America's Cup Foil Problem and the ETNZ Rule Loophole
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- čas přidán 8. 07. 2024
- Americas Cup foil design is complicated and the winning design may be hiding behind a controversial rule interpretation.
This video aims to set a 'base' to describe the foil design challenge, behind purely hydrodynamics. We shall be following up with detailed analysis of INEOS Team UK, American Magic, Luna Rossa and of course Emirates Team New Zealand.
Thanks to Weta27 for the great photos.
#AmericasCup #MozzySails #LoyalToTheFoil - Sport
You guys are the gold standard of commentary this cup. Well done.
Nathan is the gold standard. These guys are great to learn from also
Massive thanks for the massive effort put into this and your other AC videos, especially when you have a day job. Very informative and really adds to the enjoyment of these fabulous boats and racing.
good job. you are addressing questions I have not completely formulated. appreciate the bump!!
love the videos, really effective breakdown and great to watch
your analysis is brilliant - makes the whole regatta so much more interesting!
Very interesting. Thanks.
You guys have a great Chanel here. Love your in depth analysis👍👍
Awesome video! Thanks for the insights. Loved being able to see you talk about this stuff as well, as opposed to watching a still image. Keep the content coming!
Awesome, thank you!
MORE CONTENT!!! I couldn't agree more with others here; your analysis is so brilliant! I'd like to learn a ton more from you and your guests.
Loving this detail - Huge effort - thanks tons
Excellent really enjoy your discussions
Interesting material to say the least, however, its not only the foils at play here, that is just one dynamic. ETNZ were ahead of the game, in the last Americas Cup when it came to foiling, so I would not imagine that they would do anything illegal, as that would be against their own ruling. Interpretation is different by every team, and you saw the English boat go through massive changes to be more in sync with the kiwi boat, after the Xmas boat, and before March you will see more changes coming out completely on all boats. It's just a pity there aren't more racing. American Magic are very quick, and the puffy conditions on Auckland harbor might just suit them. Be careful not to over think things, as theres a powerhouse above the waterline as well.
these boats are just amazing and super exciting to watch, what a success of a regatta so far. Great video , foils are so new to all of us so these sorts of discussions are really valuable.
Great explanations. Keep them coming. Well done.
excellent area to look at, really the key , like f 1 and the tyres as these are the bits that transmit the forces so huge impact on performance
Foil development is fascinating as are twin skin sails which are also worth looking at in detail. The sails are particularly interesting because they could be fitted to a conventional boat with huge improvement, while foiling of course requires a whole new boat underneath the mast.
I'm a sailor and a glider pilot and for years have been disappointed that sailing seems to be so far behind the huge steps gliding has taken in aerodynamics since the use of firstly GRP and later carbon fibre/Kevlar as construction materials. At last, the technology is finally on a course to diverge as it should have done many years ago.
So to the foils. Well we have different Reynolds numbers to deal with in gliding. In other words the viscosity of water is greater than air, but the cruising speed of a fully loaded modern glider which sits at between 80 and 110 knots of airspeed with high wing loading means the issues of induced drag, laminar flow, boundary layer turbulation, pressure leakage, camber changing flaps and wing tip vortices are very similar. Glider wings are a compromise between low speed and high speed flight. Exactly the same for foils. I'll be very interested to watch your next video and keen to comment where I can.
Great explanation . It's that sixth in the Topper Worlds which gives him such an air of authority.
Well done on some fantastic content and insights, keep it coming. Really intrigued by the interpretation of the laws here, specifically the direction ETNZ have gone. I agree, I don't think this is the last we will hear of this! It would be fantastic to get your perspective on the development changes the challengers have room to consider between the 24th Feb (Oooh Controversial) and the start of racing for the cup!
Loving these new AC missiles and loving your in depth analysis, very much appreciated.- Penzance SC
The best sailing channel by far. Tnx Mozzy !
Auckland. NZ
Super informative. Thank you 🙏🏼
Great series... keep it up!!
👍 Mozzie, that's a great background on the complexities of the foil system, especially for those who haven't spent the past months figuring this out! `
Thank you! Cheers!
Cool insight there Mozzy. The Kiwis are - or has someone who is - incredibly clever at taking a rule then thinking around it to come up with an interpretation that's a game changer. So the 2013 Cup boats, the mega cats, weren't meant to foil, the foils themselves weren't meant to move around, but they sidestepped that by moving the whole foil casing around and coming into that Cup with a massive speed advantage. My guess is that the same genius probably wrote the rule you're looking at here, and has come up with a pretty flash work-around, which you're alluding to. Looking forward to your next vid!
