[Continued from Part III]
(https://www.rocketryforum.com/threads/31-5-semi-ellipsoidal-parachute-build-part-iii.164480/)
8. Attaching the shroud lines.
This started out being more difficult than sewing flat-felled seams. The problem was with the round nylon cord. It rolled when I tried running a stitch through it. I tried walking the needle by turning the handwheel instead of using the pedal. But I could see where it might take a week to do it this way.
Then I remembered the presser foot I bought for doing rolled hems. It didn't work for that, but for feeding cord, it was perfect.
But first we must answer that burning question: Shroud lines from side to side? Or to adjacent corners? I am now of the opinion that it doesn't make a bit of difference once the lines are gathered at the harness point. Moreover, managing the lines as you stuff the fabric—and the lines—through the machine opening (which you have to do if you're crossing the canopy) to lock your stitch is not just unwieldy, it's downright bunglesome.
I'll add this: I crossed the canopy with my lines, and despite my efforts to prevent it, three of the lines are twisted enough to form a loop when they are relaxed. Several are crossed. (I'll hide that crap situation underneath three inches of heat-shrink tubing at the harness. But I'll still know I did it wrong.)
If I were doing it again, I'd attach the lines at adjacent gores. (I can't change these lines. If I unstitch them, I'm left with a mess of perforations.) That said, the following describes how to attach lines to adjacent gore seams.
This is the machine ready to lay the first line:
Important! Lay the fabric wrong side up for this. (Shroud lines belong on the inside of the canopy, not the outside.)
Before that, though . . .
Figure out how long your lines need to be. In my case, I wanted 35" shroud lines. Multiply that by 2 (down one side, up the other). Add the amount of line that will be sewn to the seam (mine was 2-1/2"). Multiply that by 2. Then add how much you think you'll need at the bottom for whatever your harness arrangement will be. I used 5". So I cut six lines 80" long.
Important! For heavier rockets, increase the length of line that is stitched to the canopy.
With disappearing ink, mark the end of each line where it will cross the edge of the canopy. In the picture above, it's the place on the line that is under the foot, right at the back edge of the canopy.
Swap out the standard presser foot with the rolled hem foot. (If you don't have one, get one. It is much, much easier.) Set the stitch to zigzag, and the stitch length to 3. (I don't know if the numbers on machines are universal. They ought to be if they're not.) Whatever gives you 10 to 12 stitches per inch (one complete stitch—left hole, right hole).
With the parachute on your lap, position the first seam under the foot, wrong side up. Lay the line behind the machine and pull the end toward you, underneath the foot, then lay it on top of the seam with the ink mark at the back edge of the fabric. Lower the foot. Run the handwheel a half turn back and forth while watching the needle, to see how wide the stitch is. You want the width of the zigzag to be just outside the sides of the line. If necessary, lift the foot and shift the seam a little to one side or the other to make sure it's centered once you have your stitch settings where you want them.
With the edge of the canopy just at the rear of the foot, the seam centered under the needle, and the line centered on the seam, lower the foot. Now pull the end of the line up through the hem loop. (The only time you'll have to touch it is if it slips out of the loop, and at the very end of the stitch.)
Walk the needle for the first several stitches. (Zigzagging has a greater tendency to bunch the fabric at the start.) Now, with your hands flat on both sides of the seam, press the pedal, adjusting side to side if needed as you go.
Stop 1/8" short of the end of the line. Set the stitch length to 0. Then run about 6 stitches in place to lock it. With the needle down, lift the foot and turn the material 180 degrees. Lower the foot and raise the needle. Set the stitch to straight, width to 0, length to 10 stitches per inch.
When you set the stitch width to 0, you'll notice the needle move back to the center. Lift the foot and adjust the fabric so the needle is dead-centered over the line. Lower the foot, then turn the handwheel slowly watching the needle descend. If it is not exactly centered, raise the foot slightly and adjust the material.
Important! This next stitch is the one that will bear all of the force on deployment. (The zigzag merely holds the line in place so you can straight stitch it.) Make it centered, and make it straight!
Slowly sew your way back to the edge of the canopy. Stop when you're 1/8" from the end. Raise the needle and set the stitch to zigzag, width to whatever it was on the previous zigzag, length to zero. Lift the foot and adjust the material so the needle is just outside the side of the line. Then lower the foot and run about 6 stitches in place to lock it.
Lift the needle and foot, cut the top and bottom threads, then move to the next seam over (left or right, it doesn't matter) and set everything up for the other end of the line.
Important! Pull the line through your fingers loosely to untwist it and get rid of any loops. The line must be as straight and true as possible.
With the seam under the foot and the line free of twists and loops, flip it around the back of the machine, holding the end so it doesn't twist. Lay it on the seam and lower the foot.
Repeat the process for this end of the line. Then for the rest of the lines.
Your line attachments should look something like this:
And that, my friends, is how you make a parachute. Or, at least, one way to make a parachute.
In closing, I want to apologize for the length of this thread. I used to teach college classes, and it was important to me to reach everyone—even those who struggled to understand. So if my 'wordiness' bugs some of you, remember why I did it this way. (Truth be told, I'm a novelist. I like writing.)
Feel free to add suggestions, corrections, tips, or ask as many questions as you want—anything that might make this thread better for anyone who wants to make their own parachute. Thanks for reading. And stop by anytime. (We're open all night.)
