Author Topic: 3-D printed foils.  (Read 3923 times)

SUPeter

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Re: 3-D printed foils.
« Reply #30 on: December 18, 2018, 02:37:11 PM »
With the tube epoxied in place I then mix some epoxy with micro balloons and milled fiber  and fill the remaining portion of the well between the remaining ribs.  This strongly locks in the tube and prevents any flex or movement of the insert tube.  The lightweight fill surrounds the tube to the full thickness of the wing only in the very center of the wing.  As you can see I use 2 part expanding polyurethane to fill the rest of the wing except for the wing tips where again I use epoxy, milled fibers and micro balloons. 

SUPeter

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Re: 3-D printed foils.
« Reply #31 on: December 18, 2018, 02:51:26 PM »
Here is another picture of the fill process.  2 part polyurethane foam( SecureSet, fence post foam 6 lb density I think)  After all is filled and faired with microballoons I then vacuum bag 2-3 layers of 6 oz glass with resin pigmented black.  Since I only use one layer of 3K carbon twill to finish I wish not to see the white fill and glass underneath.  The wing is strong enough with just the glass but the extra layer of carbon is even stronger and definitely looks better. 

SUPeter

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Re: 3-D printed foils.
« Reply #32 on: December 18, 2018, 02:53:40 PM »
I only use one bolt to hold the wing the fuselage.  It fits into a stainless nut place into the very end of the fuselage insert.

SUPeter

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Re: 3-D printed foils.
« Reply #33 on: December 18, 2018, 03:00:35 PM »
Here is where it gets interesting.  I not only use the square tube insert of the fuselage to provide stiffness and rigidity in the wing but also use an additional insert above to further decrease wing movement in relation to the fuselage.  This need not be done in the vertical orientation that I have used but can also be accomplished horizontally if one desired.  Again, my fuselage is almost entirely carbon made from many wraps and layers of 24K tow.  Adding this extra support makes the system very strong and even better, it is very easy to change wings as I do not need to hammer the one wing off before putting a new one on.

SUPeter

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Re: 3-D printed foils.
« Reply #34 on: December 18, 2018, 03:02:44 PM »
Here is the wing and the  extra carbon 3K twill( 3-4 layers) I vacuum bagged onto finished wing and fuselage.

SUPeter

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Re: 3-D printed foils.
« Reply #35 on: December 18, 2018, 03:08:44 PM »
Here it is again,  you can still see the release agent on the nose.  I have not yet had any trouble with this system but time will tell.  Once I finish my 41 inch wing, I may be singing a different tune.  I feel the extra strength of the laced wing combined with the high strength filler around insertion point and the glass and carbon skin will definitely handle the extra stress involved with large wings.  I will however be using 2 layers, maybe 3, of 3K carbon twill on the largest wing... All else should remain the same.

Newps

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Re: 3-D printed foils.
« Reply #36 on: December 18, 2018, 03:09:54 PM »
Very nice, that is a slick setup.
L41 SIMSUP S4 - 7'4" x 30 1/4" x 4 1/2" 112L
L41 SIMSUP S5 - 7'6" x 27 1/2" x 4 3/16" 106L
L41 SIMSUP S4 - 7'8" x 31"x 4 1/2" 122L - Modded w/ a King's TUT Tuttle box and using a King's foil.
L41 SIMSUP S4 - 7'10" x 30 1/4" x 4 1/2" 120L
Starboard Whopper - 10' x 34" x 4 1/3" 171L - w/ FCS GL-1 fins

surfcowboy

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Re: 3-D printed foils.
« Reply #37 on: December 19, 2018, 02:56:06 AM »
SUPeter, thank you so much. This is a fascinating technique.

Ok, questions.

First, can you clarify your layup? You mention 3 layers of glass and then one layer of carbon in the first shot that talks about layup but then later reference 3-4 layers of carbon. Iím assuming more carbon for larger wings?

Second, the hardest thing for me was figuring out how to drill a hole perfectly aligned with the internal nuts in my fuselage. Itís easy for the first wing as you drill through it all and insert the nut. But once you have a fuselage and make a wing over it in carbon you can see to drill the matching hole. How do you accomplish this alignment?

Third, clarifying that you build the initial wing structure and let it cure. You build your fuse insert as you explain. And then you cut out the center rib and carbon struts just enough to seat the insert, yes?

I was wondering about making the center with two ribs spaced just wide enough for the fuse insert. Then you could just cut or bend the carbon tow struts enough to insert it in between? Not sure if thatís easier or not but it seems like it might be.