Thanks for the work your putting into this, like you I get frustrated with the commentary lack of depth. But that said the commentator job is to (kiss) inform newbies as well. Glad we’ve got you to guide us “under the hood”.
excellent analysis, thanks
Keep them coming, brilliant content!!
Tom, great videos, your Engineering back ground is coming to the fore. You have moved on a long way from Topper sailing at Nantwich. All the best in the analysis of tactics & boat technical performance in the upcoming America’s Cup final. David
Thanks David!
Great to see you talking
Great to have a face to a voice. Good work. Keep up the techsplaining 👨✈️🇦🇺
Very interesting analysis, good job!!!
Great Analysis. You refer to Angle of Attack a number of times... It's preferable to use Angle of Incidence when describing the angle of the foil reference plane to a fixed reference on the boat. Angle of Attack is normally used for describing the actual, instantaneous angle of the foil reference plane to the free stream. This varies constantly with boat attitude and vertical motion. Sorry to be picky!
Yeah sorry! Hopefully it's clear enough. The angle of incidence fixes AoA in displacement, as the elevator isnt doing anything and hull buoyancy is supporting the weight... but once flying the two become different as the boat can be pitched
Aha! I too have described it as "initial AoA with reference to the hull's MWP"... must remember "AoI" in future. 😎
@@maxhugen aka 'rigger's angle of incidence'...
thanks for the detailed information, well done
Really enjoyed this. Thanks. And go deeper!!!!!
much better than your previous blank screen !
Great video, on the foils we have seen some teams use different foils like you mentioned in the video. You mention this for testing. I am proposing this strategic they have one side for more lift to get the boat up and foiling and once they have enough speed to tack or jibe have the other side to set for speed.
Seems very impractical to me.
They would be stuck with having to be on the same tack direction for every unplanned liftoff, and would only be faster on the other tack.
Thanks! This is great stuff.
Great stuff yeah go for the analysis and speculation I’m loving the overlap of engineering and sailing
Thanks for digging into this, I've been hoping for a detailed look at foil arguments, and seem to have found it!
I introduced NACA sections to a number of classes back in the 1970's and 80's, here in the 'States. Fortunately, with a little therapy, I was able to overcome my boat building compulsion, and moved on to greener fields. However, I still get turned on when I hear, "fluid flow"!
Information. Very good mate
Great video...these boats are beyond amazing
Great insight
Thanks guys. Details matter.
Great video thank you
Nice analysis. Those aircraft flaps you're speaking of are called Fowler flaps, and their distinguishing feature is the increase the surface area of the planform by their extension (in addition to changing the AOA), which is what I suspect the rules prohibit, in this case.
Tom brilliant analysis, i am an Engineer and lover the techs stuff translated into Americas cup technology and boat differences , keep it up😀
Great ‘explainer’ of a deep dive. Please keep ‘em coming and nice not to have to stare at your logo while you’re talking;-)
Great analysis. It would be interesting if a community could manage to design a AC75 like a Open AC75 project.
Hi Mozzy, this video is your best yet for me, clear and concise in clearing up the developments on rules. I think you're right about this not being the last we will hear about this flap issue which is a shame because I personally don't want the cup to be marred by technical / legal challenges. I have a couple of questions I want you to stick your neck out on:
1. Do you 100% believe that INEOS will continue to use these "Delta" foils until the AC final (if they get there of course)
2. Do you think we will see any more iterations of this ETNZ foil before the AC final?
You have to wonder whether despite being symmetrical, the foils can be actuated on an asymmetric basis to say, reduce loading and the possibility of cavitation of the foil half nearest the water surface.
Very interesting indeed
Hi, I would like to share some consideration. In my point of view ETNZ have done a lot of research in reducing the surface under the water. So a T wing was the perfect chose. The projected surface to generate lift force is the same of a Y foil but with less surface/drag. What I can see is that ETNZ can adjust the wing, up or down, so the force can work also to fix the roll moment. Sail and foil can work together to generate a resultant force between the vertical and the transversal axes. Saying so, it could come out that having a limited surface area under the water and the possibility to lower or rise the drift, in conjunction with the sails, is what ETNZ is really focused. Having small wings can be dangerous only in very light winds. TY.
Well done mate very interesting!
