Windfoiling

[Beasho]

The sad report is that IT DIDN'T WORK.

My first attempt was on the Clam Sandwich.  Light air, and a sinking board - NO DICE.

The second attempt was in more air 15 - 25 on the Hi Per tech.  Plenty of wind.  BUT I couldn't get the foil to fly.

Only when going over sizable chop, ~ 2 feet, would the foil partially engage and not let me drop down the back of the wave.

I am convinced that the box placement is too far AFT to allow me to unweight the front of the board.  The combination of rear placement and weight of Sail and Board forward left me trying to fly by doing wheelies from my rear pinky toe. 

3 Options:

• Install a Tuttle Box further forward
• Intall a mast mount further BACK on the Hi Per Tech
• Buy a new board

None of these are ideal.  The least complex might be get a 2 bolt Chinook mast base and install on Hi Per tech. 

PS:  The Slingshot 125 looked pretty nice but it's $2,000 for a gamble.

[Dwight (DW)]

Beasho, my suggestion is you should get junk windsurf board you can uphaul. You absolutely need to be able to uphaul. Then place a Tuttle box forward.

[Admin]

The 105 Slingshot looks pretty nice.  5'10.  105 is still plenty to dry uphaul and  limp home on.  Wonder if anyone demos this stuff .

[SUPladomi]

I'm having difficulty getting my head around foil mast placement. It seems that all the racers at the PWA foil event in Japan were running basically as far aft as possible.

And why wouldn't you do the same for SUP board? You hear so much about front foot pressure. It seems like the easy way to balance things out is to move the mast aft.

[starman]

Apples and Oranges would be my uneducated guess. Like Wardog mentioned, the foil on a sailboard is just a bigger fin. When powered up on those boards you are basically transferring all that drive from the sail to the foil with your back foot. Pretty much like you would with a big racing fin.

The SUP foil is getting most or all of it's drive from wave energy, there is no other external power source (other then "pumping" the board). So I would think the foil placement and design is quite a bit different.

Here is the link to the HyperNut foil board: http://star-board-sup.com/2017/board/74-x-30-hyper-nut-foil-board/

Then there is the Slingshot windsurfing foil board:  http://www.slingshotsports.com/Dialer-145-Foil-Board#.WV5s34qQz64

[Dwight (DW)]

I'm having difficulty getting my head around foil mast placement. It seems that all the racers at the PWA foil event in Japan were running basically as far aft as possible.

What I discovered last summer foiling...

Mast in normal location felt best when learning.

The better I got, the more responsive I wanted everything.  Eventually I was building boards with mast tracks 5" farther back than normal

[yugi]

.

[Beasho]

Mast in normal location felt best when learning.

The better I got, the more responsive I wanted everything.  Eventually I was building boards with mast tracks 5" farther back than normal

On the Hi Per Tech there was almost NO Chance of getting the foil to fly with the mast in the normal position.  Plenty of wind and I could hear the foil humming.  But the 9' Hi Per Tech was ideally suited to a 6.5 Meter sail aka BIG.  This meant a forward track allowing for enough rake to get the Center of Lift of the sail to align above the Center of Resistance which was typically directly between the rear footstraps, if not slighly closer to the rear foot.

[Beasho]

The video is compelling:

https://www.youtube.com/watch?v=b-FuNGg_QR8

[Dwight (DW)]

Going by memory my fast foot was 120-125 cm from tail

Somebody should measure estimated center of lift point on front wing to center of mast on Slingshot windsurf foil. Post here. Beasho could take that and guess how much to move Tuttle forward.

[Dwight (DW)]

Just measured my buddies NP foil. 10" center of lift front wing to center of mast. It feels like half the weight of SS foil

[SUPladomi]

I'm having difficulty getting my head around foil mast placement. It seems that all the racers at the PWA foil event in Japan were running basically as far aft as possible.

What I discovered last summer foiling...

Mast in normal location felt best when learning.

The better I got, the more responsive I wanted everything.  Eventually I was building boards with mast tracks 5" farther back than normal

I just want to be clear that we are talking about the same thing. I was referring to the placement of the Tuttle box for the mast of the foil. I believe you are talking about the mast track position of the sail.

Unless I misunderstood, one of Beasho's options was to move the Tuttle box forward. This seems counter to the setups of all the windfoilers in the picture I posted and as you can see here.


I have a very limited grasp of physics but the big question for me is why would a SUP and windfoil have different mast (of the foil) placement anyway? Starman made an attempt to address it but I'm still stuck on the lift.

It seems from what I've read that generating lift is the easy part (apparently not in Beasho's case at the moment) by just weighting the back foot. It appears that you counteract this by really weighting the front foot. To my not very complex mind, with the mast (of the foil) in a more aft position, you are balancing all the lift generated with your body weight being forward of the mast. What am I missing?

[Dwight (DW)]

...why would a SUP and windfoil have different mast (of the foil) placement anyway?

Windsurfers are stuck with existing Tuttle box placements.....so foil has to be designed around this handicap.  Meaning it needs an extra long fuselage to place the lifting wing forward enough.

While any other board, surf, SUP, kite is not limited by a pre-existing Tuttle box, so those foils can be designed with a short, design efficient fuselage. The Tuttle boxes moved up.

[peterwSUPr]

Yes, I was just about to say the same thing.  The fuselage has to be strong if it is long to the front wing, so there has been a move to have the front wing quite close to and sometimes overlapping the front of the mast.  It's hard to know from photos where the wing actually is.  It's the wing position relative to the feet which is most important in terms of lift and balance. 

Another name for the "mast" is the "strut".  It is a less common name and yet it probably is more technically correct.  Especially with windfoils, the term strut is much less confusing.  I was having trouble figuring out which mast we were talking about at times.

Peter

[SUP Sports ®]

I'm having difficulty getting my head around foil mast placement. It seems that all the racers at the PWA foil event in Japan were running basically as far aft as possible.

And why wouldn't you do the same for SUP board? You hear so much about front foot pressure. It seems like the easy way to balance things out is to move the mast aft.

Aloha SUPladomi,
You have to understand that there are basically two branches of windfoiling developing now...high performance racing with advanced foils...solid with up to 70 layers of carbon...attached to Formula-like boards and sails...and, recreational windfoiling with tuned down foils (aluminum and carbon...or, carbon/hybrid) being retrofitted to existing sailboards...using existing sail rigs...as well as purpose built gear now being developed... and, also crossover multi-sport SUPs...etc...

The companies interested in windfoil racing are manufacturing boards specifically for that...not retrofitting existing boards for windfoiling to appeal to a broader range of sailors...so, it's an arm's race at the top of the high performance heap...and, it seems like the Europeans are leading the way in that arena because there is an active racing scene there...etc...

They do place the mast of the foil aft because they have experience from Formula with very flat tail rockers...etc...it is faster and they have more leverage over the foil...wide tailed boards are important here because they allow you the leverage over the foil to fly the board level or very slightly dip the windward rail...dipping the leeward rail while flying with sail pressure present is not recommended unless you like to be body slammed...;-)

Wider tailed windfoilng boards with foils placed aft are also less reactive...small adjustments in foot or sail pressure don't get transferred to the foil as quickly or as sharply...touch downs in windfoil racing are like spinouts in regular windsurfing...racers that have the skill to jibe with the foil without touching down, usually differentiate themselves on the podium with better results...