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#1 Thilo

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Posted 24 April 2012 - 11:11 AM

Im proud to show you our new A-Cat wing.

Photo by Andreas Hartmann

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#2 Tornado_ALIVE

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Posted 24 April 2012 - 11:23 AM

Nice, any more pics.... How about on the water.

#3 can-UK

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Posted 24 April 2012 - 11:24 AM

Nice.. looks fast!

#4 T.Paasch

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Posted 24 April 2012 - 11:47 AM

So will you race it at the German Nats next week?

#5 Tony-F18

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Posted 24 April 2012 - 01:06 PM

Awesome location for pictures as well, must have been quite a bit of work to get it in there.

#6 Dog

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Posted 24 April 2012 - 01:20 PM

Beautiful!...I think this is the next area of exploration for the class.

#7 Acatman

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Posted 24 April 2012 - 01:47 PM

I think there is one being built in melbourne. Possiible for a flyer2

#8 pontoon

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Posted 24 April 2012 - 01:49 PM

What is the weight of the mast. Looks very nice btw

#9 AUS

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Posted 24 April 2012 - 02:18 PM

Thilo, crazy crazy... That looks amazing! Are you coming to Europeans?

Cheers Ben Moon

#10 SimonN

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Posted 24 April 2012 - 02:51 PM

Looks great. Some more pics would be nice. And yes, what does it weigh!

#11 TornadoSail2016

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Posted 24 April 2012 - 03:43 PM

Love the looks of your new wing. Looks to be a big step above Ben's first wing. Where are you testing it?

#12 PJD

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Posted 24 April 2012 - 04:03 PM

Yo Thilo

that looks really cool.

When is the first test / what about wismar next week? cu there.

PJ

#13 PJD

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Posted 24 April 2012 - 04:37 PM

http://prezi.com/qm-...need-for-speed/

Check out this link . pretty impressive project.
Will be really interesting to see how Thilo is performing against the soft rigs........
His wing looks highly sophisticated,state of the art.

Looking forward to see what can be learnt in terms of performance possibilities on an A.
The latest soft rigs with the flexible masts are so well developed nowadays ,they will be hard to beat over a wider wind range...

But good that Thilo is trying this out!





PJ

#14 SimonN

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Posted 25 April 2012 - 12:43 AM

Great link, PJ and all credit to the team for posting all that detail.

This is something I have been planning for nearly 2 years but keep pulling back from for one reason and one reason only - weight. It's not just a matter of keeping the boat down to 75kgs, which I believe is achievable. The real problem is the distribution of that weight. In all the calculations I have done, the centre of gravity of the rig moves up and the overall weight is heavier than a conventional mast and sail. This isn't a problem on flat water but ever time I get close to starting to build, I sail in choppy conditions and even witha conventional rig, I get horrified at how much the inertia from the rig effects upwind pitching. It leads me to believe that a wing will be faster on flat water and downwind, but upwind in chop, I think it is a killer. I then heard that this is exactly what Ben Hall found. He called it "the tail wagging the dog".

Unless shown otherwise, I will only go ahead when I can work out a way of building a wing that is light enough and with a low enough centre of gravity. As such, I would love to know how much this wing weighs! However, for all of that, great respect and all the best to Thilo for doing this. It's really exciting!

#15 Dog

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Posted 25 April 2012 - 12:51 PM

Interesting point, On the other hand, a soft sail requires high tension loads to shape it which have to be resolved in the structure. I would expect using a wing would permit reductions of weight in the platform. However the higher center of gravity is a negative. I guess in the C class with 25 length pitching is less of an issue.

#16 AClass USA 230

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Posted 25 April 2012 - 12:56 PM

Great link, PJ and all credit to the team for posting all that detail.

This is something I have been planning for nearly 2 years but keep pulling back from for one reason and one reason only - weight. It's not just a matter of keeping the boat down to 75kgs, which I believe is achievable. The real problem is the distribution of that weight. In all the calculations I have done, the centre of gravity of the rig moves up and the overall weight is heavier than a conventional mast and sail. This isn't a problem on flat water but ever time I get close to starting to build, I sail in choppy conditions and even witha conventional rig, I get horrified at how much the inertia from the rig effects upwind pitching. It leads me to believe that a wing will be faster on flat water and downwind, but upwind in chop, I think it is a killer. I then heard that this is exactly what Ben Hall found. He called it "the tail wagging the dog".

Unless shown otherwise, I will only go ahead when I can work out a way of building a wing that is light enough and with a low enough centre of gravity. As such, I would love to know how much this wing weighs! However, for all of that, great respect and all the best to Thilo for doing this. It's really exciting!


It's exciting and sexy for sure and Simon is spot on to what Ben Hall found with his wing rig. But also what Ben found was the rig became a two person job to setup that required more time, is more complicated to transport, and is most assuredly more expensive than the current soft rigs. If Thilo has come up with a rig that overcomes the weight and upwind pitching issues above, the class will be holding it's breath as to whether the sailors who win the regattas will only be those who can afford and live with a wing. Not mentioned also is the durability issue. What happens in a hard capsize with the sailor possibly on top of the capsized rig? The current rigs have a good chance of surviving that type of incident unharmed. And finally, I doubt our insurance companies would insure a boat with a wing rig (or might initially but after the first claim for a broken wing ban us from coverage). I don't think the AC crews are calling Boat US when they crash one of their rigs.

I hate to be the one to sound negative because I do appreciate what Thilo and Ben have done but realistically with the current degree of development allowed in the class, a successful wing rig will have significant implications to how the class will progress in the future.

#17 TornadoSail2016

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Posted 25 April 2012 - 02:48 PM

It's exciting and sexy for sure and Simon is spot on to what Ben Hall found with his wing rig. But also what Ben found was the rig became a two person job to setup that required more time, is more complicated to transport, and is most assuredly more expensive than the current soft rigs. If Thilo has come up with a rig that overcomes the weight and upwind pitching issues above, the class will be holding it's breath as to whether the sailors who win the regattas will only be those who can afford and live with a wing. Not mentioned also is the durability issue. What happens in a hard capsize with the sailor possibly on top of the capsized rig? The current rigs have a good chance of surviving that type of incident unharmed. And finally, I doubt our insurance companies would insure a boat with a wing rig (or might initially but after the first claim for a broken wing ban us from coverage). I don't think the AC crews are calling Boat US when they crash one of their rigs.

I hate to be the one to sound negative because I do appreciate what Thilo and Ben have done but realistically with the current degree of development allowed in the class, a successful wing rig will have significant implications to how the class will progress in the future.

Bob,

You bring up many great points here. One that I had not thought about was the insurance issue and I can see this being a problem. When watching the vidoes on them setting this wing up it looks like three people were involved. I am not sure if this is because it is new and they are learning how to work with the wing or if it will take 2-3 each time it is raised. It also looks like a taleer wing then Ben's was and I remember the aluminum sail box he built for his for transporting it. this could be the other big issue with wings especially if you are traveling a distance to compete in events like the upcoming worlds in Islamorada.

TTS

#18 SimonN

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Posted 25 April 2012 - 03:07 PM

The insurance issue is real, but I think that we would not be looking at total write offs and most wing damage could be repaired. It's interesting that in the Moths, Adam May made the lightest wing but it was also the strongest, due to it being more simple than the wings Bora had.

As for the rigging, I am sure that a wing can be rigged on your own with some thought about systems, but just like now with our current masts, most prefer to have a hand in raising the mast (or at least we do in Oz!). I can see that it is likely to take up more space in the boat park as the wing is assembled and prepared to be raised.

I suspect that if somebody makes a wing work in a wide enough range of conditions, we will find ways to overcome the problems. And overall, a wing is likely to be cheaper to run that the current rigs as you won't have to buy a new sail every season (or whatever it is you do). Even if wings develop and you need a new one, the second hand markety for a wing will be a lot better than for a sail, as it should be far easier to keep in good condition and it won't stretch.

#19 AClass USA 230

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Posted 25 April 2012 - 03:26 PM

The insurance issue is real, but I think that we would not be looking at total write offs and most wing damage could be repaired. It's interesting that in the Moths, Adam May made the lightest wing but it was also the strongest, due to it being more simple than the wings Bora had.

As for the rigging, I am sure that a wing can be rigged on your own with some thought about systems, but just like now with our current masts, most prefer to have a hand in raising the mast (or at least we do in Oz!). I can see that it is likely to take up more space in the boat park as the wing is assembled and prepared to be raised.

I suspect that if somebody makes a wing work in a wide enough range of conditions, we will find ways to overcome the problems. And overall, a wing is likely to be cheaper to run that the current rigs as you won't have to buy a new sail every season (or whatever it is you do). Even if wings develop and you need a new one, the second hand markety for a wing will be a lot better than for a sail, as it should be far easier to keep in good condition and it won't stretch.


Good points but I still believe handling (off the water) for a single sailor could be a significant issue to still overcome especially if you enjoy the simplicity and ease of setup, breakdown, and transport of the current rigs. I'm skeptical about a single sailor setting up a wing rig and getting on and off the water safely on a windy and gusty day. I like that I can launch or retrieve my boat with the sail down if I need to. I watched Ben launch his wing rig several times and he always had a helper standing by. A Moth wing is a lot smaller than an A-Class wing so I am sure much easier to deal with. Still, it would really turn the heads of my local yacht club to see me with a wing rig!

#20 SC65

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Posted 25 April 2012 - 04:55 PM

Why is it that each time someone comes up with something bold and amazing in what is considered to be a construction class, the critics emerge from the graves and start whispering that it is not practical... etc.
There had never been a hrydrofoiling A-Cat which proofed to be faster than the conventional designs, yet the pure fear of it led to significant rule alterations til today limiting the potential of the A-Class, yet it did not prevent the emergence of curved daggerboards, outclassing conventional boards in most conditions. Wing sails first have to proof that they are faster, and there probably will be a day they will, or maybe this one is already, but it's all part of the game. Is it healthy for the class? Probably not, but the spirit of a construction class is not to slow down or hinder development, but to encourage it. There is always a choice. We can all sail lasers or other one designs, if we want to exclude the design aspect for defining of what is the fastest combination of sailor and boat.

The moth class got so paranoid last year, when Bora showed his wing, that people were immediately calling for it to be banned, although it so far hasn't proven to be faster than the conventional rig.
In contrast, when someone comes up with faster foils, no one complains, since everyone nowadays accepts those lifting foils as a standard, Rohan Veal was crucified for not that long ago.