Glad you enjoyed it
Super interesting.. all this stuff about the way the teams are exploiting loopholes is super interesting! 📷 On too👍
Outstanding foil overview . Very well done. Interested in complexities of AC rudder design rules and your thoughts about related" vulnerability to loss of control" in vertical and horizontal planes under extremes of foiling loads. Appreciate any discussion ... perhaps in forthcoming analysis?
Well done. Good on ya.
Cracking jumper action, solid video beyond my understanding!
Cheers Colin! It's cold here back in blighty!
Good effort guys. I enjoyed the discussion. As a scientist I'm always sceptical of someone saying definitively that x is because of y. Unless they can show a correlation.
you can make a mechanical device using levers on the same moving part with different movements . On a delta wing plane like a Avro Vulcan or the B-2 bomber no prob , we use to do it all the time with model scale air craft
super interesting
OMG Mate, I think you have opened up a whole can of worms with this beauty,, Love it
Let the shit show start.
As the Orange man said
if they are talking about me.....that's good,???
Seems like a rule gone mad. I might have tried writing, " The foil must have two symmetrical control surfaces that can move independently. " Now if they want they could create a foil that can move independently but also that could lock together later under sail. Seeing the motion is not a 'must be'. Thanks for the dive into the rules, pictures and diagrams it really helps show what 'makes' the boat.
(Anyone that has ever done Odyssey of the Mind or Destination Imagination understands rules are written to be challenged, overcome, but not ignored. )
They need an open category, if they don't have 1 already with no rules in regards to building of the boats. That will produce some amazing technology.
Thank you!
Welcome!
The 'flaps' are more like elevators operating on aircraft tail-plane rather than flaps which increase drag and reduce stall speed - usually for landing. I build RC model aircraft and elevators are often operated individually and in some configurations can also operate as ailerons (to control roll). I don't see how the added complexity of operating each half separately is needed or why using co-ordinated operation would be seen as a rule infringement.
Interesting talk but I would be more interested in the hydrodynamics of different aerofoils (hydrfoils?) which are of big interest in aircraft of all types - sailplanes are particularly interesting as efficiency is critical in unpowered flight.
good as ever Mozzy, thanks. anything you can do on the 'yellow card' ?
Fascinating stuff and thank you for removing that annoying silhouette.
Ineos has a keel like Admiral Nelson's boat....
Would love a video on the measuring and what defines a fine or yellow card on non compliance on non performance parts. It’s seems harsh that interpreting an opening in the main, agreed it’s non compliant but if its not performance enhancing why not just a fine. Dalton says he will review the measurement rules but surely he’s hardly impartial and non partisan!
That’s the AC for you! The Defender makes and controls the rules. The NZ team know what they’re doing here.
@@tcdossor copy that
Great insight, thanks. Are you going to do one on the rudder and the way that can modify the angle of attack of the main foils and even have some effect on the sail aerofoil shape in relation to apparant wind? Btw, much prefer seeing you speak rather than the static image.
I like mozzy... videos but go Team N.Z. Aotearoa vorever!
So accoding to Mozzy Hoyle TNZ should be vibrating madly. N crashing n burning all around th track,with their tiny edgy anhedral foils... but they're smooth as..and fast as.. why???? 😉
Very nice video, very interesting to see these F1’s running on the water. On the basis of the airfoil design and mass, I’m a bit confused, as it stated that “the portion of a mass (%) of a component, is determined by aligning the unmodified portion of the origina.... ....and determining the mass of all the regions” The way I look at it, imagen a restarle (L + H ) L = 10, H = 1, if I was to take the rectangle, ac cut. It into 10 equal parts, then it would be 10 segment L1, H1, if say the mass of these segments are equal to 1, then If I was to change H and reduce that to .5, now each segment would be L 1, H 0.5, but the mass could essential be the same. Look at it as a little box that has no weight, no mater how you scale these boxes, say H, as long as each one had a stone of mass=1 in them, then it would be compliant? That in a wing, has lot’s of room to design around... I think 🤔. What am I missing?
Glad they designed a foiling monohull. The Cats were great but America's Cup is about Monohulls I reckon!
The main underwater foils attract most of the commentary, but the rudder foils, and sails mast combination are even more complicated. I think even a 12 metre would go faster with those rigs.
Asking this question here because the other comments seem rational: what are those rectangular fairings a few metres up on the standing rigging? LR doesn’t seem to have them.
The fairings are to stop resonance in the rigging. Not sure why or how LR doesnt have them
@@MozzySails
Thanks for the quick and understandable reply.
So, like Stockbridge dampers on power lines.
