A first model kite - probing the kite building ground

[Exult]

OK I know, this and that person made a few stitches into something kite like, that is on a larger scale quite small news - but not for me. And that is what the below is much about - a rookie's perspective on kite sewing.

A small beginner practice project to get going and to determine difficulties. The span width of this mini speedwing is 34.5cm. Trailing edge hem turned out to be problematic.

Another very small beginner practice project to get going and to determine difficulties. This truncated mini test kite bag had too little material when folding the lid around seam. Also, how should one hide the seam on the inside close to the opening?

Why build such a small kite? The main reason is to practice and identify the problematic details/procedures while wasting close to a negligible amount of material. It also makes it easier to relate to texts like ( https://sites.google.com/site/kites4all/home/kite-sewing-101 ) and provide a better motivation and focus when reading up on the craft. If you start by doing early on, your eyes might also open up when studying your own (purchased) kites and their designs.
The main remaining difficulty with the this kite project turned out to be to make the trailing edge hem so that it is in the same plane as the sail. The lesson from making a mini test bag is that when folding fabric over seams, more material than you originally thought might be required.

I don't believe that absolute beginners (like me) are an extra good source of knowledge other than that that they bother about bringing up topics and things that they wonder about that the more skilled ones don't. Possibly the lack of knowledge of how things "should" be done can lead to that new approaches are tested. I also believe in sharing what didn't go so well so that it can be avoided. Therefore also images of test pieces, failures and dead ends will be included in below (future) posts.
The methods displayed here is what I tried when making a first time mini kite. Suggestions?: Don't hide in the corner - Sing it out!

Yes this is a cheapo, plastic, budget sewing machine equipped with a slightly to thick needle for the ripstop of this model speedwing. Yet, being a kite sewing rookie, I didn't feel limited by the tool. Perhaps it is because I've never seen high quality and fancy features sewing machine and is therefore blind here?

Speedwing kite - what was (?) patented (anybody knows)?
First of all did, I chose to do non free patented kite? I couldn't find any patent document with searches like "speedwing kite patent", "speedwing expired kite patent"... I don't know if there are any patents today, but I wouldn't think so. Why? Because it was already mentioned as a patented kite in Stunt Kites 2 by Servaas van der Horst from 1994, quote: "Since certain aspects of the Speedwing are patented the kite may only be built for your private use". The patents seems to be at least 24 years old. This post ( http://www.kites.tug.com/Archive/kites/potpourri/speedwing.adjustment.tips ) dates the speedwing bridle patent to older than 15th June 1993, soon 25 years ago (and it also give advice on tuning the Speedwing bridle). In any case older than the 20 year limit ( https://en.wikipedia.org/wiki/Term_of_patent ) and if this would be a design patent the valid time would be even shorter. If the patent is expired, then web pages like this (as of February 2018):
https://www.kiteplans.org/planos/speedwing/speedwing.htm
works like a lost fishing net (no matter how good the intentions were), lying tangled at the ocean floor needlessly suffocating swimming fish for years to come, by stating it is patented. Only recently I've seen speedwings being offered commercially, Cross Kite's Speedwing X1 and X3 or De Paddestoel Speedwing Progress. Statements of patents should be published with an expected expiration date or filing date IMO. Also it is desirable that it is thoroughly specified what is patented (or a link to the filed patent). How wide a patent is is of importance ( https://arstechnica.com/tech-policy/2018/03/why-the-roots-of-patent-trolling-may-be-in-the-patent-office/ ).

List and discussion of tools/equipment
The Sewing Machine

This small compartment was very handy to keep the sewing machine gear in.

A handy needle threader holder made out of construction polyethene/polyethylene foil tape.

The not so old sewing machine was a Singer Simple 3210. The Singer Simple is very plastic but light to move around - can be slid on the table almost too easily. I gave a little more than 130 USD new for this tool. There are not much extra bells and whistles I guess, but I like the the storage space inside for small stuff that came with the sewing machine. An arrangement that I've found handy is to have the needle threader attached to a construction foil tape sticky side out tube on the right hand of the sewing machine. Finally, no matter the model of sewing machine, don't sit double folded over it for extended periods of time - put a couple of large books under it if necessary so that you sit comfortably when working.
Some handling hints: Balance upper lower/thread tension and set quite low. Needle up actions: Starting/stopping and changing backwards/forwards direction. However never change direction by manually rotating the wheel backwards - the wheel should be turned against you always. When making a sharp turn, lift the presser foot with the needle down and rotate the fabric around the needle. Use tape or glue to secure the glossy/slippery ripstop before sewing. If you would use sewing pins to hold the pieces together, the holes after the needles would remain.

