatro Power Pro 50# test
•   Macuatro Power Pro 65# test
•   Fins Spin 5  25# test
•   Fins Spin 5  50# test
•   Windtamer 100#  test   (this made it to 70% which is the highest % load achieved by me)

[Dave_Trible]

            Dave, I don't use a adjustable handle on my combat planes. My lines are exact length using a button style bellcrank. 60' center to center. Using leadouts to the tip would be consistently changing from plane to plane therefore I keep them all the same. We pull test prior to a match and inspect at the designated area. Unfortunately, more than once the failure I mentioned only happened in the area subjected to wear.

OK , well I still don't quite follow where the problem would be as long as you were careful to tie all the ends off equally-might require a holding fixture.  In my combat days (1970's)  we did this but did have a somewhat adjustable handle- the Hot Rock.  In any event maybe nylon guides or eyelets might help.  I'm using the nylon/teflon sheath from those RC control cable pushrods on some of my classic airplanes albeit with .027 cable.

Dave

[Ken Culbertson]

One thing I have noticed about Spectra is that for all of the reasons I find them superior, most don't seem to be giving them a chance.  I am curious why?

Ken

[Dennis Adamisin]

One thing I have noticed about Spectra is that for all of the reasons I find them superior, most don't seem to be giving them a chance.  I am curious why?

Ken

+1. 

[Colin McRae]

One thing I have noticed about Spectra is that for all of the reasons I find them superior, most don't seem to be giving them a chance.  I am curious why?

Ken

I fly with a few quite experienced pilots. I've been flying with Spectra from the beginning and really like them. But the only significant negative comment I've heard from some top pilots is that Spectra lines are 'springy' and stretch too much, thereby affecting the accuracy of the controls. Probably true, maybe not. Out of curiosity I did a stretch test comparison between 015 SS and 65# Spectra on 60' lines a couple years ago and yes, the Spectra lines stretched more, but the difference was extremely small. Loading a single line at 7 lbs (plus/minus a somewhat real load during level fight for a larger model) the SS line stretched about 3/4". The Spectra line at the same load about 1.25". Very small difference IMO. But I guess an expert pilot would notice the difference.

Also, if a pilot has a particular model trimmed for SS lines, some level of re-trimming may be necessary if switching to Spectra. And that is an exercise they don't want or need to go through. And I understand that.

And I'm curious. At the NATS, are any high level stunters using Spectra lines?

Colin

[Ken Culbertson]

I've heard from some top pilots is that Spectra lines are 'springy' and stretch too much....

Also, if a pilot has a particular model trimmed for SS lines, some level of re-trimming may be necessary if switching to Spectra....

Most of the analysis I have followed never stated how old or used the lines tested were.  I will state as a fact that new set of spectra lines will stretch more than a new set of steel but if you condition them enough, I think they actually stretch less.  I use 100lb which is similar to .018 steel.  I pull them, as a set, to 50lb+ and hold them there for a couple of minutes.  I do this three times.  Braded lines have very little memory, steel does.  They stay rigid well past the 10-15 lbs we pull them in flight. I may switch to 80lb which is far stronger than any steel lines.  I am willing to bet that a lot of the first-time users were not flying on conditioned lines or were not used to the trim. 

The second reason holds water.  They are different.  Perhaps it is the drag or the sweep being different, or maybe it is being able to see them clearly.  I use hardpoint and I can feel the plane better.  The plane definitely will trim differently and simply switching lines will have you flying an unfamiliar plane. 

Finally what I think is the real reason.  It is fishing line and real men use steel.  I wonder if they knew that 100lb Spectra was made for Bluefin Tuna. 

Ken

[GERALD WIMMER]

Hello after flying Spectra on nearly all of our models for the last 8 years I am very happy with it.
We as a family use 80 or 100lb as it stretches less then 65lb on large models and then 65lb for our smaller models and 30lb for 1/2A .
I believe they are just as good as stainless but prefer the feel and handling of Spectra an observation shared by my sons and wife .
We only use steel for combat and team race where required to.
It seems most people who do not like Spectra reject it on the basis of it is not seen as professional for top flyers to use it , like electric power was 30 years ago.