This also lays out your wing covering much better. So by the time youíre covering the wing itís really got a decently filled out and sanded profile to lay glass on, correct?

I notice in the well lit shots that there are some sort of rounded bumps or corners in the leading edge. Iím assuming that this is from the ribs sort of making a corner once sanded. Iím assuming thereís no real performance hit from this?

Could you give us some more weíll lit shots of the finished wing at different angles? I canít quite make out the smoothness of the profile of the final product and I think a lot of folks are overthinking that. I donít believe it has to be perfectly shaped into a smooth radius from what Iíve seen in my research.

This is a game changer I really think. I have to try to get some tow and experiment with this. Really original thinking man.

SURFFOILS

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Re: 3-D printed foils.
« Reply #38 on: December 19, 2018, 04:10:38 AM »
SUPeter, Iíve made surfboards since the mid 70ís and Iíve never seen such a comprehensive build of any surfcraft or component like yours. Sure thereís the cardboard  surfboards and crazy designs but your internal carbon struts are amazing. Congratulations on you ingenuity and dedication.

SUPeter

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Re: 3-D printed foils.
« Reply #39 on: December 19, 2018, 05:42:15 AM »
Here it goes.  Ill answer questions in order.
1)  First there are 2-3 layers of vacuumed 6 oz glass over a fully faired (mico balloons and epoxy) wing.  Sand glass to final shape filling if needed, but it has to be perfect.    Then 1-2 layers of 3K carbon twill on wings of the IWA size and smaller.  On larger wings, say 41 " wide I plan on going 2-3 layers of 3K carbon twill.  I really do not worry too much about fiber orientation with the carbon.  I will on the larger wing.


2)About drilling the hole with perfect alignment to the internal nut.  Well I repurpose a cardiac surgical instrument( Medtronic Octopus)  .Look it up!  I will send photo.  I'm sure it can be done with a movable jig that is firmly attached to the fuselage.  If I find my stash of these I can try to send you all one. 

3) I simply use a hacksaw or reciprocating blade to cut a channel a little wider than the tube you are inserting. You do not want the cords pressing on the tube causing misalignment of the tube in the wing.  Use a very thick filler to bridge the gap between tube and cords.

4) Again, the 6 oz fiberglass layers are put over a perfectly faired and shaped wing.  Then the galss is further sanded to a finished form.  All this before final layers of mainely cosmetic carbon. 

5)  Yes my leading edges are angular(slightly).  I do not believe it affects performance but then again, testing would be required to determine this.  It does make sanding easier since individual  segments are on the same plane.

SUPeter

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Re: 3-D printed foils.
« Reply #40 on: December 19, 2018, 05:50:13 AM »
By the way.  Do I feel that wings need to be shaped to absolute perfection?  Hell no.  I actually think small imperfections are better at keeping the boundry layer smaller, decreasing vortice formation.  This may be why I hear GoFoils hum and whistle and mine are silent.  I may never know for certain but its just a hunch.  As far as a final finish,  I put a fill coat over the final vacuum bagged carbon.  I then use a cabinet scraper to take down all the proud spots and ridges.  After this I wet sand in the direction of flow (400 grit).  After this I then do what I call a "rub off".   I put a dab of resin on a section and rub it in with  gloved fingers and the I use a clean dry cloth to rub it off until dry.   It deepens the carbon look and smooths it just a little more. 

SUPeter

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Re: 3-D printed foils.
« Reply #41 on: December 19, 2018, 06:03:39 AM »
I hope this works. 

This flexible arm is clamped to the fuselage and is able to be locked in place by turning the butterfly at the end.  I have an epoxy block at the end whit a hole that accepts a long drill bit to assure block lines up precisely with nut in fuselage.  I then take out the bit, put the wing on, reinsert the bit and now I know exactly where to drill to find the nut.  Im sure something else could be fashioned which holds the drill bit in a proper position while the wing is both off and on. 

SUPeter

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Re: 3-D printed foils.
« Reply #42 on: December 19, 2018, 06:04:51 AM »
Here is another shot

SUPeter

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Re: 3-D printed foils.
« Reply #43 on: December 19, 2018, 06:05:50 AM »
And another.  Hope this makes sense.

SUPeter

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Re: 3-D printed foils.
« Reply #44 on: December 19, 2018, 06:11:39 AM »
PS - Please do not show these pics to my wife.  This is what I do when the shop is too cold and she is not home.