My point is we should encourage development rather than starting to discuss all the potential negatives. Life is all about dreams and I appreciate those who share theirs with us.

My 2 cents.

#21 samc99us

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Posted 25 April 2012 - 04:59 PM

Droooool on the platform!

On the insurance issue, I don't see how this is any different than how the boats are insured now. You insure the boat for the value of the platform+rig. Most companies won't insure sails. In the case of a wing, I would think the insurance company would at least cover the front mast portion. The rest, well, time to learn how to work with carbon!

The bigger issue is certainly durability. If lots of people are flipping and breaking rigs, crying to the insurance company than it is likely they will simply stop insuring A-Cat's period. Fortunately, most of the cat racing community I've been a part of turns to insurance as a last resort. I would think more people will become proficient in repair work and more builders may step into the class as building wing sails can be fun!

I haven't been following the Moth developments lately,and am failing to recall if wings were banned in that class? Is development still ongoing in Moth wing world?

#22 PJD

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Posted 25 April 2012 - 06:34 PM

Insurance is about the last thing i thouhgt of !
Catamarans are anyway hard to insure all-risk in Holland. Racing is excluded.
Many racers only carry 3rd party liability insurance

The big challenge with a wing sail is making it work all over the wind range, and make it pratical.
Like an inflatable kitesurf like wing or something. A really innovation step would be welcome,not an AC or C replica .

Gybing an carbon piece of art like Thilo's wing in 25kts wind , trying to make the gate in the heat of the fight....... then you also need carbon balls .....
Looking forward to see theThilo's wingracing in EU.


PJ

#23 blunted

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Posted 25 April 2012 - 07:01 PM

Bravo, nice job guys.

B

#24 Amati

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Posted 26 April 2012 - 12:28 AM

You should be proud. Diggin' the building too. Testing should be fun!

#25 pontoon

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Posted 26 April 2012 - 06:40 AM

.......................
Gybing an carbon piece of art like Thilo's wing in 25kts wind , trying to make the gate in the heat of the fight....... then you also need carbon balls .....
Looking forward to see theThilo's wingracing in EU.


PJ


This exactly why i did ask for the weight of the mast, it is a state of the art piece of work but what is it's weight.
I have seen Ben Hall sailing with his wing in 2007 and made some photo's on shore and it was very nice to see how it was made and this mast would be probably the same.
Ben sailing in free air was down wind absolute faster then the others . Interesting to see how the development continues.

Hans

#26 Thilo

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Posted 28 April 2012 - 10:10 AM

english version here
http://prezi.com/atr...il-development/

#27 AClass USA 230

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Posted 28 April 2012 - 11:49 AM

Why is it that each time someone comes up with something bold and amazing in what is considered to be a construction class, the critics emerge from the graves and start whispering that it is not practical... etc.
There had never been a hrydrofoiling A-Cat which proofed to be faster than the conventional designs, yet the pure fear of it led to significant rule alterations til today limiting the potential of the A-Class, yet it did not prevent the emergence of curved daggerboards, outclassing conventional boards in most conditions. Wing sails first have to proof that they are faster, and there probably will be a day they will, or maybe this one is already, but it's all part of the game. Is it healthy for the class? Probably not, but the spirit of a construction class is not to slow down or hinder development, but to encourage it. There is always a choice. We can all sail lasers or other one designs, if we want to exclude the design aspect for defining of what is the fastest combination of sailor and boat.

The moth class got so paranoid last year, when Bora showed his wing, that people were immediately calling for it to be banned, although it so far hasn't proven to be faster than the conventional rig.
In contrast, when someone comes up with faster foils, no one complains, since everyone nowadays accepts those lifting foils as a standard, Rohan Veal was crucified for not that long ago.

My point is we should encourage development rather than starting to discuss all the potential negatives. Life is all about dreams and I appreciate those who share theirs with us.

My 2 cents.


Question for you is if you are an A-Class sailor or outside the class.

If Thilo's wing turns out to be superior to the current generation of rigs (and there is a better than 50/50 chance it could), the implications to the class will be significant in both positive and negative ways. I have concerns I'll no longer be able to afford to play the game at that level. It will be what it will be based on how the class decides to manage this technology if it proves superior in performance in all conditions.

#28 SimonN

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Posted 28 April 2012 - 12:33 PM

Looking at cost isn't, IMO, the key issue. I think there is a strong argument to say that while the short term cost of buying a wing is significantly more than buying a mast and sail, the longevity of a wing means that the lifetime costs go down. In addition, there is a lot more chance of home building of wings and, maybe a little more realistic, I would expect to see kits for home completion. If a new, better wing comes along, your existing wing should still have lots of life in it so it can be sold on.

The real problem is practicality and that is a whole different story. Just for starters, imagine at a regatta having to drop the rig at night. Then look at how quickly you can rig and egt on teh water at the moment. Steve Brewin maintains he can be on the water 12 minutes after arriving at a venue (which is why he is so often late!!). Even if we take that with a pinch of salt, it really will take a lot longer to rig a wing, it needs more space and it needs help from others.

I do believe that wings will have a negative effect on the class, but is that a reason to ban it. If we wanted the class to be as big a spossible, we would need to reduce all development because that certainly puts off people. Look at masts. You simply cannot be consistantly competitive without a new generation mast and i know people are put off the class on that one factor alone.

The bottom line is that development classes are exactly that and to start saying we should stop certain developments because it will effect popularity is totally against teh spirit of a development class. A development class says that it stays true to it's purpose. In fact, one of the things I love about the Int.14 is that if things become static for too long, they change the rules to get development going again.

This whole "ban it" concept is also wrong on another level. It is saying we can forecast what will happen to a class and although I make a prediction above, I do not know that wings will be negative for the class. I heard exactly the same things in the Moth class but about foils. There were calls to ban foiling because it made the boat too hard to sail, launching was too difficult and it made the boats a lot more expensive.I don't think any of the pro-foiling lobby forecast it would lead to a huge boom in Moths but they won the day anyway and now look what has happened. The reason it didn't get banned is because of the development spirit of the class even though many felt it would harm the class.

In some ways I hope wings do prove good, because I have the design of a wing here and have been lacking the conviction to build. I do know that if we do go over to wings, we will go through a period of pain. For me, that pain will be finding ways to make rigging so much easier, as I am sure it will be in the end.

Of course, the very fact I support not banning the wing means it will be banned. in most development classes I have sailed, there has at some point been a kneejerk reaction to a development leading to a ban that I have fought hard against. I hate kneejerk reactions in development classes because people vote with their own personal agenda and wallet without thinking about the good of the class in general In many cases, the bans I have seen have now been overturned after people have fully understood what they banned when another class has shown it is OK.

#29 Jose Dauden

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Posted 28 April 2012 - 03:32 PM

Congrats Thilo, fantastic job - hats off to you and your team!!!

Dont give up and keep pushing the winged A-Cat!

The arguments of those defending "keep things as they are", are valid, but guys, dont forget that if it was not for innovation, all of you guys wouldnt be sailign the fantastic A-cats you have today...

Thilo, would you and your friends be open to build one of these wings "scaled-up" for a Tornado?

I am serious. I have been dreaming of this for years, but there is no chance I can get people with knowledge and technical means to build one here.

If positive, please write to me at cdauden@uol.com.br

Sail fast, cheers,

Jose

#30 SC65

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Posted 28 April 2012 - 05:29 PM


Why is it that each time someone comes up with something bold and amazing in what is considered to be a construction class, the critics emerge from the graves and start whispering that it is not practical... etc.
There had never been a hrydrofoiling A-Cat which proofed to be faster than the conventional designs, yet the pure fear of it led to significant rule alterations til today limiting the potential of the A-Class, yet it did not prevent the emergence of curved daggerboards, outclassing conventional boards in most conditions. Wing sails first have to proof that they are faster, and there probably will be a day they will, or maybe this one is already, but it's all part of the game. Is it healthy for the class? Probably not, but the spirit of a construction class is not to slow down or hinder development, but to encourage it. There is always a choice. We can all sail lasers or other one designs, if we want to exclude the design aspect for defining of what is the fastest combination of sailor and boat.

The moth class got so paranoid last year, when Bora showed his wing, that people were immediately calling for it to be banned, although it so far hasn't proven to be faster than the conventional rig.
In contrast, when someone comes up with faster foils, no one complains, since everyone nowadays accepts those lifting foils as a standard, Rohan Veal was crucified for not that long ago.

My point is we should encourage development rather than starting to discuss all the potential negatives. Life is all about dreams and I appreciate those who share theirs with us.

My 2 cents.


Question for you is if you are an A-Class sailor or outside the class.

If Thilo's wing turns out to be superior to the current generation of rigs (and there is a better than 50/50 chance it could), the implications to the class will be significant in both positive and negative ways. I have concerns I'll no longer be able to afford to play the game at that level. It will be what it will be based on how the class decides to manage this technology if it proves superior in performance in all conditions.


I believe decisions in a construction class should not be driven by fear but rather by fascination and courage. Because of fear, there is a minimum weight (which luckily was initiated when the boats were quite light already and not 105 kg as 20 years earlier), an ill issued ballot to ban hydrofoils (which required a lot of work and negotiation to be refined, and yet didn't prevent the emergence of curved boards, making all earlier platforms outdated within one year), and the constant talk that this and that should be banned to limit costs and to allow further the growth of the class. The good old time however, where a Bim 2000 for 8.000 Euro would be an affordable and competitive starter boat are long gone and all efforts to keep costs down have not led to the desired effects. I also think the times where people built A's in their garage are mostly gone. There are noticeable exceptions but the majority of sailors like to buy a competitive package ready to sail straight out of the box. Then there is this talk that wings, hydrofoils etc harm the class, yet as soon as someone puts something up like Thilo or earlier Ben Hall, it immideatley draws significant attention and makes it to the frontpage of sailing magazines over night. How can publishing harm the class?

There are various ways to respond to a development, where the class associations feel the need to cater for their members needs or concerns. Please be reminded for a moment that class associations are built around the class definitions, they always have a political agenda which can be in dispute to the spirit of the original class rules they refer to. Specially in the A-class, a lot of members don't really care whether it's a construction class, they joined the class because the boat is cool, the racing tight and the fleets growing etc... but they might also prefer that their costly boat remains competitive as long as possible, which is surely not something you can demand from a construction class, which should stimulate creative developments and constant evolution.