The needle

Not so sharp, surprisingly blunt needles - the sharpest of them (all 90/14 machine needles in the above image) was the one I had been using all the time. It was possible to see the reflection from the window in the tip, which was not possible or hardly not possible with the sharper (and not in the above image collage) hand sewing or sewing pins that I had. To the left in this collage is the microscope used here.

After sewing the kite I looked into which needle I had been using and the state of the needle tip after the kite (and other mostly practice stuff pieces) and paper sewing. In this project I used the regular point (style 2020) needle that came with the sewing machine. It was of the dimension 90/14 (of a scale going from 60 to 110 (European standard) or 8 to 18 (American standard). A regular point needle will will go into the fabric threads, while a ball point style needle will go between the fabric threads. The ballpoint needle seem to be good for knitted fabric ( http://www.singerco.com/sewing-resources/machine-needles ). 
In the Make Magazine web-site I found a link to a graphical cheat sheet for choosing a machine needle ( https://makezine.com/2013/11/20/infographic-choose-the-perfect-sewing-machine-needle/ ): http://www.sewingpartsonline.com/blog/finding-perfect-sewing-machine-needle-infographic/ . The needle size table there seems to suggest that I instead should have gone for a finer needle than the 90/14 needle that is for slightly thick fabric (like flannel).
Not until the kite was finished I examined how sharp or should I say blunt the needle tips were - no needle (the one I had been using or the spares - all 90/14 needles) tip would puncture your skin unless you applied some force. The point diameters were between about 0.14-0.22mm and the light from the window could be reflected in all of them. Quite unexpected was that the one that I had been using all the time was the sharpest! It had slightly more than half the radius of the bluntest (spare) needle! It appears like all the times I did practice stitches and practiced adjusting the thread tensions while sewing in paper didn't do any harm to the needle tip. I guess that one should change the needle and use a matching one when doing the much thicker nose and LE dacron. The microscope used here was a mini and budget one bought at a sale for about 7USD. With some practice it is possible to hold the camera/mobile so that the images can be obtained.

Other Tools

Some tools used for the project. The French curve and the caliper belonged to my father:

• A wood burning iron pen tool - for hot cutting the ripstop. Screw the tip in properly to conduct the heat well.
• A revolver single-hole punch pliers. Was handy when making the card board template for the opening in the sail for the spreader fittings.
• A french curve template for drawing the curve when making the rounded panels that will give a the sail a camber.
• A caliper and (folding) ruler for bridle measurements.
• An angle hook (instead of a non-existent set square)
• A thick thread to use instead of a compass (that was needed due to the lack of grid paper).
• A pair of scissors.
• A "lead" pencil to draw directly on the ripstop when "cold cutting" with the scissors.
• A book: Stunt Kites 2 by Servaas van der Horst from 1994
• A kite: Speedwing X1 - a nice 3D reference.

To be continued...

[makatakam]

You will expand your tool collection with time, but what you have now is enough to make some very good kites. My avatar is the second kite I sewed. Very simple compared to the first which was a frameless foil. They are all fun, and each will teach you some new technique that will be useful in all future builds.

[Breezin]

Very nice start Exult. The material for my 1st build is black and orange. Imagine that . Brilliant minds think alike LOL.

[Exult]

23 hours ago, makatakam said:

My avatar is the second kite I sewed.

I much like how the pattern gets inverted along the curve that could be an extension of either side's TE in your avatar. I've done some QLK pattern design thinking at the time when ordering the ripstop, but I have not yet come to the "graphical punch line" or some "panel layout twist" as I consider your QLK pattern to be an example of.

23 hours ago, makatakam said:

expand your tool collection...

...will teach you some new technique

It would be interesting reading IMO, if everyone's building aha moments, however minor, resulted in an image and a short text (though personally I might have a problem with the short part occasionally ).

19 hours ago, Breezin said:

The material for my 1st build is black and orange. Imagine that . Brilliant minds think alike LOL.

