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Author Topic: .015 x 7 strand vs .015 x 19 strand  (Read 3671 times)

Offline John Rist

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.015 x 7 strand vs .015 x 19 strand
« on: October 10, 2016, 09:56:31 AM »
Tom Morris has the .015 by 62 ft lines in both 7 strand and 19 strand.  Same price for both.  What are advantages and disadvantages of each.  I will be using them for stunt.  ???
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Offline Mark Scarborough

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #1 on: October 10, 2016, 10:10:14 AM »
19 strand is nice limber, and flexible, but fragile, I wont use them because I fly off grass by myself, and they would not last.

My opinion, unless you are fastidious with your line maintenance, AND you fly well enough to need the last 2% performance advantage, I dont think the 19 strand is a good direction to go
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Online Lauri Malila

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #2 on: October 10, 2016, 10:22:16 AM »
I never found the 19-strand lines more fragile, other that getting some loose strands near ends if I was not carefull with handling the ends.
But they do have more air drag and weight than 7-strand lines. I don't know which one plays a bigger role in the stretchy feeling, the drag or actual stretch.
At the moment I'm a big fan of Russian carbon steel lines. I think they have 3 or 4 strands.

Lauri

Offline Matt Colan

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #3 on: October 10, 2016, 08:31:58 PM »
19 strand is nice limber, and flexible, but fragile, I wont use them because I fly off grass by myself, and they would not last.

My opinion, unless you are fastidious with your line maintenance, AND you fly well enough to need the last 2% performance advantage, I dont think the 19 strand is a good direction to go

I actually found the opposite with 19 strand lines.  I have done back to back flights on two different airplanes and found the 7 strand to be better.  To me, the airplane felt easier to fly with the 7 strand lines.  I found it easier to fly any maneuver with a corner and lock in the bottom easier.
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Online Brett Buck

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #4 on: October 10, 2016, 09:00:14 PM »
I actually found the opposite with 19 strand lines.  I have done back to back flights on two different airplanes and found the 7 strand to be better.  To me, the airplane felt easier to fly with the 7 strand lines.  I found it easier to fly any maneuver with a corner and lock in the bottom easier.

   Of course.  The 19-strand are a little bit more stretchy so the control will be less precise.

     Brett

Offline M Spencer

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #5 on: October 10, 2016, 09:09:38 PM »
Back in Medieval times ,
in the 70's in N.Z. , the stunt deros used FOURTEEN INCH grooved ply Line Reels .  %^@

Made the suckers a lot less prone to disorder ( the Lines , not the pilots ) . and could reel em in & out at walking pace , to clear the circle .

Stranded Lines , and single strand , of the reel - usually have ' curls ' .

Having a elper hold Ea. Line in Ea. Hand whilst you run a rag down Ea. ( Simultaeneously & carefully ) the LINE Revolves in the others hands .
Sometimes SIX Runs down the wires are neccesary to get the revolving to discontinue .

Youll Find Half the previous STRETCH has dematerialised , on the old stretch / pull test trick . and the length has grown , perhaps .


Offline Steve Helmick

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #6 on: October 10, 2016, 09:19:04 PM »
Tom Morris was apparently surprised when I asked for 7 strands the last time I ordered lines from him, because he emailed me to confirm that.

The 19 strands are soft, supple and all, but most the guys I fly with were put off them by the likelihood of individual strand failure, since the wire strands are so much smaller, and we were flying off hard surfaces.

I think IF I flew off a good grass field, I'd be less worried about that and more likely to use 19 strands, so opinions vary on that. There is, of course, a variation of grass quality. Mark flies on part of a grass strip airport...probably not as lush as a soccer field like we will probably be flying on next year.

I flew with some 19 strands for a season or two and didn't really have any problems with them, but went to 7 strands anyway, 'cause line trouble is pretty deadly if you don't catch it in time, especially over pavement with pretty expensive (to me) engines that may be hard to replace.  D>K Steve
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Offline Matt Colan

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #7 on: October 10, 2016, 10:27:35 PM »
   Of course.  The 19-strand are a little bit more stretchy so the control will be less precise.

