Tornado-Cat

Boats and foils comparison

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1 hour ago, uflux said:

Perhaps you need to go back and watch the racing again?? ETNZ light wind foils had a much wider wind range than the competition. Watch a couple of upwind legs against Artemis and tell me their vmg was not better. Not much point going fast if you can't point to the mark...

Upwind vmg is not pure speed and I never said that Vestas could win a race, that is not point discussed here.

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3 hours ago, rh3000 said:

You are talking to a flat earthist... it's not worth the bother ;-)

Coming from the one who said: "The total weight (of the arm) has increased in this case by just 33kg per foil ... The true number could just as easily be 3kg"

I guess it was a joke at the time too :)

 

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5 hours ago, Tornado-Cat said:

Upwind vmg is not pure speed and I never said that Vestas could win a race, that is not point discussed here.

No, the point is that you had a nice couple days off...and came back forgetting we were discussing racing whilst you were gone. Racing requires winning, don't bother with the lecture of vmg. Hope it's your Friday here, your ready for another couple of days off.

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3 hours ago, Tornado-Cat said:

Coming from the one who said: "The total weight (of the arm) has increased in this case by just 33kg per foil ... The true number could just as easily be 3kg"

I guess it was a joke at the time too :)

 

No no... the updated rules show they have been increased by 219kg - do try and keep up old chap! :rolleyes:

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7 hours ago, Tornado-Cat said:

Boink, sorry but you are wrong on all points, Really? Let's have a look.......

1)      How can you pretend that NZ Foils were more refined and less forgiving than some other boats in AC35? TNZ was not not the fastest on a straight line, Artemis was.

Wow, so you think designing the fastest boat in a straight line, is the prize that all teams are chasing? Or instead design a boat that can win the Americas Cup? Which team will be remembered from Bermuda.......? Yeah good one. Remind me to hire you to lead the design team when I need a regatta winning design - can you imagine the debrief by Artemis post Bermuda - Artemis Design Team -"But Torben we designed the fastest boat in a straight line....." Torben's response (polite) "Close but no Cigar boys......" (not polite & honest) "Are you fucking kidding me??? I spend millions and you give me a one trick pony.......... JFC, even I know that is the most childish approach to winning the hardest trophy in sailing....... Fucking idiots....... Your fired........"

The global platform was more stable, thus globally faster, because of the foil and the computer assist dot system, and perhaps the hydro.

So I actually wrote "With the track record in Bermuda of having the best control system  and more hydraulic pressure - NZ were able to use more refined foil shapes (that were by nature - less forgiving  i.e. less stable) to devastating effect. " 

Even though you claim I am wrong Your response is : thus Globally Faster - because they had superior foil, control and hydraulic systems.

So where in your response are you not reiterating all the points that I had already made??????????

2)      You think that Flipper foils lower because her belly touches water, - I dont write this at all - I believe the underside shape allows her to fly lower with possible touches that have far lower consequences if they do touch, than the flatter scow shapes - see Ineos thread for my reasoning - this is an important distinction and difference that passes you by.

in fact it’s the contrary, Manta and Orca can fly lower without touching the water. - Possibly, but, more importantly, they dont fly low. No one one knows if this is deliberate moding, or due to control systems that prevent them chasing a high risk strategy (of touching) or because if they touch a large flat scow shape will stick so much more than the NZ shape. I repeat - no one knows - but it is logically possible and plausible, again another concept that flies clear over you. 

You are also wrong with your other statement: higher is more aero drag - But it is....... Would you like to re-read the evidence

wvela4.jpg

I also actually wrote: "We have seen the reasoning that the closer you fly the hull to the water surface the lower the apparent wind force that will generate global drag on the whole package is at the lowest level possible - high is safe - but more draggy. "  

but also less hydro drag from the foil arm on an AC75. - I dont disagree with this - but I didn't make reference to it either  (but have on the Ineos thread) - are you going to try and lecture me about all the things I haven't written about ???? Great posistion to take - Oh the hatred is strong within you isn't it?

You also miss the point, that lower is more RM. What is the best combination? I think no teams knows yet, and surely not you. - I repeat my answer to the case above - when you try to lecture me about all the things I haven't written about...........

3)      Care to explain how that works with the AC75? So Flipper flies lower with most of the rudder out of the water? We saw it’s not the case. - See the Ineos thread idiot....

4)      Wrong, an AC75 does not sail like a moth and no boat has been seen sailing that way on a regular basis, Flipper included. -  I do not claim that any of these boats will ever sail like a Moth with windward heel of 25-35 degrees of Veal Heel, and have written that several times in many threads - but I have seen evidence of sailing to windward - where a few degrees of widward heel is being chased.

Also, wrong to say the heel to windward would increase the RM, and it would decrease the power of the sail. - Well please enlighten me how with a few degrees of heel to windward - where the Mass of the Rig now adds to RM (rather than reducing it with the opposite) as well as futher laterally spreading the Foil arms to as close to horizontal without water contact, and yet while the rig is heeled these few degress, it is not producing any less outright force, yet it is vectored slightly above horizontal, so no adding to the vertical downward pressure that the main foils have to counter act (please remember - flight is actively sought in this style of boat) - thereby giving a global gain through lower induced drag of a foil working less hard to maintain altitude - do you not increase RM???????

and how As far as your “virtuous circle towards higher performance”, ah ah…. Read the response above and then (coherently) explain how this is not a virtuous circle?

If you are going to be an Alan Partridge character - get it right........ 

5)      Yes, for sure the other teams have slower foils, …. In your wet dreams only. - So I actually write "Or, design super stable foil shapes that are easy to fly but are probably a fraction slower in outright velocity, turns and acceleration........" But in true trolling fashion you wish to twist actual comments into something else. Good one.

As to Wet Dreams - not a sufferer - just a very healthy sex life with a gorgeous female - she makes me very happy - unlike you...... 

6)      How can you be so wrong: Bernasconi said they will take the easy way to copy any good ideas coming from the other teams. And it makes sense. - Ummm, so my original comment referred clearly to the design ethos that the team will most likely go for a difficult to operate design with extremely high potential; rather than play it conservative and design a more forgiving boat that ultimately has an overall lower potential. 

Not what you have twisted it to meant...... Quelle surprise mon ami!

We have just witnessed a blue sky design moment - this is a moment where 4 different design teams have - without collaboration or insight into each others work - produced 4 unique designs that represent the different thinking approaches to a new rule. All designs going forward from here will be a bastard love child of DNA from all four designs to a greater or lesser extent - more DNA from those ideas that have worked or rival designs that they have evaluated to be positive.  So not only is your comment inappropriate, neither it is revelatory.......

Let me help with your poor comprehension:

revelatory
/ˌrɛvəˈleɪt(ə)ri,ˈrɛv(ə)lət(ə)ri/
adjective
 
  1. revealing something hitherto unknown.
    "a revelatory experience"
     
    Of course all designers are going to take cues from other sources - but that has not happened with these four boats - you dolt.

