Before we get any further into this topic, I want to encourage and remind folks to browse through the 'Technical References' thread in this sub-forum - particularly posts #1, 2, 3, and 11 - referring to the Knacke text - both 1978 (post 2 & 3) (Post #2 is the Irvin Industries (better quality) version of the Knacke_1978 text), and the 1991 (post 1) editions and the Edgar G. Ewing classic on 'Ringsail Parachute Design' from 1972 (post 11). The links are all there for these very relevant and comprehensive texts on recovery systems and, if you have even the most minimal and remote interest in the Ringsail, the Ewing text is a must read. I will be referring to these periodically throughout all this as Knacke_1978, Knacke_1991 (where appreciably different) and 'the Ewing text' (in regards to the ringsail) when and where appropriate. Go get them.
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Can you sew?
If we go back and look again at the title of this thread, notice the key word, "CONSTRUCTING a Ringsail Parachute Canopy." There's one piece of equipment we'll have to 'make peace' with in order to do that: a Sewing Machine. So, Can you Sew?
The short answer is: "Of COURSE you can!!!"
There may be some who say, "Real Men DON'T sew." Well, 'real' men recognize that skills in this area allow them to have things others won't have - I have a killer hunting vest (altho I don't hunt anymore) that surpasses anything I've ever seen in the marketplace. I have some killer chaps (altho I don't hunt anymore <g>) that, again, is equally unique and all this is because I learned how to sew (and, yes, I've got David Coffin's book and am gearing up for some killer golf pants too <g>). BTW, I also have some rather decent parachutes as well <g>. Note, also, that some (most) of the major fashion brands out there: Christian Dior, Ralph Lauren, et. al. (even Levi Strauss) are all men - so count yourself in good company. Just think of all the cool things you can have (like bag deployment devices, too - designed EXACTLY like you would prefer).
I have been pondering over the last few days as to how deep I wanted to get into a 'Sewing Intro' in this thread - and was initially thinking of covering most aspects of it here. However, with all the good videos online and books and webpages, I think - for the sake of brevity (is this *brief*?? <g>) - just covering the most germane aspects unique to doing 'lightweight, structural' sewing (what parachutes are) and leaving the rest to the internet. If there are particular questions, fire back here with them and we'll cover as they arise.
The main issue with sewing parachutes is that you are dealing with a lightweight fabric - which can sometimes be a little difficult (bunching up, not feeding correctly), but, truthfully, I really haven't suffered that much with these issues, so I'm not exactly sure where these people are coming from with their cautions on it (one trick in dealing with this is to inter-layer some tissue (that thin paper that your shirts come in at Christmas) to provide a little body and then ripping it out once the stitch is finished). But again, I've never had to do that.
As to the type of sewing machine needed - all these fancy electronic machines today (that *do* interest me) are not really needed and that is because of one thing: the stitches you will use. There are only two stitches that will cover (for all intents and purposes) ALL your stitching needs in recovery system construction: a straight stitch and a zig-zag stitch (and, in truth, a 'straight' stitch is simply a zig-zag stitch with zero width (or, maybe it's the other way around - a zig-zag stitch is simply a straight stitch with a width other than zero)). You don't need any kind of 'fancy' machine to do that - in fact, some of these 'small scale' sewing machines that you can find on Amazon for $50 will do most of this (heavy, multi-layer stitching of bridles, etc may be the area where these little machines have problems). Other than that caution, just about any sewing machine can handle the tasks needed for parachute construcion.
Fundamentally, sewing with a sewing machine is forming 'lock stitches' continuously thru some material (ripstop, leather, denim, etc). In order to do that, it will take two independent lengths of thread - the 'top' thread and the 'bobbin' (or bottom) thread. The miracle of the machine is that these threads can be entertwined with each stitch without having to actually cut and break the threads to get them entertwined with each other (Google "sewing machine principle" or look here (pay particular attention here to the "LOCK" stitch)):
https://home.howstuffworks.com/sewing-machine1.htm
These are some of the basic items of operation you need to pay attention to (refer to photo):
1) The Presser Foot: The presser foot is what holds the fabric down to the 'table' and allows the needle to be extracted after the stitch is formed as well as apply pressure on the fabric to allow the 'feed dogs' (underneath) to advance the fabric (ready for the next stitch). There is a lifting lever (usually on the back of the machine) that allows you to lift the foot up off the table (this is how you first position the fabric in the machine). Rotate the handwheel (by hand, obviously <g>) to pierce the fabric pieces and locate your initial stitch, get everything aligned and then lower the foot and off you go. You may have to adjust the pressure that this foot exerts to allow the 'feed dogs' to advance the fabric correctly ('feed dogs' are little ratcheting teeth UNDER the fabric that advances the fabric for the next stitch). I am not aware of any machine that doesn't have an adjustment for presser foot tension (or pressure) - so consult your owner's manual (it'll usually be right over the presser foot at the top of the machine - see photo).
