Really good explanation of the differences, at the start of the video i was thinking the energy from the wind used to generate lift must be a contributory factor in terms of limiting conversion of wind to top speed. Any consumption of energy produces a drag, even the generation of sounds consumes energy reducing speed and effectively becomes drag 🙂 Not as obvious as the board hitting chop, but the same effect. Also sounds really tricky sailing the foil because of the lift needing constant modificaiton by shifting weight forward and back. Give me a fin any day 🙂 Sheet in, hook in, straps and go 🙂
Hi Nils nice video. I have the feeling that windfoil espacially in the amateur part of the sport has not that much future as wingfoil is taking this part. In my lake you see mostly fin or wingfoil. Those who started on the foil moved from wind to wingfoil. What do you think?
Thank you Nils for this video. Although it is not based on pure measurements and mathematics, it gives a very deep study of what is really going on with the principles of windfoiling. You brought up many aspects that theoretically explain the hydrofoil phenomenon and you helped me to put my thoughts in the right order. I appreciate your work and I am expecting your next video with much anxiety.
I could imagine having something like flaps on regular airplane wings that help to create more lift when flying at low speeds. On your foil, you would have an ultra thin wing with as little drag & lift as possible, optimized for the highest speeds. With the flaps in their retracted state, the wing does not provide enough lift to get you flying, so then you extend the flaps to create more lift. Once you are flying, you can retract the flaps and you are left with the exact right amount of lift for super high speeds. I think only by being able to interactively adjust the lift / area / angle of attack while flying, it's possible to reach more speed because even still now, sailors fight with foils' stability at high speeds. Also IMHO, we need a self-stabilizing height adjustment system to provide more even flights, kind of like the auto correction system on moths to help prevent the foil breaching the surface. The problem right now is that if a human tries to counteract to a potential crash, it sometimes causes an oscillation and instead of correcting the mistake, it amplifies the spikes due to a small delay / reaction time. Then a crash cannot prevented. No human can react faster than a machine sensing and acting at almost light speed with micro corrections of flaps. Imagine flying on auto-pilot and it automatically checks that the fuselage is at the correct depth. Additionally, you could have a gyro on your board to make the board, sail and foil have an ideal / stable angle. I am pretty sure something like this will come eventually, the more the PWA will become like F1. 😆The sailor could also have some buttons on the boom to adjust the lift of the foil, similar to an adjustable outhaul but instead of finetuning the sail, they can finetune the foil. So on a reach, they set their wings on less lift for maximum speed and before the jibe, they set it to more lift to get maximum stability during a slow maneuver. This would also provide brands with an opportunity to charge even more money to the average sailor and make the whole sport even more technical. win-win!🤣 If any brand needs ideas, please contact me, I have tons more what could be tried and tested. 😂
Hey Nils! Thanks for the video. At 15:22 - you leaning back feels unnatural. I do know how unstable the foils become from 30kts upwards. I also understand that is a hell of a wind you are sailing with this big of a sail. But it is doable. What i can always recommend is that if you pass lake garda, pay the guys at vascorenna a little visit. You can always show them and they will tell you what they would change. Nothing wrong in getting more opinions.
So adjustable wings is the next thing i guess. That it is Automatically adjusting by for example a spring system that is easily inter changeble by spring strengths you can choose depending you weight. So you can lean back like windsurfing again 😂
Interesting material. I wonder if the efficiency of the foil might be appreciated more if the wind speed were limited. Which is fastest in 10-15 knots of wind might be more applicable and interesting to the average sailor. Personally, I find foiling to be not so much fun in overpowered conditions but being powered just enough to fly and then dialing in the forces for speed is where it shines.
Its interesting. I think it will take a lot of £££/€€€/$$$. When I started foiling I thought I'd never go faster on a foil of any description than my largest windsurf board and sail a 125l/80cm and 8.5m, and I havent yet. As a freerider 8.5m Ezzy 2 cam with 25 knot 10s average. Best on the foil is 22 knots 10s average with a 6m, on a Phantom freeride mast with 730 slalom foil. The local hot shot slalom sailors havent gone faster on any foil setup then they have done with 8.5m slalom sails on large slalom boards - 140l/85cm size. I see Jenna Gibson has a new PB at Sotavento, 28.91 knots 10s average in GPS-Speedsurfing. I'll check if she has gone faster on her big slalom kit.