Regards Gerald

[Colin McRae]

 It is fishing line and real men use steel.

Ken

I also think this is the primary reason. Real pilots are not catching fish. 

[Ken Culbertson]

I also think this is the primary reason. Real pilots are not catching fish. 

And Bluefin Tuna have problems with the Hourglass! 

Ken

[Dennis Adamisin]

And Bluefin Tuna have problems with the Hourglass! 

Ken

Ya know Ken, its easier to trim a stunt plane than it is to tune-a-fish...

[Ken Culbertson]

Ya know Ken, its easier to trim a stunt plane than it is to tune-a-fish...

From what I hear, you Can't tune-a-fish! 

[Dan McEntee]

  I have been using Spectra lines on most of my .35 to .40 size models for a couple of seasons now, and exclusively on the smaller 1/2A stunt models and trainers. I find them to me much more durable and love the feature that they do not pig tail and kink. For flying stunt, I have found they shine the best when doing the vertical and overhead maneuvers. I have found that every model I have used them on has had better performance in these maneuvers. For a typical ARF Nobler, the weight difference between metal and Spectra lines was very significant. I forget the exact numbers but when I made up a set for a Nobler ARF, the steel lines and reel weight something like 2 1/2 ounces while the equivalent length of Spectra lines and reel was a few grams, more or less the weight of the reel and metal clip..

   I wonder why some use line that is so heavy for flying smallish stunt models. I weigh the model and determine what the pull test would be, then I add 10 pounds to that and that is the weight of the line I use, usually rounded up because there isn't a very wide selection of line at Bass Pro when I go  there. And I have been using Spectra brand, just to avoid any confusion on my part, and buy it locally, as I have both Bass Pro and Cabela's store right close to me. I use the loop and knot that is in the video presented in this thread by Mike Stinson, with the loop doubled like he shows because it just makes sense, and add in the welded metal rings suggested by Dennis Adamisin, then I can use and change normal line clips as desired. So far I have not had any issues with the lines I have made up and use. I remember reading that some one from over seas suggested just a drop of clear silicone to help secure the knot against slipping, as it will remain flexible, and that may help settle anyone's fears of a knot slipping.

    I have mentioned before that this thread contains just about ANYTHING a person could want to know about making up a set of lines using Spectra, and it should be pinned to the top of some section, probably the "At The Handle" section, just to make it easy for people to find.

  Type at you later,
    Dan McEntee

[Ken Culbertson]

   I wonder why some use line that is so heavy for flying smallish stunt models

I have wondered the same thing.  I fly a 70oz PA on 100lb that pulls steady around 10-15 lbs.  I finger fly and actually like the pull.  The pull test is around 45 which is 1/4 the rated strength or 1/2 if you consider the knots and 8-10 times normal flight.  Actually 65 would probably suffice and 80 definitely would.  Granted, they would take more conditioning to remove the stretch, and you couldn't use them for Tuna ( Bonita maybe). Are we perhaps still scared of them?

I agree 100% on the verticals and overheads.

Ken

[Colin McRae]

I also use Spectra for my stooge line since there is little if any stretch. And always the high visibility yellow color for my flying lines which makes them easier to see on the ground.

And the side benefit of lower cost. It costs me about $7 to make up a set of 80# rated 60' lines.

I've only used the PowerPro Brand. Can't speak to other brands. I also did a simple strength test cuz I was curious. I made up a single 2' long line using 65# Spectra and the modified surgeons double loop knot on both ends as shown in the video. And no end rings, but just using my normal line clips. I loaded my fish scale in 5# increments all the way up to 60# with no breakage or knot slippage. That simple test satisfied me on the rated strength of the lines.

Have also read that some have seen lines break at well under the rated strength. But not sure what brand they used or type of knot used. But that is not what I have seen if using the proper knot and PowerPro brand.