Last: “The whole team ethos is geared towards taking and exploring the hard route”This is not Kiwi ethos, - no, it is ETNZ ethos  

it’s Kiwi pathos, - I'll let the Kiwi's tell you what their pathos is...... Good Luck with that one....... They are still pissed at the RWC - so happy to take out their frustrations on a super bloke like yourself who denigrates their nation.

at least yours. - Yet again your hatred leads to make assumptions, and we know what that means.......I am not a Kiwi, Nor am I in NZ, nor is NZ "my team", but continue to draw all the wrong conclusions that your Trolling brings.

It’s simply not true. - Correct; nothing that you have written is true.......

Ah, like a good premier cru, you never fail to deliver: your petty hatred, lack of comprehension and twisting of narrative to suit your agenda........

TC = Trolling C**t

Do you need help with comprehending that one as well?????

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1 hour ago, rh3000 said:

No no... the updated rules show they have been increased by 219kg - do try and keep up old chap! :rolleyes:

I posted it when published if you had been keeping up. :)

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19 hours ago, Boink said:

Ah, like a good premier cru, you never fail to deliver: your petty hatred, lack of comprehension and twisting of narrative to suit your agenda........

TC = Trolling C**t

Do you need help with comprehending that one as well?????

There is no hatred here, just trying make you understand your strange ideas. In most of your points you backpedal and try to explain you did not say it, so not necessary to come back on it.

I am going to try to understand your long and circonvoluted discourse on RM.

1) a few degrees of heel to windward - where the Mass of the Rig now adds to RM (rather than reducing it with the opposite)

2) as well as futher laterally spreading the Foil arms to as close to horizontal without water contact,

3) and yet while the rig is heeled these few degress, it is not producing any less outright force,

4) yet it is vectored slightly above horizontal, so no adding to the vertical downward pressure that the main foils have to counter act (please remember - flight is actively sought in this style of boat) - thereby giving a global gain through lower induced drag of a foil working less hard to maintain altitude - 

5) do you not increase RM???????  

 

1) No this boat is not a moth, the mass of the rig will not add RM as the foil is already at the exterior of the boat and not under the hull. You may even slightly decrease the length of the lever arm

2) Yes, could slightly increase RM with the windward foil closer to the water, but at the risk of touching water and slowing the boat

3) No, if the rig is heeled it will produce less force

4) Yes, less pressure on the sail = less pressure on the foil. With a windsurfer we cant the sail to windward when we have too much pressure, not to go faster.

5) No, no increased RM, and no team is doing it.

Hasta  manana  :)

 

 

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On 11/10/2019 at 5:03 PM, Boink said:

Fly the boat with a degree or two of windward heel upwind to get the rig mass to add to RM and vector your sail lifts ever so slightly upwards - everything starts to virtuous circle towards higher performance. 

You can't have it both ways: if using heel to move the centre of mass of the rig to windward increases RM, then changing the rig's lift vector to have a vertical component counteracts its weight, reducing RM. There is also lost power from the canted rig.

Maybe there's a net performance gain, maybe not. If your "virtuous circle" worked they'd sail the boat with the mast horizontal to windward.

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I agree with @Boink In an over powered situation they might heel to windward like moths immersing the windward foil for greater leeward control.  Using excess power to lift weight so more forward speed can be achieved.

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12 hours ago, RobG said:

You can't have it both ways: if using heel to move the centre of mass of the rig to windward increases RM, then changing the rig's lift vector to have a vertical component counteracts its weight, reducing RM. There is also lost power from the canted rig.

Maybe there's a net performance gain, maybe not. If your "virtuous circle" worked they'd sail the boat with the mast horizontal to windward.

Exactly.  

They can design and contort the sails, foils and rudder to give them the power and RM that they need at any given time.  The hull will be sailed such that it gives the least aero drag.  It is not a one class sail competition where you have to adjust the boat to make up for lack of design or control in the foils and sails.

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1 hour ago, Herfy said:

Exactly.  

They can design and contort the sails, foils and rudder to give them the power and RM that they need at any given time.  The hull will be sailed such that it gives the least aero drag.  It is not a one class sail competition where you have to adjust the boat to make up for lack of design or control in the foils and sails.

Is not about speed it is about VMG upwind. The additional lift allows you to point higher. They know what they are doing :)

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13 hours ago, Kiwing said:

I agree with @Boink In an over powered situation they might heel to windward like moths immersing the windward foil for greater leeward control.  Using excess power to lift weight so more forward speed can be achieved.

Kiwing, I see what you mean, however : 27.4 The AC75 Class Yacht is not designed to resist righting-moment created by hydrodynamic downforce on
the windward foil

Cheers

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If the foil is in it's top position which seems very low on ETNZ then they can't stop it from being in the water (and helping)!

Apparently you can put a new top stop in for a race as long as you don't move it.

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15 minutes ago, Kiwing said:

If the foil is in it's top position which seems very low on ETNZ then they can't stop it from being in the water (and helping)!

Apparently you can put a new top stop in for a race as long as you don't move it.

I wondered about that too. If that especially-long ww foil is that close to the water then heeling to ww may include immersing some part of it - with either bad drag or good RM and leeway consequences. 

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27 minutes ago, Kiwing said:

If the foil is in it's top position which seems very low on ETNZ then they can't stop it from being in the water (and helping)!

Apparently you can put a new top stop in for a race as long as you don't move it.

What we have seen with Flipper is the foil tip going into the water during transition, but we don't know if it can help balance the boat by providing some lift, which is allowed.

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1 hour ago, Tornado-Cat said:

What we have seen with Flipper is the foil tip going into the water during transition, but we don't know if it can help balance the boat by providing some lift, which is allowed.

Not again with the Batshit crazy idea that the foil tip hitting the water provides lift.

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2 hours ago, barfy said:

Not again with the Batshit crazy idea that the foil tip hitting the water provides lift.

Agreed it would be a drag penalty far out weighing any small amount of additional lift. Non-starter.

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It would be for leeward force. so vertical with flap control.

windy conditions, so reducing sail power would reduce RM required.

taking some weight off main foil would reduce drag, hence increase speed.

Hull shape would allow quite some angle if required?  not that they would need a lot?

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2 hours ago, uflux said:

Agreed it would be a drag penalty far out weighing any small amount of additional lift. Non-starter.

Agree, same as having an appendage hanging under the hull that plows into the surface of the water from time to time would have a drag penalty.

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2 hours ago, uflux said:

Agreed it would be a drag penalty far out weighing any small amount of additional lift. Non-starter.

The only time we have seen it with Flipper was when they lost balance and fell to windward after transitions. The fact they touched water might also be due to longer foils.

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1 hour ago, Herfy said:

Agree, same as having an appendage hanging under the hull that plows into the surface of the water from time to time would have a drag penalty.

Hardly comparable dude.

This forum is like listening to talk back radio :lol:

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39 minutes ago, Tornado-Cat said:

The only time we have seen it with Flipper was when they lost balance and fell to windward after transitions. The fact they touched water might also be due to longer foils.

A momentary touch of a foil is not an issue if those foils are giving you an advantage over your opponent...

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4 hours ago, uflux said:

Hardly comparable dude.

