In this video we explain how hydrofoils work. Believe it or not, most of the common explanations of how hydrofoils work are incorrect or incomplete at best. We'll take you through the misconceptions and share an intuitive, easy to understand explanation of where lift comes from. Enjoy!
Special thanks to following channels for making their content available for re-use under creative commons license:
• Dock Step Off Foil Rod...
• Aquila Hydro-Glide Foi...
• Stealth Volga
• Riding small boards is...
___
Gear we use + discount codes: www.ourkitelife.com/p/gear-we...
"We talked to aerospace engineers and we watched University lectures on fluid mechanics"... you guys are truly next level!
@Sky Man You sound like someone whose very insecure in their intelligence. You dont have the capability to actually understand the science and the math so you start making absurd claims with no evidence backing it up. You're so desperate to convince yourself that you have it all figured out and that the people who were able to actually dedicate themselves to science are a bunch of fools. How sad and pathetic lmao
No they're not next level. If they talked to aero space engineers they talked to the wrong people, because we are talking HYDRO foils and NOT air foils. Water is incompressible and so using the air foil analogy is TOTALLY incorrect. If they talked about an aircraft in supersonic flight, they would be closer to getting the technical explanation right. Ignore everything she said except for the part about changing the flow direction of water, because that is where the lift occurs. She forgot to mention you can never have just one foil either. They always come in pairs. Leading foil and trailing foil to maintain balance - without 2 foils, instability would occur.
@@gerhardkutt1748 Thank you for injecting a little reason into this blur of confusion, including that of the presenters.
@Sky Man dude, have you ever even scienced? Every word you posted increasingly showed how unaware you are of how it works. You, my friend - and I don't mean this perjoratively - are a textbook case of the Dunning-Kruger effect. And on a side note, doing research shouldn't not be something commendable, it is expectable... If you believe anything without sufficient evidence, you're being irrational *by definition* . I'm not educated on the matter and don't know anything about @Gerhard Kutt 's comment, but this seems like a good demonstration of how easily we can fall for the argument from authority fallacy, and ignore the fact the people who research things "for us" are also fallible.
@Sky Man Glad you liked it!
I love how easy it is to just randomly stumble upon a great video.
Nice work. As an engineering analyst I didn't expect you to explain this so well. We can't even agree on how it works! Luckily there has been significant empirical data gathered for our home shaped hydrofoils to be developed from. I'm enjoying putting my work into my pleasure, shaping boards and foils to work that much better. In 1996 I was flying a home built personal hydrofoil on Lake Tapps outside of Seattle while working as an analyst to Boeing. My lovely family put me off for 25 years, but I'm back at it, kite foiling and wing foiling with an amazing crew down here in NZ! Woo-Hoo!
Thanks Greg. Glad you are back to foiling and from what we know there is a lot of wind in NZ, kind of jealous.
Whats a decent low budget wing foil setup?
I'm 30 min from lake tapps! Beautiful lake
Holy cow! You guys are raising the bar for all other kiting channels!! I didn’t expect to be taken back to my chemical engineering fluid flow class but enjoyed your academic explanation nonetheless!!! Nice work and keep the educational videos coming. The technical aspect of this sport can be intimidating at times but it’s also what makes it so cool! Thanks so much for your work on your channel.
that was the most complete explanation of dynamic lift I've ever experienced. Excellent work!
I was thinking about designing a mini hydrofoil for a project, but needed info on how exactly they worked so that I would make one that was effective. This video was 100% perfect and did a phenomenal job answering all of my questions, and some I didn't know I had! Bravo, great stuff all around!