The moth, like various people have pointed out, went to such an transistion. Nowadays boats are very expensive, pretty fragile, highly impractical (setting up, rigging, launching, sailing) and yet despite all those potential class killer attributes... booming! There is no weight limit in the class but there are many restrictions not even published, where certain developments have been banned for the so called benefits of the class. Personally, I believe most limitations have been always supported by the builders, who have the interest to build their boats with the least changes as possible over a long period of time, to reduce costs for tooling and to ensure vital profit...

So where do you draw the line? Th A-class didn't ban carbon masts, which made the ceaper aluminium masts obsolete. There were many advantages in the carbon mast, the next evolution to wing sails might not offer. In the moth class, sailors accept the negatives for the pleasure and excitement the current package can generate. But even their, wings are greeted with reservation. For the A, the class should learn from their mistakes and not ban something which isn't there yet. Once something threatening is around, there are other ways to encourage development rather than banning it. It would be easy to sail together, yet defide results into a wingsail development class and the softrig fraction, simialr what the mini 6.50 were doing. There might be other ways to allow the wing protagonists to race without 'killing' the class. Like the freaks who bring these astonishing achievements to the party, the class needs to remain creative and courageous as well. Banning is already done in one design classes, where it belongs to ensure all boats are as equal as possible.

#31 tiger11

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Posted 28 April 2012 - 07:23 PM

What a stunning looking wing ____
My concern would be how do you transport it to regattas ?___
where do you store it ?
I sail at a club where we all (12 As) store our boats in undercover racks and hang our masts from the ceiling, we would have to build a new club house to store wings !

#32 captain horizon

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Posted 28 April 2012 - 10:47 PM

Great looking wing Thilo!I just want to clear up some misinformation on the front page story. Firstly the wing was by no means overweight. I was told by all the expert wing nuts that I would be hard pressed to build a wing that was less than 34 kg. my original weight goal was 27.2 kg or less. In fact the final all up weight was 24 kg. this compares to a mast, sail, battens, boom, Mainsheet system and traveler at 21.2 kg. The big difference is that the CG of the wing is about 2 meters higher than the soft rig. As reported in this thread, this dramatically increased the pitching and really hurts upwind performance even in a moderate chop. It will be interesting to see if Thilos wing is lighter. I think he will experience the same thing I did especially in a venue like Islamorada if the wind is out of the NE to SEE directions. The C class also suffers from pitching due to the wing weight but it not nearly as dramatic as the A Class. And no the stiffness of the rig was also not a problem . The real problem was time in the boat learning the rig.I built my rig in 2007 but I doubt that other than maybe design improvements that the rig was built with new or higher technology. The majority of the components in my rig were autoclave cured using high modulus carbon. I noticed in Thilos blog that all his components were wet layup. Lots of ways to build things but certainly wet layup is not higher tech than autoclaved parts.As far as rigging the boat with the wing, not that big a deal. My wife Nan (wing Sherpa) helped me each morning at the Worlds install the rig. It took an average of 25 minutes from trailer storage to ready to launch. Heck at my age it almost takes that long to suit myself up for a days sailing. I did make a special trailer to transport and store the wing but judging from the cool trailers I have seen in Europe and the US lately this is a minor problem. I suppose if everyone in the boat part had wings it could be a logistic problem. Cost of the wings certainly is a big factor. Even with doing a lot of the work myself the cost of my wing was close to that of a complete new boat. To achieve the weight that will be competive expensive materials need to be used. I was was right on minimum weight at the Worlds at 75kg.It will interesting to see how Thilo does at Lake Garda in the big breeze. Good luck and hope all the great design and hard work pays off.
Ben HallUSA 99

#33 SimonN

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Posted 28 April 2012 - 10:57 PM

What a stunning looking wing ____
My concern would be how do you transport it to regattas ?___
where do you store it ?
I sail at a club where we all (12 As) store our boats in undercover racks and hang our masts from the ceiling, we would have to build a new club house to store wings !

Most wing designs I have seen are for 4 piece wings and as such, they could be stored between the huls on the racks. What would be needed is a frame to take them, but that wouldn't take too much work, although, yes, it would take some. As for tramsport to regattas, again, it would need a frame to place the parts of the wing on top of the platform, but it is all achievable.

I wonder whether the issue is really practicality or more to do with the changes we would need to make to make it practical. For instance, I admit that designing and making a frame to transport the wing is an added PITA on top of actually making the wing. The good news is, rather like with trailers, once you have it, you won't need another.

Having said all of that, I do expect that if succesful, wings will be banned. It's another reason why I have put off making one - if I do a good job and it works, I will be limiting the lifespan of my investment.

#34 Thilo

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Posted 28 April 2012 - 11:37 PM

Hey,

thanks for the compliments!

I ll try to answer most of the questions I read in the posts:

First of all, it is realy difficult to rig the wing. We decided to go for a way like the C-Class is doing it. But still you will need an extra or two hands.
Transport and storing is easy. I ve got a big box trailer, where I leave the boat inside, even during the winter, which can be really tough here.

Building the wing is possible at home, atleast if you have a big garage. We got the offer to build it at our university in a place 6 by 14m. Thanks for that and a big thank you to all our sponsors as well.
I use more or less the same tools I build my boat with. The only tool we bought for the wing was a CNC 3 axis milling maschine.

Even the problem to insure the wing isnt any. My boat insurance offert me to insure it for 1.5% of the value.
If anybody needs a contact, also for any normal A-Cat, give me a call.

In the end I hope that the Class will be gently enough to not ban a wing or any other thing equal. I was one of the first how experemented with curved foil and had a full setup for real foil, but then the Class baned them.
Hopefully we will not see anything like that again.

Now I ll prepare for the next tests. And if everthing works like we want, we will see the wing racing soon.
And please no more questions about when I ll race it the first time or wheather I ll race it at the German Championship next week. You ll all the wing performing when the time has come.
I dont want to be in a desaster like the MaySink last year.

#35 captain horizon

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Posted 29 April 2012 - 01:29 AM

1335653834[/url]' post='3691173']

1335641028[/url]' post='3690983']
What a stunning looking wing ____
My concern would be how do you transport it to regattas ?___
where do you store it ?
I sail at a club where we all (12 As) store our boats in undercover racks and hang our masts from the ceiling, we would have to build a new club house to store wings !

Most wing designs I have seen are for 4 piece wings and as such, they could be stored between the huls on the racks. What would be needed is a frame to take them, but that wouldn't take too much work, although, yes, it would take some. As for tramsport to regattas, again, it would need a frame to place the parts of the wing on top of the platform, but it is all achievable.

I wonder whether the issue is really practicality or more to do with the changes we would need to make to make it practical. For instance, I admit that designing and making a frame to transport the wing is an added PITA on top of actually making the wing. The good news is, rather like with trailers, once you have it, you won't need another.

Having said all of that, I do expect that if succesful, wings will be banned. It's another reason why I have put off making one - if I do a good job and it works, I will be limiting the lifespan of my investment.

Not a good idea Simon. If you try to put a wing on a framework on top of your platform it would be ripped to shreds at highway speeds. Absolutely needs to be in an enclosed trailer

#36 SimonN

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Posted 29 April 2012 - 03:55 AM

1335653834[/url]' post='3691173']

1335641028[/url]' post='3690983']
What a stunning looking wing ____
My concern would be how do you transport it to regattas ?___
where do you store it ?
I sail at a club where we all (12 As) store our boats in undercover racks and hang our masts from the ceiling, we would have to build a new club house to store wings !

Most wing designs I have seen are for 4 piece wings and as such, they could be stored between the huls on the racks. What would be needed is a frame to take them, but that wouldn't take too much work, although, yes, it would take some. As for tramsport to regattas, again, it would need a frame to place the parts of the wing on top of the platform, but it is all achievable.

I wonder whether the issue is really practicality or more to do with the changes we would need to make to make it practical. For instance, I admit that designing and making a frame to transport the wing is an added PITA on top of actually making the wing. The good news is, rather like with trailers, once you have it, you won't need another.

Having said all of that, I do expect that if succesful, wings will be banned. It's another reason why I have put off making one - if I do a good job and it works, I will be limiting the lifespan of my investment.

Not a good idea Simon. If you try to put a wing on a framework on top of your platform it would be ripped to shreds at highway speeds. Absolutely needs to be in an enclosed trailer

What's to stop the framework having a lid? There is no need for an enclosed trailer, although some may find that easier. However, to modify an existing trailer to an enclosed one is a lot more difficult than making a frame to sit on top of the boat. On the other hand, a fair number of trailers here in Oz have a ox on them already. I haven't measured mine, but wouldn't be surprised if it wasn't possible to put a framework on there to take a wing. Maybe it is easier than I thought!

#37 SimonN

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Posted 29 April 2012 - 04:37 AM

Hi, Thilo. A few comments

Hey,

thanks for the compliments!

I ll try to answer most of the questions I read in the posts:

First of all, it is realy difficult to rig the wing. We decided to go for a way like the C-Class is doing it. But still you will need an extra or two hands.

I was really surprised to see that. Ben Hall rigged his boat on its side and IMO, it seems to me to be the safest and easiest system. It's how the Moth guys rig their wind. The C's don't really have that option because of weight and height. The challenge with their way is that if the wind isn't from a constant direction, it all gets a bit crazy. There was a video of teams hoisting the wing in the last LAC that put me off that technique! However, whichever way you do it, extra hands are pretty useful!

Even the problem to insure the wing isnt any. My boat insurance offert me to insure it for 1.5% of the value.

I think the concern is about what happens after the first few claims. I hope you don't break your wing, but if you do, it will mean that 100% of A Class wings in Europe have had claims and you won't get insurance unless the insurers think it was a one off event. the other factor that would be interesting to know is how much you have the wing insured for. I would imagine the commercial cost of a wing is going to be significantly more than a current mast and sail.

In the end I hope that the Class will be gently enough to not ban a wing or any other thing equal. I was one of the first how experemented with curved foil and had a full setup for real foil, but then the Class baned them.
Hopefully we will not see anything like that again.

I share your sentiment but there are strong feelings about this. I think the only way of us not seeing a reaction is either if you aren't fast or you can show that it really isn't more trouble. Enclosede trailers, extra people to rig the boat, not beinga ble to leave the rig up overnight and more are all things that will make people react. Just by way of example, where we had our Nationals last year in Queensland, the boats were left on a beach with no more than 300mm between boats, the water coming up to about 1 metre away from the boats and the other side of the boats was a small bank and the road. I really am not sure how you would have been able to rig a wing on that beach. Even taking masts down was done by wheeling the boats back onto the road. There would have been nowhere to store the wings overnight as the trailers weren't kept next to the boats.