2) (Top) Thread Tension: If your stitches are 'loose' and not pulled nice and tight (they look 'bulbous' on one or the other side), you'll need to adjust the thread tension. Almost always, this can be accomplished by adjusting the TOP thread tension. There are ways to adjust the bottom (bobbin) thread tension if adjusting the top just doesn't do it - but it is rare that you would have to resort to bobbin thread tension adjustments, but it is there if you need it. You should be aware that getting the stitches TOO tight will result in feeding problems (i.e. the feed dogs can't advance the fabric - as the thread tension will pull the fabric back - resulting it way too short stitch lengths, bunching and fouling etc). It's a balancing act - but, fear not, one that CAN be balanced with a little patience and perserverance. This is why you take practice runs after an adjustment.
(On the bobbin photo, the thread enters the bobbin carrier at {1} goes under the 'leaf' spring and exits at {2}. Notice the tension adjustment.)
3) Stitch length and width: Both of these are infinitely variable (generally), but I mostly use stitch counts of 8 to 12 (or 14) stitches per inch (longer stitches (i.e. lower numbers) on heavier material) and widths of '0' (for straight stitches) up to whatever seems right when you're really 'zig-zagging' (zig-zagging for, mainly, to 'lay down' material over some reinforcing tape - or to provide some stress relief (they'll 'accordian out' when needed under stretching forces without 'popping' or breaking)).
4) Reversing button (lever): You need to know how to make your machine sew backwards, because reverse stitching is how you start (and stop) each run of stitching (this locks the stitching together, preventing unravelling). Basically, start your line of stitching 1/4" or 3/8" *downstream* of where you'd like to start, then back into your starting point, then go forward into your stitch. At the end, back up again for 1/4" or so into your line of stitching, then lift your presser foot, raise the needle, and cut your threads (pull out 4" or 5" to tie off if you desire). On my machine, reversing is just a button in the center of the stitch length adjustment that I press for as long as I want to back up (see photo).
One note on starting: you should always have about 4-6" of thread 'hanging loose' out of the bobbin and top (main) thread after you cut off the previous line of stitching. Take both of these and pull (slightly) to the rear before starting your next line of stitching.
5) Stopping and turning: If you are not finished with a run of stitching - just need to turn (hard), stop the machine with the needle DOWN (into the fabric). Then lift your presser foot, rotate your fabric to the desired direction, lower the foot and continue. This way, the run of stitching is continuous and you don't have to reverse, cut or tie off the previous run of stitching. (And there's nothing preventing you from doing a little reverse stitching if this turn needs a little extra reinforcing). Notice I emphasized "DOWN" in regards to needle position when you stop. Try it the other way (with the needle UP) and you'll appreciate why I emphasized DOWN!! <g>
Some additional sewing hints:
6) It is sometimes helpful to help the sewing machine carry the fabric by grasping your layers of fabric both in front of and behind the presser foot and put a little tension on it - just stretching it out a little bit (won't take much) and then pulling it through the the presser foot/sewing needle portion (you are, in effect, taking over the job of the feed dogs - but only feeling your way to what they would naturally want to do and just helping them out a bit). Thin fabrics, like the F-111 ripstop, can sometimes slip a little and this technique helps overcome that tendency (and assures nice, even, stitches).