Except for being being orange/black ripstop destined for the brilliant minds , the price was also quite OK when ordering. Your currently empty (well "B"-avatar) avatar is perhaps reserved for your future DIY beauty in orange and black?

[Breezin]

Haven't really thought about an avatar. Still working on my LE and haven't cut the sail yet. Tomorrow I'll get the rest of the frame and shape shifter stand off parts ordered.

 

[Exult]

Needle dimensions

My plan was to write about the material used rather soon after the equipment, but then I realized that I hadn't understood the needle dimensions yet. So I started to find out about it and I found things not so straight forward.

First problem I see with saying that a needle size is "90/14" is that there are no units. 90 pieces of what or 14 pieces of what - the text "90/14" just doesn't say anything in itself. If, but only if, you know the conventions you have a chance. First with knowledge about the convention the numbers are given a meaning.

The second thing is that there are two numbers for the to express the one and same diameter. If the relation between these two numbers was simple, it shouldn't be required to provide both of them.

How the size codes (Y-axis) depends on the needle diameters (X-axis). The needle diameter is here expressed as in the NM system where the unit is 0.01mm or equivalently 10µm.

The European number metric (NM) system
The European/number metric/NM system is almost sane, it is just the needle dimension expressed in units of 1/100 of a mm (or in units of 0.01mm or 10µm). As long as you know this it is nice and linear scale. E.g. NM 90 corresponds to 0.90mm - just as you would expect. If you mean that a needle is 0.9mm it would be better to write it like that directly with the unit included IMO.

The Singer/US size code
And now over to something completely different - the Singer/US size code. The nicest thing that can be said about it is that it exists (a sub) range(s) of linear needle diameters (part of this range is recognized in the above link http://www.singerco.com/sewing-resources/machine-needles ). There are thicker needles outside this range, but then the size code no longer varies linearily with the needle diameter ( https://en.wikipedia.org/wiki/Sewing_machine_needle , http://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Category_Code=needle_size_conversion_chart , http://apparelscience.com/index.php/apparel-science/technical/85-apparel-science/technical/150-needle-number-system ). This info is plotted in the above diagram. The non linearity starts already at needle dimensions of 1.2mm (120/19). Then, for thicker needles, a small change in the Singer size code starts to correspond to a large change in needle diameter. Another funny thing about these size codes is that to express really small values one would need to use negative values if one would extrapolate the curve for small values with a straight line. Not keeping things clear and simple takes away power from the user/DIYer by obfuscating matters IMO.

The needle tips provided with the sewing machine (yes the same image as image as above).

Types of sewing machine needles. The image is in the public domain as given in https://en.wikipedia.org/wiki/File:Sewing-machine-needles-types.jpg .

Looking at the µscope images in the original post  and comparing them to the Wikipedia needle graphics, the needle tips that came with the sewing machine looks like something between an universal needle and a needle for stretch material. Considering the beginner tool the needles came with, a Singer Simple, perhaps the needles provided were chosen towards the more robust side with slightly rounded tips?

[Exult]

List of material and related thoughts/discussion/background
The Ripstop

When ordering the ripstop I wasn't certain that I was ordering the right thing, so I more or less went after what was offered at a low price. Afterwards I did some more thorough comparison...

• Black and white nylon ripstop M-40 44g/m^2, Metropolis Drachen. 44g/m^2 seems to be about standard thickness when seeing  what is offered in kite stores. On the other hand Icarex PC31 polyester with a mass of 31g/m^2 seems to be good for the low wind kites (as stated in Drachenmarkt). For really light sails there is 25g/m^2 mylar that can be bought in kite shops.
• Orange 60D Polyester ripstop (70g/m^2), Wolken Stürmer. I got this polyester at a good price, 4.40 EUR per metre. This feels thicker than (most?) of my other DLKs, possibly with the exception of the Fazer XL and Fazer XXL Maesto3. For this little model kite I used it as an LE dacron substitute, but also for the trailing edge.

I find the numbers appearing in the names of the ripstops confusing. I don't mean the number of g/m^2 but numbers like M-40, PC31, sometimes even just a number appearing after the type. In this context the (somewhat sad unit of - see below for an explanation) Denier becomes most sensible to describe the roughness of the ripstop. To my understanding it is the thickness of the thread used to make the ripstop. The feeling of Orange 60D ripstop is somewhat rougher then the sails of the kites that I got. So it is a question of experience and knowledge, but it would be educational to have a small (2cm² would be sufficient) sample chart of various types of ripstop.