This forum is like listening to talk back radio :lol:

Talkback radio after midnight 

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On 11/16/2019 at 7:24 AM, Tornado-Cat said:

1) No this boat is not a moth, the mass of the rig will not add RM as the foil is already at the exterior of the boat and not under the hull. You may even slightly decrease the length of the lever arm -  incorrect - the boat lifts from a point roughly at the end of the foil arm - however the COG of the boat is roughly somwhere around the heel of the mast - therefore the more that the boat can be sailed when these 2 points are the most horizontally separated - without dragging either hull or windward foil in the water is the point of greatest RM - and that is not when the mast is sailed bolt upright, with the windward foil a long way off the water surface.

2) Yes, could slightly increase RM with the windward foil closer to the water, but at the risk of touching water and slowing the boat - so fucking what? You think they are practicising and developing flying techniques and protocols to fly nice and clear of the water surface and give up free RM when going to windward? Remind yourself, you will only see this deliberate heeling to windward when sailing upwind - it maximises VMG. 

3) No, if the rig is heeled it will produce less force - again incorrect, the total force that the Rig generates does not alter regardless of its orientation - what changes is the vectoring of those total forces - when the rig is heeled slightly to windward the total force can be summed as having both a forward vector and an upward vector. This is why I have  consistently talked about small amounts of windward heel - NOT sailing like a Moth you idiot. When a boat like this has Rig Power to excess, but only limited RM; then trading some of this Rig Power in the forward vector to relieve pressure that the immersed foil has to create, from a canted rig angle creating an upward vector, allows the foil to run less AOA to generate the lift that is required to maintain optimum forward motion at less drag - everyone is already in agreement that the team that generates the most useable power on the lowest drag platform will improve their chances significantly.

4) Yes, less pressure on the sail = less pressure on the foil. With a windsurfer we cant the sail to windward when we have too much pressure, not to go faster. - Not a valid comparison - bone headed analogy, but I would be happy if you did leave to go windsurfing..... You probably have a Div2 board or windglider and consider that to be the height of product development.

5) No, no increased RM, and no team is doing it. - Yes, increased RM, lower lift effort required from immersed foils, thereby lower drag to achieve same lift - therefore higher performance.

 

On 11/16/2019 at 3:32 PM, RobG said:

You can't have it both ways: if using heel to move the centre of mass of the rig to windward increases RM, then changing the rig's lift vector to have a vertical component counteracts its weight, reducing RM. There is also lost power from the canted rig.

No - the mass of the boat stays constant - but the mass that the foil has to support, is lessened - therefore the foil can run more "neutral" or in lower lift mode which is accompanied by lower drag properties. Its the lower drag, along with increased RM which raises the overall performance. Everything that can be done by the Rig in the "air" medium to generate power and yet slightly unload the hydrofoils allows those foils to either be physically smaller or run less flap, thereby generating less drag - and whilst water stays 800 more dense than air, any drag reducing modes will have virtuous outcomes........

Maybe there's a net performance gain, maybe not. If your "virtuous circle" worked they'd sail the boat with the mast horizontal to windward. - Yeah Good one, This is just as Boneheaded as TC and as provocative as it gets......  Maybe you should take your own advice and get yourself Horizontal i.e. Go have a lie down and keep well away from the keyboard.

So get with the programme, going to windward, fully powered up; they are looking to maximise RM by heeling the platform to separate lift point from COG, which happily also causes a rig orienation where excess rig power can be angled upwards slightly to help unload the hydrofoils; so expect to see a few degrees(probably not even close to 10), of windward heel on these boats. After that they struggle to keep hulls or windward foils clear, and the penalty for dragging those outweighs the gains. Downwind, upright is King.

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Who said the mass changes?

You're claiming more RM by shifting the weight to windward by canting the rig, but not allowing for the loss of RM from the canted rig creating vertical lift, this bit: "…but the mass that the foil has to support, is lessened…".

Stop theorising and do some mathematics. E.g. canting the mast 5° shifts its CM 1 m in the direction of cant. Add to that the weight of the sail (unknown, make a guess) and work out how far the entire boat CM has moved on a lever arm about 5.4 m long. Now calculate the lift from tilting the sail 5° and deduct it from the weight of the boat and calculate the RM again.

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14 hours ago, Boink said:

Boink the more you write, the more it shows that your theories are lacking and that you don’t know much about sailing.

The boat lifts from a point roughly at the end of the foil arm - however the COG of the boat is roughly somwhere around the heel of the mast - therefore the more that the boat can be sailed when these 2 points are the most horizontally separated - without dragging either hull or windward foil in the water is the point of greatest RM - and that is not when the mast is sailed bolt upright, with the windward foil a long way off the water surface.

Wrong, the foil arm is already about horizontal, so if the boat heels to windward the effective length will decrease and will not increase the RM.

The total force that the Rig generates does not alter regardless of its orientation - what changes is the vectoring of those total forces - when the rig is heeled slightly to windward the total force can be summed as having both a forward vector and an upward vector. This is why I have consistently talked about small amounts of windward heel - NOT sailing like a Moth you idiot. When a boat like this has Rig Power to excess, but only limited RM; then trading some of this Rig Power in the forward vector to relieve pressure that the immersed foil has to create, from a canted rig angle creating an upward vector, allows the foil to run less AOA to generate the lift that is required to maintain optimum forward motion at less drag - everyone is already in agreement that the team that generates the most useable power on the lowest drag platform will improve their chances significantly.

Wrong, if the rig is horizontal it will not generate power. If you sail a windsurfer with too much windward cant you don’t have enough power et not enough speed. You do it to get out of the water with a sinker, not for speed.

Not a valid comparison - bone headed analogy, but I would be happy if you did leave to go windsurfing..... You probably have a Div2 board or windglider and consider that to be the height of product development.

Wrong, it is a valid comparison. And I did it with a Windsurfer, Windglider, Crit D2, but also sinkers and others. What do don’t know is that I also tried it on a Tornado, it just does not work. I am speaking of canting the rig, raking however is interesting downwind when windy.

Yes, increased RM, lower lift effort required from immersed foils, thereby lower drag to achieve same lift - therefore higher performance.

No, the lift interest is diminished by the loss of pressure on the sail.

 

 

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15 hours ago, Boink said:

 

So get with the programme, going to windward, fully powered up; they are looking to maximise RM by heeling the platform to separate lift point from COG, which happily also causes a rig orienation where excess rig power can be angled upwards slightly to help unload the hydrofoils; so expect to see a few degrees(probably not even close to 10), of windward heel on these boats. After that they struggle to keep hulls or windward foils clear, and the penalty for dragging those outweighs the gains. Downwind, upright is King.

You come with old theories from the 70s when windsurfers thought that the lift would make them go faster. Did you sailed fast boats since? I beleived the same thing, ....until I tried.

You are just wrong. If you had been right high performance cats, trimarans who cross the oceans would use it upwind with a sail canted to 45 degrees for exemple. You know what ? they don't. The only ones who do that are the trimarans to put the sail plan vertical when they load a float. Have you seen any fast foiler with it ? No, they don't.

