Foil stuff sizes vs conditions

Ok. Quite a few questions::

- i don't yet figure how does it work with SLALOM foil boards. Is it correct it's similar as fin stuff, where you combine board and fin size according with the wind and water state? Meaning: if 91 cm wide board should be the power house for light and medium condition, what are the right situations to use the 81 cm and the 71 cm?
And still, does it worth (for the avg joe) trying to foil (very) powered up instead of reducing stuff size being in easier control=faster?

- what are the conseguences (in terms of feeling, ride and safety) when you foil (for given condition) not coherent board/sail/wing stuff?

Regarding my stuff - yes, I have now packages for light (<10 knts.), medium (>10-15 knts.) and highwind (>15 knts.).

PD Foil-comp 91 / 1000 or 800 foil (size 990 or 840 cm2) / 115/105 fuse and 107 mast / most 8.0 (or 7.0) Foil-Race sail

PD Foil-Comp 78 / 740 or 671 foil (size 700 or 570 cm2) / 101 fuse and 95 mast / most 6.0 (or 7.0) Foil-Race sail

Of course I have to use different mast-angles and stabilizers shim for all combinations.

PWA guys used mostly 91 boards even with higher wind speeds because it the extra width gives extra control.
A lot of brands have come out with 81 and 71 boards and very small wings so we have to see what the new season will bring.
The small wings don't need so much sail power to go fast so maybe we will see 81 boards in 17 knots+

It depends on your style, weight and preferences.
Do you like to blast around overpowered or will you go for the smallest sail you can get away with.
If your weight is 70 kg and you don't compete than a 81 board with 2 wings and a 8.0 and 6.0 will cover 8-18 knots .
Heavier guys in area's with low/moderate winds will go for the 91.Smaller sails are nicer on smaller boards. Smaller boards will fly faster/easier with same sail area as bigger boards.
I use the 91 with 9.0 and 8.0 and the 81 with 8.0 - 5.0. The 81 with the 8.0 takes of earlier than with the 91.
Just harder to control in stronger winds and you loose up/downwind angle. A 6.0 on a 91 feels weird to me.

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w100 said..
Ok. Quite a few questions::

- i don't yet figure how does it work with SLALOM foil boards. Is it correct it's similar as fin stuff, where you combine board and fin size according with the wind and water state? Meaning: if 91 cm wide board should be the power house for light and medium condition, what are the right situations to use the 81 cm and the 71 cm?
And still, does it worth (for the avg joe) trying to foil (very) powered up instead of reducing stuff size being in easier control=faster?

- what are the conseguences (in terms of feeling, ride and safety) when you foil (for given condition) not coherent board/sail/wing stuff?

-generally, yes--but foil slalom is somewhat less sensitive to board size compared to fin slalom; in a competitive slalom fin fleet you would need at least 2 and ideally 3 fin boards to cover the whole range of conditions from 9.0/8.4 down to 6.2/5.8 and smaller. in a fin slalom fleet you can still get away with one board (91cm, if you need to use 9m, which you would in fleet races if not consistently over 15 knots). Presuming you are talking about foil slalom boards, I would put the useful ranges of a 3-board quiver like this: 91: 7-20kn, 81: 12-25, 71: 20+. That said, I don't think we will see much slalom racing being done on 71cm foil race boards (for now at least), which seem to be more suited for long distance type race like the Defi wind if you want to line up against the fins in 20+ knots of breeze and 6m sails and smaller.
-depends on what the average joe wants to do. there is no universe in which you do not need to be (very) powered up to be competitive on a race course, whether it's fin or foil. of course you still need to be able to control your setup, which generally means a smaller size sail then you would have held down on a slalom fin course
-too small a wing for the conditions generally means you will have difficulty to get going and stay up in the jibes/lulls; too big a wing on the other hand means your top end speed will stall out as it will get increasingly difficult to load up the foil for speed without exploding (foiling out & crashing)

FWIW,
At 140lbs, I was out yesterday in 27knot gust on a I76 with 3.6 goya fringe. I have a weather station on my boat dock with good exposure, so should be fairly accurate. Was a bit challenging, but managable. Jibing in deep chop/swell was my biggest problem.

You already know the answer.

In the beginning I had the AFS-2 with F700 wing. My learning curve was long and painful. After 18 months of such pain, I got the F800 wing and started using it at Lake Mojave. It was a game changer.

