DTill

Bonded dynemma, need design help?

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Going to  build a 1.5 sized quad using  .51 oz. Dynemma bonded with  3m 9485 tape. I want to build a SUL quad, framed with P90's, hot cut LE holes "freilein style ".  I want to add a little belly  to it to increase  sail area. Already have some 3 winds diamond bridles to use. Want to keep the  dimensions  as close to 1.5 size to use the bridles. I'm  ready  to go just  need  some  direction. Can I join the 2 triangles with a 2" flat seam at the V and reinforce the V? Rev has a diamond in the center, is that needed to distribute  the forces? Anyone  have a good link to a bonded build thread. I've  searched but hadn't  found much other than  " you should  do  one".20181128_185902.jpg

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And i have a bunch of tape. This fabric is hard to find. Don't want to  screw up the first project.

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Just possibly, that shouldn't be your first build? Try a similar sail, but with less "precious" cloth? A little practice first .......

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I will tell you when it comes to the Dyneema Cloth (aka Cuben fiber) be mindful of the tools you use to cut. it will actually dull metal scissors, shears and rotary cutters.. 

 

FWIW, Flymarket still has Challenge Polymax for $3 a yard.. great for experimenting with, without breaking the bank. Only one color but cheap enough to make mistakes. I used it for my first kite (indigo Sunrise) I didn't make out of tails. It's also the fabric I used in a few recent experiments (Diamonds Squared) that haven't gone well. When trying something new a cheaper fabric will let you know if it's work using the more expensive fabric on the next one. I also used it for one of the colors in my first Diamonds kite.

3/4 oz. Challenge Polymax navy blue ripstop polyester
$3.00

 

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The  challenge poly isn't  on there  website anymore.  I guess I'll  try a mesh! Prism micron tails. 100% mesh? 2" strips 2" holes? Just wanted to build one and find the hiccups. 

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5 hours ago, DTill said:

The  challenge poly isn't  on there  website anymore.  I guess I'll  try a mesh! Prism micron tails. 100% mesh? 2" strips 2" holes? Just wanted to build one and find the hiccups. 

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Looks nice..Looks very well done and should be quite airworthy.

And for the Challenge PolyMax, it's in clearance..

https://www.flymarketkites.com/clearance/

https://www.flymarketkites.com/clearance/34-oz-navy-blue-ripstop-polyester

 

 

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So past me screwed  over future me again, how should've  I finished this edge. Do I create a double fold bias tape and attach the loose tail ends to it, or just say screw it and sew a leading  edge directly to it. Do you really need mesh on a mesh kite?

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My first several kites did not have the edge binding at all. I still don't edge bind at the top BUT Edge binding will give you a cleaner look.  I did have the screening on all but one kite so far. 

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Leading edge mesh isn't necessary if there is enough ventilation near the leading edge so that it doesn't "block" wind pressure when the kite is moving in reverse. It's practicality will vary in relation to the amount and location of the venting. A "pressure dam" at the leading edge will reduce speed and control in reverse flight. If the pressure can't "slide" all the way to the leading edge because it blows out through voids in the sail then it offers no resistance to motion or control inputs. Very complicated aerodynamics happen and sometimes the best way of achieving desired results is through trial and error. If you plan ahead during the build you can include or omit a feature such as leading edge mesh, and then later add or remove it easily if you've allowed for the possibility.

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Agreed, can't even put a price on "experimenting", that is where all of your personal preferences will rise & reign supreme eventually!  What do you like on that kite right now?, ... what would you prefer IF it could be changed towards a known objective? (for instance:  "I want to be able to catch 120s",... that necessitates a killer glide that can penetrate up-wind predictably.)

How much bend in the leading edge construction makes a kite that turns within it's center, but simply WILL NOT rotate on a wing tip?  How much stiffness in the leading edge itself prevents that difference from rearing it's ugly head?

If the kite will not back-up it might as well not be a quad at all!  Tuning the leaders is merely determining where on the handles that "down" (reverse flight/tricks/absolute control) takes effect.

I have always been a fan of edge binding personally.  Take your binding material and fold it in half, (crease that edge HARD, against a piece of glass or with a steel ruler, then fold those two outside edges in towards the middle, then crease it again, finally place that center (folding as you sew or adhering & folding to sew), such that the edge of the sail is captured in between 2 thicknesses of edge binding on each side.  Most folks use a triple zig-zag to effect this binding.  STRONGLY consider two rows of straight stitches slightly offset from each other instead.  Edge binding makes a hard ribbon that slices thru the air when flying in reverse.  The better the ribbon is constructed the better/easier the reverse flight becomes.  Ah, but there's always the other side,... what is it in this example you ask?  Well the great ribbon you've just finished will vibrate at a different level that a single thickness behind it.  Those vibrations will create stress fractures and eventually the single thickness immediately next to the edge binding will fail.  Does a shortened lifespan of the sail warrant improved flight dynamics?  Only your answer matters!

The venting (or holes left open, whatever your solution) along the leading edge "assists" with reverse flight.  Do you have to have it?  Speed Series Revs don't, they fly backwards almost as fast as a 1.5 will fly forward!  Indoor and SUL quads don't need it to fly beautifully in reverse.

How wide and where to locate "said venting" might be fun objectives to consider as experiments.  Change only one variable at a time so you can control the experiment,... scientific principle.  Four variables and wild oversteer happens, but which one made it the worst or which combination of 2 variables totaled such a profoundly negative impact?  Hey maybe you'd like MORE oversteer yet, this is fun!  Just change one thing at a time.

Ideally, do this experimenting with a friend, cooperative projects are simply the best!