     Brett

That's exactly what I felt.
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Online Howard Rush

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #8 on: October 10, 2016, 10:59:34 PM »
I don't have the data handy, but I measured elasticity in tension for both 7- and 19-strand lines and found them about the same. Staystrates are stiffer.  I'd expect the Russian or Ukrainian line to be stiffer also.  I got some F2B line from Viko several years ago.  It was too small in diameter for AMA, but not for F2B, which has no diameter requirement (or didn't the last time I looked).

Mark Rudner saw some data that suggested that three-strand F2C lines have less drag than other lines the same diameter.  Maybe 19-strand lines do have more drag than 7-strand lines. Try one line of each species and look to see if one blows back more than the other.
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Online Brett Buck

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #9 on: October 10, 2016, 11:14:44 PM »
That's exactly what I felt.


  I am surprised anyone still uses the 19-strand lines, just due to the tendency for damage.

     Brett

Online Howard Rush

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #10 on: October 10, 2016, 11:23:21 PM »
To change the subject a little, has anyone used 19-strand leadout wire?
The Jive Combat Team
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Offline John Rist

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #11 on: October 11, 2016, 04:06:04 AM »
Well 7 Strand it is. I am planing to learn some of the pattern this winter and maybe take a stab at a contest next summer.  It sounds like 7 strand has fewer maintenance problems - a good thing.  At my flying skill level I doubt I could feel the difference if in fact there is a difference..

Time for  D>K  Thanks all for the info
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Online Lauri Malila

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #12 on: October 11, 2016, 07:14:53 AM »
I don't have the data handy, but I measured elasticity in tension for both 7- and 19-strand lines and found them about the same. Staystrates are stiffer.  I'd expect the Russian or Ukrainian line to be stiffer also.  I got some F2B line from Viko several years ago.  It was too small in diameter for AMA, but not for F2B, which has no diameter requirement (or didn't the last time I looked).

Mark Rudner saw some data that suggested that three-strand F2C lines have less drag than other lines the same diameter.  Maybe 19-strand lines do have more drag than 7-strand lines. Try one line of each species and look to see if one blows back more than the other.
[/quote

Isn't that clear; 19-strand line has bigger cross area which makes it heavier. Also, the  ross section is closer to round, round shape has bigger drag. That gives the stretchier feeling, not the measured stretch.
Humidity also
Plays a role in stetch of  braided cables but I doubt it's important in this scale. L

Offline Mark Scarborough

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #13 on: October 11, 2016, 08:23:40 AM »
To change the subject a little, has anyone used 19-strand leadout wire?
I have them on my Green pile of balsa for what its worth,, They are painfull to wrap the ends other than that I have observed no issues,, ( I did have a couple strands fracture when I tried it the first time, but modified my technique and it was fine)
For years the rat race had me going around in circles, Now I do it for fun!
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Online Howard Rush

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #14 on: October 12, 2016, 12:23:46 AM »
I have them on my Green pile of balsa for what its worth,, They are painfull to wrap the ends other than that I have observed no issues,, ( I did have a couple strands fracture when I tried it the first time, but modified my technique and it was fine)

You didn't perchance snag a broken strand on a leadout guide Sunday?
The Jive Combat Team
Making combat and stunt great again

Offline John Park

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #15 on: October 12, 2016, 06:14:11 AM »
Being English, I grew up using Laystrate tinned 3-strand lines (the same as the currently-available Staystrate).  When I started using 7-strand lines, I couldn't believe (a) how fiddly it was, trying to make up the ends, and (b) how springy, not to say spongy, they felt compared with what I was used to.  It's just a pity Staystrate costs three times as much, or I'd use nothing else.  I can't imagine using 19-strand.
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Offline Mark Scarborough

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Re: .015 x 7 strand vs .015 x 19 strand
« Reply #16 on: October 12, 2016, 08:09:02 AM »
You didn't perchance snag a broken strand on a leadout guide Sunday?
Howard, I have not looked specifically for that, but on my preflight "walk around" I did not notice anything, probably worth a look though.
I think Sunday was a combination of things primarily driven to disaster by the pilots desire to make a " good showing" and fly my bottoms down instead of being safe,,

I shall inspect for that tonight though
For years the rat race had me going around in circles, Now I do it for fun!
EXILED IN PULLMAN WA
AMA 842137


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