I know this might seem like I am just being negative but I am actually a supporter of wings in the class. However, it is up to those of us who want wings to prove to the others that theycan be practical enough

Now I ll prepare for the next tests. And if everthing works like we want, we will see the wing racing soon.
And please no more questions about when I ll race it the first time or wheather I ll race it at the German Championship next week. You ll all the wing performing when the time has come.
I dont want to be in a desaster like the MaySink last year.

Good policy. At least you aren't making huge claims for your wing before you sail. Good luck with the trials.

BTW, I am sure it was deliberate, but you forgot to tell us how heavy the wing is :D

#38 Rawhide

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Posted 29 April 2012 - 06:56 AM

Im proud to show you our new A-Cat wing.

Photo by Andreas Hartmann

That is the sexiest thing on water I have seen for a long time. Can I get one as a kit, with all the pieces numbered so I don't build it upside down?
Nothing personal, but I hope (and expect) that wings will remain a novalty. I would rather sail in a fleet of 60+ with soft sails than 10 with wings. but would love one to play around with.

#39 RParentsail

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Posted 29 April 2012 - 10:42 AM

How did you even get it in that building?!

#40 Catnewbie

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Posted 29 April 2012 - 11:02 AM

Congratulations Thilo, great job.

With regards to the pitching moment issue, and height of wing's GC, I would like to take advantage of Thilo& Ben Hall attendance on this forum to provide a suggestion which is also a question.

Instead of C-Cat where the crew moves under the wingsail for tacks and jybes, it seems that for an A-Cat, the crew will move behind the wingsail.

Considering both aerodynamic efficiency and pitching moment issue, I have been wondering why not to close the gap between the wingsail's foot and the trampoline ?

Doing so one would increase the wing aspect ration by a factor 2 (from 5 to 10), decrease induced drag significantly, as illustrated in the JavaFoil user's guide (page 25), and consequently increase Lift/Drag ratio.

This significant pick-up in efficient could lead to lower wing, with lower GC, reducing pitching moment accordingly.

Best regards

W

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#41 Thing1

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Posted 29 April 2012 - 11:02 AM

Truely, it is a thing of beauty.

One of the things I love about the A-class is the elegance and simplicity of great design. In the wing I see elegance, but no simplicity.

As a midfleet (on a good day) sailer, if it becomes the new standard, and the soft sail B fleet is not well catered for, I'm out of the class.

T1

#42 furling

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Posted 29 April 2012 - 11:26 AM

I want one just like that one but i want mine to be inflatable with carbon stiffeners velcroed to the sides for added support, bit like an exo-skeleton. How cool would that be, just blow up your main

#43 captain horizon

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Posted 29 April 2012 - 12:30 PM

Congratulations Thilo, great job.

With regards to the pitching moment issue, and height of wing's GC, I would like to take advantage of Thilo& Ben Hall attendance on this forum to provide a suggestion which is also a question.

Instead of C-Cat where the crew moves under the wingsail for tacks and jybes, it seems that for an A-Cat, the crew will move behind the wingsail.

Considering both aerodynamic efficiency and pitching moment issue, I have been wondering why not to close the gap between the wingsail's foot and the trampoline ?

Doing so one would increase the wing aspect ration by a factor 2 (from 5 to 10), decrease induced drag significantly, as illustrated in the JavaFoil user's guide (page 25), and consequently increase Lift/Drag ratio.

This significant pick-up in efficient could lead to lower wing, with lower GC, reducing pitching moment accordingly.

Best regards

W



Yes with my wing you would go behind the wing in tacks and jibes. I like your idea of a tramp sweeping wing but extra care would be needed to make sure the curved boards would not be in the way (ie down) during jibes. Even with straight boards I put a couple of holes in the wing when the boards were up.And Thilo rigging the wing with the boat on the side is WAY easier than the C Class method.

#44 sailingkid

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Posted 29 April 2012 - 12:59 PM

The only way the class became the awsome speed machine they are now is through allowing development. To ban something because its too hard to transport seems stupid to me. I'm sure there were ban it! Reactions when the carbon mast first came out, or maybe the first non-timber boat. The class already banned foils, before we got a chance to see if a fully foiling A is faster then a traditional displacement boat, and in the end curved boards became more refined and made most of the fleet obsolete pretty quickly anyway.

I feel that we risk becoming like a controlled development class, e.g you can do whatever you like as long as it fits in an 18' long box, but you can't have foils because they're expensive, and you can't have wings because people couldnt figure out how to change their trailers even though most of the fleet (myself included) still need to

#45 sailingkid

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Posted 29 April 2012 - 01:02 PM

Spend 5k on the latest mast. Sorry for the split posts, my phone crashed.

Sorry if that came across as harsh but I feel a development class should remain just that. Well done on the wing by the way, it looks great.
Sailingkid

#46 pcraig

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Posted 29 April 2012 - 07:19 PM

Ben Hall rigged his boat on its side and IMO, it seems to me to be the safest and easiest system. It's how the Moth guys rig their wind. The C's don't really have that option because of weight and height. The challenge with their way is that if the wind isn't from a constant direction, it all gets a bit crazy. There was a video of teams hoisting the wing in the last LAC that put me off that technique! However, whichever way you do it, extra hands are pretty useful!


Simon, for info the wing on Invictus was rigged in the same way as Bens A-class wing, ie the boat was tipped on its side. The reason we broke Invictus at the 2004 event was that a gust caught the tramp while she was on her side and she righted herself and smashed the top hull down onto the dolly smashing the hull and knocking a bulkhead out. Since then the subsequent Invictus wings have been rigged like the other Cs. Its definately the safest way to rig the boat.

#47 samc99us

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Posted 29 April 2012 - 10:42 PM

Congratulations Thilo, great job.

With regards to the pitching moment issue, and height of wing's GC, I would like to take advantage of Thilo& Ben Hall attendance on this forum to provide a suggestion which is also a question.

Instead of C-Cat where the crew moves under the wingsail for tacks and jybes, it seems that for an A-Cat, the crew will move behind the wingsail.

Considering both aerodynamic efficiency and pitching moment issue, I have been wondering why not to close the gap between the wingsail's foot and the trampoline ?

Doing so one would increase the wing aspect ration by a factor 2 (from 5 to 10), decrease induced drag significantly, as illustrated in the JavaFoil user's guide (page 25), and consequently increase Lift/Drag ratio.

This significant pick-up in efficient could lead to lower wing, with lower GC, reducing pitching moment accordingly.

Best regards

W


Someone needs to check there math. Adding 2 feet to the base of the mast isn't going to double your aspect ratio. The formula is b^2/S, where b=wing span and S=wing area. Wing area=sail area= fixed at 150 ft^2. Mast length is ~9 meters, or 29.5 ft. Assuming you have a 2 foot gap on your current boat, the mast height is effectively 27.5 feet. Current soft sail rigs thus have an AR=5.05. Add 2 feet for a deck mounted boom, your effective mast length is now 29.5 ft (not practical but close for arguments sake), that gets you an AR=5.8. Ignoring Reynolds number effects, drag goes down as AR goes up, so max theoretical performance increase is a 15% drag reduction of the rig. Taking into account some loss of lift for the lost area at the top of the rig and you might be closer to 10% theoretical drag reduction of the rig. 10% is certainly significant in a racing boat, but you look at the additional factors involved that Ben has mentioned and I have seen on some near deck-swept rigs (18 squared), I doubt you'll see the performance increase. One blown tack and it's all out the window.

The advantage would mostly be in lowering the C.G of the rig, which may be a significant problem. We do not know what weight Thilo's rig is or where the C.G is at. I doubt it is better than Ben Hall's, simply because of the construction methods, but it is possible if things were designed and rigged differently. Either way, I certainly think A-Cat wings have a future and the c.g issue is potentially lessened by the curved foils addition of pitching stability to the boat.

#48 HobieAnarchy

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Posted 29 April 2012 - 11:42 PM


Congratulations Thilo, great job.

With regards to the pitching moment issue, and height of wing's GC, I would like to take advantage of Thilo& Ben Hall attendance on this forum to provide a suggestion which is also a question.

Instead of C-Cat where the crew moves under the wingsail for tacks and jybes, it seems that for an A-Cat, the crew will move behind the wingsail.

Considering both aerodynamic efficiency and pitching moment issue, I have been wondering why not to close the gap between the wingsail's foot and the trampoline ?

Doing so one would increase the wing aspect ration by a factor 2 (from 5 to 10), decrease induced drag significantly, as illustrated in the JavaFoil user's guide (page 25), and consequently increase Lift/Drag ratio.

This significant pick-up in efficient could lead to lower wing, with lower GC, reducing pitching moment accordingly.

Best regards

W


Someone needs to check there math. Blah, blah, blah . . .

Someone needs to learn about the end plate effect and difference between effective aspect ratio and actual aspect ratio.

You also need to learn proper grammar (there vs. their).

#49 demon936

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Posted 30 April 2012 - 03:08 AM

Although i love this wing and i love the idea of the wing i think it would be bad for the class if soft sails became obsolete. Its not practical and for a class that already struggles for new blood it would be a backwards step.

#50 Rawhide

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Posted 30 April 2012 - 03:33 AM

Looking at cost isn't, IMO, the key issue. I think there is a strong argument to say that while the short term cost of buying a wing is significantly more than buying a mast and sail, the longevity of a wing means that the lifetime costs go down. In addition, there is a lot more chance of home building of wings and, maybe a little more realistic, I would expect to see kits for home completion. If a new, better wing comes along, your existing wing should still have lots of life in it so it can be sold on.

The real problem is practicality and that is a whole different story. Just for starters, imagine at a regatta having to drop the rig at night. Then look at how quickly you can rig and egt on teh water at the moment. Steve Brewin maintains he can be on the water 12 minutes after arriving at a venue (which is why he is so often late!!). Even if we take that with a pinch of salt, it really will take a lot longer to rig a wing, it needs more space and it needs help from others.

I do believe that wings will have a negative effect on the class, but is that a reason to ban it. If we wanted the class to be as big a spossible, we would need to reduce all development because that certainly puts off people. Look at masts. You simply cannot be consistantly competitive without a new generation mast and i know people are put off the class on that one factor alone.

