Hey LeeD, I hate days like that.

I agree with some of the comments above. I tend to rig more for the gusts so that I can survive them. When it lulls, you have more sail range to keep flying, but slogging on a floaty-enough board works, too.

Yesterday's conditions on the Snake River were like that. 5-30. I rigged both 5.0 and 6.4, but each one was good for, maybe, 30% of the time.

I think the answer to such conditions is to use a huge front wing with a really small sail on a floaty board. A 3.9 with a i84 would have worked, but, alas, I have neither.

I wonder if a small front wing and bigger sail might have....been the same misery.
My Naish 1236cm is big for my 170 lbs so maybe a 600 sq kitewing 11 might work.

My big problem is lulls in the wind.
We're downwind of an 11 mile fetch.
Berkeley can drop from 20 to 5 in minutes, and the 2' tall windswell persists forever because Crissy Fields and Treasure Island are still blowing 25 and cause the windswell.
Slogging is really difficult, small sail, 122 Naish, old man with weak legs.

I got out last night in some wind I've not really foiled in before. 18mph, gusting to almost 30 on my anemometer. Rigged the smallest sail I have (6.0 Flyer) and used the i84. Way overpowered, but still had fun. The foil plate was at 3/4" forward from zero, and I felt really had to push down with my back foot to get it up flying. Probably should have been a 1 3/4" or 2" forward of zero. I feel like I naturally want to be back foot heavy from my windsurfing days... but it doesn't feel right, or work for me to be that way when foiling. Could have easily used a 4.7 sail.
It may have been the strong wind last night, but I felt like the i84 was a bit twitchy, perhaps it was the rearward location of the foil mast. But it definitely felt different than the i99. The i99 is SO SMOOTH and predictable to me. I really like it.
Time to start shopping for a 4.7-5.0 sail.
Any suggestions on a closeout or used sail that would fit an RDM 430 mast?

Lots shops sell used sails.
18-30 I"d be on 4.2 and 85 liter slapper.
Try a 2.5 with the 84 wing.

exca8tor said, "I have had both the i84 and i99 in "B" position. The sail mast has been pretty much in the center of the mast track everytime I've been out." And "I had the i99 at 0" and the i84 at about 1" or 1.5" forward of "0" (hopefully that makes sense) ".

Slingshot recommendation for the I 99 foil: WIND: This wing works ONLY on The Levitator boards that offer an adjustable track mount that allows you to slide the whole foil system forward.

Wow, this is way different than the slingshot recommendation. Can't argue with success.

I'm thinking about trying the I99 on my wizard 150 in the C position. The trouble is that it is a big pill to swallow if I can't get it to work.

Select to expand quote

lakeeffect said..
exca8tor said, "I have had both the i84 and i99 in "B" position. The sail mast has been pretty much in the center of the mast track everytime I've been out." And "I had the i99 at 0" and the i84 at about 1" or 1.5" forward of "0" (hopefully that makes sense) ".

Slingshot recommendation for the I 99 foil: WIND: This wing works ONLY on The Levitator boards that offer an adjustable track mount that allows you to slide the whole foil system forward.

Wow, this is way different than the slingshot recommendation. Can't argue with success.

I'm thinking about trying the I99 on my wizard 150 in the C position. The trouble is that it is a big pill to swallow if I can't get it to work.

I had GREAT success using the i99 in C position on my Fanatic Falcon LW 2 Saturdays ago. 8-12mph breezes with an 8.0 Ezzy Cheetah.

What do you guys think is a good size spread for a quiver of sails? Currently I have a 10.0, 8.0, 7.0, 6.0 and 4.8.
Currently looking for something smaller than the 4.8... was thinking 4.0, but kind of feel like 3.8/3.9 might be smarter.....?

8,6,4.5,3.5.

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excav8ter said..
What do you guys think is a good size spread for a quiver of sails? Currently I have a 10.0, 8.0, 7.0, 6.0 and 4.8.
Currently looking for something smaller than the 4.8... was thinking 4.0, but kind of feel like 3.8/3.9 might be smarter.....?

are you going to be foiling with the smaller sails or jumping on a small board/fin?