I feel I must largely must pass on the question of the feel of nylon vs. polyester ripstop. Of the ripstop material I got at home (two colors of nylon Contender Superkote 75, three colors of nylon Metropolis Drachen Spinnaker M-40 and one polyester Wolken Stürmer Spinnaker 60D), only two ripstops does not rustle paper like - two Spinnaker nylon M-40). All other ripstops does rustle both nylon and polyester. The ripstop polyester on a few of my kites that I also compared also rustled. So summing these few ripstop observations up: polyester rustles while nylon might rustle - if it doesn't rustle it should be nylon. Correct? Btw, would mixing nylon and polyester ripstop be a big no-no (or could one use it in areas where low stretch is required - a bit like a somewhat flexible mylar?)?

Though I now have done some limited work with the ripstop there are several things about the material that are still not clear. Is keeping track of the slightly more glossy side of any importance? Does the ripstop have any main/straight/lengthwise grain/warp direction (over the supposedly spongier cross grain/weft direction) of any importance? How should one orient the main grain in a DLK or a QLK? Could one draw the ideal main grain "field lines" on a sail?

If bias grain strips is an improvement when applying over rounded edges (like a TE or some opening in the sail) when making a hem, it is not a huge one - I'd need to do some more testing to be able to make my mind up here. Also all spinnaker (ripstop) strips for i.a. TE are cut along the grain - not the bias. With the ripstop coating, is bias strips of any importance? Can you remove the ripstop coating in some solvent to make better bias tape?

The thread

• Black sewing thread, Avion E, #60/3 (mass of 60m is 1g), 600m roll. This tread appears a bit thick in relation to my kite model (Just to put it into relation to something: Drachen Markt offered slightly thicker (#50/3) thread as well (perhaps a Drachenmarkt heritage of Mikael Ryll's "Pure"-series of large DLKs?) - otherwise this seems to be some kind of standard.) Used it to the black and white sail.
• An unknown thin white cotton(?) thread that was used for the LE. Thread dimension and colour matched the LE better than with the thick black one. You shouldn't use cotton with ripstop should you? What was the drawback? Cotton too stiff to distribute load (I think that I read somewhere)?

After finishing the kite the white thread was still (big surprise) of unknown material. I therefore did a test to see of the white thread burned in the same way as the black one and some other threads as well while I was at it. All but one thread burned rapidly while leaving a blob of solid residue including the white previously assumed "cotton" one. So it seems like the white was instead a plastic thread (polyester most likely since they are common). The one exception in burning style was an old thick thread that burned slowly (and smelled differently) leaving only ash (probably cotton). Warning that old thread kept glowing after the fire itself was blown out as can be seen in the image!! Pinching the thread between the thumb and index finger put it out completely. The glow of the thread was hardly visible in the bright daylight...

A combustion comparison test to figure out the material of the white thread (well at least compare it to the known polyester thread). Warning, all treads burned rapidly and the old thick black one kept glowing after the fire was blown out.

Weight number wt and the number of strands/ply - a kind of sane unit of length per mass

The three strands of the #60/3 thread.
The "/3" part in 60/3 is the ply of the thread, i.e. how many strands it contains.
The "60" part of the above thread, the "weight number", is written as 60wt in the US standard. For a 60wt thread it takes 60(kilo)metres to make 1(kilo)gram of thread. Or alternatively expressed in mass per metre:
1/(60m/g) = 0.017 g/m

Denier - a seemingly arbitrary unit of mass per length
Another, more messy, measure of thread thickness is denier. Denier is the mass in gram for 9000m.
To convert from denier to wt: 9000/denier
To convert from wt to denier: 9000/wt ( https://en.wikipedia.org/wiki/Thread_(yarn) ). So the thread above expressed in Denier would be (along with the somewhat funny unit):
9000/60 = 150 g/9000m

Simplify:
150 g/9000m = 0.017 g/m = 17 mg/m
I.e. 150 denier corresponds to 17 milligram per metre.

Verdict
Not surprisingly we got the same mass per length when calculated directly from the weight number or from the Denier of the thread. If one would like to determine how much mass the thread contributes with using deniers would be less obvious. A much easier unit for this would be the above mg/m IMO. Though the weight number would be quite OK for intuitive estimations like: I used about 30m thread for the kite, then the mass of the thread should be about half a gram". OK, it seems like the thread is not a large contributing factor of the weight of a kite anyhow.