The bottom line is that development classes are exactly that and to start saying we should stop certain developments because it will effect popularity is totally against teh spirit of a development class. A development class says that it stays true to it's purpose. In fact, one of the things I love about the Int.14 is that if things become static for too long, they change the rules to get development going again.

This whole "ban it" concept is also wrong on another level. It is saying we can forecast what will happen to a class and although I make a prediction above, I do not know that wings will be negative for the class. I heard exactly the same things in the Moth class but about foils. There were calls to ban foiling because it made the boat too hard to sail, launching was too difficult and it made the boats a lot more expensive.I don't think any of the pro-foiling lobby forecast it would lead to a huge boom in Moths but they won the day anyway and now look what has happened. The reason it didn't get banned is because of the development spirit of the class even though many felt it would harm the class.

In some ways I hope wings do prove good, because I have the design of a wing here and have been lacking the conviction to build. I do know that if we do go over to wings, we will go through a period of pain. For me, that pain will be finding ways to make rigging so much easier, as I am sure it will be in the end.

Of course, the very fact I support not banning the wing means it will be banned. in most development classes I have sailed, there has at some point been a kneejerk reaction to a development leading to a ban that I have fought hard against. I hate kneejerk reactions in development classes because people vote with their own personal agenda and wallet without thinking about the good of the class in general In many cases, the bans I have seen have now been overturned after people have fully understood what they banned when another class has shown it is OK.

Simon I disagree with almost every point you raise.
Looking at cost isn't, IMO, the key issue. I think there is a strong argument to say that while the short term cost of buying a wing is significantly more than buying a mast and sail, the longevity of a wing means that the lifetime costs go down. There is absolutely no evidence to support this view. The pressure to build winds light will by necessity mean they have a limited life span even if they do not die a premature death in a capsize or onshore handling error.
In addition, there is a lot more chance of home building of wings and, maybe a little more realistic, I would expect to see kits for home completion. Maybe but they will still be significantly more expensive than a soft sail and most sailors likely have neither the inclination, skill or workshop to build a wing, and realise the time would be better spent on the water.If a new, better wing comes along, your existing wing should still have lots of life in it so it can be sold on. Assuming that it is superseded quick enough to not have been destroyed or added a few extra kilograms in repairs how much will a superseded wing be worth?
The real problem is practicality and that is a whole different story. Just for starters, imagine at a regatta having to drop the rig at night. Then look at how quickly you can rig and egt on teh water at the moment. Steve Brewin maintains he can be on the water 12 minutes after arriving at a venue (which is why he is so often late!!). Even if we take that with a pinch of salt, it really will take a lot longer to rig a wing, it needs more space and it needs help from others. Fully agree with this point. You also have to think about how you are going to transport the wing each weekend, where you are going to store it and dont forget the safety implications of not being able to drop the sail if you get caught out in a blow, or even just capsizing to sit out a sudden squall.

I do believe that wings will have a negative effect on the class, but is that a reason to ban it. If we wanted the class to be as big a possible, we would need to reduce all development because that certainly puts off people. Look at masts. You simply cannot be consistently competitive without a new generation mast and i know people are put off the class on that one factor alone. No you do not need to stop all development, just make reasoned decisions about what direction is best for the class.
The bottom line is that development classes are exactly that and to start saying we should stop certain developments because it will effect popularity is totally against teh spirit of a development class. A development class says that it stays true to it's purpose. The A is and always has been a restricted development class. In fact the single most influential event in the success of the class over the past years has probably been the introduction of the 75kg minimum weight limit.
In fact, one of the things I love about the Int.14 is that if things become static for too long, they change the rules to get development going again.


This whole "ban it" concept is also wrong on another level. It is saying we can forecast what will happen to a class and although I make a prediction above, I do not know that wings will be negative for the class. The A class association has not had a history of making premature or rash decisions. In fact one of the strengths of the class is that decisions are made for the benefit of the bulk of the membership without undue influence by the vested interests of manufacturers as occurs in a lot of other classes.
I heard exactly the same things in the Moth class but about foils. There were calls to ban foiling because it made the boat too hard to sail, launching was too difficult and it made the boats a lot more expensive. I don't think any of the pro-foiling lobby forecast it would lead to a huge boom in Moths but they won the day anyway and now look what has happened. The reason it didn't get banned is because of the development spirit of the class even though many felt it would harm the class. I would suggest the reason it didnt get banned is that a majority of the class decided that the benefits outweighed the negatives.

In some ways I hope wings do prove good, because I have the design of a wing here and have been lacking the conviction to build. I do know that if we do go over to wings, we will go through a period of pain. For me, that pain will be finding ways to make rigging so much easier, as I am sure it will be in the end. I personally dont think wings will be anything other than a curiosity for the foreseeable future, so see no real reason to rush to ban them. But if it ever got to the point that you needed a wing to compete, I think this would decimate the numbers in the class.

Of course, the very fact I support not banning the wing means it will be banned. Oh to have so much influence.
in most development classes I have sailed, there has at some point been a kneejerk reaction to a development leading to a ban that I have fought hard against. I hate kneejerk reactions in development classes because people vote with their own personal agenda and wallet without thinking about the good of the class in general. It is extremely condescending to think that the members of the A class association are not capable of making an informed decision on the issue without it being a kneejerk, whether or not you agree with it or not.
In many cases, the bans I have seen have now been overturned after people have fully understood what they banned when another class has shown it is OK. Or perhaps they made the correct decision at the time and that this was revisited at a later date due to changed circumstances, such as how the initial banning of carbon fibre when it was prohibitively expensive has now been reassessed in a lot of instances.

#51 Catnewbie

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Posted 30 April 2012 - 09:19 AM

Mr Hall,

Thank you for your kind answer, in my blueprint, I didn't pay attention to the centerboards problem, Now I will.Thanks again.


Hi Samc99US,

You could have a look at the following link, especially "The Optimun Planform" workpaper, It will enlight HobieAnarchy relevant remark.
http://www.tspeer.com/. "A must read"

Now, with regards to wing storage related problem, I would like to expose my soft rig related problems;

In Europe, if you let you carbon toy at your sailing club all the year, even if tightly tied on the road trailer, your 9 meters mast is nowhere in a safe place. If you don't come every week-ends other dudes will use your boat, and most of the time everything which can be seperated from the platform will be looted.

Now standard garage size is just 2,30m wide, just enough for the hulls/plateform, and barely 18/20feets long, so not enough to store your 9 meters mast, but often, high enough to have the boat suspended at the ceiling, above your car.

With a splitable wing, I solve my safety problems, my storage problems, the looting problems as well and so on, I just create a new trailer problem, easier to solve than the 9 meters garage problem.

An alternative would be to buy a secondary house with a huge garage near the sailing club, but I am not sure it would be a cost effective solution
.
Among other reasons, that is why I am a pro-wing

Cheers everybody

W

#52 Rawhide

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Posted 30 April 2012 - 10:16 AM

Mr Hall,

Now standard garage size is just 2,30m wide, just enough for the hulls/plateform, and barely 18/20feets long, so not enough to store your 9 meters mast, but often, high enough to have the boat suspended at the ceiling, above your car.

Before I got a bigger house, I used to store my mast under the eaves of the house. had two ropes on pullies that I slipped over each end and pulled it up underneath. Out of sun and weather and harms way.

But new house near the water with huge garage or boat shed is the better option.

RH

#53 SimonN

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Posted 30 April 2012 - 12:49 PM

I guess I need to clear up a few things!

The pressure to build winds light will by necessity mean they have a limited life span even if they do not die a premature death in a capsize or onshore handling error.That is certainly not supported by what we have seen in the C's and speaking to others who have developed and sailed with wings, it isn't their experience either. With the C's, look how old the wing that Steve Clark destroyed was and that is by no means the oldest wing out there. If it is strong enough to be practical for an A, it will last a long, long time.


...and dont forget the safety implications of not being able to drop the sail if you get caught out in a blow, or even just capsizing to sit out a sudden squall. I have to admit I haven't considered the safety implications and even now, hours after I read this, I am not sure either way. I cannot remember seeing anybody drop their sail because they got caught out in too much wind, but I can see that might happen. It also raises the issue of rescue and, in particular, rescue crew who have no experience of winged boats

I do believe that wings will have a negative effect on the class, but is that a reason to ban it. If we wanted the class to be as big a possible, we would need to reduce all development because that certainly puts off people. Look at masts. You simply cannot be consistently competitive without a new generation mast and i know people are put off the class on that one factor alone. No you do not need to stop all development, just make reasoned decisions about what direction is best for the class. We will have to agree to disagree. We constantly get people posting on this forum that even the current amount of development is too much and is reducing fleet sizes in Europe. I am never sure any decision to change rules ina development class is really "reasoned".
The bottom line is that development classes are exactly that and to start saying we should stop certain developments because it will effect popularity is totally against teh spirit of a development class. A development class says that it stays true to it's purpose. The A is and always has been a restricted development class. In fact the single most influential event in the success of the class over the past years has probably been the introduction of the 75kg minimum weight limit.The restricted development thing is an interesting point. The only classes with wider rules I know of are the C Class and the moth. To me, that is one of the really interesting things about the A
The A class association has not had a history of making premature or rash decisions. In fact one of the strengths of the class is that decisions are made for the benefit of the bulk of the membership without undue influence by the vested interests of manufacturers as occurs in a lot of other classes. I am sorry but I happen to disagree about the decision making, but to make it clear, i believe this to be true of most classes and I should have made that very clear. It seems to me that people do not really consider the facts but vote on emotion. In the A's, I look at 2 recent rule situations to back this up. First, there was the rule changes to control hydrofoils and curved boards. While the guys who wrote the rule did so with the best of intentions, Landy admitted to me at the nationals that they were wrong, in as far as he had just got his boat completely out of the water foiling when the paper to support the rule change said that the changes would prevent that. However, the rank and file didn't even know what they were really voting for. For instance, i have been attacked for not knowing the rules by so many people when I have suggested the use of winglets on rudders and have been told that they were banned. Simply, people voted for a ban on something they didn't understand because they were concerned that they were going to get boats that fly. The second example is the recent vote on the use of GPS devices. I am sorry to say that so many comments at the AGM where this was discussed were at best misguided and at times simply wrong. It was all about people being able to beat people because they had a GPS device which would tell them how to sail a better VMG.If it could really do that, why have Velocitec dropped VMG from their latest devices? Even more rediculous is the fact that the vote didn't prevent people from using electronics to show VMG, because it is possible to by systems which would show that anyway and they cost a hell of a lot more than a Velocitec GPS. Simply put, sailors as a whole do not make reasoned decisions but make decisions based on their own prejudices and on the effect they think it will have on their own position in the fleet and cost.