Fascinating, well presented. And to think, I put a kayak up on a submerged foil around 1960, but I could not paddle so fast for long. I still remember tying a line to the kayak and having a person tow me onto the foil for a sustained ride. As soon as the kayak popped up on the foil, he went head over heels as the foil abruptly reduced the load on the tow rope as it lifted the kayak above the water. I went on to fly possibly the first of what is called the Rogallo Wing and it"s motorized form, the trike. I could have stayed with the hydrofoil!
with dc motors and batteries of today i am sure a double v surface piercing foil on a kayak would work with the motors at the bottom of the v but i know i will never get round to it but at least you tried bravo
And in the end, I am always blown away at the thought that the relatively small main and rear wings can generate enough lift to push not only the board but the weight of my body up and out of the water. Fascinating!
Thanks for the comparison of the different explanations/factors for lift. One thing not mentioned is the general shape of a wing: it is a stretched teardrop (teardrop is the most aerodynamic shape). A straight "stretched teardrop" that has the trailing edge lower in the airstream would get lift because of the angle of attack alone (1) (like sticking your hand out the car window, due to molecular collisions, pressure differential, or whathaveyou). A flat board would also receive such lift, but it wouldn't slide through the wind as well as the straight-stretched teardrop shape. We don't often see such zero angle-of-attack straight "stretched teardrop wings, though. ... Stretching the top side of the teardrop while keeping the bottom straight and while keeping the angle-of-attack at zero degrees (2) would also provide lift (due to the Bernoulli effect), but we don't see this alone often either. Combining 1 and 2 gives more lift than either one alone. ... You can also see from the blades of a household electric fan that the local angle of attack increases as air moves over the blade. The inside of the curve of the blade gradually pushes harder and harder on the air molecules as the airflow gets pushed more and more. I don't know if this is force (3) from my above analysis or just an aspect of (1) and (2) twisting together. ... And when an airplane flies upside down, the angle-of-attack has to be increased enough to overcome the downward "lift" caused by Bernouli effect of the longer bottom side of the wing (and the curved shape, I guess). This is why such flights are slower and require more engine power to execute. They're inefficient and always at near-stall.
Planes that are designed to fly upside down have much more symmetric aerofoils, often with much less camber - they will also have adapted empennage to allow the presevertaion of a (relative) positive angle of attack on upside down flight. A modern commercial simply would not be able to fly upside down (or not very long atleast without greatly exceeding ultimate loading specifications in the tailwing)
Laurie went HARD on hydrodynamics, and I love it. I knew most of these principles already - and BTW the full explanation for lift is all of the above (to varying degrees in different flight regimes) plus compression lift at trans/supersonic speeds - but it's really cool to hear it from a kiteboarding expert's perspective.
I wouldn't say she went HARD on it, as I didn't see any formula or equations, but still it was a good vulgarisation
I never knew what was under those cool floating surfboards. Always thought it was a motor. Great physics lesson.
Thank you, I have never quite understood hydrofoils. I can only learn by seeing, so descriptions are just words that mean things to everyone else. You taught someone something today
Great video Yuri and Laurie! I’m sure a ton of research and work went into this one. Great comparisons of the 3 theories (with great visuals) which provide a good understanding of the aero/hydrodynamics associated with foil lift. So, should we anticipate the next step will be about the impact foil shape has on lift, drag and speed? Well put together guys, keep them coming! 👍👍👍😀
You could be a great professor!! 😅. Remember studying this during Wind design for buildings. Awesome content.
Thanks! 😄
This video confirms what I have thought about lift for about 50 years. I never believed the first explanations, and this seems to me to be so obvious. Thanks! I feel vindicated.
This video reminds me studying for my professional license of Engineering. Solving problems using the Bernoulli equation to find pressure head.
yeah, same.
I use these equations every day
Much, much, more information then I set out to look for... but I watched it all because it was engaging, informative and well put together. 👏🏻
Excellent video. I'm not an engineer, but understood a good amount of this. It's really refreshing to see people make the effort to understand and explain, kudos.
Your explanation is compensative. I was just looking for an explication on this subject after viewing the America's Cups yacht races. Thank you.
Love your videos! Thanks for taking the time to dig into topics with method and persistence. Great fun watching and learning.
