straight vs. cascaded lines

[livenletfly 0]

whats the advantages and disadvantages of these 2 line options?
heres what i can think of. straight lines= more consistant trim but more parasitic drag. cascaded lines= less drag, more affected by line shrinkage due to the fact one line controls multiple attacments.

what are your thoughts?

>

[tcnelson 1]

i don't know...no experience with straight lines but, i am interested in the question.

"Don't talk to me like that assface...I don't work for you yet." - Fletch
NBFT, Deseoso Rodriguez RB#1329

[billvon 2,989]

Straight lines = easier relines, greater strength

I'm suprised no manufacturer has yet tried the paraglider method of cascading lines - left to right instead of back to front.

[masterrigger1 2]

We have!!

MEL
Skyworks Parachute Service

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[bob.dino 1]

More info?

How did it perform? Did it noticably affect the openings or flying characteristics? Any maintenance concerns? etc, etc...

Thanks!

[Rdutch 0]

Quote

Straight lines = easier relines, greater strength

I'm suprised no manufacturer has yet tried the paraglider method of cascading lines - left to right instead of back to front.

Icarus was playing around with that on their 11 cell.

Ray
Small and fast what every girl dreams of!

[nicknitro71 0]

I am jumping an Alpha 99 that still had its first line set.

I relined it with HMA non-cascaded lines. I trimmed it like a Cobalt, made the lines 15 cm longer, and put a different slider.

Making the lines was a bit of a pain because there are so many! I did not bartack them; I used the Jump Shack non-sewing finger trapping method and it has been working well.

The Tecnora lines I used are different than what Precision and HiperUSA use. They come from a different manufacture, they are 352 LBS minimum, they are thinner, and black due to a UV coat.

The reduction in bulk is 50% above the cascade and 25% below the cascade; quite a difference.

The canopy has been completely transformed. Because I have done many things I don't know which factor contributed the most.

The differences are: more consistent openings; more carved toggle turns (not as snappy); lighter front riser pressure, much longer recovery arc; faster flight; steeper angle of incidence; greater bottom end and flare; also the canopy looks flatter span-wise.

The lower control lines are made of Dacron 400 LBS.

I should be able to get 1000 jumps with this set up.

Bottom line "Daddy likes it!"

Memento Audere Semper

903

[masterrigger1 2]

The Colbalt canopies have the same trim and line set as the Viper and Alpha.

As far as the bulk issue....
The Continuious lines can add more bulk.
725 Spectra is 1/8 inch wide and 1/16 thick
350 Technora is almost 3/32 inch wide and 1/16 thick

If you total the Length X width X thickness to find the total area, you might just be suprised at the outcome.
This is why you do not see the PD boy's jumping continious line Sets on the distance canopies.

This is also why the openings are better on Continuious lines sets, more line grip on the slider grommets all the way down the lines.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[nicknitro71 0]

Quote

The Colbalt canopies have the same trim and line set as the Viper and Alpha

Not true. Ask Stane about it. The trim has been changed during the years. Minor stuff but it's not the same.

Quote

The Continuious lines can add more bulk

Not in this case. 50% in reduction of the bulk above the cascade, 25% below it.

Quote

350 Technora is almost 3/32 inch wide and 1/16 thick

You have not seen the stuff I use, much thinner than CSR's. Contact E.L. Wood Braiding Co. Inc 607.849.9663 if you want to know the specs on the stuff they made for me.

Memento Audere Semper

903

[masterrigger1 2]

Quote

Quote

The Colbalt canopies have the same trim and line set as the Viper and Alpha

Not true. Ask Stane about it. The trim has been changed during the years. Minor stuff but it's not the same.

Quote

According to Dan Preston they are the same!

***The Continuious lines can add more bulk

Not in this case. 50% in reduction of the bulk above the cascade, 25% below it.

Quote

350 Technora is almost 3/32 inch wide and 1/16 thick

You have not seen the stuff I use, much thinner than CSR's. Contact E.L. Wood Braiding Co. Inc 607.849.9663 if you want to know the specs on the stuff they made for me.

Will do!! Also PM Sent..
MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[nicknitro71 0]

Quote

According to Dan Preston they are the same!