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Paducah said..

excav8ter said..
What do you guys think is a good size spread for a quiver of sails? Currently I have a 10.0, 8.0, 7.0, 6.0 and 4.8.
Currently looking for something smaller than the 4.8... was thinking 4.0, but kind of feel like 3.8/3.9 might be smarter.....?

are you going to be foiling with the smaller sails or jumping on a small board/fin?

Right now I'm only thinking of foiling.... I will probably eventually bust out my old 9'2" Bruce Jones.... but not for a while.

Select to expand quote

excav8ter said..

Paducah said..

excav8ter said..
What do you guys think is a good size spread for a quiver of sails? Currently I have a 10.0, 8.0, 7.0, 6.0 and 4.8.
Currently looking for something smaller than the 4.8... was thinking 4.0, but kind of feel like 3.8/3.9 might be smarter.....?

are you going to be foiling with the smaller sails or jumping on a small board/fin?

Right now I'm only thinking of foiling.... I will probably eventually bust out my old 9'2" Bruce Jones.... but not for a while.

I do 10.0-9.0 (Phantom Iris foilracing sails) 4.9-3.8-3.0 (S2Maui Dragon 4-batten wave), If only foiling its fine, if you want to do some wave the gap is too large between 4.9 and 3.8. Thats why for 2020 I also ordered a 4.3. I can make the gap from foiling with 9.0 to foiling with 4.9 easy. From foiling 9.0 to a waveboard with 4.9 is a stretch, but with some diapers and especially other racers around pushing me to keep on going its quite doable. For foiling only the gaps between the sails are perfect.

Funnily enough the jump from 3.8 to 3.0 for wave works quite well, but I guess thats because in that wind range all sails are too big and too small at the same time because it gets incredibly gusty where I live when the wind reaches a certain threshold... (30 knots is never 30 knots, its practically always 25-40, 30-50, or 35-60)

If there's any wave wind foiling in my future, it will be downwind wave foiling.

I got out this afternoon for a few hours on my Duotone 4.8 Super Session with the I84 front wing. Had a dang good time, even though it was only 40 degrees. Could definitely have used a smaller sail... 3.8/3.9 may have been pretty close to perfect.

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lakeeffect said..
exca8tor said, "I have had both the i84 and i99 in "B" position. The sail mast has been pretty much in the center of the mast track everytime I've been out." And "I had the i99 at 0" and the i84 at about 1" or 1.5" forward of "0" (hopefully that makes sense) ".

Slingshot recommendation for the I 99 foil: WIND: This wing works ONLY on The Levitator boards that offer an adjustable track mount that allows you to slide the whole foil system forward.

Wow, this is way different than the slingshot recommendation. Can't argue with success.

I'm thinking about trying the I99 on my wizard 150 in the C position. The trouble is that it is a big pill to swallow if I can't get it to work.

The i99 has worked on every board we have tested so far. I use the i99/42 on the wizard 125 in B, others use i99/48 in C.

it ultimately depends on rider weight, rig set up or riding style.

Boards tested (All tuttle box)

Wizard 125
Horue Tiny 120
Horue Tiny 95
JP pro 135
Horue slant 135

Select to expand quote

CoreAS said..

lakeeffect said..
exca8tor said, "I have had both the i84 and i99 in "B" position. The sail mast has been pretty much in the center of the mast track everytime I've been out." And "I had the i99 at 0" and the i84 at about 1" or 1.5" forward of "0" (hopefully that makes sense) ".

Slingshot recommendation for the I 99 foil: WIND: This wing works ONLY on The Levitator boards that offer an adjustable track mount that allows you to slide the whole foil system forward.

Wow, this is way different than the slingshot recommendation. Can't argue with success.

I'm thinking about trying the I99 on my wizard 150 in the C position. The trouble is that it is a big pill to swallow if I can't get it to work.

The i99 has worked on every board we have tested so far. I use the i99/42 on the wizard 125 in B, others use i99/48 in C.

it ultimately depends on rider weight, rig set up or riding style.