Thanks Tomas, glad to hear you enjoy our videos. Cheers!
Excellent narrative and explanation. Really well done. Would love to see a 2nd part dealing in more detail with upside down wings and flat wings.
great video! re: planes flying upside down, fwiw, when flying an RC model plane upside down, you typically have to add a bit of elevator angle to counteract the 'downward' lift being generated by the inverted wing. Probably similar in real life.
Inverted flight also uses Newton's 3rd law, not Bernoulli Effect (or you'd crash). Wing's optimum Angle of Attack is ~4-5°, so when flying inverted you also create a 5° AoA by pushing forward on the yoke, elevator down ( now "up") to point the inverted wing upward. Takes practise because it's counter-intuitive. (Old PPL pilot, C152, and engineer).
By adding down elevator when inverted, you are effectively increasing the angle of attack, which then creates lower pressure and lift on the bottom of the inverted wing. Inverted R/C planes that do not have symmetrical wings do not fly great inverted as you are often flying on the verge of a stall because of the angle of attack.
I was extremely impressed with the quality, presentation style, editing, and thoroughness of the video. You guys are going to have hundreds of thousands of subs one day, and honestly ya'll could broaden the target audience and you'd 100% succeed.
Thank you 🙂
@@OurKiteLife the announcer voices confidence, poised yet delicate, carefully refined with hard facts, this girl knows what she is talking about, in contrast to other outta touch who simply voice read words.
Cool cameo by Rod Parmenter of Foil Buzz at 1:27! (His '87 classic VHS "Hard Winds a Blowin" drew me to the left coast in search of nuking winds decades ago).
Excellent video! I'm about to move to a beach town with a small season for surfing, windsurfing and kite boarding, so I've been looking into wing surfing. This video is very informative and clear. Subscribed!
Thoughtful, intelligent, complete. Thank you!
Keep going guys! At this rate you'll be the number one kite channel in no time... Thumbs up! Great video.
Thanks so much 🙂
OMG! The first video I've seen that actually get's the physics of wings correctly! Well done!
Keep in mind that streamlines do not reach the end of airfoil at the same time. Look for Holger Babisnky's explanation on how airfoils generate lift, for more knowledge. PS: airfoils work virtually the same way as hidrofoils.
>> Keep in mind that streamlines do not reach the end of airfoil at the same time. I'll bet that's why she said exactly that.
I've been working with wings since the late 80's. We talk about this constantly, and i've never seen a better, clearer explanation. I kept wait for you to leave something out like AOA, but nope, covered, not only covered but gave the ratio's as well. Will be bookmarking and sharing this as the number one best explanation for how wings work, especially when thicker skulls insist on arguing. Brilliant.
Thanks Dean
This video was clearer than any fluid mechanics textbook in the world
Thank you for the video!!! Was really searching for a good explanation and you did it. Can’t appreciate it enough
Thanks, glad you liked it!
A really great explanation of how this works!
Excellent content. So valuable and well researched. Thank you
Very refreshing to not just hear the canned explanation with no thought behind it if it actually makes sense. Great job!
Well done. Great summary. It's like myth busters for kiters. Often wondered if it was angle of attack forcing water down or shape of wing for lift ... Or a combination of a bit of both.
Finally, I found an explanation! Thank u.
Appreciating your hard work!
I was thoroughly excited watching this.
Nice to see the Bell and Baldwin HD experiments getting a shout out. In fact they did a ton of experiments with kites as well that led them to form the AEA and become some of the first humans to fly. Happy to report, some generations later their great grandkids are still flying kites and riding foils, often at the same time. I think if my great grandfather was alive today (F.W.Baldwin) he would be a kite-foiling nut for sure.
no way, your great grandfather was Casey Baldwin?
@@OurKiteLife Yep. Quite a legacy he left. A born and raised Torontonian as well. We still see the Bell family when we visit Baddeck, and we laugh about how excited him and Bell would be to see me out on the water with my kite / foil.