Flipper does not sail like that either and when it does they immerse their ww large foil tip in the water. If your theory was so good they would have designed a smaller foil to allow more ww heel. Fact is that they did not, you are wrong.

RobG who has excellent tech knowledge demonstrates with maths too.

Your theory does not work and is 50 years old, time to keep up Boink, Doug Lord is pretty more advanced than you now. :D

 

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4 hours ago, Tornado-Cat said:

Wrong, the foil arm is already about horizontal, so if the boat heels to windward the effective length will decrease and will not increase the RM.

I assumed that the RM lever is from the centre of the foil to the centre of mass of the boat, a distance of about 5.4 m and up at about 15° from horizontal (complete guess but seems about right). Likely not a perfect model but good enough for here.

So heeling to windward will effectively lengthen the arm due to moving the CM further from the foil horizontally as its weight acts vertically due to gravity, not at 90° to the arm as might occur with a torque wrench. The same thing with a vertical rig can be achieved by raising the arm and foiling lower, the advantage of windward heel is that the rig CM (which is about 13 m above the deck and maybe 1,000 kg all up) moves to windward much more than the rest of the boat.

The question is whether this increase in RM is cancelled by lift from the canted sail and loss of rig efficiency. Observation of foilers with canting rigs that could cant them to windward but don't says yes: an upright rig is better and the "lift from windward heel is faster" theory doesn't work. Anecdotal evidence seems to confirm it, even windsurfers try to get their sail upright. Is there a correlation between arm length and windsurfer performance? :-)

My guess is they'll optimise RM by raising and lowering the arm in conjunction with minimising drag from the immersed part of the arm, keeping the rig as upright as possible.

BTW, I tried scaling the length of the foils between INEOS and ETNZ based on both boats have a 5m beam and think the ENTZ ones were only about 200 mm longer. They also don't seem to be at the maximum allowed length.

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4 hours ago, Tornado-Cat said:

You are just wrong. If you had been right high performance cats, trimarans who cross the oceans would use it upwind with a sail canted to 45 degrees for exemple. You know what ? they don't. The only ones who do that are the trimarans to put the sail plan vertical when they load a float. Have you seen any fast foiler with it ? No, they don't.

I seem to recall that Vestas Sail Rocket 2 sailed by Paul Larsen had it's wing canted to 45 degrees, it managed 65 knots in 2012.

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1 hour ago, Terry Hollis said:

I seem to recall that Vestas Sail Rocket 2 sailed by Paul Larsen had it's wing canted to 45 degrees, it managed 65 knots in 2012.

Yes, but that was a very peculiar boat that was optimised for speed on a starboard square reach.

The leeward float on which the wing was mounted flew above the water, the rig was likely canted to some optimal angle to achieve that as the only other aero lifting surface was the beam attaching the rig to the main hull. It probably didn't have enough lift on its own and the float likely needed to fly pretty early else there'd be massive lee helm. Also, Sail Rocket's sail area isn't limited by a class rule so could be whatever it needed to be without other considerations. Lost power due to using some as lift for the float could be compensated for with a bigger sail.

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3 hours ago, RobG said:

The question is whether this increase in RM is cancelled by lift from the canted sail and loss of rig efficiency. Observation of foilers with canting rigs that could cant them to windward but don't says yes: an upright rig is better and the "lift from windward heel is faster" theory doesn't work. Anecdotal evidence seems to confirm it, even windsurfers try to get their sail upright. Is there a correlation between arm length and windsurfer performance? :-)

 

Nah, reducing any loading on the skeg, especially lift.  

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Why do people insist on putting sailing principles from other classes of boat onto the AC75?

there isn’t another boat out there that sails with the same design principles so why try and apply principles that don’t fit? 
 

sail rocket? Did it have to get around a course up and down wind on both tacks? No, did it have a surface piercing cavitating foil that directly opposed the force generated by the canted rig? Yes. Does an AC75? No.

windsurfers are still thinking board width is important and sailing upright as a result, they can’t can’t to windward as the masts are too short and boards too wide. Kites have had it sussed for years as have moths with long verticals narrow hull widths etc 

 

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18 hours ago, Terry Hollis said:

I seem to recall that Vestas Sail Rocket 2 sailed by Paul Larsen had it's wing canted to 45 degrees, it managed 65 knots in 2012.

Correct, Vestas is I think the only example where it works, but if you look at this photo your realize that the sail works a bit like a kite. The cant does not relieve the weith of the boat but the sail itself.

yandy70555.jpg

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19 hours ago, RobG said:

I assumed that the RM lever is from the centre of the foil to the centre of mass of the boat, a distance of about 5.4 m and up at about 15° from horizontal (complete guess but seems about right). Likely not a perfect model but good enough for here.

So heeling to windward will effectively lengthen the arm due to moving the CM further from the foil horizontally as its weight acts vertically due to gravity, not at 90° to the arm as might occur with a torque wrench. The same thing with a vertical rig can be achieved by raising the arm and foiling lower, the advantage of windward heel is that the rig CM (which is about 13 m above the deck and maybe 1,000 kg all up) moves to windward much more than the rest of the boat.

 The question is whether this increase in RM is cancelled by lift from the canted sail and loss of rig efficiency. Observation of foilers with canting rigs that could cant them to windward but don't says yes: an upright rig is better and the "lift from windward heel is faster" theory doesn't work. Anecdotal evidence seems to confirm it, even windsurfers try to get their sail upright. Is there a correlation between arm length and windsurfer performance? :-)

My guess is they'll optimise RM by raising and lowering the arm in conjunction with minimising drag from the immersed part of the arm, keeping the rig as upright as possible.

BTW, I tried scaling the length of the foils between INEOS and ETNZ based on both boats have a 5m beam and think the ENTZ ones were only about 200 mm longer. They also don't seem to be at the maximum allowed length.

Agreed with both points.

The pictures show that the moths can bring both the rig, hull, crew to windward with the cant, thus allowing more RM and less pressure to LW from the sail.

However AC75 already have the hull and wing to windward vs the foil, so canting will not really increase the length of the lever, or by very small. So, as you say the weight of the wing will be cancelled by the loss of rig efficiency. They can also play with the angle of the windward arm: the lower = the more RM and the less possibility to heel to windward because the tip of the foil would hit the water..

letsgetwet.jpg

Capture.PNG

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23 minutes ago, Tornado-Cat said:

Correct, Vestas is I think the only example where it works, but if you look at this photo your realize that the sail works a bit like a kite. The cant does not relieve the weith of the boat but the sail itself.

yandy70555.jpg

The rig was /is like that purely to line up is pull directly opposite the foil that was producing the lateral resistance 

 

not about relieving weight of the rig or any other fanciful shite, it was purely for a single purpose with no concessions to any of the useless crap ( getting around an up wind/downwind race track) that the 75s moths etc do and get in the way of actually going fast 

 

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4 hours ago, JALhazmat said:

sail rocket? Did it have to get around a course up and down wind on both tacks? No, did it have a surface piercing cavitating foil that directly opposed the force generated by the canted rig? Yes. Does an AC75? No.