7) Working on parachutes in the confined quarters of a sewing machine will necessitate gathering a lot of fabric (at times, especially on the larger canopies) and 'cramming' it through the open portion of the arm (between the needle and the main pedestal of the machine). You shouldn't worry about creasing or wrinkling the fabric (I always wash mine, anyway, when finished - so that relaxes any wrinkling). The main thing is to constantly pay attention as to *where* the fabric is in regards to where the seam is to be (what I would call the 'upcoming seam'). If you get too focused on watching the 'needle area' (where the sewing is actually occurring), you may overlook the fact that the upcoming seam is caught or jammed under some of the other fabric and this will prevent a free flow of fabric into the 'needle area'. The result is the stitches get *very tiny* <g> because the feeding of the fabric is hung up and the feed dogs can't move the fabric. Going slow helps a lot, but the bottom line is "situational awareness" - pay attention.
8) Somewhat related to the advice above is to also periodically stop and look UNDER the fabric to see what the bottom side is doing. If you are not careful, some of the other fullness in the canopy can get caught up with the portion feeding into the 'needle area' and get sewn into the seam you are working on. Only option then is to "rip it out" (with apologies to J. Evans Pritchart - from 'Dead Poets Society' <g>, "I want to hear R I P P I N G!") And the tool for that is a 'seam-ripper' (something you'll surely get used to if you sew long enough):
9) Bobbins: You'll need to learn how to wind your bobbins (you'll use the same thread as your top thread). Study your sewing machine's Owner's Manual on how to do this. Most bobbin winders are a little shaft on the top of the machine adjacent to the Handwheel (over near your top thread supply).
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However, as to these machine adjustments and sewing hints - first thing is to just sit down and sew a little - because (considering adjustments) everything may be adjusted just fine (we're assuming here that you are using the 'family' sewing machine - so SOMEbody must have had things 'kind of' adjusted before you got here.) BIG HINT (for family peace): IF you make changes, MAKE A NOTE of where things were BEFORE you start - and then return them to that prior setting before turning this 'ship' over to the (real) Captain). In truth, these little 'tweaks' are really minor and something you'll easily master.
If you've never sewn before - take an hour or two on a Saturday afternoon, grab some scrap material (out of the 'rag bin') and just simply get familiar with the machine. There's no need to go like a banshee -- GO SLOW! so you can watch the machine and learn it's personality. Speed comes later. Grasping concepts comes now.
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Materials and hardware:
A few things about the materials you'll be working with:
Needles:
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There are two (broad) types of needles (with some additional special purpose needles) that are available: 'Regular' point (sharp) and 'Ball' point (as you can see in the second photo, there's a wide range of needle types that extends beyond just 'sharp' and 'ball point'). The Ball point needle has a slightly rounded tip - used for sewing double-knits and is designed to push the fabric fibers apart as it penetrates them (otherwise, being knit, it can pull the fine fibers out of the fabric and create unattractive stitching). Regular point has a sharp, near-needle point and is generally used for woven fabrics (rip-stop nylon is woven) - but I've actually used both types of needles in parachute sewing and they work fine. Given a choice, go with 'Regular' and try the Ball point when you want to see what it's like. Sizes: There are several sizing 'schemes' for needles, but what you want is the finest needle you can get -- generally a Size 9 (and they go up beyond 18-20, but that's about as big a needle that will work with home sewing machines). I use a Size 9 (where I can get away with it (i.e. if my thread is fine enough) but sometimes 11 or 12) for fabric sewing and Size 18 for bridles (with heavier thread).
Thread:
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It is unwise to sew an article such as this that will be put under stress (sometimes severe) with anything like 'normal' polyester sewing thread -- you need something heavier. Threads are sized by a couple of (legacy) sizing metrics, but the (somewhat newer) TEX sizing is the simplest and most logical (if you dig into it, you'll find some *weird* sizing systems). TEX is the weight in grams of a fiber 1000 meters (1 KM) long - so, the larger the number, the heavier the thread. Here's a reasonably good comparison chart (also shows breaking strength). You'll want to scroll down to the 'Anefil Nylon' section:
https://www.amefird.com/wp-content/uploads/2009/10/5-Thread-Size-Comparison-Chart-2-4-10.pdf
... and another really good document gets into it in a little more detail:
https://www.ylicorp.com/cpanel/document/a_thread_of_truth.pdf
Normal sewing thread is in the neighborhood of TEX 20 to TEX 25. A really nice thread (especially for radial seams on the smaller (under 36") canopies) is a TEX 35 (or Size 'A' (sometimes 'AA') in military parlance) - but probably the most universal thread for the scale of most canopies is TEX 46 (or Size 'B' (sometimes 'B/2')). The largest that most home machines can handle (generally) is TEX 69 - 70 (or Size 'E') and this is generally good for bridles and such (maybe also skirt and apex vent hems on the larger canopies). You can use a Size 9 needle for TEX 35, but you'll need to bump on up to a Size 11 or 12 needle for TEX 46 (and Size 16 or 18 needle for the TEX 69 - Size 'E' thread). Don't ask about Size 'C' or 'D' thread because it must have been obsoleted decades ago (if it ever existed), as I've never seen nor read of any.