Of course, the very fact I support not banning the wing means it will be banned. Oh to have so much influence. I hope you are using as much sarcasm and cynicism as I was
in most development classes I have sailed, there has at some point been a kneejerk reaction to a development leading to a ban that I have fought hard against. I hate kneejerk reactions in development classes because people vote with their own personal agenda and wallet without thinking about the good of the class in general. It is extremely condescending to think that the members of the A class association are not capable of making an informed decision on the issue without it being a kneejerk, whether or not you agree with it or not.]I will state again I made a general statement and don't mean it as an attack on A Class sailors. However, having sailed development classes for 35 years, i see the same thing happen time and again.

Finally, I would like to point out that I have said it is up to those who support wings to find ways of making them practical and to prove it to the fleet. If that cannot be done, and there is a groundswell of opinion that wings should be banned, so be it. And FWIW, I believe it is highly unlikely that wings will prove to be enough of an all rounder that they will become compulsory.

#54 hump101

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Posted 30 April 2012 - 01:41 PM



Considering both aerodynamic efficiency and pitching moment issue, I have been wondering why not to close the gap between the wingsail's foot and the trampoline ?

Someone needs to check there math. Blah, blah, blah . . .

Someone needs to learn about the end plate effect and difference between effective aspect ratio and actual aspect ratio.

Does anyone have any data to show how effective a trampoline is at acting as an end plate on a wing? I remember C's years ago with sailcloth gaskets on the bottoms, but not sure what is proposed would eliminate all (or even much?) crossflow, especially on a mesh tramp. Would appreciate some numbers on this if someone has them.

#55 HobieAnarchy

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Posted 30 April 2012 - 02:50 PM

Does anyone have any data to show how effective a trampoline is at acting as an end plate on a wing? I remember C's years ago with sailcloth gaskets on the bottoms, but not sure what is proposed would eliminate all (or even much?) crossflow, especially on a mesh tramp. Would appreciate some numbers on this if someone has them.

I don't have any data, but I'm certain that the effective chord length multiplier is significantly less than the ideal of 2 with an infinite solid end plate.

Things that degrade it:
- Flow through the trampoline. Obviously, a mesh trampoline is going to allow more spanwise flow to escape than a solid trampoline.
- Disturbed flow from hulls, water, fittings, etc. at the bottom of the wing.
- Imperfect fit between the wing and the "end plate"

In reality, there's likely to be some improvement, but it's a fine balance between the gain in efficiency, complexity and practicality.



#56 Tcatman

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Posted 30 April 2012 - 03:37 PM

Fact of life... There are lots and lots of classes to sail.
The builder culture in A class has morphed quite a bit... now the A class seems to have a lot of sailors who buy in at one level of technology... play for one to three years.... see that their technology is now dated and make a decision.... upgrade with another 10-15K.... or find another toy to play with.

.... rumor is that the oracle guys bought 5 or 6 DNA's.... do you look at those new guys as A class converts and class growth... or "here today.... gone tomorrow" ?

Do you care?

ITA16 brought this issue up a while ago... He ID'd churn as a major problem.... Some of the people who poo poo 'd this issue now raise questions about wings... proving the point... EVERYONE HAS LIMITS

Do you measure the class at the level of the Worlds and NA's.... or at the level of viable local clubs with regional sailing schedules? (This is the core issue from my point of view) ????

YMMV

#57 SimonN

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Posted 30 April 2012 - 09:56 PM

.... rumor is that the oracle guys bought 5 or 6 DNA's.... do you look at those new guys as A class converts and class growth... or "here today.... gone tomorrow" ?

It's not a rumour. They were at the Australian Nationals in January and I think it was 5 people associated with Oracle. While there is no doubt that they are now sailing A's because of the AC, when you look at who they are, there is a fair chance they will stay with the class, maybe not every season but when they can. I think that Darren Bundock will keep sailing them, while Tom Slingsby sailed one back in 2009 before the AC went multi and while the competition in Oz remains as good as it is, maybe he will keep sailing them. I think that James Spitthill has now sailed an A for 4 years and with his friendship with some of the fleet and his brother-in-law and father sailing them, he might well keep going. I suspect the others are less likely to stay in the class

Do you care?

Not really! Even without the AC and the AC sailors, A's were doing OK. :)

ITA16 brought this issue up a while ago... He ID'd churn as a major problem.... Some of the people who poo poo 'd this issue now raise questions about wings... proving the point... EVERYONE HAS LIMITS

I believe that the issue that ITA16 raised is rather different. I readily admit that wings are a quantum leap, while I believe that what ITA16 was concerned about was normal, evolutionary development. But you are right. Everybody has limits.

Do you measure the class at the level of the Worlds and NA's.... or at the level of viable local clubs with regional sailing schedules? (This is the core issue from my point of view) ????

YMMV

Good last question and I don't know the answer. However, while I do not like banning things, I am coming to the view that if the class was to suffer badly, then wings might need to be banned. All I would ask is that it doesn't happen until we know exactly what the issues with wings are. IMO, this thread shows what I am worried about, people assuming they know what the future with wings would look like. They may be right, but unless we allow some experimentation, we will not know and I think there is a chance that wings might actually be good for the class.

#58 piv

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Posted 01 May 2012 - 04:20 PM

Great work Thilo. I really hope it sails fast.

The simplest rules are the best for development classes. Most attempts at controlling something by rules just add to cost.

But big fleets like the A need some stability to keep current fleets and development to have a future. Development can always be done outside the rules. I am currently working on a boat that is kind of like an A class, but really it isnt. I dont think it would be good for the A class, but it mighl be a good boat. The A class is the fastest thing to benchmark against.

It will be up to the A class members to decide on wing sails. Perhaps if someone really gets practical hydrofoils to work on any cat, which hasnt happened yet, then they might look at that too. In the meantime, if you are into development, dont worry about the rules, just see what you can do. If you like tinkering within the rules, thats fine too.

If the A class does ban wing rigs and add even more restrictive hydrofoil rules, dont worry. Build whatever you like in "the essence of the A class rule", ie LOA 5.48m, Beam 2.3m, Sailarea 13.94m2, and pace against an A class. Call it original A or A+ if you like. If it sails really good, tell the world and come and sail it in Perth. If it doesnt work, let us know so we dont waste time trying the same thing. Have fun.

#59 ita 16

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Posted 01 May 2012 - 05:18 PM

Fact of life... There are lots and lots of classes to sail.
The builder culture in A class has morphed quite a bit... now the A class seems to have a lot of sailors who buy in at one level of technology... play for one to three years.... see that their technology is now dated and make a decision.... upgrade with another 10-15K.... or find another toy to play with.

.... rumor is that the oracle guys bought 5 or 6 DNA's.... do you look at those new guys as A class converts and class growth... or "here today.... gone tomorrow" ?

Do you care?

ITA16 brought this issue up a while ago... He ID'd churn as a major problem.... Some of the people who poo poo 'd this issue now raise questions about wings... proving the point... EVERYONE HAS LIMITS

Do you measure the class at the level of the Worlds and NA's.... or at the level of viable local clubs with regional sailing schedules? (This is the core issue from my point of view) ????

YMMV


+1
Again,it is right to innovate,but without exceeding the limit,we must now digest the curves boards and the new rig,also a wing now is premature. MY family has been producing class A for 45 years,I think I have enough experience when I talk about this topic. Let's take the opportunity to express their thoughts even I members who are not present at international events. I think the Class A is in deep crisis,hidden by the current fashion,the fashion of the catamarans. Who loves the class A does not want to ruin it with egocentrism. It's really nice work Thilo but I think that not being the right time seems to use the wing in the class A races.

#60 david r

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Posted 01 May 2012 - 07:16 PM

Great work Thilo. I really hope it sails fast.



It will be up to the A class members to decide on wing sails. Perhaps if someone really gets practical hydrofoils to work on any cat, which hasnt happened yet, then they might look at that too. In the meantime, if you are into development, dont worry about the rules, just see what you can do. If you like tinkering within the rules, thats fine too.

If the A class does ban wing rigs and add even more restrictive hydrofoil rules, dont worry. Build whatever you like in "the essence of the A class rule", ie LOA 5.48m, Beam 2.3m, Sailarea 13.94m2, and pace against an A class. Call it original A or A+ if you like. If it sails really good, tell the world and come and sail it in Perth. If it doesnt work, let us know so we dont waste time trying the same thing. Have fun.


why stick within the A class to tinker? just call it an 18 square.

#61 SimonN

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Posted 02 May 2012 - 05:41 AM


Fact of life... There are lots and lots of classes to sail.
The builder culture in A class has morphed quite a bit... now the A class seems to have a lot of sailors who buy in at one level of technology... play for one to three years.... see that their technology is now dated and make a decision.... upgrade with another 10-15K.... or find another toy to play with.

.... rumor is that the oracle guys bought 5 or 6 DNA's.... do you look at those new guys as A class converts and class growth... or "here today.... gone tomorrow" ?

Do you care?

ITA16 brought this issue up a while ago... He ID'd churn as a major problem.... Some of the people who poo poo 'd this issue now raise questions about wings... proving the point... EVERYONE HAS LIMITS

Do you measure the class at the level of the Worlds and NA's.... or at the level of viable local clubs with regional sailing schedules? (This is the core issue from my point of view) ????

YMMV


+1
Again,it is right to innovate,but without exceeding the limit,we must now digest the curves boards and the new rig,also a wing now is premature. MY family has been producing class A for 45 years,I think I have enough experience when I talk about this topic. Let's take the opportunity to express their thoughts even I members who are not present at international events. I think the Class A is in deep crisis,hidden by the current fashion,the fashion of the catamarans. Who loves the class A does not want to ruin it with egocentrism. It's really nice work Thilo but I think that not being the right time seems to use the wing in the class A races.

You need to be very careful with comments like this. You think the class is in "deep crisis". I think that those in Oz would say it is very healthy, even if you try to take the AC sailors out of the picture. And from what I can see, the class is growing in the USA at the moment. What is hiding the real state of the class is the global economic crisis. I read yesterday that Spain is now officially back in recession while we all know that much of teh rest of Europe is in a financial mess. So, if we see a downturn of A Class sailing in Europe, is that due to the recession or due to curved boards and bendy masts?

Having said that, I do think that the wing issue is very different from curved boards and bendy masts.