 

 

Sailing on two boards/tacks is irrelevant to the discussion on high performance;  you could have a canting rig a la some past experimental tilting wing US and French C Class cats -  and may have an even faster boat than Vestas SR? But the point made earlier is regarding canting rigs; they have been proven to work; look at the ORMA designs with their rigs canted well over to windward. They don't do that just to look strangely pretty. Or to piss off conventional thinkers.

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1 hour ago, Groucho Marx said:

Sailing on two boards/tacks is irrelevant to the discussion on high performance;  you could have a canting rig a la some past experimental tilting wing US and French C Class cats -  and may have an even faster boat than Vestas SR? But the point made earlier is regarding canting rigs; they have been proven to work; look at the ORMA designs with their rigs canted well over to windward. They don't do that just to look strangely pretty. Or to piss off conventional thinkers.

Oh, but windsurfers don't do it so it can't be realistic. (Sarcasm font)

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2 hours ago, JALhazmat said:

The rig was /is like that purely to line up is pull directly opposite the foil that was producing the lateral resistance not about relieving weight of the rig or any other fanciful shite, it was purely for a single purpose with no concessions to any of the useless crap ( getting around an up wind/downwind race track) that the 75s moths etc do and get in the way of actually going fast 

 

.....Even the fuselage “hull” is oriented to face the design AWA to reduce drag......

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On 11/19/2019 at 11:34 AM, Tornado-Cat said:

You are just wrong. If you had been right high performance cats, trimarans who cross the oceans would use it upwind with a sail canted to 45 degrees for exemple. You know what ? they don't. The only ones who do that are the trimarans to put the sail plan vertical when they load a float. Have you seen any fast foiler with it ? No, they don't.

Pleased to see you are still writing ignorant shit on forums. You want a fast foiler that uses a canting rig? How about the Groupama C Class. That had a canting rig which was seen as giving it a big advantage. The general view is that canting rigs are faster on foilers but are far more unreliable and very hard to make work particularly when changing tacks. This is why they have been removed from ocean racers. There is an old adage - to finish first, first you have to finish. There are practical reasons why you cannot cant a rig 45 degrees on a boat you need to tack (think about the rigging geometry), while boats that you trapeze off also have a limitation because the more you cant  the more the trapeze wire gets close to  vertical and the harder it is to stay on the side of the boat. Canting rigs have been tried on the A's, and they are faster in a straight line, but there are just too many problems tacking/gybing, and staying on the boat. Often, the fastest straight line set up won't get you around the race course the quickest. Making a boat sailable, turning corners and reliability cannot be ignored.

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On 11/18/2019 at 10:19 PM, RobG said:

Who said the mass changes?

You're claiming more RM by shifting the weight to windward by canting the rig, but not allowing for the loss of RM from the canted rig creating vertical lift, this bit: "…but the mass that the foil has to support, is lessened…".

Stop theorising and do some mathematics. E.g. canting the mast 5° shifts its CM 1 m in the direction of cant. Add to that the weight of the sail (unknown, make a guess) and work out how far the entire boat CM has moved on a lever arm about 5.4 m long. Now calculate the lift from tilting the sail 5° and deduct it from the weight of the boat and calculate the RM again.

You tell me to stop theorising....... Yet you then write, that by healing to windward you can move the CM by a metre, in a class where RM is ultimately restricted. However, you choose to debunk my reasoning by not exploiting a mode whereby you can gain additional RM for effectively free........ Because any team that can develop a flight control system to chase these outer edges of performance gain will. And remind yourself which team had the best control system in the last cycle....... and to what effect they translated that to......

Remind yourself, when fully powered, up these boats have Rig energy in excess of what the RM can handle. But you are suggesting that you, and by extension, they, would not try to maximise RM to its absolute limits, which coincidentally, reduces rig energy pressing on the immersed foil, which in turn allows it to operate with less flap and less drag, and also allows the whole package to fly in a fraction less apparent wind, but I am pilloried for such fanciful thinking, yet we are seeing video and photos of this happening. 

We are talking exploiting the boundaries to their limit, becuase that is what AC teams do. A change in orientation of flying the boat by a few degress only - which you yourself recognise as moving in a beneficial direction. 

I'm not even going to respond to the trolling by TC, for the reasons given by others. 

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3 hours ago, Groucho Marx said:

Sailing on two boards/tacks is irrelevant to the discussion on high performance;  you could have a canting rig a la some past experimental tilting wing US and French C Class cats -  and may have an even faster boat than Vestas SR? But the point made earlier is regarding canting rigs; they have been proven to work; look at the ORMA designs with their rigs canted well over to windward. They don't do that just to look strangely pretty. Or to piss off conventional thinkers.

The Ormas had it at the time in order to keep the mast vertical when the float leeward float was in the water. It was the same for Dogzilla at the time. Read this interview of Marc Lombard on the point in 2013, it was about: " the windpressure remains horizontal"

https://www.bymnews.com/americas-cup-33/marc-lombard-english.php

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2 hours ago, A Class Sailor said:

Pleased to see you are still writing ignorant shit on forums. You want a fast foiler that uses a canting rig? How about the Groupama C Class. That had a canting rig which was seen as giving it a big advantage. The general view is that canting rigs are faster on foilers but are far more unreliable and very hard to make work particularly when changing tacks. This is why they have been removed from ocean racers. There is an old adage - to finish first, first you have to finish. There are practical reasons why you cannot cant a rig 45 degrees on a boat you need to tack (think about the rigging geometry), while boats that you trapeze off also have a limitation because the more you cant  the more the trapeze wire gets close to  vertical and the harder it is to stay on the side of the boat. Canting rigs have been tried on the A's, and they are faster in a straight line, but there are just too many problems tacking/gybing, and staying on the boat. Often, the fastest straight line set up won't get you around the race course the quickest. Making a boat sailable, turning corners and reliability cannot be ignored.

That looks like Simon's ignorant shit once again.

Yes, Cammas on Groupama had a canted rig, but if it was true that they were faster because of it they would have kept it in other races, isn't it ? Fact is that they did not.

You don't believe me? fine, do you know which Ultim is now heading the race Brest Atlantique?

https://www.brestatlantiques.com/

It's Edmond the Rothchild, and guess what Sébastien Josse says about it :

Il y a dix ans, nous nous interrogions sur la taille des enrouleurs de voiles d'avant, de la force que supportaient les winches, si on mettait des vérins pour certaines fonctions ou de la bascule sur le mât. Aujourd'hui, on ne se pose plus ces questions mais on se demande quel angle donner aux flaps (comme les volets des ailes d'avion), quel type, quelle envergure.

" Ten years ago we were asking ourselves questions about the size of the head sails rollers, the strength of the winchs, if we would use hydrolics for some use, or if we were canting the mast. Today, we don't ask ourselves these questions anymore but what optimum angle give to the flaps, their type, their width."

https://www.bateaux.com/article/26313/maxi-edmond-de-rothschild-un-nouvel-ultime-plan-d-eau

Now last guess,  who is the architect ? it's Guillaume Verdier. Who is the crew ? Charles Caudrelier and.......Franck Cammas.