One general principle in sewing is that you match the thread to the fabric (as to the fiber type - nylon, polyester, etc). If you're sewing nylon (we are), then "it is recommended" to use nylon thread. Also, threads come in (generally) two 'finishes': 'Bonded' or 'Soft' - with 'Bonded' having a sizing applied to it for a harder finish. That's generally what we want, although I do have some nice, 'Soft' TEX 45 mil surplus thread that sews real nice. Can you violate these recommendations (as to matching thread to fabric) and use polyester? Sure. Will the canopy disintegrate in the air? Probably not. Should you? Well, when I can find 8oz spools (several thousand yards) of bonded nylon for $3/spool (not your normal price), then why would I want the hassle of wondering if that polyester thread *really is* all that much better? (As one additional point, you will note in the thread properties chart (link above), the Anefil Nylon is about 10%-15% stronger than polyester for the same size - so why wouldn't you want the stronger thread (especially since it also matches the fiber type of the material I'm sewing)?)
Go read "A Thread of Truth" (above) - there's a whole lot more to learn there.
Where to get it? Keep your eye out for surplus deals - because you can find some truly great bargains if you just look - but the best (recent) place I've given some business to is Southern Threads in Chattanooga:
https://stores.ebay.com/SEWINGTHREADSRUS
Here's some TEX 35 threads:
https://www.ebay.com/itm/v33-Lightweight-NYLON-POLY-Alterations-Leather-Thread-/111209630290
... and some TEX 46:
www.ebay.com/itm/v46-Lightweight-Nylon-Poly-Alterations-Leather-Thread-/200844999287
... and some TEX 69:
https://stores.ebay.com/SEWINGTHREADSRUS/69-Tex-70-/_i.html?_fsub=3160354011
(I will admit that the costs of some of their TEX 46 and 69 threads are a little more than what I remember earlier in the year when I bought some -- but the TEX 35 are still some good deals - and useful in many places in a small scale parachute. UPDATE: I did some checking and one change these folks have made recently is 'Free Shipping' but even with that, the costs are about double what my orders back in January 2014 were. Oh, well - back to searching again.)
How to use such large (bargain) spools of thread? Well, one thing about this is that the thread needs to 'pay out' off the top of the spool - not spin round and round (like the little spools normally used). You can buy a thread stand something like this:
www.ebay.com/itm/1-PC-SINGLE-SPOOL-LARGE-IRON-CAST-BASE-THREAD-STAND-SEWING-MACHINES-/270971250629
... or, just make one out of an old broom handle, a small piece of 1/4" p/w and a small piece of aluminum welding rod (with a little bit of dacron fishing line and some Elmer's):
This last photo shows the 'context' for the homemade thread stand - looking at the rear of the machine from above. Note the little 'pin' where the more conventional (i.e. smaller) spools of thread would rest. The hole in the bottom of the broom handle slides down over this.
I'll leave off the actual materials in the canopy (actual fabric and reinforcing/binding tapes) until we get to that.
Until then...Can you Sew?? Just remember, the only difference between an expert in this and you (assuming you're not) is that the expert simply knows a few things about this that you don't. Sooo... go fix that.
-- john.
p.s. If, however, you are sewing a new uniform for Captain Kirk or some seat covers for a DeLorean-based time machine, this one may be more appropriate:
edits:
9-6-2014: added hints 6,7,8
9-10-2014: added hint 9, minor grammar edits and updates to the 'threads' section