I think the convention of expressing the thread dimension without (well "proper") units adds to the confusion. So a 60wt thread should be referred to as a 60m/g thread IMO. Denier on the other hand is a somewhat sad unit. Choosing 9000m as the base length for the Denier sounds quite arbitrary as well. If on would like to express the mass per length - just do so (as above):

1/(60m/g) = 1/60 g/m = 0.017 g/m = 17mg/m

This makes much more straightforward, 17 milligrams per metre!

Paper-stitch drill: Make every stitch end up where you want. Make the stitch length large so you clearly can see the result. I can't guarantee that this control will make your kite fly better, but it will at least feel better when you see the result.

I still don't know if/when to do a forward/backward seam to attach the thread when starting or just a backward seam. I still haven't decided if two or three stitches would be good either. When studying the stitch length the reverse stitches are shorter the the forward - you can't go into the old holes with the needle when reversing direction. Is this a bug or a feature? Anyhow it seems like two forward stitches matches about three backward stitches.
When the seam is finished (after reversing to attach it) and after cutting off the thread you end up with one piece of thread on the upper side and one piece of thread on lower side. The next step I did was simply to tighten the threads somewhat.

After the kite was finished I got a recommendation on how attach the threads when the seam is finished from a college at work (who is into horses and some sewing - not kites). More on this in a later post...
 

Heat shrink tubing (for fittings)

For the fittings I used general purpose polyolefin (6mm initial diameter) heat shrink tubing. Shrink ratio is 2:1, but it appears that you can shape it somewhat further with your finger tips after it has done its initial shrinking while it is still hot and soft. The fittings made from this heat shrink tubing were "semi soft" (after cooling down). The initial wall thickness of 0.28mm and the resulting wall thickness of 0.56mm (from data sheet) might sound as very thin, but it kind of suited this small kite. If one would like to make larger and stronger diameter fittings there are other sorts with resulting wall thickness of several mm, dependent on initial wall thickness and shrink rations ( https://www.elfa.se/en/cable-wire/heat-shrink-tubing/standard-heat-shrink-tubing/c/cat-DNAV_PL_090803 ). Note that I have no idea of the strength. Heat shrink tubing material vary, but I think of the polyolefin as the standard one though. The heat shrink tubing fittings might be worth checking out for light low wind fittings?

Looking on my 4D I've always thought that the LS to stand off fittings looked a bit over dimensioned in relation to the standoffs. Even more so now with when my eyes gotten used to the mini speedwing heat shrink tubing fittings.
Beware if you intend to use polyolefin heat shrink tubing close to sleeved dyneema bridle lines - the core will most likely melt (though heat shrink tubing around bridle lines of other core fibres might work).

Other material

• 190cm, Climax 35kg sleeved neon orange bridle line. To me this long total bridle line length was a bit surprising. Also that the knots themselves takes up so much length (even for this narrow line) was a bit of a surprise: a single overhand knot of a double line correspond to 1.4cm (0.55"). I really like this small dimension line. This line is easy to work with and the knots last.
  The wing tip tensioners of my Shadow is a narrow orange sleeved dyneema. I wish I had used this nice line to secure the battens of my Fazers to get lasting knots. The most difficult cord I used was one intended for bricklayers. It was absolutely hopeless, constantly undoing itself- I had to secure the knots with heat glue. Sleeved rubber cord was almost as bad requiring occasional tightening. A fishing line would probably have worked? I'll see how the latest attempt will go - reusing some old broken kite line (dyneema/spectra) residues to secure the battens.
• A few cm 4mm (outer diameter) hose for the nose. Heavier but more robust nose alternative than the heat shrink tubing. No work required to make it cylindrical as when instead making the nose by heat shrink tubing. An observation, instead of shrinking when applying heat, this non-heat shrinking hose could be widened enough to slide it onto the relatively slightly too thick barbecue pin.
• Surgical tape. Good for holding cardboard template on the ripstop while hot cutting. The tape will be out of your way, since the heat will cut the tape as if it never was there in the first place. Also good for keeping ripstop in place when sewing and for preventing ripstop corners being poked downwards by the needle into the hole towards the bobbin.
• Cardboard from some empty food package.
• Contact (rubber) glue worked for gluing the panels together, albeit a little difficult to distribute evenly (old sample?). A paper glue stick turned out to be no good for this purpose, only to (as an alternative to surgical tape) somewhat attach the card board templates to the ripstop before hot cutting.
• 3mm barbecue sticks (bamboo I believe - very hard anyhow). Used for the frame of the model kite. Also used as a tool to remove the tape when close to the presser foot of the sewing machine.
  A detour: When discovering how strong those bamboo sticks were when cracking one I found these (hardly original) inspiring to use in kiting. Hmmm... Imagine something like this reed kite looking like something like a dragonfly/bird/moth ( http://www.firstkites.nl/vliegend riet.html ), but a little more lasting and portable. Could one make such a kite out of bamboo strips? Looking around on the topic of slitting bamboo strips I ended up on this very precise handling of it when making fly fishing rods ( https://www.youtube.com/watch?v=BYfeeyYaXgY ). There for a second he shaped the strip with a heatgun. Immediately I thought ahh perhaps something to shape the wings of a insect bamboostrip SLK? Making the wings into an elongated "8" of a curved bamboo strip. No, no, no, straighten up now @Exult, you are never going to learn something properly if you don't stay on track and choose not to do things sometimes.