Loving your videos, explanations and your input into the technicalities of these wonderful things! Please keep them coming! Engineering porn! 😎
Would really enjoy more foil comparison analysis between the teams. Curious, if team NZ win easily, could it all be down to their direction of foil development? How much difference could their lower aspect foil make? Has there been a situation in other foiling classes that would give us some clues. I think I read that the NZ foil now resembles some recent board foils.
Fluid mechanics 101 wasn't nearly this fun.
Good analysis, but I'm not sure about the Ineos ability to change the aoa. What you say makes sense, but you could change the aoa with minimum mass change if the component is measured separately from the arm (and nothing seems contrary to this for me), than to change the aoa it's only sufficient to change the geometry of the foil attachment to the arm.
The attachment angle to the arm is described in the cad file they send, which is the crux of the problem. They could build up areas and fair back areas to achieve a new AoA, but it would be very, very fine change.
Any idea why some of the teams are using anhedral? (tilting downwards of the foils). In aeroplanes you use it to decrease lateral stability (roll). But it doesn't make too much sense to me that they'd want to reduce that in these boats.
My guess is to provide a bit more lateral force i.e. like you would get from a traditional centre/lee board. So, to help with steering and reduce leeward drift.
Could you imagine how fast these things could be if the only rules are length and wind power.
Just watched a CZcams vid of ETNZ training today with the new T Foil (I think). Looking a little unstable at times. Their ride height is incredibly low, just kissing the water. I’m curious about the upwind angle they’ll achieve. Using T Foils on Windsurfers you get the better angle if you rail the board to windward to give upwind lift. ETNZ have less upwind grip/lift with the T Foil versus a foil with more Anhedral.
Suggest you open a patreon account. I appreciate your work and would hope that many could be supportive.
Finally got around to it :) www.patreon.com/MozzySails
Excellent video, intriguing analysis, terrible jumper continuity...! ;o)
Ha! No one would have noticed otherwise!
why on earth would changing the angle of incidence of the foil change the mass distribution of the foil? the two seem nearly completely unrelated. It would load or unload the flap, perhaps requiring control system modification, but perhaps not, as those loads are not huge compared to the lift generated - reducing control actuation loads is one of the main purposes of having a flap.
the mass distribution of the foil is defined relative to the foil arm. If you change the connection angle to the foil arm (AoI), then suddenly you have moved 100% of the mass in the foil. You are only allowed 20% change.
Too bad the shape of the foils used is not disclosed. Would help much more to understand why Team NZ uses those flat and short chord hydrofoils.
Hi again guys! I’ve now subscribed!
I watched this video on foils design a few days back, but something’s been running through my brain that I would
Iike to share with you just for the sake of thought/discussion.
From memory, in this video you state that the foils have to be symmetrical about the supporting arm. I was wondering, does this mean just dimensionally?
The thought I have is that could a team create a dimensionally symmetrical foil (so comply with the rule book) but make the inboard half of the foil hollow & as light as possible, enabling them to put all the weight on the outside half of the foil?
Taking this idea one step further, if the above passes the rule book, then we have seen designs with a central bulb, ‘what if’ a bulb was added to each end of the foil, make the inboard bulb hollow and light, and put as much weight as possible in the outer bulb.
I appreciate that the weight is only a part of the righting forces involved, with the hydrodynamic righting forces probably being the lions share, when at speed at least, but as they say at Asda, ‘every little bit helps’ ;-)
So, the question is, does the rule book permit symmetrical dimensioned foils but asymmetric weight distribution?
....& if so, is anyone doing this? & what do we think the advantage could be?
Discuss:
Not sure etnz would have bet their entire campaign on this interpretation. Their bulbs have always been tiny, perhaps they are using a novel approach towards actuation. And I'm not sure they would want to loose the ability to control the flaps independently. The latest video of them practicing shows the lee tip clear of the water from a long distance off, surely you would want to control a ventilated wing differently from a deeply submerged one?
Great videos, thanks mozzy.
They will have a contingency plan for sure. Plus it be quite easy to fully split the flaps, but just maybe not nice.
I think you are also right in that a big part of their performance is tip exposure and management of that
May I request a 'to boom or not to boom' Cupcast next please?
Does it mean that the 2 flaps have to move up and down together?