 

 

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7 hours ago, Groucho Marx said:

Sailing on two boards/tacks is irrelevant to the discussion on high performance;  you could have a canting rig a la some past experimental tilting wing US and French C Class cats -  and may have an even faster boat than Vestas SR? But the point made earlier is regarding canting rigs; they have been proven to work; look at the ORMA designs with their rigs canted well over to windward. They don't do that just to look strangely pretty. Or to piss off conventional thinkers.

Canting would imply It can be canted from side to side as it is plural.

SR rig is it’s just a fixed inclined wing
 

sorry which boat MAY have been faster than SR? Not seen anything remotely close in speed ever. 

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1 hour ago, JALhazmat said:

Canting would imply It can be canted from side to side as it is plural.

SR rig is it’s just a fixed inclined wing
 

sorry which boat MAY have been faster than SR? Not seen anything remotely close in speed ever. 

A radical foiler trimaran with a canting rig might be/will be? faster than one way traffic VSR.

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12 hours ago, Tornado-Cat said:

They can also play with the angle of the windward arm…

No they can't—see rule 27.3. The FCS only allows the arm to be at positions between 0° (fully lowered) and about 80° to 90° (highest permitted sailing position, final angle to be determined). It can't be stopped between there and 119° (fully raised).

9 hours ago, Boink said:

You tell me to stop theorising…

Theories are fine, but without some attempt to quantify the effect, they're just ideas. I'm not saying you're wrong, only that your logic doesn't seem sound for the reasons I outlined. Show me the numbers.

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4 hours ago, Groucho Marx said:

A radical foiler trimaran with a canting rig might be/will be? faster than one way traffic VSR.

Sure ... ;-) 

it terms of outright speed VSR isn’t getting done by tri with a canting rig.

 

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16 hours ago, Tornado-Cat said:

That looks like Simon's ignorant shit once again.

Yes, Cammas on Groupama had a canted rig, but if it was true that they were faster because of it they would have kept it in other races, isn't it ? Fact is that they did not.

You don't believe me? fine, do you know which Ultim is now heading the race Brest Atlantique?

https://www.brestatlantiques.com/

It's Edmond the Rothchild, and guess what Sébastien Josse says about it :

Il y a dix ans, nous nous interrogions sur la taille des enrouleurs de voiles d'avant, de la force que supportaient les winches, si on mettait des vérins pour certaines fonctions ou de la bascule sur le mât. Aujourd'hui, on ne se pose plus ces questions mais on se demande quel angle donner aux flaps (comme les volets des ailes d'avion), quel type, quelle envergure.

" Ten years ago we were asking ourselves questions about the size of the head sails rollers, the strength of the winchs, if we would use hydrolics for some use, or if we were canting the mast. Today, we don't ask ourselves these questions anymore but what optimum angle give to the flaps, their type, their width."

https://www.bateaux.com/article/26313/maxi-edmond-de-rothschild-un-nouvel-ultime-plan-d-eau

Now last guess,  who is the architect ? it's Guillaume Verdier. Who is the crew ? Charles Caudrelier and.......Franck Cammas.

 

 

Who's Simon? Are you are playing the same game as others have tried, guessing who I am. Another fail to your credit :D

I don't follow any of your "logic". You are suggesting that because they aren't using it, it doesn't work. That is completely wrong. Canting the rig works. it worked on the Groupama C Class, it works on A's and it works on boats of all scales. By "works", I mean that in a straight line, it has been proven to be faster than a non canting rig. That is not the issue. As with any form of racing, it is never the ability to produce straight line speed that counts. it is the ability to sail a particular course the quickest. At one extreme, that means that I can beat Paul Larsen and SailRocket around a standard windward/leeward course, despite his boat being capably of over double my speed. The reason why canting masts are not used in the big ocean going tris is because they were incredibly unreliable. They kept falling over the side. They also took a long time to tack/gybe during which they were very vulnerable to dropping the rig. On the A's, those who have tested canting rigs say it is faster, but the systems needed make the boat too complex to sail and a canted mast makes trapezing really tough, so we don't use it.

Your problem is that you seem to think if people are not using something, it is because it doesn't work or makes the boat slower. That is a poor deduction. There are many things we do not use that could make a boat a lot quicker, but we don't for any number of reasons. As an example, consider the A Class and wing rigs. We all know that a C Class style rig would make an A quicker. Glenn Ashby actually developed Ben Hall's A Class wing when he worked for Oracle (it was the basis of their mega wing) and he reported to the class that it would make existing rigs obsolete. Despite that, nobody else has built a wing, even though it would mean they had a significant advantage over the fleet. The reason why is simple, because one capsize would not only finish your regatta but also potentially write off a very expensive piece of equipment. Nobody is capably of sailing a foiling A on a regular basis without a capsize, so it would be stupid to use gear that cannot survive a capsize.

Stop thinking that non use or no longer used systems mean they don't make a boat faster in a straight line. This comes back to the Groupama C Class. It was the perfect size of boat with enough crew sailing in the right conditions to make it worthwhile to use a canting rig, which they did to great effect. It worked. Period.

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8 hours ago, JALhazmat said:

Sure ... ;-) 

it terms of outright speed VSR isn’t getting done by tri with a canting rig.

 

Agreed, it will be difficult to beat Vestas Sail Rocket - but it will occur.

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2 hours ago, A Class Sailor said:

Who's Simon? Are you are playing the same game as others have tried, guessing who I am. Another fail to your credit :D

I don't follow any of your "logic". You are suggesting that because they aren't using it, it doesn't work. That is completely wrong. Canting the rig works. it worked on the Groupama C Class, it works on A's and it works on boats of all scales. By "works", I mean that in a straight line, it has been proven to be faster than a non canting rig. That is not the issue. As with any form of racing, it is never the ability to produce straight line speed that counts. it is the ability to sail a particular course the quickest. At one extreme, that means that I can beat Paul Larsen and SailRocket around a standard windward/leeward course, despite his boat being capably of over double my speed. The reason why canting masts are not used in the big ocean going tris is because they were incredibly unreliable. They kept falling over the side. They also took a long time to tack/gybe during which they were very vulnerable to dropping the rig. On the A's, those who have tested canting rigs say it is faster, but the systems needed make the boat too complex to sail and a canted mast makes trapezing really tough, so we don't use it.

Your problem is that you seem to think if people are not using something, it is because it doesn't work or makes the boat slower. That is a poor deduction. There are many things we do not use that could make a boat a lot quicker, but we don't for any number of reasons. As an example, consider the A Class and wing rigs. We all know that a C Class style rig would make an A quicker. Glenn Ashby actually developed Ben Hall's A Class wing when he worked for Oracle (it was the basis of their mega wing) and he reported to the class that it would make existing rigs obsolete. Despite that, nobody else has built a wing, even though it would mean they had a significant advantage over the fleet. The reason why is simple, because one capsize would not only finish your regatta but also potentially write off a very expensive piece of equipment. Nobody is capably of sailing a foiling A on a regular basis without a capsize, so it would be stupid to use gear that cannot survive a capsize.