One has to also consider the Water state, generally only very high speeds with windsurfing can be achieved with smallish boards and fairly flat water, soon as the water gets choppy and wavy then it’s much harder to go very fast with a windsurfer and the foil boards have and advantage with smoother rides as well as needing less wind to get planning vs much larger sails, swings and roundabouts lol. I have sailed with Vincent and he’s insanely fast and fastest person I believe at at West Kirby, enjoyed watching 🥳🥳🥳
Well on powerboat, foil can't by any mean win over skimming boat, because they gave less drag at high speed, why you would need foil if you already almost not touching water ?
Ive been wondering whether a different geometry might be possible that makes breaching less severe. Maybe a small second wing below the main one or v shaped foil wing. If you knew that breaching wasnt going to be catastrophic you could push much harder like on the fin. The foils need to get smaller too, if you add up the area of all the surfaces of the foil, its probably more then the area of a fin + board tail. For flatvwater speed ive been wondering whether you could have a very smal low level foil an a board that is very low drag when it touches down with massive tail cutouts. And then you would be just skimming the surface full power......i think there are still a lot of possibilities for experimentation that arent electronic or mechanical control systems.
Biegsame Foils könnten die Zukunft sein. Also ähnlich wie ein Formel 1 Frontflügel. Dann könnte der Auftrieb verringert werden, wenn man schneller ist.
Silly questions: doesn't the large distance between the sail and foil masts induce its own drag in the water? Doesn't it also generate considerable torsional forces, requiring the design of hyper-rigid foils? Are shortening this distance, or even the idea of a double front-back foil, stupid?
What about a foil mast with 2 levels of foils. So that when you are getting up to speed, you have 2 levels in, and then once you are going faster, you have just one? And the different foils could be tailored to the different speeds.
how about a "V" foil as an alternative to T foil? the faster one goes the faster the V goes up with less induce drag or profile drag. BTW, thank you very much for your effort creating this video
The problem I’m quickly seeing is the lift of the foil profile is speed dependent. Therefore to go faster you’d need a profile that is very non-aggressive which would provide next to no lift at slower speeds. This would likely require getting towed in by someone to get started, even with higher winds. The other option being a dynamic or variable lift foil which theoretically would be ideal but in a realistic application, would be bulky with motors creating more drag in the water thus limiting top speed.
the question is if it would still count as a speed record if you need to be towed in to get started... but i think there is a lot more room to build wings with less lift and drag as the current smal wings can still easily be started
i use my Foil like a Fin in gusty conditions as i keep my board down like old school planing... to me the sound of a board planing is the best especially on a Slalom Board.. i can get away with this as i got the Original Neil Pryde AL Death Foil.. PMSL as it knows no Limits.. just Damn Scary
Cyclists know that around 25Kph (≠13,5kts) aero drag is the biggest drag you have to fight with. Same on windsurf, whatever they use a fin or a foil. The rig has to be more streamlined with a better aspect ratio, the rider has to wear a streamlined suit and helmet and more… It is a minimum, IMHO. Very good analysis, by the way.
the problem is not the foil stability. The problem is the all gear stability. Formula kite is much more faster than windfoil. The foil is similar, but the gear is very diferent so you get the stability
But foil in the competion nowdays is superior because of the increadilble lift which makes it fast at slow speeds i.e. the jibe of lulls of the wind. In top speed on the course there is no real advantage with the foil, or has this really changed?
Average speed is higher. As well in freeracing and freeriding. In a few years they reached topspeeds over 40 knots. How much years were needed on fin to achieve 50 knots +?
cool story bro wait and see .. every single damn thing in this world has ups and downs .. foil is for ladies who cant push the fin . nuff , said , now go trim your front wing , get catapulted , and get back and trim it back again till you go like goyard ... gimme a break now fuck off would you .
depends on the conditions but generally yes, average speed is higher, took fin a while to get to 50 knots, who knows, maybe the foils will get there, like i said it's just my opinion that it will not be achieved...
Nice analysis, Nils. I think you are right that we are getting to the point where dynamically controlled foils would be needed to push more speed
Really good explanation of the differences, at the start of the video i was thinking the energy from the wind used to generate lift must be a contributory factor in terms of limiting conversion of wind to top speed. Any consumption of energy produces a drag, even the generation of sounds consumes energy reducing speed and effectively becomes drag 🙂 Not as obvious as the board hitting chop, but the same effect. Also sounds really tricky sailing the foil because of the lift needing constant modificaiton by shifting weight forward and back. Give me a fin any day 🙂 Sheet in, hook in, straps and go 🙂
Hi Nils nice video. I have the feeling that windfoil espacially in the amateur part of the sport has not that much future as wingfoil is taking this part. In my lake you see mostly fin or wingfoil. Those who started on the foil moved from wind to wingfoil. What do you think?
