Messages

436

Foil SUP / Re: Diy sup foil

« on: May 10, 2018, 04:00:24 PM »

Foil is out of the bag.  Excess is trimmed and I'm satisfied.  Very stiff while supported at each end with my 155 lbs standing on middle.  I am unable to appreciate any twist but I truly will not know until I fashion the adapters to fit the board and fuselage.  Thickness- 14.9mm x 122mm x 68.6 cm.

437

Foil SUP / Re: Diy sup foil

« on: May 10, 2018, 11:56:42 AM »

With a good deal of cord lacing of the internal skeleton in all direction(36 cords in all) I was able to achieve considerable stiffness both longitudinally and rotationally.  I usually lay both glass and carbon in 45 and 90 degree orientations.  For this mast I only needed to lay them longitudinally.  Again, I will take it out of the bag when I get out of work. Hopefully it's good and solid and I won't need any more layers.  Let you know later.

438

Foil SUP / Re: Diy sup foil

« on: May 10, 2018, 09:48:09 AM »

Its still in the bag but I'm pretty sure the 3 layers of 6 oz glass  and the 3 layers of 3K carbon cloth is going to be enough.  I'll let you know as soon as it cures.

439

Foil SUP / Re: Diy sup foil

« on: May 05, 2018, 02:33:17 PM »

Here is the finished foil.

440

Foil SUP / Re: Diy sup foil

« on: May 05, 2018, 02:24:04 PM »

I thought I'd give the laced wing technique a try in creating my new short mast.  I am curious to see just how many layers of carbon it will take to make this stiff enough.  My original mast took 12 layers of 6oz fiberglass covered with 7 layers of 3K carbon twill, 45/90.  All this over 10mm of plywood/glass core.  The short mast should make surfing river waves a bit easier since most of the major turbulence is near the river bottom.  Very much liking the new foil on rivers and behind boats,  have not yet had it in the surf.

441

Foil SUP / Re: Diy sup foil

« on: April 12, 2018, 07:38:26 AM »

A noticeable benefit of using both an endoskeleton and an exoskeleton is the ability to make very thin wing sections with considerable strength.  Anyone have experience with longish winglets?  I can always grind them back if they prove to be of no benefit.  Next step is vacuum bagging some carbon onto these wings.

442

Foil SUP / Re: Diy sup foil

« on: April 04, 2018, 12:14:27 PM »

just wet it out, let it cure, cut to shape, drill it, glue wing profile template to anhedral form, lace it.

443

Foil SUP / Re: Diy sup foil

« on: April 01, 2018, 11:48:48 AM »

Great idea about using cured rods of 48K tow bent over to form curves.  Ill have to try that.  I also have some 2mm coremat which would make great stuff for wing profile templates instead of using plywood. 

444

Foil SUP / Re: Diy sup foil

« on: April 01, 2018, 04:11:57 AM »

I tried the CAD thing but I found it to be a waste of time since I already know what I'm aiming for.  I just draw up planshapes according to the surface area I need and use different thickness wings based upon their use.ie - behind boats, large waves, small waves, river waves....
My goal was to create a strong wing as quickly and inexpensively as possible in order to test and tweek.  Without using carbon I can create a usable  wing for what I'm guessing is about $30-50.00.  If you are lucky , carbon fiber 24K tow can be found in large 4 lb rolls for $30-40.00.  This one roll could probably make 30 wings?  Maybe more?

445

Foil SUP / Re: Diy sup foil

« on: April 01, 2018, 03:25:49 AM »

I use a tiny bit of cellophane/plastic wrap under the clamps or you could just push a pointed tooth pick of appropriate size into the hole with the cord to pinch it in place.  When cured just cut them off.  I really like the idea of the divinicell wing profiles,  Ill have to try that.

446

Foil SUP / Re: Diy sup foil

« on: March 31, 2018, 12:35:03 PM »

Not sure about the weight since I do not own a very accurate scale.  Probably a little more than a kai go foil due to the increase in structural support.  I have a little play using a non-tapered fuselage insert but I plan on shimming it out some more with some filler.  I like the idea of being able to change the wing position fore and aft.  Gives me something to experiment with.

447

Foil SUP / Re: Diy sup foil

« on: March 31, 2018, 05:35:01 AM »

     Non tapered so that I can adjust the distance between the mast and the wing.  Forward wing  position for pumping, back position for increased stability.  Its too bad all this lacing must be covered up with filler and carbon.  It looks real cool as it is.

448

Foil SUP / Re: Diy sup foil

« on: March 31, 2018, 04:08:38 AM »

     Well, to start you need a form which will follow the anhedral of the bottom side of the wing.  Each wing segment is scroll  sawed from 3mm ply based upon the airfoil shape you require.   The pattern of 1/8 inch holes is then drilled into each plywood wing segment.  Once done, these wing segments are hot glued, bottom down, to the anhedral shaped form.  This holds them in place for the next process.
I use one 24K piece of carbon fiber tow, folded in half and long enough to thread through entire width of wing.  Tie a knot at the folded end.   At the other end  use a tightly wrapped layer of scotch tape to make the cord ends easy to thread through holes in wing segmnets.  Like the hard ends on shoelaces.  Before threading the cord, it must be wet out with epoxy resin.   Slow cure resin helps since lacing the wing will take 3 hrs or so.  Wet out one at a time, thread it through first hole,  then twist the cord 10-15 times before threading through the other holes.  The knot will keep one end in place.  Small clamps, small clothspins or i use surgical instruments kold the other end.  Do it again, until you are done.   So you are threading a very flexible, damp, twisted piece of carbon fiber. Once cured, the entire wing can then be removed from the anhedral form.  be sure not to use too much hot glue.  Just enough to hold them in place.
     With the laced wing removed I then turn it over, bottom side up and loosely lay a piece of wet out 6 oz fiberglass.  It helps to let this glass layer drape down between the wing segments so it rest on the carbon laces. let it cure in this upside down position.
     Once cured,  I then cut out the space in the wing center where I will need to insert the square carbon tube that the fuselage will fit into.  Making sure its square to wing and of proper angle of attack(1-3 degrees) I use a very dense filler(milled fibers, wood flour) to attach cut carbon cords to inserted piece.  Let cure.
     Placing wing back onto anhedral form, I then fill the segments.  The very ends I fill with a high strength filler.  Around the fuselage insert, I use a lighter mix of microballoons and milled fiber,  the rest is 2 part expanding polyurethabe.  It ends up being pretty light since most strength is gained from internal skeleton.
     Sand or file to shape than recoat with microballoons. Keep sanding. You will be amazed at how strong this wing is even without its glass skin or carbon cloth. 
      I then vacuum bag a layer of 6oz fiberglass before adding 1 layer of 3K carbon twill.  Sometimes i omit the fiberglass and just go with the carbon cloth.
      As with all my wings, they tend to be overbuilt and with some experimenting one could build more flex into the system and make them even lighter. 
     Hope this helps!
     

449

Foil SUP / Re: Diy sup foil

« on: March 30, 2018, 05:37:36 PM »

Las one, I promise

450

Foil SUP / Re: Diy sup foil

« on: March 30, 2018, 05:20:40 PM »

I'm getting good at this now