(https://www.rocketryforum.com/threads/31-5-semi-ellipsoidal-parachute-build-part-iii.164480/)
8. Attaching the shroud lines.
This started out being more difficult than sewing flat-felled seams. The problem was with the round nylon cord. It rolled when I tried running a stitch through it. I tried walking the needle by turning the handwheel instead of using the pedal. But I could see where it might take a week to do it this way.
Then I remembered the presser foot I bought for doing rolled hems. It didn't work for that, but for feeding cord, it was perfect.
But first we must answer that burning question: Shroud lines from side to side? Or to adjacent corners? I am now of the opinion that it doesn't make a bit of difference once the lines are gathered at the harness point. Moreover, managing the lines as you stuff the fabric—and the lines—through the machine opening (which you have to do if you're crossing the canopy) to lock your stitch is not just unwieldy, it's downright bunglesome.
I'll add this: I crossed the canopy with my lines, and despite my efforts to prevent it, three of the lines are twisted enough to form a loop when they are relaxed. Several are crossed. (I'll hide that crap situation underneath three inches of heat-shrink tubing at the harness. But I'll still know I did it wrong.)
If I were doing it again, I'd attach the lines at adjacent gores. (I can't change these lines. If I unstitch them, I'm left with a mess of perforations.) That said, the following describes how to attach lines to adjacent gore seams.
This is the machine ready to lay the first line:
Important! Lay the fabric wrong side up for this. (Shroud lines belong on the inside of the canopy, not the outside.)
Before that, though . . .
Figure out how long your lines need to be. In my case, I wanted 35" shroud lines. Multiply that by 2 (down one side, up the other). Add the amount of line that will be sewn to the seam (mine was 2-1/2"). Multiply that by 2. Then add how much you think you'll need at the bottom for whatever your harness arrangement will be. I used 5". So I cut six lines 80" long.
Important! For heavier rockets, increase the length of line that is stitched to the canopy.
With disappearing ink, mark the end of each line where it will cross the edge of the canopy. In the picture above, it's the place on the line that is under the foot, right at the back edge of the canopy.
Swap out the standard presser foot with the rolled hem foot. (If you don't have one, get one. It is much, much easier.) Set the stitch to zigzag, and the stitch length to 3. (I don't know if the numbers on machines are universal. They ought to be if they're not.) Whatever gives you 10 to 12 stitches per inch (one complete stitch—left hole, right hole).
With the parachute on your lap, position the first seam under the foot, wrong side up. Lay the line behind the machine and pull the end toward you, underneath the foot, then lay it on top of the seam with the ink mark at the back edge of the fabric. Lower the foot. Run the handwheel a half turn back and forth while watching the needle, to see how wide the stitch is. You want the width of the zigzag to be just outside the sides of the line. If necessary, lift the foot and shift the seam a little to one side or the other to make sure it's centered once you have your stitch settings where you want them.
With the edge of the canopy just at the rear of the foot, the seam centered under the needle, and the line centered on the seam, lower the foot. Now pull the end of the line up through the hem loop. (The only time you'll have to touch it is if it slips out of the loop, and at the very end of the stitch.)
Walk the needle for the first several stitches. (Zigzagging has a greater tendency to bunch the fabric at the start.) Now, with your hands flat on both sides of the seam, press the pedal, adjusting side to side if needed as you go.
Stop 1/8" short of the end of the line. Set the stitch length to 0. Then run about 6 stitches in place to lock it. With the needle down, lift the foot and turn the material 180 degrees. Lower the foot and raise the needle. Set the stitch to straight, width to 0, length to 10 stitches per inch.
When you set the stitch width to 0, you'll notice the needle move back to the center. Lift the foot and adjust the fabric so the needle is dead-centered over the line. Lower the foot, then turn the handwheel slowly watching the needle descend. If it is not exactly centered, raise the foot slightly and adjust the material.
Important! This next stitch is the one that will bear all of the force on deployment. (The zigzag merely holds the line in place so you can straight stitch it.) Make it centered, and make it straight!
Slowly sew your way back to the edge of the canopy. Stop when you're 1/8" from the end. Raise the needle and set the stitch to zigzag, width to whatever it was on the previous zigzag, length to zero. Lift the foot and adjust the material so the needle is just outside the side of the line. Then lower the foot and run about 6 stitches in place to lock it.
Lift the needle and foot, cut the top and bottom threads, then move to the next seam over (left or right, it doesn't matter) and set everything up for the other end of the line.
Important! Pull the line through your fingers loosely to untwist it and get rid of any loops. The line must be as straight and true as possible.
With the seam under the foot and the line free of twists and loops, flip it around the back of the machine, holding the end so it doesn't twist. Lay it on the seam and lower the foot.
Repeat the process for this end of the line. Then for the rest of the lines.
Your line attachments should look something like this:
And that, my friends, is how you make a parachute. Or, at least, one way to make a parachute.
In closing, I want to apologize for the length of this thread. I used to teach college classes, and it was important to me to reach everyone—even those who struggled to understand. So if my 'wordiness' bugs some of you, remember why I did it this way. (Truth be told, I'm a novelist. I like writing.)
Feel free to add suggestions, corrections, tips, or ask as many questions as you want—anything that might make this thread better for anyone who wants to make their own parachute. Thanks for reading. And stop by anytime. (We're open all night.)
Last edited:
Time to start a new parachute company.