#62 ita 16

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Posted 02 May 2012 - 06:59 AM



Fact of life... There are lots and lots of classes to sail.
The builder culture in A class has morphed quite a bit... now the A class seems to have a lot of sailors who buy in at one level of technology... play for one to three years.... see that their technology is now dated and make a decision.... upgrade with another 10-15K.... or find another toy to play with.

.... rumor is that the oracle guys bought 5 or 6 DNA's.... do you look at those new guys as A class converts and class growth... or "here today.... gone tomorrow" ?

Do you care?

ITA16 brought this issue up a while ago... He ID'd churn as a major problem.... Some of the people who poo poo 'd this issue now raise questions about wings... proving the point... EVERYONE HAS LIMITS

Do you measure the class at the level of the Worlds and NA's.... or at the level of viable local clubs with regional sailing schedules? (This is the core issue from my point of view) ????

YMMV


+1
Again,it is right to innovate,but without exceeding the limit,we must now digest the curves boards and the new rig,also a wing now is premature. MY family has been producing class A for 45 years,I think I have enough experience when I talk about this topic. Let's take the opportunity to express their thoughts even I members who are not present at international events. I think the Class A is in deep crisis,hidden by the current fashion,the fashion of the catamarans. Who loves the class A does not want to ruin it with egocentrism. It's really nice work Thilo but I think that not being the right time seems to use the wing in the class A races.

You need to be very careful with comments like this. You think the class is in "deep crisis". I think that those in Oz would say it is very healthy, even if you try to take the AC sailors out of the picture. And from what I can see, the class is growing in the USA at the moment. What is hiding the real state of the class is the global economic crisis. I read yesterday that Spain is now officially back in recession while we all know that much of teh rest of Europe is in a financial mess. So, if we see a downturn of A Class sailing in Europe, is that due to the recession or due to curved boards and bendy masts?

Having said that, I do think that the wing issue is very different from curved boards and bendy masts.


QED! Give me a whistle when the class is being destroyed. I've already spoken too much time on this subject in the past. If I can give a final word of advice: listen to the voice of the masses,they sustain this class! Greetings to all

#63 piv

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Posted 02 May 2012 - 10:57 AM

Hey Thilo, can you tell us a bit more about the theorey and design of your wing please. If you feel like letting us all know a bit more, then here are some questions. Maybe it will help everyone get even more interested.

What CFD did you do and what were you looking for?

Did you do a CFD comparison of the wing and a standard wing mast and sail? What was the difference?

The planform looks to be more tapered than a current A class sail, why is that?

Did you try different chord ratios and different thickness ratios of the first and second element? If so, why did you end up with the design you have?

Did you use standard NACA 4 digit airfoils? Or another standard airfoil, or did you design some custom ones?

It looks like you have sailed it in light conditions. What do you think so far?

Does the twist control need some aerodynamic loading to make it twist, so that the twist control is really a twist limit? Or can you induce twist mechanically for light airs.

What conditions do you think it will be good in?

#64 Amati

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Posted 02 May 2012 - 11:03 AM


Great work Thilo. I really hope it sails fast.



It will be up to the A class members to decide on wing sails. Perhaps if someone really gets practical hydrofoils to work on any cat, which hasnt happened yet, then they might look at that too. In the meantime, if you are into development, dont worry about the rules, just see what you can do. If you like tinkering within the rules, thats fine too.

If the A class does ban wing rigs and add even more restrictive hydrofoil rules, dont worry. Build whatever you like in "the essence of the A class rule", ie LOA 5.48m, Beam 2.3m, Sailarea 13.94m2, and pace against an A class. Call it original A or A+ if you like. If it sails really good, tell the world and come and sail it in Perth. If it doesnt work, let us know so we dont waste time trying the same thing. Have fun.


why stick within the A class to tinker? just call it an 18 square.



:)

#65 Catnewbie

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Posted 02 May 2012 - 11:24 AM

ITA16,

The A-Cat crisis seems to be mostly a bimare crisis, I don't understand why you complain all the time about high-tech developments, because, during your so called 45 years experience, you know perfectly that your business pratices have provided you with unfair competitive advantage,which amounts at 20% of the boat public price.

Doing so, you have rigged a 20% barrier to entry for your potential concurents, in the A-Cat low-tech segment.

So you should not be surprised if the competition has arised from the high-tech segment. It is a natural consequence of your above-mentionned business practices.

With gazoline at 1.7/ liter in Europe, around 8.50 $ /gallon, I am not sure the boat price is the actual discriminant, for an A-Cat sailor who plan to attend most of the major events in Europe.

What is important it is not the 25 000 boat price, it is the difference between the price you purchase the new boat and the price you sell it after 2/3 years.

If you consider an extrem exemple, imagine a dude who bought a NIKITA, 10 years ago at twice the price of a bimare, his boat is still competitive today , and still have value on the second-hand market.

Now consider your typical customer, he bought first a Javelin, then 2 years later he bought a XJ, then a few years later he changed for a V1, and again moved for the V1R and one year later he got your new V1R 2012.

For each boat swap, he gave up 3000 to 5000 and never won a significant regatta, while spending the same gazoline/hotel/regatta fees than the NIKITA's owner.

Customers are more rational than you seem to think, otherwise you will have a monopoly on the A-Cat market.

It is not only an A-Cat story, your F18HT and other F16 suffer from the same desease.

Work hard on R&D instead of complaining about development all the time, and you will see a brighter future instead of praying for the end of the A-Cat class

Regards to all

W



#66 ita 16

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Posted 02 May 2012 - 11:55 AM

catnewbie, you spend all your time in all world forums telling fables and invented falsehoods about Bi .... and yet you do not realize that no one believes your words. every time I write on this forum you give me axles, I do not know if you're paid to do this, I do not know who you are, but many friends and clients have asked me to denounce you for the stories that false words, we do not want to do this because we think you're a man alone and unhappy! all of our clients make a tour in our factory in the production departments, people can see how to produce a cat, so do not think that your invented words can create damage that you want! please you to stop this stupid war that nobody cares , if you have any doubt about the Bi .... You can easily ask by phone or visit our factory whenever you want! we have no problem! Regards, Michele

#67 Catnewbie

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Posted 02 May 2012 - 12:22 PM

PIV,

Even if Thilo is in best position to provide answers to your questions, I cannot resist to provide you with my modest analysis:

The CFD tool used for the 2 elements analysis seems to be JAVALFOIL, according to the screen hard-copies provided by Thilo.

As it is a 3 elements wing, the split ratio seems to be 56% 44% of the total wing chord. While the 2 elements Ben Hall's wing seemed to be around 50%/ 50% split ratio.

Element 2 (the hinged flap on the first element) provides asymetry for the first element and the wing is likely to be optimimun with a different split ratio, than a 2 elements wing.

But on this point, I think only Tom Speer can provide a correct analysis.

The elliptical spanwise area distribution with what seems to be a sharper leading edge that NACA series, (as far as I can see on the picture showing the base of the wing during painting.)

These observations mean to me that the design philosophy aims to optimize windward performance, considering that the wing's extra power downwind provide enought edge, and does not need to be optimized further.

Check the thread "Fred is in so much trouble" and make the exegesis of Blunted/Steve Clark/ Tom Speer posts ( alphabetic order)
.
I am sure Thilo has printed all the posts and has been reading every nigh before blue-print completion.

Cheers

W

PS: Sorry ITA16, but where is the relationship between your blabla and the Cat sailor budget management issues (gazoline price /second hand market/ cost of bboat swap)??

#68 piv

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Posted 02 May 2012 - 12:41 PM



Great work Thilo. I really hope it sails fast.



It will be up to the A class members to decide on wing sails. Perhaps if someone really gets practical hydrofoils to work on any cat, which hasnt happened yet, then they might look at that too. In the meantime, if you are into development, dont worry about the rules, just see what you can do. If you like tinkering within the rules, thats fine too.

If the A class does ban wing rigs and add even more restrictive hydrofoil rules, dont worry. Build whatever you like in "the essence of the A class rule", ie LOA 5.48m, Beam 2.3m, Sailarea 13.94m2, and pace against an A class. Call it original A or A+ if you like. If it sails really good, tell the world and come and sail it in Perth. If it doesnt work, let us know so we dont waste time trying the same thing. Have fun.


why stick within the A class to tinker? just call it an 18 square.



:)


Whatever the name, it doesnt matter. The existing A class rules make a lot of sense, practical size, length and beam, transports ok on trailer or in container and can be lifted easily, its about as big as a single handed cat can be. Ok maybe a bit light on for light wind sail area but that has been made up with awesome efficiency and light weight. If you make something fast you need to sail it against something. The fast craft now are kiteboards, windsurfers and moths and catamarans in medium and above and IRC in light winds (no particular order). The A is the fastest single handed catamaran. Kiteboards, windsurfers and moths are "in the water craft", A cats are the only ones that dont fall over all the time (with me sailing anyway). So if you can pace against an A, then you know you are fast. If you want some bounds to stay practical, then the A class rules are pretty good. But hey, if you want 6m beam, 10kg weight and 20m2 of sail, then more power and good luck to you. My aim for development is to achieve the fastest practical single handed craft around a typical course (WL or triangle or slalom or downwind distance) in any normal conditions (say 3kt to 30kt winds, open coastal waters). Ideally it will beat windursfers, kiteboards and Moths. An A is a good starting point. My own personal view is biased, I have mainly sailed windsurfers, skiffs and cats, not that interested in kiteboards, dont feel like learning to sail a Moth properly and I think their rules are too restrictive for me. Thilo deserves big commendation for his hull developments, past foil developments and now his wing developments. It will lead in some way to better boats. It think the A class has adversely restricted its development with its hydrofoil (ie hull appendage distance from the centreline) "catamaran" rules in the same way the Moth declared itself a monohull and only allows foils on the centreline. The other reason for working in or around an already established development class is the future it holds and racing forces practical development. Hobie Trifoilers and the Rave hydrofoil did their own thing but in a really narrow way that in the long run has proven to be no where near as practical on the race course as the Moth foiler. What happened with Moths is truly remarkable. A relatively slow boat, made a technological leap and became arguably the fastest boat. The A class also has the potential to go from being a fast boat to even faster, either by gradual development or by some new technology. Relaxing the rules for yourself (im not arguing for any changes to the A class rules, they are good rules) might just make some of the development go a bit easier. Also I suggest to anyone who wants to try something, dont try to second guess what rules might change later. When sailers started thinking about foils on Moths they had no idea the class would eventually revert to its "monohull" ethos and introduce the rules which effectively limit foils to passing through the water on the centreline. As it turns out, that Moth rule pushed development to a good place. However the Moths have also introduced a "single sail" interpretation to wing rigs, which makes slots illegal and therfore destroys virtually any chance of a wing rig being better than a sail. If any new rules are to be added to A class in relation to wing rigs, I think they should be (and based on the recent rule changes, probably would be) based around the ethos of the catamaran and practicality, rather than banning wings per se. Fortunately the A class currently allows sloop rigs, so there is no logical reason to decide they cant have slotted wings. Maybe something as crazy as "at least 80% of the sail area shall be able to be lowered (and raised?) by one person in 10 minutes with the boat afloat and the lowered sail must fit within the length and beam of the boat". That sorts out most of the issues of practicallity, safety and parking lot space in one sentence, but makes the design pretty demanding or limiting. I tried to achieve that on Spitfire, it kind of worked, but probably a conventional rig might have been better. But with more development its possible. Maybe nothing is needed. If Thilo's, Hall's or someone else's wing turns out to be practical and fast, then I think it would be great to see them on a big fleet. The next big thing is to get foils working properly on a multihull, ie working as well as they do on a Moth. The A class rules make that a virtual impossibility, but the basic A class is a good starting platform with a good rig, good beam, good length, low weight and a good fleet of baseline performance to pace against. If it isn't faster then there is no point.