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3 hours ago, Paul LaMasters said:

  Take your binding material and fold it in half, (crease that edge HARD, against a piece of glass or with a steel ruler, then fold those two outside edges in towards the middle, then crease it again, finally place that center (folding as you sew or adhering & folding to sew), such that the edge of the sail is captured in between 2 thicknesses of edge binding on each side.  

Krijn on GWTW started  a excellent thread "folding dacron" in building and repair.

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S_T_O_P

you don't want a Dacron edge bind, (WAY too heavy & thick) you want 3/4 ounce nylon or 1/2 ounce Icarex,... ideally cut into strips of appropriate thicknesses AND on an angle, like 45 degrees.  

Lazy? Some kite building suppliers have ready-made rolls of edge binding material (1.5 inch width = 3/8 edge binding final size), but if you have curves to edge bind, making your own will allow it to bend much easier,... curves have to be stretched to fit that shaping, stretching along a curvature is easier in my experience with the material angled.  TEST yours first.

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If you are using 2" tails for the mesh, why not use 1" tails for your edge binding.. I've used a lot of ribbon tails to accomplish this task personally.. a 30' ribbon tail is usually less than $8.  Either way you have options..

Agree with @Paul LaMasters that this is not the place for Dacron. The additional strength and weight creates almost as many issues as it solves.. Icarex or .75 Nylon will do the job nicely and relatively inexpensively. 

Given your color scheme, Orange would be a nice look.

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While not a builder in any way, my guess is that not all the materials mentioned would hold as sharp a folding mark or crease. Dacron is fairly "stiff" . Sometimes the folding crease is seen on brand new kites, before the kite stretches  out some. 

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Icarex will hold the crease better than Ripstop Nylon but both will hold a crease. Dacron is in general tougher to fold but really holds the crease. Good thing too, if it din't it would be very hard to keep it in alignment for the leading edge sleeve. The principles of folding the crease are pretty much the same. more effort required for some materials. a lot less pressure for delicate materials..

FWIW,Some fabrics just will not hold a crease and I'm not sure what techniques work best for them . I just don't use them for the most part (personal choice.)

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Creased a 2in tail into double fold bias tape for the LE. Attached 1.1oz.  mesh w/ 1in bow in the leading edge. Re-enforced  all the corners. Ready for lead edge  tomorrow.  Thanks for everyones input. Should I change the threads subject  to be more appropriate " New guys first  kite build ". D.T.

 

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I've got a little sag on the left side of the sail. It would be alot of seam ripping and resewing. How perfect does the first one need to be? Power forward and see how it flys?

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And you wanted to use the other fabric?!?! 

Give it a try. Don't like, fix it!

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I've got enough framing and parts to build 4. Next 2 will be dynemma bonded ultralights. Probably a 1.5 and b2. Might have enough fabric to do a Zen size instead of the B2. Can't find a Zen sized plan anywhere.

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11 minutes ago, Wayne Dowler said:

And you wanted to use the other fabric?!?! 

Give it a try. Don't like, fix it!

Keeping mesh square is really hard. I should've bound the leading edge when I originally taped it out. Live and learn, it's my first time sewing a kite. Lay off I'm not bazzer. Is this why riff gives me most of his tips in a pm?

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1 hour ago, DTill said:

Lay off I'm not bazzer. Is this why riff gives me most of his tips in a pm?

SHHHHH!! :)

@DTill  Positive no ill intent was there.. The secret is not your first kite.. The secret is, "Is your latest one better than the one before?"  As long as that answer is "yes"  OR you are learning from the experience then you are making progress. Build it, fly it, learn from it and build the next one better. There will always be critics. Keep in mind EVERY ONE of those critics only knows what you've told them and they've only seen what you've shown them.  Ignore the critics and listen to your own self evaluation. Send your kite to a friend who's flying you respect and ask them for their honest opinion. You don't owe anyone anything and I personally am very glad you've started this adventure. I've had a blast and you are on the same path.. Keep it up. Your first one looks far more professional than my first one. I had no pattern and no Rev or other Hadziki Wing to base my design on.  Every kite you make has something to teach you. Not every one will be your showcase kite. I look at a few of my early efforts and wonder how they flew at all. FWIW, I still have my first mesh made from tails.. DUCT TAPE reinforcements and all..

 

As for the design and a little sag, you'll be surprised at how forgiving the sail design is. Finish it up, try it out and learn what it looks like and acts like from 90' away when it's backlit by the sun.. A little sag or a stitch mistake won't show from there. Be willing to make mistakes, you'll learn something new from each and every one of them.

 

 

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Sorry, just a little jab, didn't mean anything by it. But you now see how hard it can be. Glad riff is helping. He has built more kites in recent history that anyome I know.

Do not know of any Zen plan out there. Bazzer made them for Rev. He hasn't built a Phoenix version.

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scale up a 1.5 b-series platform's dimensions (until you get to the size of a rev one ~ a 20 percent increase). A 30 inch tube is going to now become 36.

a sixteen inch magic stick goes to 19.2 using this math (we actually use 18 inches)

adding more curvature to the leading edge OVER THE TOP, (not left to right), thru affixing the knots, washers and end-caps down tightly on that leading edge sleeve area, such that all this crap is underneath the sail and in-between the kite and frame.  Your hand should fit in there and touch nothing.  It's a reflex technology without the mechanism, this creates that killer glide you will so soon come to love!

flexible frame turns w/I it's center, or if you added a big curvature built into the leading edge (L-R), a stiffer frame or a straighter leading edge construction will "track" better, but not fill with power as quickly when flailing

Quad wings this size will hide any construction flaws, specially during flight dynamics {unless you've really (s)crewed-up big time!}

Enjoy the journey, knowledge is the objective, flying your first home-built project is just the thick icing on the cake

 

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