Since then I have used the LP with the 940 wing. That also was good.

And now since then, my goto wing is the Moses 950. When I'm in Florida I keep trying to use the game changing F800, but keep going back to the i76 for its improved and consistent ride.

So, besides surface area and planform and aspect ratio, there is also the airfoil profile and washout and fuse length. All these impact how a foil lifts and performs and feels.

Point it, find your sweet spot foil and enjoy it. If you don't make all your jibes in flight, so what. You still jibed and are off on a new tack. 100% dry.

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bel29 said..

w100 said..
Ok. Quite a few questions::

- i don't yet figure how does it work with SLALOM foil boards. Is it correct it's similar as fin stuff, where you combine board and fin size according with the wind and water state? Meaning: if 91 cm wide board should be the power house for light and medium condition, what are the right situations to use the 81 cm and the 71 cm?
And still, does it worth (for the avg joe) trying to foil (very) powered up instead of reducing stuff size being in easier control=faster?

- what are the conseguences (in terms of feeling, ride and safety) when you foil (for given condition) not coherent board/sail/wing stuff?

-generally, yes--but foil slalom is somewhat less sensitive to board size compared to fin slalom; in a competitive slalom fin fleet you would need at least 2 and ideally 3 fin boards to cover the whole range of conditions from 9.0/8.4 down to 6.2/5.8 and smaller. in a fin slalom fleet you can still get away with one board (91cm, if you need to use 9m, which you would in fleet races if not consistently over 15 knots). Presuming you are talking about foil slalom boards, I would put the useful ranges of a 3-board quiver like this: 91: 7-20kn, 81: 12-25, 71: 20+. That said, I don't think we will see much slalom racing being done on 71cm foil race boards (for now at least), which seem to be more suited for long distance type race like the Defi wind if you want to line up against the fins in 20+ knots of breeze and 6m sails and smaller.
-depends on what the average joe wants to do. there is no universe in which you do not need to be (very) powered up to be competitive on a race course, whether it's fin or foil. of course you still need to be able to control your setup, which generally means a smaller size sail then you would have held down on a slalom fin course
-too small a wing for the conditions generally means you will have difficulty to get going and stay up in the jibes/lulls; too big a wing on the other hand means your top end speed will stall out as it will get increasingly difficult to load up the foil for speed without exploding (foiling out & crashing)

What are some symptoms of the board being too big in this case?

I know that my 6.6 and my 5.8 feel goofy (especially 5.8) on a 95cm wide board but the 7.5 feels ok. 9.0 the best. Don't know how to describe what I mean but it definitely felt "off" even though I was able to get flying.

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bel29 said..

aeroegnr said..

What are some symptoms of the board being too big in this case?

I know that my 6.6 and my 5.8 feel goofy (especially 5.8) on a 95cm wide board but the 7.5 feels ok. 9.0 the best. Don't know how to describe what I mean but it definitely felt "off" even though I was able to get flying.

imho it has to do with angle/distance between mast base and footstraps, especially the back strap. with a smaller sail on a wider board (say 6m or smaller on a 91/95 wide board) the stance becomes a bit awkward, and you feel that your backfoot in particular wants to be closer to the centerline of the board. sure, you can still foil on it, and even go fast, but it becomes harder--as in: control becomes trickier--to lock in the board with both feet to push for max speed. maybe being too outboard gives you too much leverage over a smaller front wing, making it harder to find the balance point. my 2ct. (Ps: just to be clear, my premise here is that to go really fast on a reach you need to have both feet in the straps to be able to keep constant windward/downward pressure on the front wing)

Ok, thank you. So maybe then what I'm feeling on that 95cm is what you are describing. May have to try a narrower board at some point when it's really blowing. Or just try using my Wizard with the i76 on a windy day where I can get away with a 5.0.

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w100 said..
Is it correct to say that "slalom" foil stuff works best when you power it up with (almost) same sail size as fin stuff for given condition?
Off course it can work also with tiny smaller gear but then it looses its interest?

It seems that way. I've seen freeride foils, much larger area, get going with 7.0 and below when I'm on a 9.0, on days when the smaller guys are on a fin with 7.5ish trying to get bump and jump, but it was marginal for the fin guys. Short video with bad view below, I'm on a 650/115+/9.0 going downwind, you can see a winger on a 6.0ish and the fin guy out with I think a 7.5 pushing more upwind.