Stop thinking that non use or no longer used systems mean they don't make a boat faster in a straight line. This comes back to the Groupama C Class. It was the perfect size of boat with enough crew sailing in the right conditions to make it worthwhile to use a canting rig, which they did to great effect. It worked. Period.

Yes, it worked in some conditions, I tested it myself on an old Tornado, I could control my rig with 3 points, the results were not scientific but enough to learn from the experience.

As for the other experiences on multis and the As, I was mainly to relieve Leeward float and push water and expected to gain a lot. I found out it helped to have the rig vertical with a small cant when the boat is heeling in order to prevent the pressure of the sail toward the water. With 45 degrees it's hell, believe me, and not necessary because you would need more than 30 kts to make it powerful enough. I used a system of pulleys coming back to the center of the tramp on a central adhoc beam. I stopped the experiment after breaking a shroud, probably using too much pressure for too long. So, troubles, small gains, extra weight, not a miracle solution.

As Josse is saying, there is much more to gain working on foils and that is what they logically do now.

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2 hours ago, A Class Sailor said:

Who's Simon? Are you are playing the same game as others have tried, guessing who I am. Another fail to your credit :D

I don't follow any of your "logic". You are suggesting that because they aren't using it, it doesn't work. That is completely wrong. Canting the rig works. it worked on the Groupama C Class, it works on A's and it works on boats of all scales. By "works", I mean that in a straight line, it has been proven to be faster than a non canting rig. That is not the issue. As with any form of racing, it is never the ability to produce straight line speed that counts. it is the ability to sail a particular course the quickest. At one extreme, that means that I can beat Paul Larsen and SailRocket around a standard windward/leeward course, despite his boat being capably of over double my speed. The reason why canting masts are not used in the big ocean going tris is because they were incredibly unreliable. They kept falling over the side. They also took a long time to tack/gybe during which they were very vulnerable to dropping the rig. On the A's, those who have tested canting rigs say it is faster, but the systems needed make the boat too complex to sail and a canted mast makes trapezing really tough, so we don't use it.

Your problem is that you seem to think if people are not using something, it is because it doesn't work or makes the boat slower. That is a poor deduction. There are many things we do not use that could make a boat a lot quicker, but we don't for any number of reasons. As an example, consider the A Class and wing rigs. We all know that a C Class style rig would make an A quicker. Glenn Ashby actually developed Ben Hall's A Class wing when he worked for Oracle (it was the basis of their mega wing) and he reported to the class that it would make existing rigs obsolete. Despite that, nobody else has built a wing, even though it would mean they had a significant advantage over the fleet. The reason why is simple, because one capsize would not only finish your regatta but also potentially write off a very expensive piece of equipment. Nobody is capably of sailing a foiling A on a regular basis without a capsize, so it would be stupid to use gear that cannot survive a capsize.

Stop thinking that non use or no longer used systems mean they don't make a boat faster in a straight line. This comes back to the Groupama C Class. It was the perfect size of boat with enough crew sailing in the right conditions to make it worthwhile to use a canting rig, which they did to great effect. It worked. Period.

Beating sail rocket around an upwind downwind course is like saying you could beat a top fuel drag car in  the Paris Dakar rally in a full blown desert racer.. 

as in the most pointless comparison ever. 

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3 Swiss guys target 80 kts on water.

- Wing and mast are gone.

- the rear foil will just resist against to pulling force, they claim unlimited power thanks to the super ventilating profile

- another foil in the front to control the direction

- two lateral foils to support the hull

- one aero flap at the rear for longitudinal stability

- 3 times more powerful than Vestas Sailrocket 2

 

 

https://voilesetvoiliers.ouest-france.fr/bateau/foiler/sp80-un-engin-suisse-vise-80-noeuds-a-la-voile-alors-que-le-record-du-monde-est-a-65-f8b54cae-0ad3-11ea-adb7-776ec54bacaf?fbclid=IwAR2Hz7aT0MnrAVxWL86t3OcscJO6mop6iPsILI_CiRpzD5B7huHaRVSBTnM

MjAxOTExNzAwM2EyZjA2MTQyZjQ2YjdmNWE5ODMxODQ4MDI5ZDA.jpg

MjAxOTExM2FjNjA1MWMxYzE2YzhhNmQ5NGRlZTJjMWQ0OTc0MGU.jpg

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^Dumb questions time: Has there been any kind of prototype built and splashed yet? How are the kite control lines to be manipulated?

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1 hour ago, Sailbydate said:

^Dumb questions time: Has there been any kind of prototype built and splashed yet? How are the kite control lines to be manipulated?

Trial and error?

F92AD7B7-A998-4813-9F32-F1A62AFAEC8D.jpeg

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59 minutes ago, Sidecar said:

Trial and error?

F92AD7B7-A998-4813-9F32-F1A62AFAEC8D.jpeg

Fuuuuk. Good luck with that, guys.

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7 minutes ago, Tornado-Cat said:

 

Could explain the reason of an elevator on the stern of the project.

It's not the stern they'll need to worry about. Controlling the kite will be the challenge. That pic is EXACTLY what I had in mind for a probable outcome.

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7 minutes ago, Sailbydate said:

It's not the stern they'll need to worry about. Controlling the kite will be the challenge. That pic is EXACTLY what I had in mind for a probable outcome.

Yep, and that already happened to Jacob's Ladder, a few decades ago.

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51 minutes ago, Tornado-Cat said:

Yep, and that already happened to Jacob's Ladder, a few decades ago.

Really? Jacobs ladder completed a full Ariel flip and landed just like sail rocket?

 

or they had a crash ? 

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31 minutes ago, JALhazmat said:

Really? Jacobs ladder completed a full Ariel flip and landed just like sail rocket?

 

or they had a crash ? 

They jumped in the air, I saw them sailing on the water a few days before.

And now, Le Gaignoux brothers testing one of the first kite (some had already used water skis)

jaclad2.jpg

1984._Premier_test_d'un_C-kite_par_les_frères_Legaignoux_sur_une_annexe_de_voilier.jpg

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None of that helps my understanding, TC. Obviously the concept works with a human pilot - and has for yonks. 

So, how's the kite control going to work for SP80?

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1 minute ago, Sailbydate said:

None of that helps my understanding, TC. Obviously the concept works with a human pilot - and has for yonks. 

So, how's the kite control going to work for SP80?

It seems clear that commands will be connected to a human pilot, I could tell you more about how a wing parachute works, but not a kite. I guess JALhazmat can.

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2 minutes ago, Tornado-Cat said:

It seems clear that commands will be connected to a human pilot, I could tell you more about how a wing parachute works, but not a kite. I guess JALhazmat can.

Gashby and his Xbox controller? Yeah. That could work. ;-)

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TC digging up pics from the 70s and  80s doesn’t equate to sail rocket

in terms of sp80, sail rocket set the platform and theory for the platform layout and they are now trying to move it on

in terms of control system the only thing close would be what Don Montague has done with his kite boat Over in San Francisco,

but that is with an inflated kite,  Can they adapt it to a soft foil kite in terms of launching and recovery? Then again it’s not going to have the same practically considerations as Dons kite boat did.