If you think that double sided tape is missing from the above list you are right - got a roll now, but that is for a next project.

[Paul LaMasters]

here's another great set of plans, the Dunton/Taylor Kite flies indoors to easily 25 or 30 mph without any adjustments

it's a fast climber too, a couple of thousand feet in only a few moments!

http://www.kitebuilder.com/wiki/pmwiki.php/KitePlans/00074

Every kite flier should carry this kite, to break it you need to slam it in the car door, merely stepping on it will not suffice.

[photomom]

I've made two Dunton Taylor box deltas and am plannning the colors for a third.  When the wind is too low for any other kite, my DTs will go up and hang in the air.  Love this kite.

[Exult]

8 hours ago, Paul LaMasters said:

here's another great set of plans, the Dunton/Taylor Kite flies indoors to easily 25 or 30 mph without any adjustments

it's a fast climber too, a couple of thousand feet in only a few moments!

http://www.kitebuilder.com/wiki/pmwiki.php/KitePlans/00074

I appreciate your comment not so much for the recommended kite model (that however seems to be a popular one), but more for a pointer to and a remainder of a place of many kite plans and much knowledge.

Building this particular suggested kite model would lead me into the unknown (past petrol station/toy store kites of my childhood) territory of SLKs. There I'd need to handle scary things like kite anchors popping out of the ground and then starts to smash things and people, multi kite anchors when you want to be on the safe side, kite refusing to go down, gloved handling of kite line, (and worse) un-gloved handling of kite line, wind changing direction forcing a rapid change in the set up, wheels for walking down the kite (and really hope that you won't get hit by the anchor in your back and who knows even an (with line length) increased risk to do a Benjamin Franklin (ZZAP!). SLKs are scaaary - personally I'd wouldn't like to meet one in a dark alley... 

Really, I do have a respect for SLKs and think that I unfortunately haven't the time to learn to deal with them now. Another contributing factor is that I have no one locally to learn from. On the other hand I never thought that QLKs were my thing until soon a year ago, so I don't know for how long my SLK hesitation will remain. And I must confess that I have spent some time thinking on how to make tetra kites with easy handling...

[Paul LaMasters]

Ha, I'm a pure quad-head myself Exult, but once in awhile a reliable SLK indoors is great fun for beginners and masters alike.  The fact that is ALWAYS flies regardless of the conditions outside is just a fringe benefit.  The D/T only has one flaw, you have to make it yourself.

I stopped building kites when Bazzer and Eliot Shook became available to me, but all the stuff is still in a room of the homestead.  I'm an immediate gratification kind of guy, but I have tough expectations on how the kite should fly and how long it should last, even with me beaten' on it constantly.

Enjoy the builder journey, almost nothing is more rewarding than the first flight with the kite you made all by yourself!