Boards tested (All tuttle box)

Wizard 125
Horue Tiny 120
Horue Tiny 95
JP pro 135
Horue slant 135

Thank you. I've been following you posts, Exca8tor's, and others. There is a lot of experiences that says the I 99/48 or/42 in the B and C position is a workable combination. I suspect I will add it to my foil quiver next spring. I've looked at a calculated neutral point for a bunch of combinations including the I84/48, I84/42, I76/48, I76/42, and G68/42 and the neutral point doesn't change more than an inch and one half. I'd do the I99/48 and I99/42 but I don't have a leading edge to leading edge measurement for either of them. If someone has one of these configurations in their garage and would measure it for me I would calculate a neutral point and center of gravity with a 10% static margin and share the results in a post. It would be interesting! Below is what I'm looking for. I use a cloth tape from my wife's sewing box.

Select to expand quote

lakeeffect said..

CoreAS said..

lakeeffect said..
exca8tor said, "I have had both the i84 and i99 in "B" position. The sail mast has been pretty much in the center of the mast track everytime I've been out." And "I had the i99 at 0" and the i84 at about 1" or 1.5" forward of "0" (hopefully that makes sense) ".

Slingshot recommendation for the I 99 foil: WIND: This wing works ONLY on The Levitator boards that offer an adjustable track mount that allows you to slide the whole foil system forward.

Wow, this is way different than the slingshot recommendation. Can't argue with success.

I'm thinking about trying the I99 on my wizard 150 in the C position. The trouble is that it is a big pill to swallow if I can't get it to work.

The i99 has worked on every board we have tested so far. I use the i99/42 on the wizard 125 in B, others use i99/48 in C.

it ultimately depends on rider weight, rig set up or riding style.

Boards tested (All tuttle box)

Wizard 125
Horue Tiny 120
Horue Tiny 95
JP pro 135
Horue slant 135

Thank you. I've been following you posts, Exca8tor's, and others. There is a lot of experiences that says the I 99/48 or/42 in the B and C position is a workable combination. I suspect I will add it to my foil quiver next spring. I've looked at a calculated neutral point for a bunch of combinations including the I84/48, I84/42, I76/48, I76/42, and G68/42 and the neutral point doesn't change more than an inch and one half. I'd do the I99/48 and I99/42 but I don't have a leading edge to leading edge measurement for either of them. If someone has one of these configurations in their garage and would measure it for me I would calculate a neutral point and center of gravity with a 10% static margin and share the results in a post. It would be interesting! Below is what I'm looking for. I use a cloth tape from my wife's sewing box.

I can try and get that measurement later tonight, unless someone beats me to it.

Select to expand quote

excav8ter said..

lakeeffect said..

CoreAS said..

lakeeffect said..
exca8tor said, "I have had both the i84 and i99 in "B" position. The sail mast has been pretty much in the center of the mast track everytime I've been out." And "I had the i99 at 0" and the i84 at about 1" or 1.5" forward of "0" (hopefully that makes sense) ".

Slingshot recommendation for the I 99 foil: WIND: This wing works ONLY on The Levitator boards that offer an adjustable track mount that allows you to slide the whole foil system forward.

Wow, this is way different than the slingshot recommendation. Can't argue with success.

I'm thinking about trying the I99 on my wizard 150 in the C position. The trouble is that it is a big pill to swallow if I can't get it to work.

The i99 has worked on every board we have tested so far. I use the i99/42 on the wizard 125 in B, others use i99/48 in C.

it ultimately depends on rider weight, rig set up or riding style.