Can you explain how the grinders power is used EG can they store power
Love your insight Vid's! Just a quick note on your possible advantage for "one" flap design. I don't think it is as advantageous as many would think. One connection would have to be stronger to take the equivalent loads compared with two being split. Or much larger single actuator compared to two. Yes, possibly more connections, but this is minor weight in the scheme of things. As Ben always says, nothing comes for free! (ps, I've not really forgiven him for calling Dean an Idiot during the hook, race 17, 34th AC in San Fran... No need for abuse buddy!) - Or was that Jimmy that said either or both, lol ??
Where do the mechanics fit?
Sorry if this has been asked before but what is the site you use for virtual eye analytics? Is that openly available? I love that kind of stuff.
It's on the AC website, under racing tab and is called 'virtual eye'
@@MozzySails everything I thought I knew about the world is wrong! I was just going to the youtube virtual eye. Anyway, really sad to see Ineos team UK go, if ETNZ was going to lose I wanted it to be to the UK, but keep up the great analysis. You're my favourite AC related channel.
love the videos, but could you turn off the auto mic cut out during silences?
Seems like happy road apples.
So, ETNZ have the lowdown on flaps and foils regarding the rules... and whichever challenger gets to the AC cup will be protested as having illegal flaps...end of Cup.... :)
@5:21 you point out that there is one flap....but as the camera zooms in on the foil you can see the same white markings and indeed 3 of which form a straight line on the bottom half of the wing which seems to indicate that they do indeed have 2 flaps. Just that one has more paint peeled away than the other
Is there a case for a rule breach here?
@@tcdossor No it doesnt seem like it. They came up with the design so I doubt they wouldve made the mistake of not following their own rule on the most important part of the boat itself. Also like I pointed out it looks like theres actually a flap on the other part of the wing but it just isnt as worn out as the other side.
I can't believe that they didn't test this foils in pool where they usually test models.
Too much computer simulations .....but they couldn't predict bubbles in the time of immersion ?
That's kind of embarrassing for such a massive budget program.
They're not actually allowed tank testing, to keep costs down
Watching this, I'm wondering what the intent of the rules was. For example, why does a foil have to be symmetrical? Was this so the teams didn't have too many design choices to make, which might have handed a big advantage to a team which happened to hit a great design?
So they didn't end up with foils that projects 'too far' out to one side, thereby making them dangerous if someone fell in and also limiting boat maneuvers in close proximity?
@@chrismartin5870 Sure, but they could have allowed them to be asymmetrical within the limit box.
I believe it was primarily to reduce design variables. The holders who create the rules want some area in which a team can design but not too much freedom so the team who can spend the most wins. In a sport dominated by big spenders, they want to encourage smaller teams to be able to mount a challenge and at least take part.
6 foils are allowed per team, can the teams choose which to use for any race? Or it’s just 6 chances to develop the foil design?
Well guys I was wrong and you were right, Looks like the Brits are going home without the cup.
On another vid of yours I spoke about ultra-sound to break the water along the leading edge of your blade, it creates very small and therefore controllable size bubbles that eliminates cavitation at the 45 and extends that a long way forward.
I would have thought you 3 guys would like to play with this as it's needed to get past 55.
It's too late for UK they didn't get the tech in time, NZ did but I'm not close enough to know if they used it, my contact indicated they had.
Either way, I hope the UK can come back tomorrow, They are down in speed by 3 km, even with No.1's on they fell off the foil after being toed up to foil. There's a problem and it isn't the skip this time.
I'd love to talk to you about what creating millions of tiny bubbles in front of a flying foil feels like, it creates a vacuum to fly into.
Sound travels at what speed under water? and if you can break that water with sound around the thickness of a piece of paper in a 10mm strip along the leading edge, what resistance does the flying blade run into?
Now you have a "slipcoat'' made of air at the flick of a switch and the grinders power it.
But you have to be able to foil first.
What I'm saying and now asking you guys to run so's you Know, is between you build a new foil and have a play, test tanks are boring but water get hard at speed.
It's the uncontrolled explosions of pressure created by a moving object in water that causes cavitation and any water rising up above the surface is being put there by which one of those grinders? So be kind and eliminate as much water being thrown up as possible ... use Ultra-sound, everything works better when you do bubbles small.
I'm hoping this helps your guys next project, CU ... and oh ... ps ... I wouldn't be keen on running a crap load of boats using ultra-sound, I'm absolutely not sure what the fish think and that's serious to me.
You inferred that ETNZ pushed the boundaries of legitimacy, but also this could be litigated, could you say which team (s) have indicated they may take it further? And when?
No team have indicated they will take it further. But, we had further rule interpretations only a month ago and not all the questions were answered (rule committee said insufficient detail in question). So, I don't see it as completely resolved.