[Exult]

Hot cutting the ripstop

Got the sail dimensions from the Stunt Kites 2 book. Made a scaled down version of the smallest speedwing. Liked that it was a design coming with a camber. This book mentions that the speedwing is a patented design - I doubt it very much since it is so old (however making an exact copy of a certain Speedwing model commercially available is another thing). I drew the panels first on paper (would have been quicker using cross ruled paper) and then used the pen to transfer the pattern to cardboard to serve as a template for later hot cutting. The thick black thread served as a make shift drawing compass when drawing the triangles of the panels

 

Cutting with a hot iron for wood burning (about 15USD, 30W, 19 different tips). One need to make sure that the tips are well screwed in for best performance(/heat transfer). The sharp blade tip was a bit of a disappointment since it didn't conduct enough heat to melt the ripstop. The narrow conical tip worked instead. There was no need to remove the surgical tape before cutting - the tip just burned rapidly through as though it wasn't there. Did not notice much (any?) difference between the cutting of the different kinds of ripstop here.

[Exult]

Gluing, taping and sewing
 

Since I had no double sided tape I tried gluing the panels together. The first attempt was to glue the panels together with a glue stick for paper - worthless and close to no effect! Then I switched to the contact rubber glue - a solvent smelling turbid snot like glue that works well for flexible stuff like e.g. foam rubber. It was a little tricky to distribute evenly (old glue sample?), but held the panels well together. Did I have the patience to wait until the two glued surfaces were completely dry before joining then (as you should for this type of glue)? - No, but it worked out anyway. Here the panels were glued face to face. The stitches and seam used was a straight stitch plain seam. A first seam was made closest to the centre of the panels. On the rear side of the kite, the brighter panels were folded over the darker panel and sewed with a seam closer to the edge. Folding the black panels over the white panels would have caused the black panels to be partly visible through the front side of the sail (ugly). In the third image above you can see the resulting camber of the sail.

 

The orange strip of the trailing edge was just folded double around the black and white panels and held in place with tape. As can be seen in the second image the resulting hem is not so good. Perhaps use some type of glue and let it dry while keeping the strip flat in the same plane as the trailing edge of the sail by putting a book on top? The pockets covering the wingtips are not yet in place.

[Paul LaMasters]

some builders' "hot tack" with the cutting tool,... take a fine edge soldering iron tool tip and make it more needle like still with a jeweler's file or emery board.  Lightly tack every few inches to weld the fabric strips in place.  The best kept secret to this technique is to sew thru the hot tack holes and hide 'em!  You can pick-up a hot tackers work and see their holes when backlit usually, 'cause hiding 'em entirely is tough.

SprayMount light-tack adhesive from several feet about of the work and let it drift down onto the fabric is another technique to prevent that material from slipping around.  Go light and see if it's enough to hold, .....you don't want to clean-up with bEnzene if not required.

some use blue painter's tape to hold pieces in place, slowly removing it just before entering the jaws of the sewing machine.

Some folks waste fabric with the Randy Tom Method, using full pieces of every color, sew the parameter thru all layers and cut away color afterwards from both sides until you arrive at the desired layer.

some builders used a spray bottle with just water in it, wet capillary action holds the pieces in place and needless to say, clean-up is a breeze, no foul chemicals to inhale either

Go to a workshop on kite building and steal everyone's best ideas, see which way works best for you, practice before you waste expensive materials.  The amount of labor is not different if you cheap-out of the fabric choices available.

[Exult]

Thank you @Paul LaMasters for the nice suggestion of methods!

On 2018-04-20 at 3:10 PM, Paul LaMasters said:

take a fine edge soldering iron tool tip and make it more needle like still with a jeweler's file or emery board.  Lightly tack every few inches to weld the fabric strips in place.  The best kept secret to this technique is

That is a nice idea. I could sacrifice one of the funnier shaped (= never used) hot iron tips and weld a needle to it (if the flux core welding tool now restarts nicely after two-three years of rest). The hardness of the needle should prevent it from going blunt (if that would be a problem). Add some excess material around the needle and file it into a cone to help the heat transfer to the needle tip.

On 2018-04-20 at 3:10 PM, Paul LaMasters said:

SprayMount light-tack adhesive from several feet about of the work and let it drift down onto the fabric is another technique to prevent that material from slipping around.  Go light and see if it's enough to hold, .....you don't want to clean-up with bEnzene if not required.

If I get hold of the spray mount bottle I think that I'd use the panel templates to mask off the areas that I don't want  light-tack on. Put the template on top of the cut out ripstop panel, then shift it one cm or so to expose one edge of the ripstop panel at a time. Now there is less need to just go lightly with the spray. 
Or one could perhaps spray the tacky stuff on a piece of plastic into a small puddle and use a small brush to distribute it along the edge. But I have no idea if this tacky spray is easily distributed with a brush however.