Great video; I appreciate the fact that you took us through the different explanations and research points. Thank you.
amazing description, I really like this kind of video. good job to the team who made this. thanks
This is the first solid presentation explaining lift in its various theories and finally a solid visual and clear theoretical explanation of it. You guys are amazing! Thank you!
This is the best explanation on youtubue of hydrofoils, thank you.
Im Building a hydrofoil rn and this vedeo helped me a lot, thanks : Ofc I subscribed👍
Wow that was comprehensive great job
Great explanation. Did not expect that!
i absolutely love this channel! So much info in a easy way to learn.
This is well done! Entertaining and educative. Thank you
Thank you 🙂
If you ever try wakeboarding, on the take off, it's best to point the board to the side a bit or you will be fighting the high pressure force from under the board when pointing towards to boat. The shape of a wing can exaggerate this effect to generate lift. Nice video on this topic! In science I think air and water are considered fluids.
For any Fluid Dynamics expert The vorticity generated by the boundary layer deflects downward the flow and for the conservation of momentum the wing is pushed upwards NO DEBATE
Wow you really did your homework...Wonderful.👏 Thank you !!
Love watching your videos!!
Bell didn't invent the telephone, he just marketed it, Antonio Meucci was the inventor
he didn't invented the telephone neither the hydrofoil since Forlanini and Crocco already build 2 different hydrofoiling boat in 1906 and 1907 while Bell arrived in 1912
@@marcofrancioni1155 All great inventions had been made in the "greatest country of the world" - where else?
Baal ....
Meucci FTW
@@mucsalto8377 LOL
Thanks for this great explanation. The Bernoulli explanation I was fed at Engg school caused a lot of confusion as it is a complete abstraction from intuition and every day experience and a very inadequate explanation as you point out in your examples which could also include canvas wings. The top of the wing induces suction which in the extreme case in a liquid medium results in Cavitation . This explanation links lift and Cavitation. Great Job and thank you.
Nice video. Must point out that the ones well described here are not “different theories of lift” instead they are individual explanations of the various forces acting on a wing all together creating lift.
I know bro but it's a chick doing it so don't expect much lol
Best explanation so far .
wonderfully researched. Great explanation!
Thanks Fred 🙂
I'm an engineer and I learned something by this video - very impressive
Thanks! Happy to hear :)
New video!!! How much am I waiting for these videos
best ever explaination ❤️ thank you so much for wounderful information 👍🏻💐
Many thanks for this explanation video. Have a nice day.
This is great. I think I've done most of the same research you guys did to make this video, and this is probably the best simple-ish explanation I've seen. Everything else is either so simple as to be wrong (usually covering just the first "equal time" idea from this video) or requires a math degree to understand. You guys did a great job with this. Also, you got my friend Rod downwind foiling here in the Gorge in there, which is cool, too. :)
Thanks Tyler. Good to know his name now, Rod, as we used creative commons clips in this video. That particular clip I believe was from foil buzz
@@OurKiteLife Rod (with a 'd' 😉) Parmenter.
Well produced video I was looking for something that explained hydrofoil but I kinda think the airplane lead was unnecessary. There are major differences with the interactions of rudders, ailerons & wings. I get that they are wing like and provide lift. I would have liked to hear what some challenges that builders had to overcome before finished products. But it still helps me understand more
The best explanation for wind over wing.
The best and informative kite channel in the world.
Our Kite Life and OK Kiteboarder are the most amazing KZhead kite channels.
Thank you 😊
Well, that was enjoyable. I follow a lot of science explanation videos on KZhead, and not any kite surfers, so it's interesting that KZhead knew to recommend me this video.
nice presentation made it easy for old guys to understand
Nice explanation. Well done.
Science geeks! I love it! :-) By the way, before using the term "geek", I searched the web and attended university lectures. I found three definitions, but most experts agree, a "geek" is "a knowledgeable and obsessive enthusiast". I think the definition fits.