I don't want to go off the tangent on this one but ask the person who actually designs and makes these canopies!

Memento Audere Semper

903

[cobaltdan 0]

there have been minor changes over the years and some customer requested variances produced, e.g. some of the privately labeled canopies for gunter/winchester/skydepot. however the basic planform, airfoil and trim are almost identical. we are speaking of small tweaks and our recommended line specs now are that which are used on the cobalt. i will be glad to fax/email anyone complete line specs from any revision past or present.

sincerely,

daniel preston
www.atairaerodynamics.com (sport)
www.atairaerospace.com (military)

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[roq 0]

"I did not bartack them; I used the Jump Shack non-sewing finger trapping method and it has been working well."

Hi Nick
Caution. The no bartacked lines with tecnhora lines
don't seem good idea

The tecnhora lines is aramide. The aramide is very sensitive to knots, abrasion, moisture and UV. The jump shack method "non-sewing finger trapping method" is good for spectra lines because the spectra is not sensitive to knots but no good for aramide lines.
This process is similar than the knots and knots in aramid lines can make the reduction of resistance in 10 to 30 %

Roq

[nicknitro71 0]

Thanks Roq,

I did a pull test on the lines and they broke not at the knot so it seems it does not cause any reduction in strength.

I've also heard of other people having success with the Jump Shack method with HMA. I'll keep an eye on them anyway

Honesty I think the line suffers more damage from the single stitch required for HMA than from the JS knot that is actually not a knot per se. Time will tell...

Memento Audere Semper

903

[cobaltdan 0]

i just did a quick test with technora lines from el woods (nice stuff btw).

i broke 3 pieces on our universal test machine with a knot in the center. all three broke on the knot...?

sincerely,

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[nicknitro71 0]

Did you use the Jump Shack no-sewing finger trap?

Memento Audere Semper

903

[cobaltdan 0]

no i did not, samples were tested with a square knot.

if you want to send me samples of the jump shack no-sewing method, i would be glad to test them and post the graphs.

12" long with eyes at both ends. eyes should be able to pass a .75" rod through.

sincerely,

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[nicknitro71 0]

Will do. Is this the correct address?

499 Van Brunt Street, Suite 3B
Brooklyn, NY 11231
USA

Memento Audere Semper

903

[roq 0]

About knots in aramid lines see:

http://www.gingliders.com/normanlausch/

Roq

[cobaltdan 0]

yes, that is the correct address. if possible ups/fedex is best as we are on a pier in an industrial complex. mail is typically quite slow to us.

sincerely,

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[masterrigger1 2]

Quote

Quote

Did you use the Jump Shack no-sewing finger trap?

Nick,
I have! In my test the localized location of the "pass through" will be the culprit. When that spot sees non-linear loading and wear, it will fracture there.

MEL

Skyworks Parachute Service, LLC
www.Skyworksparachuteservice.com

[Rdutch 0]

Quote

no i did not, samples were tested with a square knot.

if you want to send me samples of the jump shack no-sewing method, i would be glad to test them and post the graphs.

12" long with eyes at both ends. eyes should be able to pass a .75" rod through.

sincerely,

Jump shack doesn't use the no bartack, double fingertrap method anymore. I dont know exactly why, but it isnt 100% effective.

Ray
Small and fast what every girl dreams of!

[johnny1488 1]

I used it on my own brake lines and didnt like the way it wore. Seemed to pull through itself over time. Dont know how to explain it better but I didnt like the way it looked.

Johnny
--"This ain't no book club, we're all gonna die!"
Mike Rome

[cobaltdan 0]

ok i received the sample of technora line with the edges terminated using the jump shack method from nicknitro.

it was placed into our galdabini universal test machine. result the 352 pound rated line broke at 315.15 pounds immediately above the inside tail of the finger trap. it did not break at the knot.

i relayed the data to nick and he will be sending a dozen more samples to test (cant draw too many conclusion s from a single test). i am a little concerned that the line should have surpassed 352 pounds...

sincerely,

Daniel Preston <><>
atairaerodynamics.com (sport)
atairaerospace.com (military)

[roq 0]

I think that the line will break at more low streng after a few jumps.
Just my opinion...

Roq