On 2018-04-20 at 3:10 PM, Paul LaMasters said:

some use blue painter's tape to hold pieces in place, slowly removing it just before entering the jaws of the sewing machine.

I have used (very) small pieces of surgical tape here. To peel them off, the tip of a BBQ stick was very handy. The tape bits could be removed from even under the "toe" of the presser foot.

On 2018-04-20 at 3:10 PM, Paul LaMasters said:

Some folks waste fabric with the Randy Tom Method, using full pieces of every color, sew the parameter thru all layers and cut away color afterwards from both sides until you arrive at the desired layer.

Thank you, but no thanks I'm afraid that I must say - wasting is not my cup of tea. Even If I got hold of a large amount of ripstop at a good price, ruining most of it would leave something of a bad taste in my mouth.

On 2018-04-20 at 3:10 PM, Paul LaMasters said:

Go to a workshop on kite building and steal everyone's best ideas, see which way works best for you

I'm afraid that the only persons showing up here are the three old familiar ones - me, myself and I.

To my knowledge I'd need to travel "in time and space" to find a workshop: 
http://tangokites.org/       - an old site devoted to kite making/flying and mostly SLKs and tango (yes the dance).

On 2018-04-20 at 3:10 PM, Paul LaMasters said:

practice before you waste expensive materials

I really think the practice part is mandatory. The improvement when applying a method that is new to you is especially pronounced between the first and second attempt. Though there will still remain room for further refinement of the method after the second iteration.

Kite building experience can also be gained piece by piece - Kite repairs can also get you kite making experience without requiring much materiel. In this model speedwing project I did not get any experience in the more common type of thick fabric DLK nose sewing. The recent repair of the (long time punctured) HQ Maestro3 nose only required a negligible amount of material. This fabric was seat belt thick and with a really solid feel so that I felt, not to cause any line snags around the nose, that I had to melt the edges into a tapered wedge like shape with the hot iron first (mostly). The thickness of the fabric and the hardness of the molten areas was a good sewing exercise. And naturally, I started off with some test pieces first (in orange and blue above).

[Exult]

Making of the cut out for the LE fittings (+ misc.)
OK, there was some time ago since the latest post in this unfinished topic. That is quite silly, since the photos are already taken and most of the text written (this semi-finished state is unfortunately not unique for this text).

First image: Making the template for the hot cutting of the LE cut out for the spar fittings. The hole punch pliers were helpful when making the small radius inner round corners.

Second image: Hot cutting the wing tip pockets. The edges melts and joins the edges of the template and the card board working surface. To separate them I use strips of cardboard.

Third image: Before doing more or less anything on the mini kite I test it on pieces first. The red fittings are made of heat shrink tubing. Warning: It looks ugly and the fitting are  backwards - somewhat misleading image.

Fourth image: The cardboard strip is for prying lose the ripstop and template after the hot cutting. (Also representative for the sewing work is the large amount of tape strips)

[Exult]

Making of the LE fittings

First image: Time to do the fittings.

Second image: The (polyolefin) heat shrink tubing I got shrinks at 125degC to half its original diameter. While still soft directly after shrinking it is sometimes beneficial to shape it or try to compact it further using the finger tips. Using a (initially) wider heat shrink tubing from the assortment bag gave a higher wall thickness. Unless getting hold of a thicker walled heat shrinking tubing type, the heat shrink fittings would be for indoor and/or small kites only. There are many dimensions (up to 4mm, 1/6 inch, of resulting wall thickness) and materials of heat shrink tubing, but if it would be good (or cheap) for general use I don't know - Beware I have not tested heat shrink tubing fittings on a real/standard sized kite (anyone?).

Third image: Cut the side of the heat shrink tubing that would be facing the wing tip at an angle to make the edge of the fitting to become circle shaped after shrinking it (later). Impale it in the middle of the longest side. Then you need to also put the spreader in before applying the heat to shrink the tube to give it the right shape so that the opening doesn't become to small for the spreader.

Fourth image: A robust alternative to to heat shrink tubing for the nose was to use a narrow hose. It was initially a little bit too narrow, but it could be softened by heating it somewhat, so it could be slid onto the barbecue sticks.