Thank you Nils for this video. Although it is not based on pure measurements and mathematics, it gives a very deep study of what is really going on with the principles of windfoiling. You brought up many aspects that theoretically explain the hydrofoil phenomenon and you helped me to put my thoughts in the right order. I appreciate your work and I am expecting your next video with much anxiety.
I'm glad you enjoyed it so much :)
I could imagine having something like flaps on regular airplane wings that help to create more lift when flying at low speeds. On your foil, you would have an ultra thin wing with as little drag & lift as possible, optimized for the highest speeds. With the flaps in their retracted state, the wing does not provide enough lift to get you flying, so then you extend the flaps to create more lift. Once you are flying, you can retract the flaps and you are left with the exact right amount of lift for super high speeds. I think only by being able to interactively adjust the lift / area / angle of attack while flying, it's possible to reach more speed because even still now, sailors fight with foils' stability at high speeds.
Also IMHO, we need a self-stabilizing height adjustment system to provide more even flights, kind of like the auto correction system on moths to help prevent the foil breaching the surface. The problem right now is that if a human tries to counteract to a potential crash, it sometimes causes an oscillation and instead of correcting the mistake, it amplifies the spikes due to a small delay / reaction time. Then a crash cannot prevented. No human can react faster than a machine sensing and acting at almost light speed with micro corrections of flaps. Imagine flying on auto-pilot and it automatically checks that the fuselage is at the correct depth. Additionally, you could have a gyro on your board to make the board, sail and foil have an ideal / stable angle. I am pretty sure something like this will come eventually, the more the PWA will become like F1. 😆The sailor could also have some buttons on the boom to adjust the lift of the foil, similar to an adjustable outhaul but instead of finetuning the sail, they can finetune the foil. So on a reach, they set their wings on less lift for maximum speed and before the jibe, they set it to more lift to get maximum stability during a slow maneuver. This would also provide brands with an opportunity to charge even more money to the average sailor and make the whole sport even more technical. win-win!🤣
If any brand needs ideas, please contact me, I have tons more what could be tried and tested. 😂
Hey Nils! Thanks for the video.
At 15:22 - you leaning back feels unnatural. I do know how unstable the foils become from 30kts upwards. I also understand that is a hell of a wind you are sailing with this big of a sail.
But it is doable. What i can always recommend is that if you pass lake garda, pay the guys at vascorenna a little visit. You can always show them and they will tell you what they would change. Nothing wrong in getting more opinions.
So adjustable wings is the next thing i guess. That it is Automatically adjusting by for example a spring system that is easily inter changeble by spring strengths you can choose depending you weight. So you can lean back like windsurfing again 😂
Interesting material. I wonder if the efficiency of the foil might be appreciated more if the wind speed were limited. Which is fastest in 10-15 knots of wind might be more applicable and interesting to the average sailor. Personally, I find foiling to be not so much fun in overpowered conditions but being powered just enough to fly and then dialing in the forces for speed is where it shines.
💯 on point
Its interesting. I think it will take a lot of £££/€€€/$$$. When I started foiling I thought I'd never go faster on a foil of any description than my largest windsurf board and sail a 125l/80cm and 8.5m, and I havent yet. As a freerider 8.5m Ezzy 2 cam with 25 knot 10s average. Best on the foil is 22 knots 10s average with a 6m, on a Phantom freeride mast with 730 slalom foil. The local hot shot slalom sailors havent gone faster on any foil setup then they have done with 8.5m slalom sails on large slalom boards - 140l/85cm size. I see Jenna Gibson has a new PB at Sotavento, 28.91 knots 10s average in GPS-Speedsurfing. I'll check if she has gone faster on her big slalom kit.
You have one error, lift (and drag) doors not increase linearly with velocity.
F = CL * A * ρ * V² / 2
One has to also consider the
Water state, generally only very high speeds with windsurfing can be achieved with smallish boards and fairly flat water, soon as the water gets choppy and wavy then it’s much harder to go very fast with a windsurfer and the foil boards have and advantage with smoother rides as well as needing less wind to get planning vs much larger sails, swings and roundabouts lol. I have sailed with Vincent and he’s insanely fast and fastest person I believe at at West Kirby, enjoyed watching 🥳🥳🥳
Well on powerboat, foil can't by any mean win over skimming boat, because they gave less drag at high speed, why you would need foil if you already almost not touching water ?
