Messages

31

The Shape Shack / Re: Hollow foil board construction method

« on: December 16, 2022, 11:34:48 PM »

You really need to use prepreg with nomex or all the resin runs into the cavities. Which means an oven as well.
 

32

The Shape Shack / Re: Hollow foil board construction method

« on: December 16, 2022, 08:01:44 PM »

Skip to about 2.30 if you don't want to watch all of it.

33

The Shape Shack / Re: Vunderfoil

« on: December 12, 2022, 10:30:50 AM »

You need to use a program for hydrofoils.
 I have been lucky enough to meet people that have been involved in some pretty high end foiling sailing. They said the major break through was designing hydrofoils not just using existing NACA shapes.
 What you see doing is awesome and I love it. It will work and you will make some great stuff. But if you want to give it that little bit extra some proper CFD will make a big difference.
 It would be interesting to know if the Armstrong foils are different to other foils.
 
 

34

The Shape Shack / Re: Vunderfoil

« on: December 11, 2022, 12:16:37 AM »

I have no idea either. I just know at some point you should have designed a hydro foil and not down sized an aeroplane wing.
 Good luck and remember. You didn't make a mistake you learnt something. It's only a mistake if you stop trying and didn't learn something from it.

35

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 11:19:19 PM »

You can't make a wing 1000 times smaller and it will have the same characteristics in water as in air at the same speed.
 I would say Armstrong are using CFD with the connection to the Americas cup and Sail GP guys.
 Water temp, salinity density of water will all have an effect.
 Some guy might hate a foil and he is using it on a fresh water lake in Switzerland and another guy loves it that is using it in Australia in very salty water near the shore break with huge amounts of sand or sediment in the water. Same with damage to the leading edge. You are sand blasting it if you are foiling in water with sand or sediment in it.

36

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 11:03:53 PM »

Fundamentals are the same but huge gains got made when they stopped using aerofoils and designed hydrofoils.
 

37

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 10:59:16 PM »

You don't have to go this far. With a simple CFD program you could design 10 different fuses and test them in a morning. Get an idea of what shape and length works for what you want.

38

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 10:43:33 PM »

https://www.numeca.com/vplp-design-revolutionizing-hydrofoil-design-with-advanced-cfd-simulation-technology

39

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 12:31:46 PM »

And then since you are 3D printing your own stuff have intake slots on the front of the main foil that sucks water in. A membrane or micro pump system that sucks water in and spits it out the back of of fuse like a jet ski. Magnetic impellers?
 If you are lucky you might create a super cavitating foil. That uses small amounts of electricity.

40

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 11:50:48 AM »

Surely you can print a screw thread that stops in the same position.
 There are expensive fittings that exist in the sailing world. Maybe you could copy something like this.

41

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 11:45:10 AM »

Very simple twist lock system of changing the fuse. You could have 3 or 4 in a backpack and change them in the water.

42

The Shape Shack / Re: Vunderfoil

« on: December 10, 2022, 10:27:19 AM »

This is just awesome. Well done.
 I know a big break for foiling was when they started designing specific foil shapes and not just using existing NACA or other shapes. I think with a pretty cheap CFD program you could really get to what you want to achieve quicker.
 As Pono said with your idea of attaching the mast to the front foil directly the fuse didn't need to be as strong. So if you had T shaped or elliptical fuse you wouldn't need a tail. Maybe a flexible fuse that gave you a little bit extra kick for pumping?  I think a CFD program would help with all of this.

43

Sessions / Re: Back on the water

« on: December 04, 2022, 08:12:13 AM »

Got my fastest average speed too! Not sure what was up with my phone. Make sure I take my watch next time

44

Sessions / Re: Back on the water

« on: December 04, 2022, 08:08:04 AM »

Back out today for a short paddle. Beautiful area. Might have to look into getting the car ferry over to Giglio one day. Either paddle round the island or down wind back.

45

The Shape Shack / Re: Dave Daum Build Series - Foilboard Construction A to Z - Q & A

« on: December 04, 2022, 12:18:13 AM »

I would say just fill it. Lightly sand the area first to make sure there are no high spots.
 I had problems with wrinkles a few times. I was rushing to get the board in the bag. Doing big SUPs by yourself is stressful.
 I started using a slower epoxy. Take your time and make sure the peel ply is wet out properly and wrapped around the rails. Or it will move and wrinkle in the bag. At that point when the bag starts getting tight open the valve up and slowly increase the pressure pulling the bag tight around the rail. A lighter peel ply is easier to work with and wrap around rails. I asked a friend that does carbon boat construction to come up and help. He gave me a few very helpful tips. I also started using a heavier bag. Less chance of wrinkles.
 It took quite a few messed up boards before I got better at it.