Budget low tech kite hydrofoil DIY build a long

[Denisesewa]

First I'd like to say thanks to everyone here who has shared their knowledge and experiences, I've done a ton of reading and learned alot.

Since I am starting a foil build I thought I'd do a build a long in case anyone is interested, as I mentioned in another thread I built a foil back in 2007 based on pictures of a carrafino and a little knowledge from building slope-soaring RC airplanes, it worked till I broke it, there is now so much info here I decided to have another go building as simply as possible with just basic tools.
I started yesterday afternoon making templates of the basic parts from my modified versions of this >> http://www.seabreeze.com.au/News/Kitesu ... 49403.aspx



Then cutout 3 T-Bars from 3mm Baltic birch ply and laminated them together with 4oz e-glass in between, this morning I decided to add a fourth lamination of ply to bring the thickness up to 12mm before shaping.





I will use this curved dresser drawer ( still have to modify it a bit) to shape the anhedral and dihedral of the wings when I laminate them later today,

I hope to have all the parts for the cores laminated by tomorrow afternoon and start shaping.
Feel free to comment good or bad, I am definitely open to suggestions.

[Hawaiis]

Looking good, keep up the good work.

[davesails7]

Cool project!

What's the reasoning behind using glass between the layers of wood though? Usually glass is only on the outside of the core where it is the most effective.

[Denisesewa]

Cool project!

What's the reasoning behind using glass between the layers of wood though? Usually glass is only on the outside of the core where it is the most effective.

Well, its called for according to the author Mark Todd, I have been trying to think of a good reason myself, I think it may just be there to stabilize the ply to help avoid warping during the layup? , my experience with ply is that is isnt very stable unless supported ( leave a piece in the sun or cold temp for an hour and it will warp), anyway, my feeling is that it cant hurt and just adds to the ply count.

[Phezulu1]

Cool project!

What's the reasoning behind using glass between the layers of wood though? Usually glass is only on the outside of the core where it is the most effective.

Well, its called for according to the author Mark Todd, I have been trying to think of a good reason myself, I think it may just be there to stabilize the ply to help avoid warping during the layup? , my experience with ply is that is isnt very stable unless supported ( leave a piece in the sun or cold temp for an hour and it will warp), anyway, my feeling is that it cant hurt and just adds to the ply count.

I wouldn't trust that Mark Todd bastard

Actually that was me who wrote that guideline on Seabreeze - my red wood/carbon foil is still going strong. Nice to see someone else having a go at it.

Putting glass between the ply layers probably is not completely necessary, but helps get an even distribution of epoxy resin across the wood and helps fill in any imperfections in the ply, also helps keep the ply from pulling to either side.

Keep going, it's looking good so far.

[Arcsrule]

that is an excellent build you've got going. Now that I see how it can be done, i may give it a try. How do you mou nt the attachment plate on the end of the foil?

[Denisesewa]

Hey Mark, Nice of you to write that article, Thank You !!
Would you make any changes now that you have had your foil for a while?
I am going to make several different wing designs for it and will likely make a second T-bar, been thinking I may just hollow the middle ply of the T-bar and see how stiff it turns out.

Arcsrule- The mounting plate will have a hole the same as the profile of the T-bar which the T-bar will slide into, it is then epoxied/glassed to the T-bar. On the one I built in 2007 I had the T-bar protruded through the plate and into a pocket in the board for added rigidity.

I modified the drawer a bit to extend the clamping area.


Then drove a couple finish nails through the stack of wing lams, pulled it back apart and started laminating using the protruding nails to align the parts and keep them from shifting while clamping.




Worked out great, after curing overnight I pulled the 2 wings, base plate and T-bar, just need to trim the parts and start shaping, also have to laminate the 2 fuselage sides on this morning. Parts are very rigid.

[Phezulu1]

No, I wouldn't really change anything - I eventually made another rear wing with curved tips which improved the yaw stability a bit, but no huge change. I built the original one as an exercise to see how low tech you could go and still get something durable that worked well. It works really well, the take off speed is really low and it's super efficient - you won't need much in the way of kites bigger than 10m (or I don't anyway) - I also learned to carve to both sides and ride toeside with this foil, good low speed handling and good roll stability make it easy.

Top tip is don't skimp on the carbon - I originally tried to do this foil with basalt cloth as a cheaper substitute to carbon and it just wasn't stiff enough, I had to add the layers of carbon.

Your one is looking fantastic - you've got the shitty part of sanding in the profiles now - wear full length clothing and gloves and tape your sleeves around your wrists to stop getting the itchy stuff on you, and obviously use a good mask as well.

[Denisesewa]

Hey Mark, Well thats all great to hear, I have some experience with glass and carbon, never look forward to the grinding and sanding.
things are looking decent, everything is laminated and started the shaping on the front wing, it actually looks like a foil. kinda fun getting to different stages and checking out the progress.
Not to shabby for day 2.5

[Phezulu1]

Denis, that looks fantastic.

Feel like a proud uh...grandfather (seen as you're the father of the thing)