Ive been wondering whether a different geometry might be possible that makes breaching less severe. Maybe a small second wing below the main one or v shaped foil wing. If you knew that breaching wasnt going to be catastrophic you could push much harder like on the fin.
The foils need to get smaller too, if you add up the area of all the surfaces of the foil, its probably more then the area of a fin + board tail.
For flatvwater speed ive been wondering whether you could have a very smal low level foil an a board that is very low drag when it touches down with massive tail cutouts. And then you would be just skimming the surface full power......i think there are still a lot of possibilities for experimentation that arent electronic or mechanical control systems.
always used to fascinate me Foil Vs Fin on the pro circuit those things were flying
Great technical analisys. Which do you you think the sailor weight should be for speedsailing?
thanks, above 90kg is good i think
Biegsame Foils könnten die Zukunft sein. Also ähnlich wie ein Formel 1 Frontflügel. Dann könnte der Auftrieb verringert werden, wenn man schneller ist.
wäre interessant ob man mit sowas genug stabilität hätte...
Silly questions: doesn't the large distance between the sail and foil masts induce its own drag in the water? Doesn't it also generate considerable torsional forces, requiring the design of hyper-rigid foils? Are shortening this distance, or even the idea of a double front-back foil, stupid?
What about a foil mast with 2 levels of foils. So that when you are getting up to speed, you have 2 levels in, and then once you are going faster, you have just one? And the different foils could be tailored to the different speeds.
there are V or U foils with this purpose, would be interesting to try a concept like this
how about a "V" foil as an alternative to T foil? the faster one goes the faster the V goes up with less induce drag or profile drag. BTW, thank you very much for your effort creating this video
The problem I’m quickly seeing is the lift of the foil profile is speed dependent. Therefore to go faster you’d need a profile that is very non-aggressive which would provide next to no lift at slower speeds. This would likely require getting towed in by someone to get started, even with higher winds.
The other option being a dynamic or variable lift foil which theoretically would be ideal but in a realistic application, would be bulky with motors creating more drag in the water thus limiting top speed.
the question is if it would still count as a speed record if you need to be towed in to get started... but i think there is a lot more room to build wings with less lift and drag as the current smal wings can still easily be started
i use my Foil like a Fin in gusty conditions as i keep my board down like old school planing... to me the sound of a board planing is the best especially on a Slalom Board.. i can get away with this as i got the Original Neil Pryde AL Death Foil.. PMSL as it knows no Limits.. just Damn Scary
Cyclists know that around 25Kph (≠13,5kts) aero drag is the biggest drag you have to fight with. Same on windsurf, whatever they use a fin or a foil. The rig has to be more streamlined with a better aspect ratio, the rider has to wear a streamlined suit and helmet and more… It is a minimum, IMHO. Very good analysis, by the way.
Does the wings need to flex? If not, a square U might be an idea, like an upside down rear wing on a car.
Thanks for such a good video :)
the problem is not the foil stability. The problem is the all gear stability. Formula kite is much more faster than windfoil. The foil is similar, but the gear is very diferent so you get the stability
But foil in the competion nowdays is superior because of the increadilble lift which makes it fast at slow speeds i.e. the jibe of lulls of the wind. In top speed on the course there is no real advantage with the foil, or has this really changed?
Average speed is higher. As well in freeracing and freeriding. In a few years they reached topspeeds over 40 knots. How much years were needed on fin to achieve 50 knots +?
cool story bro wait and see .. every single damn thing in this world has ups and downs .. foil is for ladies who cant push the fin . nuff , said , now go trim your front wing , get catapulted , and get back and trim it back again till you go like goyard ...
gimme a break now fuck off would you .
depends on the conditions but generally yes, average speed is higher, took fin a while to get to 50 knots, who knows, maybe the foils will get there, like i said it's just my opinion that it will not be achieved...
it doesnt help that you still cant adjust the foil box position in a wind foiler like you can on a wing foiler
we tried that, doesn't really help, seems the current position is the best.
how about the kites? which is top speed regular or foil?
around 45kts on foil, 57,97 on regular, so also around 13 knots difference
@@WindsurfingNils wow not much faster than windfoil.
??????? So I am wrong in thinking foil sailboarts can go faster than windspeed ?? You said foils hadn't broken any speed records in sailing ?????
Foiling can travel much closer to the wind than conventional windsurfing when talking race courses
for sure, in race courses it's much superior!
Oh, too late… But: Moin Nils!
delayed Moin back to you Thomas ;)
There will be no speed record on foil. I fully agree with your arguments.