Boards tested (All tuttle box)

Wizard 125
Horue Tiny 120
Horue Tiny 95
JP pro 135
Horue slant 135

Thank you. I've been following you posts, Exca8tor's, and others. There is a lot of experiences that says the I 99/48 or/42 in the B and C position is a workable combination. I suspect I will add it to my foil quiver next spring. I've looked at a calculated neutral point for a bunch of combinations including the I84/48, I84/42, I76/48, I76/42, and G68/42 and the neutral point doesn't change more than an inch and one half. I'd do the I99/48 and I99/42 but I don't have a leading edge to leading edge measurement for either of them. If someone has one of these configurations in their garage and would measure it for me I would calculate a neutral point and center of gravity with a 10% static margin and share the results in a post. It would be interesting! Below is what I'm looking for. I use a cloth tape from my wife's sewing box.

I can try and get that measurement later tonight, unless someone beats me to it.

Thank you!

Hi Lakeeffect

Don't get to ingrained in the leading edge measurements. We all get consumed by micro adjustments on the fuse/front wing location but don't forget mast base and foot strap positions are just as important.
When I give riders my exact measurements it never really pans out (it might be a starting base but every fraction yields a different feel) so tailor make yours from experimenting. from our windsurfing days we would adjust the mast base 1-2" but for foiling 1/4" on mast base with a hole back on a foot strap creates entirely different ride.

From the leading edge of my i99 to the leading edge of the 48cm stab is 31 inches.

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excav8ter said..
From the leading edge of my i99 to the leading edge of the 48cm stab is 31 inches.

This discussed before in the discussion of longer fuselage and stability. SL55 had a picture that was measured 90 cm (35.4 inch).Below is picture sl55 provided. i99 is the same for length (to the end of the back wing).

COE is more important than leading edge.

Thank you exca8tor for the I99 S48 number and SA_AL for SL55's number for the I99 S42.

LeeD, I agree with your that COE,Center of Effect for the Sail, is important and every difference size sail I use has a different COE, but COG, center of gravity, is just as important. It's the other half of the equation. The Sail provides the Thrust and the Foil generates the Drag. The Sail is the Energy Source, the Foil is the Energy Sink.

Core AS, I agree that in and of itself the wing leading edge to stab leading edge means little. In addition I agree that the mast position and foot strap position are just as important as the neutral point and the corresponding COG along with the COE for the different sails I use. Written between your words I suspect there is a message that if I went to the beach today for a four hour foiling session I would be a lot farther ahead than if I spent four hours of calculating neutral points and COG's at home. I agree, but the Lake Erie is about 40 degrees today and the air temperature is in the 20's. So thinking about foiling is the best I can do.

I'm using a math model whose inputs are the wing aspect ratio, the stab aspect ratio, the wing area, the stab area, the wing span, the stab span, the wing root chord, the stab root chord, and the wing leading edge to stab leading edge distance. These are used to calculate a COG for a 10% static margin.

Below is a summary of the calculated neutral points and center of gravity for a number of Slingshot Wing and Stab combinations. They are numbers for the long fuse.

Select to expand quote

lakeeffect said..
Thank you exca8tor for the I99 S48 number and SA_AL for SL55's number for the I99 S42.

LeeD, I agree with your that COE,Center of Effect for the Sail, is important and every difference size sail I use has a different COE, but COG, center of gravity, is just as important. It's the other half of the equation. The Sail provides the Thrust and the Foil generates the Drag. The Sail is the Energy Source, the Foil is the Energy Sink.

Core AS, I agree that in and of itself the wing leading edge to stab leading edge means little. In addition I agree that the mast position and foot strap position are just as important as the neutral point and the corresponding COG along with the COE for the different sails I use. Written between your words I suspect there is a message that if I went to the beach today for a four hour foiling session I would be a lot farther ahead than if I spent four hours of calculating neutral points and COG's at home. I agree, but the Lake Erie is about 40 degrees today and the air temperature is in the 20's. So thinking about foiling is the best I can do.

I'm using a math model whose inputs are the wing aspect ratio, the stab aspect ratio, the wing area, the stab area, the wing span, the stab span, the wing root chord, the stab root chord, and the wing leading edge to stab leading edge distance. These are used to calculate a COG for a 10% static margin.

Below is a summary of the calculated neutral points and center of gravity for a number of Slingshot Wing and Stab combinations. They are numbers for the long fuse.

lakeeffect, you're doing better than me. During the unsailable months, instead of doing math, I buy gear I'll never use.