From one geek to another, I totally agree! I'd really love to crowd source the solution to endless flight on a hydrofoil. I need everyone's help here: kzhead.info/sun/iMyMpa2bqat6dIU/bejne.html
During a dinner conversation about some rather arcane subjects, my 10 year old son said "Dad, you're such a geek - you like to think for fun"
Brilliantly explained.
Very interesting technology. It does look like a surfer is defying the laws of density when raising above water while using these wings.
Nicely done!
Thanks for educating us.
Interesting, I wasn't aware their were multiple theories on lift. thanks
Thanks for sharing!
great work! you guys are amazing!
Very nice video! It would have been nice to put your sources in the description too :)
Thanks from my heart. Very knowledgeable information 🙏
Awesome video - love your channel!
Thanks!
Wow. So impressive!! Great info and research
Thanks, glad you enjoyed it!
Amazing knowledge shared. Thanks 🙏
Awesome video. You guys are the best. ;)
EXCELLENT EXPLANATION.
Great job.
Thank you, great video. Question though, for a foil board, you mentioned the rear wing adds stability. Would you be interested in doing another video showing the fluid dynamics of the rear wing? Or how the front wing affects water currents and how the rear wing reacts to those currents to keep the board stable? I'd really really love to better understand these concepts to help me understand better what front/rear wing combo I want to either buy or make. Thank you so much!
Loved video, helped alot💪
I feel shortchanged by my physics professors! But I never went too deep into fluid dynamics.
What you did not mention is the angle of attack, which is the measurement of how high the front of the wing is tilted. A plane can fly upside down because the front of the wing is titled higher than the back, not necessary due to one side of the wing being longer than the other side. A stunt plane has symmetrical wings (they are curved both on the top and bottom). The shape itself generates no lift, but because the wings are tilted in the direction of travel, they generate lift.
Wow! exelent works! Well done. As a aviation engineer a jast may ad that airplanes can fly down turns becouse the wing has special set of angle off attack. And you can believe or not but a lot of acrobatic airplanes has symmetric aerodynamic profile. So very professional video! My congratulations! I spent a lot of time choosing my fist hydrofoil 633 Moses Onda. Hydrofoils exactly like aircrafts all has own shape and purpose))) and the flight filings so exacting isnt it ?)
Thanks for your comment Andrew. We were actually contemplating on trying foiling with the hydrofoil upside down, but decided not to bother as when we dug deeper only certain planes can fly upside down, mostly with symmetrical wings.
Very cool, thanks!!
I loved the the video and, I need to say, what a beutiful tiny eyes girl! She is mesmerizing! :) Hope this channel grows a lot!
Thank you 🙂
This gives me ideas. Thanka
Much love to you guys. ❤
As a mechanical engineer, I just wanted to say…great video!!!!
Great video, thank you for research!! But I can’t believe you did not even mention efoils :)
We almost did just had no b-roll and the sentence was getting long. When we mentioned foil being powered by engines, sail or momentum. Now as I am thinking about it, e-foil would classify under engines... :) But yeah should of mentioned
As a fluid mechanics PhD and Aerospace engineer I went into this video with trepidation that you’d point to an incomplete/flawed explanation like Bernoulli’s equation which is a specific simplification of the energy equation that can be made under very specific circumstances. I was extremely relieved to see that your explanation focused on conservation of momentum an generally agree with almost everything you said, well done! My only concern is the assertion of a lack of understanding or consensus among scientists and engineers-the bottom line is you need at least all 5 Navier Stokes equations-conservation of mass, conservation of x, y & z momentum and conservation of energy-to fully describe real fluid flow around 3D foils. It’s very complicated and usually impossible to solve with pencil & paper but there is a general understanding.
I appreciate this video. I LOVE the science.
Quality content 👨🎨 Thanks for As a tip do add time stamps 😉