There are some very good/fast kite surfers involved in the SP80 program so they will have a handle on that side of it.

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8 hours ago, Sailbydate said:

So, how's the kite control going to work for SP80?

That's probably a secondary issue given the anchor point of the kite. Has anyone tried to pull something from about 2 third of its length? That takes some skills to not have the object go backwards or at least rotate a little. Really don't get how they can have the kite so far back.

For the controls, the acceleration can be controlled via a computer by iteration on 2 commands to reach max pulling force in forward direction (and eventually min in lateral), this is a stable optimum point for the kite. Stopping would be the next issue as slowly decreasing the pull would be the preferable way, contrary to the illustration a 4 line kite would be preferable to have depowering capability, instead of the software driving the kite away from it's max power zone and eventually crashing the kite or pulling the whole stuff up into the air, resulting probably in the pic above.

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30 minutes ago, Lakrass said:

That's probably a secondary issue given the anchor point of the kite. Has anyone tried to pull something from about 2 third of its length? That takes some skills to not have the object go backwards or at least rotate a little. Really don't get how they can have the kite so far back.

For the controls, the acceleration can be controlled via a computer by iteration on 2 commands to reach max pulling force in forward direction (and eventually min in lateral), this is a stable optimum point for the kite. Stopping would be the next issue as slowly decreasing the pull would be the preferable way, contrary to the illustration a 4 line kite would be preferable to have depowering capability, instead of the software driving the kite away from it's max power zone and eventually crashing the kite or pulling the whole stuff up into the air, resulting probably in the pic above.

Big thread drift, but if you are willing to trade parasitic drag for another central line cascade, you can stall the wing by pulling down at the center of the chord. Called a B-line stall on a paraglider, keeps the wing inflated and stable but takes the power out. Would work a treat.

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2 hours ago, Lakrass said:

That's probably a secondary issue given the anchor point of the kite. Has anyone tried to pull something from about 2 third of its length? That takes some skills to not have the object go backwards or at least rotate a little. Really don't get how they can have the kite so far back.

For the controls, the acceleration can be controlled via a computer by iteration on 2 commands to reach max pulling force in forward direction (and eventually min in lateral), this is a stable optimum point for the kite. Stopping would be the next issue as slowly decreasing the pull would be the preferable way, contrary to the illustration a 4 line kite would be preferable to have depowering capability, instead of the software driving the kite away from it's max power zone and eventually crashing the kite or pulling the whole stuff up into the air, resulting probably in the pic above.

It’s a graphic illustration..

it will be a four line kite set up.

 

two line would be the same as having a wing set up on an F50 with had no camber adjustment or sheeting angle. 

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12 hours ago, Tornado-Cat said:

1984._Premier_test_d'un_C-kite_par_les_frères_Legaignoux_sur_une_annexe_de_voilier.jpg

Optomist hull with an open design kite rig would be an interesting class! :lol:

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2 hours ago, JALhazmat said:

It’s a graphic illustration..

it will be a four line kite set up.

 

two line would be the same as having a wing set up on an F50 with had no camber adjustment or sheeting angle. 

Again,I suggest a 5 or 6 line with a center cascade, like a 3 line paraglider, which is really 3 each side. Gives the ability to adjust the profile with more accuracy than just flying and brake lines.

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I kite speed sail on kites, inflated and ram air.

all are referred to as four line, as that is what comes off the control bar

99.9 of kites are all bridled now either Leading edge only on the inflated or a series of three or four bridle sets on a ram air kite. All down to what they want to the kite to do and how much control over it they want through the sheeting range
 

Upwind performance relaunch are not a consideration on something like this, BUT that would mean them building their own kites 

there are plenty of brands that can do this or have very quick off the shelf offerings.

 

all down to its intended wind range and power requirement 

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11 hours ago, JALhazmat said:

I kite speed sail on kites, inflated and ram air.

all are referred to as four line, as that is what comes off the control bar

99.9 of kites are all bridled now either Leading edge only on the inflated or a series of three or four bridle sets on a ram air kite. All down to what they want to the kite to do and how much control over it they want through the sheeting range
 

Upwind performance relaunch are not a consideration on something like this, BUT that would mean them building their own kites 

there are plenty of brands that can do this or have very quick off the shelf offerings.

 

all down to its intended wind range and power requirement 

I was speaking to a method of depowering a ram air at 60kt, without loosing internal pressure. I'm pretty down with modern kites. And paragliders. You don't just release all but the leading edge cascade, or bridle as you say, if you want a wing above you still. Some method of quick, controlled depower will be found by these guys, I'm just suggesting they may look at paraglider tech to solve the problem.  I'm sure they will be building their own gear.

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Modern ram air kites are sealed so air isn’t getting dumped out of them When you sheet out on the bar, it’s an angle of attack change and profile change depending on how the cascades are set up 

for kite speed ram air kites on water are over 50kts already (2018)  with no handling issues or restrictions on depower.  As for paraglider tech all the big kite brands that make foil kites are paraglider  companies and that cross over happened years ago.

foil kites on land have gone much faster too with no issue 

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1 hour ago, JALhazmat said:

Modern ram air kites are sealed so air isn’t getting dumped out of them When you sheet out on the bar, it’s an angle of attack change and profile change depending on how the cascades are set up 

for kite speed ram air kites on water are over 50kts already (2018)  with no handling issues or restrictions on depower.  As for paraglider tech all the big kite brands that make foil kites are paraglider  companies and that cross over happened years ago.

foil kites on land have gone much faster too with no issue 

Paragliders have speed bars that change the profile dramatically across usually 3 points on the chord, giving 6 points on the harness as you say. At speed the rear, or brake lines are not used as they deflect the rear of the profile too much. Instead weight shift which slightly loads one entire side of the wing for more speed and a resultant change in course. Just saying before someone hooks up an expensive CF frame to a kite we may see some innovations in kite control to avoid a nasty overpowered situation. I'm pretty informed about the way ram air kites manage internal pressure and the results of not enough. The "shark nose" profile that all performance paragliders now use is an example of pushing design using CFD, I'm sure there will be some modifications to hit 85kt, 30% above current gear's top end.

Anyway, the thread cops will be here soon, glad to discuss this over PM as we come at this from different sides. I've been kiting for ten years but other than launches still haven't used a ram kite. Cheers

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On 11/21/2019 at 8:09 AM, Tornado-Cat said:

Yes, it worked in some conditions, I tested it myself on an old Tornado......

As for the other experiences on multis and the As, I was mainly to relieve Leeward float and push water and expected to gain a lot. I found out it helped to have the rig vertical with a small cant when the boat is heeling in order to prevent the pressure of the sail toward the water.

Thanks for this beautiful piece of Hypocrisy, and proof of your Trolling Nature........ You are such a piece of work 

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Those things are horrific...

kite buggy land speed record is 133kmh   On a 2.7m kite from 2013 I think 

just because the water speed is lower doesn't mean the kite isn’t capable  of the speed required. 

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