Derek's Level 2 Build

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Aquaman33
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Re: Derek's Level 2 Build

Postby Aquaman33 » Tue Apr 28, 2020 10:10 pm

NSWRA's April launch was cancelled due to Covid-19, so I have a bit more time to get this finished. Possibly another 6 months! :D

I appreciate that this build is jumping around a bit, but the one item I don't have to hand is a parachute so I decided to get that sorted. I spent lots of time researching chutes on US sites, but the exchange rate and the postage put me off. So I decided to make my own for the first time.

Used Scott Bryce's website to generate a template for a 6 gore, half hemisphere, 5 foot chute with a 10 inch spill hole.

http://scottbryce.com/parachute/spherical_parachute.html

At first I printed the template on about 8 pieces of A4, but to be honest I couldn't get them to line up properly, possibly because my home printer is a bit average. So I went to Officeworks and got them to print it full size on a single sheet of paper.

I then glued the paper template to some MDF and cut it out with a band saw.

Once the template was complete I placed it on the ripstop nylon fabric and added weights to stop it moving.

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I then used a soldering iron to trace around the template. This melts the fabric, which both cuts it and seals it so it won't fray.

This technique works really well and the edge is good enough that you don't need to hem low and mid power chutes.

Not sure on the final colour combination yet, but it will be one of these:

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Now time to start sewing.

PK
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Re: Derek's Level 2 Build

Postby PK » Wed Apr 29, 2020 8:33 am

Keen to see how you go with that chute. I'm also trying my hand at it for the first time.
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What's your plan for reinforcing the seams?
PK

I'm awesome!

Aquaman33
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Re: Derek's Level 2 Build

Postby Aquaman33 » Wed Apr 29, 2020 11:40 am

PK wrote:Keen to see how you go with that chute. I'm also trying my hand at it for the first time.

What's your plan for reinforcing the seams?


Looks great PK.

It looks like you are using more gores than me. With hindsight I wish I have gone for 8 or 10 gores instead of 6, but at the time I was trying to minimise the sewing.

Not exactly sure what I'll do to reinforce the seems. I did sew a black and white prototype and my wife suggested I fuse the seems together with this hemming tape before sewing:

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You place it between the layers of fabric and iron them together. The tape melts and holds the layers together really well and stiffens the seam which makes sewing easier (no pins required).....but it doesn't really add any structural strength.

You can see the hemming tape through the white fabric in this photo.

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I bought some really heavy duty thread, which is very hard to snap. The disadvantage of this thread is that I can only do simple straight stitches on our sewing machine. No zig-zags or anything fancy. So I did 2 rows of small straight stitches and it appears to be very strong. Can't recall what the thread is called as I bought it years ago on Ebay (and I don't read Chinese).

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I will add loops using flat nylon shock cord to attach the lines, as my sewing skills are not good enough to sew lines directly to the ripstop nylon. The loops will also add some strength.

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For the lines I plan to use this 150lb braided fishing line. Its quite thick and soft, so should work well. I found it in the bargain bin of my local fishing store.

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This version is rainbow colours so I can pick a colour that matches the chute.

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PK
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Re: Derek's Level 2 Build

Postby PK » Wed Apr 29, 2020 12:16 pm

I chose 12 gores as it's a 1.75m diameter chute.
I like the hemming tape idea. I've just been using a glue stick (as in the bad tasting giant lipstick type) to hold the corners and fiddly bits together when hemming..

I've used standard polyester thread for the hems on each panel, but used a 2mm straight stitch. Seems strong enough, time will tell...

If you have a laser cutter, it does a perfect job on ripstop nylon, the edges are neatly sealed and don't fray and it cuts a gore in seconds.

That flat nylon looks perfect, can you remember where you got it?
PK

I'm awesome!

Aquaman33
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Re: Derek's Level 2 Build

Postby Aquaman33 » Wed Apr 29, 2020 2:12 pm

PK wrote:That flat nylon looks perfect, can you remember where you got it?


It was a shock cord that came in a LOC kit. I upgraded to kevlar, so the flat nylon was surplus to requirements.

But if you search for "nylon webbing" on Ebay there are lots of options.

The other option is tie-down straps from Bunnings or an auto store, but these tend to be quite wide.


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