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Sep 23, 2019, 03:10 AM
Registered User
I think he twists and CA.

A twisted trace wire for predator fishing has been solid for years, even the modern wires that are so supple that can be knotted can still be twisted to secure.

I don’t know what strand it is but I’ve always just used the Vladimir pull wire set from Hyperflight if I didn’t have any decent braid to hand. They give you a few crimps to go with it.
Last edited by i_am_mark_evans; Sep 23, 2019 at 03:17 AM.
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Sep 23, 2019, 03:13 AM
In F3J size does matter!
roydor's Avatar
Quote:
Originally Posted by pgleesonuk
How do you secure with lines without crimping?
I wrap sewing thread around the wire and CA.
You can say it’s a “composite crimp”
Sep 23, 2019, 05:13 AM
Registered User
Quote:
Originally Posted by roydor
I wrap sewing thread around the wire and CA.
You can say it’s a “composite crimp”
You've got so much more patience than I do. Is your other hobby tying flies?
Sep 23, 2019, 05:20 AM
I'm not as bad as they say.
Quote:
Originally Posted by roydor
I use the 7 strands Beadalon wires and I’ve never had one break or but I don't crimp.
Do you guys see any difference in stretch?
I’ve never tried the 49 strands before and since it’s not available locally and costs more I’ve never tried it.
It's not about stretch, but about pliability and lack of fatigue. Also the 7 strand is more prone to take a "set" and stay formed.
I use Teflon exit guide tubes and the 49 has less drag under tension through the exits.
Want me to send you some?
Latest blog entry: AIrcraft I've built.
Sep 23, 2019, 07:29 AM
In F3J size does matter!
roydor's Avatar
Quote:
Originally Posted by drksky
You've got so much more patience than I do. Is your other hobby tying flies?
It actually takes just a few seconds, ot takes me less time than crimping.

Quote:
Originally Posted by mnowell129
It's not about stretch, but about pliability and lack of fatigue. Also the 7 strand is more prone to take a "set" and stay formed.
I use Teflon exit guide tubes and the 49 has less drag under tension through the exits.
Want me to send you some?
Less “set” is important, it can reduce the elastic behavior of the line. If the lines have bends in them they resist the springs and when force is applied they straighten out first and only then resist stretching so you get some initial flexing. I will order some and test.

Thanks
Sep 23, 2019, 10:01 AM
Registered User
A beadalon wire broke on me once during inspection but that was due to over crimping. Not sure what kind it was.
Sep 23, 2019, 10:56 AM
Time for me to Fly...
Mr. Wiz's Avatar
I picked up a little bit of good info. From now on I’ll get the 49 strand stuff.
Latest blog entry: Something old is new again
Sep 23, 2019, 12:51 PM
Come out swinging
sporter's Avatar
Thread OP
I think I will use the Spectra line.

Thanks
Sean
Sep 23, 2019, 01:54 PM
Registered User
Airbud's Avatar
I have used both spectra and beadalon.
Used spectra for the first three years. Would hang a 30 lb. weigh from it for a day or two. I would have to retrim my glider several times in a day as the day heated up (PITA).
than I switched to Beadalon. Never had the retrim problem again.
I would never go back to spectra.
Sep 23, 2019, 02:21 PM
solastagia
kcaldwel's Avatar
Quote:
Originally Posted by Airbud
I have used both spectra and beadalon.
Used spectra for the first three years. Would hang a 30 lb. weigh from it for a day or two. I would have to retrim my glider several times in a day as the day heated up (PITA).
than I switched to Beadalon. Never had the retrim problem again.
I would never go back to spectra.
That's interesting, because I don't see the trim changes you are talking about across a day or seasons with 50lb. test Spiderwire. Admittedly the temperature range on Vancouver Island is limited, but I don't notice changes like you describe.

The thermal expansion coefficient of Spectra and steel is quite different than the CF boom, so there will be length difference changes with either over large temperature shifts. I did look at this a long time ago, and I don't remember there being a huge advantage to one or the other, I'll have to dig that out again.

What kind of Spectra were you using? What lb. test?

That 0.015" 49 strand 20lb. test Beadalon seems to be expensive in Canada. Larger OD or fewer strands will increase the fatigue problem. The 0.018" is cheaper, but the larger OD won't help.

Kevin

Found the thermal expansion calculations I had done a long time ago. Spectra should be a slightly better TCE match for the CF tail boom than steel or Stainless steel, but the changes over a normal temperature change are pretty small in either case:

https://www.rcgroups.com/forums/show...&postcount=102
Last edited by kcaldwel; Sep 23, 2019 at 02:49 PM.
Sep 23, 2019, 02:41 PM
Come out swinging
sporter's Avatar
Thread OP
I picked up some of this:
I think this is what I have used before, it comes from the fishing store.

Sean
Sep 23, 2019, 04:02 PM
Time for me to Fly...
Mr. Wiz's Avatar
I severely disliked Spectra line. I had to change trims all the time, even when I did pre stretch it. Beadalon is all I use now.
Latest blog entry: Something old is new again
Sep 23, 2019, 04:24 PM
Registered User
The higher strand count wire is much more flexible than the 7 strand. I personally have not had an issue with the 7 strand. But I will be using the 49 strand in the future. Kevlar is very susceptible to temp change. Haven't used the spectra.
Sep 23, 2019, 06:38 PM
solastagia
kcaldwel's Avatar
Quote:
Originally Posted by freya
Kevlar is very susceptible to temp change. Haven't used the spectra.
But it's not! Kevlar has a very small, slightly negative CTE (-5 x 10^-6/C, -2.7 x 10^6 /degree F). It's change in length with temperature is far smaller than any metal (steel 12 x 10^6), and will be much closer to the near zero CTE of most CF composites like the boom is made of. CF by itself also has a negative CTE, but when combined with epoxy, which has a large positive CTE, the resultant composite usually has a near zero CTE.

https://www.pelicanrope.com/pdfs/KEV...ical_Guide.pdf

PII-9 (attached)

There seems to be something weird going on here. Some people's perceptions seem to very different than the engineering data. The negative CTE materials would give a trim change in the opposite direction of a steel cable, but the change also depends on whether the stab is top or bottom mounted too. Or maybe the change in control run materials coincided with a change in servos to ones that are less temperature sensitive? Some servos drift with temperature.

The thermal expansion coefficients are all small enough - less than 1 trim click for most set-ups - I find it hard to believe anyone would notice them. And Kevlar and Spectra should be no worse than Steel, and better than SS.

Baffles me, I just don't see it.

Kevin
Last edited by kcaldwel; Sep 23, 2019 at 07:51 PM.
Sep 23, 2019, 07:33 PM
Registered User
Any reason people don't use Kevlar? Does anyone make carbon fiber thread? Incconel? One could also make two part threads with appropriate proportions of steel and Spectra or something. How about just using very thin carbon rod, pull only?


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