Granted, I will go out often on the all out IQFoil kit (900/115+/9.0) when only foilers will want to be out because it isn't enough to plane even on a 9.5 and fin, so on the bottom end there is an overlap where race foils and fins are around the same size kit.

I think the separation in size really starts to become apparent in 20+kts wind, especially when you watch PWA, and the foil guys are a meter or more smaller. I personally don't enjoy running my 7.5 in 25knot gust in heavy chop on my foils, but in flat water I could probably manage it better. Or, if I had a narrower board that carried a sail <7.0 without it feeling really goofy.

...and even smaller. Phantom boys took out 3.7s, which most don't even have available

www.instagram.com/tv/CbX-l6CI61w/?utm_medium=copy_link

Small sails and (some) smaller boards abound btw during French team training at L'Almanarre (vent d'est conditions, so offshore at the Almanarre side of the Giens peninsula)

www.facebook.com/743189116/posts/10159225845449117/?d=n

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bel29 said..

aeroegnr said..

so on the bottom end there is an overlap where race foils and fins are around the same size kit.

not quite, if you compare apples to apples; 10m foil racing = 12/12.5 fw racing (and then the fw boards still loose out in VMG!)

so imho the smaller size applies to all forms of foil v fin racing (while it is true that no one really used anything bigger than 9m on a slalom course, whether it foil or fin, the reality was that fin slalom was rarely run if the wind wasn't consistently over 10 knots, which isn't the case anymore for foil slalom)

btw, on the smaller board for high wind slalom foiling: apart from the stance that gets a bit awkward, there is also the water state; unless you're in Luderitz no place stays perfectly flat when the wind hits 20 knots and more, so a narrower board becomes less prone to catching the windward rail in the wind swell/chop

This all makes sense

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bel29 said..

aeroegnr said..

so on the bottom end there is an overlap where race foils and fins are around the same size kit.

not quite, if you compare apples to apples; 10m foil racing = 12/12.5 fw racing (and then the fw boards still loose out in VMG!)

Important to take the luff lengths into account though. A 9m (foilsail) with 550+ luff is a way different sail than a 9m (slalomsail) with 500 luff. The first one is way more efficient.

For the formula sizes the foilsails keep the same luff but reduced boom length, way higher aspect ratio and thus lift to drag ratio.

Not saying the difference in luff makes up all the difference in raw area, but there is some nuance to be taken into account there.

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w100 said..

So he's using:
9.0 on a 620
6.9-7.9 on 560
<6.9 on 420

Which means me using the 9.0 on the Starboard 650 or 725 sounds about right, and matches what some other people are saying as well as what Phantom shows for their wings.

Somewhere around 7m2 I feel like I want a narrower board.

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WhiteofHeart said..

bel29 said..

aeroegnr said..

so on the bottom end there is an overlap where race foils and fins are around the same size kit.

not quite, if you compare apples to apples; 10m foil racing = 12/12.5 fw racing (and then the fw boards still loose out in VMG!)

Important to take the luff lengths into account though. A 9m (foilsail) with 550+ luff is a way different sail than a 9m (slalomsail) with 500 luff. The first one is way more efficient.

For the formula sizes the foilsails keep the same luff but reduced boom length, way higher aspect ratio and thus lift to drag ratio.

Not saying the difference in luff makes up all the difference in raw area, but there is some nuance to be taken into account there.

True re nuance. But a 40cm difference in boom length is night and day in terms of handling & feel (swing weight etc), while the same difference in luff length is much less noticeable. Guess what I wanted to say is that competing on a 10.0 foil sail is much more accessible than on a 12.0 FW sail-even if they both have the same or similar luff, the whole racing experience (pumping, transitions, range.) is totally different.

Where and when I foil, it's usually pretty gusty. 10 - 18kts
for those conditions I rig a 6m twin cam with 800/95+/255-2 combo. Any less and I rig a 7 - 7.5 with 330 stab. I'm 95kg.
reading comments from others it seems I'm rigging a bit small, but once I'm up I feel more in control. If rigging small you need to be prepared to pump hard. I guess I should really be on a 7m high aspect foil sail