DIY Foil Kites

[Liam1]

Thanks niklas, small size was mainly because that was all that was possible with the materials I had laying around. I don't think the body was all that bad in the air so will have to see if I make it smaller or not. I think next step would be 10m2, but no idea when I'll get around to it.
One small problem I see with scaling up, how do you export larger print sizes in surfplan or is that not possible with hobby? I tried setting a custom size in print to pdf but that's not allowed... Otherwise I'll probably have to digitally stitch the pages together but it would be best/easiest if it can be done through surfplan of course!

[Schietwedder]

Hi Liam,
The patterns in bigger size is no problem if you ask a local copyshop (or one online) to print A0 patterns.
If you choose overlap option in surfplan and install a .pdf reader/printer that supports A0 (foxit for example) it should work with max.10 pages A0 for a 10m kite.

Alternatively you can ask David Aberdeen from surfplan to supply you with the .dxf format of ypur kite if you send him the surfplan file and I could plot it for ypu directly on the cloth using my plotter.

If you need some cloth we'd probably find a solution for that as well just write me a pm
You can also forward me your surfplan file of the 10m and i can look over it, 4 eyes see more than 2 before cutting cloth

BR Niklas

[Rein de Vries]

Very much pleased with the first meters of the Ultra Light 11m2. Stable tips and smooth power!

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This is amazing. How many hours went into this?

Thank you! It takes me about an hour to prepare the parts for a cell and also about that time to stitch it together. Designing the wing also takes quite some time and is obviously a challenge by itself. Niklas and I had some interesting offline discussions on how to balance the various design aspects. From canopy and AR to billow and bridles, everything has to be chosen with thought.

This summer I flew the 11m2 on multiple occasions on both TT and hydrofoil, it is pretty great in performance and for me definately worth the effort. It is a versatile hobby

Nice also to see more people are interested and then the video of that very light wind session

[Schietwedder]

Some early morning session on the 4m

[Schietwedder]

[Schietwedder]

New 8m2:
I must say I was quite inspired by liams kite and some Paraglider designs which looked like a bird.
So I done one for kite foiling (hopefully)
Used the profile from the 5,6,9,11m freeride kite designs earlier in this thread but because I was a bit more carefull than with normal kite shapes regarding kite stability pulled the tips in more than I would use to (local incidence angle) and added an adjustment for the reflex in the birds “body”.

In a few days I will testfly when the conditions allow.
BR Niklas

[IWantToFly]

If that flies well you are going to be the coolest foiler on the water! I personally would have a hard time not diving it toward unsuspecting people.

[Schietwedder]

It flies rather well. Not as flawless like my other kites of course but good enough to use it on the foil for sure. It sits quite deep in the ww because of the big body i suspect.
Its rock solid, at one time in the vid I try to front stall it by pulling the dront lines down a meter, no chance.

I adjusted the mixer a bit after tightening z and loosening b so its a bit more grunty and turny now with a bit later stall.
I think i can set even more camber by loosening b than it should have some more performance.

To go on the water will have to wait abit till we are settled with the baby then a proper foiling vid will follow.
The dog likes to catch the big bird for sure.

[Liam1]

Looks great! Still hope to make my own some day but great to hear the stability is still there even when scaled up! It's probably just because of how it's laying on the floor but it seems to have a super thick profile and a lot of billow even on the the wings, is it actually like that while flying or just because of how you took the photos? It's quite difficult to see in the video.
I am surprised to hear and see how deep it sits in the window, the 2m version I made doesn't sit that deep, deeper than my Aurora or my brother's speed 5 of course, after adjusting the bridle since the first test, even though for mine, you would expect it to sit deeper because the lines way it down more relatively speaking due to the small size and it being relatively poorly constructed.

[Schietwedder]

Yes the profile is always a bit thicker when you blow it up at home without aeroforces and linetension, its like that on every foilkite.
Profile is I believe 19.3% thickness with a bit more billow I would normally use because cell aspect ratio varies and the wing cells are quite wide but I could only run a single billow value, so the billowed up profile is probably like 23% ish in some cells.

Thick profile though does not mean less performance. Race paragliders and kites are usually the thickest. Its because you are in completely different reynolds numbers which would be a super low speed airplane or hydrofoil at high angles of attack hence the thick profile helps.

Guess the main reason for why it sits deeper (more like a tube wave kite not like a freerace foil which sometimes overflies) is the high AoA in the tips for spanwise tension, the birds body drag of course, more line drag because of more and longer bridle lines.

I recently did a very high aspect 7.5m with quite an aggressive profile (lot of camber although in the front) which was having big frontstall issues because the tips have too little AoA hence there is no spanwise tension in the canopy being depowered so the centre profile flips over and does not reopen because the tips don't pull it open again as opposed to if they had bigger local AoA.
So I was a bit more careful here although I knew the profile here had way less pitching moment but anyway added more tip AoA.
In hindsight a bit less would have done also.

It's always easier though to trim a stable kite for more performance than the other way around make an instable kite more stable without loosing much performance.
Especially in this case where it was more of a fun project the stable approach was better because I did not know what the front of the birds body would cause it to do in dynamic flight situations.