Okay, so look at your chart. The numbers of CoG vary about what maybe 4 cm? Let's assume you are starting out without back straps. Look down at your (because of the cold) imaginary back foot. Gently move it forward or backward a few cm. Now, imagine gently shifting weight maybe a couple of kg from front to back foot or vice versa. There ya go. You've adjusted.

This without even beginning to worry about where the mast base is, where your boom height is, etc. which also will influence this. Yeah, you want to get it approximately right but beyond that a windfoil is still a dynamic system that requires active attempts to maintain equilibrium. Even different points of sail and different wind strengths will change how you need to balance the system out. The numbers are fun to crunch but don't spend too much time down worrying about it. It'll warm up soon enough and there's always FL or TX this time of year.

Paducah, You make a good point. I currently sail an I84 with a 48 stab. My next purchase will be an I99 using the current 48 stab. The numbers say I need to move my stance a half inch forward. Moving my back foot an inch forward would put me in balance. However if I maintain my stance and move the sail mast forward or increase the height of the boom it would do the same thing. And I can change the boom height or sail mast position on the water where changing the foot straps requires returning to the beach and walking to the car for a screwdriver.

I understand buying things you want and don't need. My wife tells me I have poor impulse control. I sit in my home in a reclining chair with the internet in my lap where I can shop the world for things I want. I want that I99 foil but don't need it to mid May of next year.

Select to expand quote

lakeeffect said..
I understand buying things you want and don't need. My wife tells me I have poor impulse control. I sit in my home in a reclining chair with the internet in my lap where I can shop the world for things I want. I want that I99 foil but don't need it to mid May of next year.

Almost every sail I own below 5.0 was bought in the summer, a time of year when I could get by with whatever my largest sail is. I hear ya!

Select to expand quote

lakeeffect said..
Paducah, You make a good point. I currently sail an I84 with a 48 stab. My next purchase will be an I99 using the current 48 stab. The numbers say I need to move my stance a half inch forward. Moving my back foot an inch forward would put me in balance. However if I maintain my stance and move the sail mast forward or increase the height of the boom it would do the same thing. And I can change the boom height or sail mast position on the water where changing the foot straps requires returning to the beach and walking to the car for a screwdriver.

I understand buying things you want and don't need. My wife tells me I have poor impulse control. I sit in my home in a reclining chair with the internet in my lap where I can shop the world for things I want. I want that I99 foil but don't need it to mid May of next year.

I was shocked that I didn't have to adjust anything when foiling the i99 (same mast base, same foot strap, same boom height etc).

I also find when using the 48 rear wing it needs much more back foot pressure and can feel a bit "draggy" and that's why I prefer the i99/42 in B position (on the wizard 125).

The i99/42 has a balanced feeling and turns faster in the gybes.. But again it is personal preference as my foiling bud swears by the i99 with 48 rear in position C and he foils just as well.

I do have to use the full body pump when using it in sub 10 mph with a 5.8 (I weigh 205 lbs/92 kg) but once the i99 hooks in, it keeps on motoring....you will love that wing for super light airs.

Select to expand quote

lakeeffect said..
Thank you exca8tor for the I99 S48 number and SA_AL for SL55's number for the I99 S42.

LeeD, I agree with your that COE,Center of Effect for the Sail, is important and every difference size sail I use has a different COE, but COG, center of gravity, is just as important. It's the other half of the equation. The Sail provides the Thrust and the Foil generates the Drag. The Sail is the Energy Source, the Foil is the Energy Sink.

Core AS, I agree that in and of itself the wing leading edge to stab leading edge means little. In addition I agree that the mast position and foot strap position are just as important as the neutral point and the corresponding COG along with the COE for the different sails I use. Written between your words I suspect there is a message that if I went to the beach today for a four hour foiling session I would be a lot farther ahead than if I spent four hours of calculating neutral points and COG's at home. I agree, but the Lake Erie is about 40 degrees today and the air temperature is in the 20's. So thinking about foiling is the best I can do.

I'm using a math model whose inputs are the wing aspect ratio, the stab aspect ratio, the wing area, the stab area, the wing span, the stab span, the wing root chord, the stab root chord, and the wing leading edge to stab leading edge distance. These are used to calculate a COG for a 10% static margin.

Below is a summary of the calculated neutral points and center of gravity for a number of Slingshot Wing and Stab combinations. They are numbers for the long fuse.

Lakeeffect, I am strugling to see the relevance of C.O.G in the context of a foil? In the context of a plane(RC or otherwise) YES. But surely the C.O.G of the foil(wings/fuse) is insignificant compared to what is driving it(Board/rider/rig) through the mast. If this is true then the position of the applied force through the mast attachment to the fuse vs. the Center of lift of the foil is what really matters... NO?

Select to expand quote

gorgesailor said..

Lakeeffect, I am strugling to see the relevance of C.O.G in the context of a foil? In the context of a plane(RC or otherwise) YES. But surely the C.O.G of the foil(wings/fuse) is insignificant compared to what is driving it(Board/rider/rig) through the mast. If this is true then the position of the applied force through the mast attachment to the fuse vs. the Center of lift of the foil is what really matters... NO?

As Paducah points out there are many factors that control the balance of the foil including sail size, wind strength, mast base position and boom height. However if you isolate the foil in and of itself, the question the COG answers where do you want to place your stance. If you only consider the foil you would want to place your stance over the COG.

What I was really trying to do with the calculations is prove to myself that the numbers match the experience of CoreAS, excav8tor, and others that there is not much difference in stance when moving from the I84 S48 foil to the I99 S48. The numbers say you have to move your back foot forward an inch, or just weight to your front foot more or adjust you mast position, or your boom height.

Math models have short comings. The short coming here is that I only analyze the foil. I don't have the smarts to analyze the sail, sailor, board, and foil. Tiesda You(Starboard) Tony Lagosz,(Slingshot), Kevin Ellway, and the guys from F4 probably can do it, but they compete against each other and thus don't talk publicly about what they think.

The COG (center of gravity) is the result of body position in this sport.

The COL (center of lift) is an aerodynamic spot on the chord of a lifting wing, usually about 1/3 back from the leading edge. This varies, of course, with planform, span, etc.

It is the COL that you want to get at, or near, the midpoint between front and back feet. If the COL is too far aft, you can't get the foil to lift and fly. If it is too far forward, you can't control the lift.

Select to expand quote

lakeeffect said..

gorgesailor said..

Lakeeffect, I am strugling to see the relevance of C.O.G in the context of a foil? In the context of a plane(RC or otherwise) YES. But surely the C.O.G of the foil(wings/fuse) is insignificant compared to what is driving it(Board/rider/rig) through the mast. If this is true then the position of the applied force through the mast attachment to the fuse vs. the Center of lift of the foil is what really matters... NO?

As Paducah points out there are many factors that control the balance of the foil including sail size, wind strength, mast base position and boom height. However if you isolate the foil in and of itself, the question the COG answers where do you want to place your stance. If you only consider the foil you would want to place your stance over the COG.

What I was really trying to do with the calculations is prove to myself that the numbers match the experience of CoreAS, excav8tor, and others that there is not much difference in stance when moving from the I84 S48 foil to the I99 S48. The numbers say you have to move your back foot forward an inch, or just weight to your front foot more or adjust you mast position, or your boom height.

Math models have short comings. The short coming here is that I only analyze the foil. I don't have the smarts to analyze the sail, sailor, board, and foil. Tiesda You(Starboard) Tony Lagosz,(Slingshot), Kevin Ellway, and the guys from F4 probably can do it, but they compete against each other and thus don't talk publicly about what they think.

This is what I am saying though. The C.O.G of the foil alone is irrelevant. You can't isolate the foil when considering C.O.G. because the foil is being driven through the mast/fuse connection. The C.O.L calculations are very interesting indeed & I think a good way to understand how stance may need to be adjusted for different foils.