#69 piv

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Posted 02 May 2012 - 01:20 PM

PIV,

Even if Thilo is in best position to provide answers to your questions, I cannot resist to provide you with my modest analysis:

The CFD tool used for the 2 elements analysis seems to be JAVALFOIL, according to the screen hard-copies provided by Thilo.

As it is a 3 elements wing, the split ratio seems to be 56% 44% of the total wing chord. While the 2 elements Ben Hall's wing seemed to be around 50%/ 50% split ratio.

Element 2 (the hinged flap on the first element) provides asymetry for the first element and the wing is likely to be optimimun with a different split ratio, than a 2 elements wing.

But on this point, I think only Tom Speer can provide a correct analysis.

The elliptical spanwise area distribution with what seems to be a sharper leading edge that NACA series, (as far as I can see on the picture showing the base of the wing during painting.)

These observations mean to me that the design philosophy aims to optimize windward performance, considering that the wing's extra power downwind provide enought edge, and does not need to be optimized further.

Check the thread "Fred is in so much trouble" and make the exegesis of Blunted/Steve Clark/ Tom Speer posts ( alphabetic order)
.
I am sure Thilo has printed all the posts and has been reading every nigh before blue-print completion.

Cheers

W

PS: Sorry ITA16, but where is the relationship between your blabla and the Cat sailor budget management issues (gazoline price /second hand market/ cost of bboat swap)??


Yes I hope that Thilo can put in his thoughts. Thanks CatNewbie for your analysis.

I think for a wing rig, the short flap on the first element is crucial for controlling the slot width. It allows a simple mechanism to independently set camber and slot width. Thanks to Barnard? and Clarke for that.

Tom Speer does have some great info. Thanks to all for sharing so much good info that makes it possible to move the technology forward. Thilos rear element looks a bit thicker than what Tom Speer suggests might be possible and I am wondering why that is. Maybe there was some construction reason.

It is interesting that the current A class sail has a big tip chord and is a long way off elliptical. The reason is for twist control and an "automatic rig", but I think it also increases the tip Reynolds number and significantly gets more sail up high in light winds when there is a strong wind gradient. It will be interesting to see how Thilo's rig goes. Good or bad it cant be directly compared with a soft sail as it has a completely different plan shape.

It is difficult to judge the concept of wing sails based on the first few prototypes. There have been very few wings built. What excites me is how well they perform with so few having been built, relative to the tens of thousands (or millions) of sails that have been made over 10 000 years or so. Remember the old windusrfers used to do 20 knots, now I have some friends who routinely do 40 knots and sometimes about 50 knots.....

Whilst there is scope for reducing the profile drag of the wing sail (it is already low), and increasing its lift, I think there is real unlocked potential in optimising its induced drag and lowering its centre of effort in a (semi?) automatic way like the soft sails.

#70 Catnewbie

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Posted 02 May 2012 - 02:06 PM

PIV,

According to your remarks, I would guess there is some project on your design board.

When discovering the wing sail, I made the same obversation with regards to short chord at the tip, with the same concerns about Reynolds.

In addition to slot control, short flap on the first element provides an increase in max Cl at the same AoA.

Some (little) twist can be achieved by a changing flap ratio along the span, with the same angle between first elt and 2 elt.

It seems to me thant the wing sections provided in the CFD screen hard-copy are a bit different from the actual one (leading edge radius) unless the perspective of the wing picture at the painting stage is misleading ??

The secong element relative thickness seems to be around 10% not so thick for a flap??

Automatic twist and flattening wing sections in gusts are obviously an step forward, but quite difficult to implement, just like morphing wing sections.

Wings are a great topic to put your brain at full use even if it will not lead to actual construction, a kind of intelectual challenge!

Cheers

W

#71 david r

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Posted 02 May 2012 - 06:00 PM

@piv
i am down with designing your own boat, but i respectfully disagree with some of your points.
designing fro 3-30 knots is fraught w/difficulties. a boat that is for 25 and above isn't going to excel in 3. a boat like an A that is optimized for moderate wind and seas is a beast in 30 knts. with seas. the rules don't want them to race in over 20knts. from what i have read.

a race board quiver would need at least 3 rigs to handle that wind range in the world cup and they don't deal with wind as light as 3knts. from my experience going up against them on my cat, i don't think that you will ever build an 18' cat that can beat a pro level board in a strong breeze around a course. maybe using hydrofoils, but then you have extra drag when not up on the foils in light wind.

if the wing proves superior on an A and an arms race develops causing the banning of wings from the class, then the 18 square class could be an option. any width, or weight is legal so an A fits into the rules, and there is room to tinker. if narrower is faster then they would be built that way. now that you need to fly the hull downwind that may be the case, but again you are back to the heavy air design vs. light air design.
As an example of the light wind/heavy wind design problem , someone could prolly make a 14-18' cat that is specifically for 25-30knts. with ocean swells that could easily beat a current A class in those conditions.

#72 samc99us

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Posted 02 May 2012 - 09:05 PM



Congratulations Thilo, great job.

With regards to the pitching moment issue, and height of wing's GC, I would like to take advantage of Thilo& Ben Hall attendance on this forum to provide a suggestion which is also a question.

Instead of C-Cat where the crew moves under the wingsail for tacks and jybes, it seems that for an A-Cat, the crew will move behind the wingsail.

Considering both aerodynamic efficiency and pitching moment issue, I have been wondering why not to close the gap between the wingsail's foot and the trampoline ?

Doing so one would increase the wing aspect ration by a factor 2 (from 5 to 10), decrease induced drag significantly, as illustrated in the JavaFoil user's guide (page 25), and consequently increase Lift/Drag ratio.

This significant pick-up in efficient could lead to lower wing, with lower GC, reducing pitching moment accordingly.

Best regards

W


Someone needs to check there math. Blah, blah, blah . . .

Someone needs to learn about the end plate effect and difference between effective aspect ratio and actual aspect ratio.

You also need to learn proper grammar (there vs. their).


End plate effect? Are you fucking kidding me? How many wings have you designed and put into production at a world class level?

Thanks Catnewbie for actually providing useful data, I have read Tom Speer's papers before but it is very detailed information and if you don't use it you'll loose it. The same goes to those asking the right questions about CFD work. I've only messed with Javafoils 2D implementation, not the latest 3D implementation with multi-panel CAD integration, which looks pretty great.

#73 samc99us

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Posted 02 May 2012 - 09:12 PM

PIV,

According to your remarks, I would guess there is some project on your design board.

When discovering the wing sail, I made the same obversation with regards to short chord at the tip, with the same concerns about Reynolds.

In addition to slot control, short flap on the first element provides an increase in max Cl at the same AoA.

Some (little) twist can be achieved by a changing flap ratio along the span, with the same angle between first elt and 2 elt.

It seems to me thant the wing sections provided in the CFD screen hard-copy are a bit different from the actual one (leading edge radius) unless the perspective of the wing picture at the painting stage is misleading ??

The secong element relative thickness seems to be around 10% not so thick for a flap??

Automatic twist and flattening wing sections in gusts are obviously an step forward, but quite difficult to implement, just like morphing wing sections.

Wings are a great topic to put your brain at full use even if it will not lead to actual construction, a kind of intelectual challenge!

Cheers

W


Reynolds number at the tip is an issue, but not that large of one. NACA four series foils are still quite efficient down to Re*sqrt(Cl)=150,000. That is easy to achieve on a wing with tip chord longer than 10 inches (254 mm). Getting more area up high is a very relevant issue. At the same time, keeping the c.g low is a concern. Also, it seems Tom disagrees with pure elliptical configurations in multi-element wings, his stuff has solid math behind it so I take him at his word.

#74 captain horizon

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Posted 03 May 2012 - 01:13 AM

1335961348[/url]' post='3696435']
PIV,

Even if Thilo is in best position to provide answers to your questions, I cannot resist to provide you with my modest analysis:

The CFD tool used for the 2 elements analysis seems to be JAVALFOIL, according to the screen hard-copies provided by Thilo.

As it is a 3 elements wing, the split ratio seems to be 56% 44% of the total wing chord. While the 2 elements Ben Hall's wing seemed to be around 50%/ 50% split ratio.

Element 2 (the hinged flap on the first element) provides asymetry for the first element and the wing is likely to be optimimun with a different split ratio, than a 2 elements wing.

But on this point, I think only Tom Speer can provide a correct analysis.

The elliptical spanwise area distribution with what seems to be a sharper leading edge that NACA series, (as far as I can see on the picture showing the base of the wing during painting.)

These observations mean to me that the design philosophy aims to optimize windward performance, considering that the wing's extra power downwind provide enought edge, and does not need to be optimized further.

Check the thread "Fred is in so much trouble" and make the exegesis of Blunted/Steve Clark/ Tom Speer posts ( alphabetic order)
.
I am sure Thilo has printed all the posts and has been reading every nigh before blue-print completion.

Cheers

W

PS: Sorry ITA16, but where is the relationship between your blabla and the Cat sailor budget management issues (gazoline price /second hand market/ cost of bboat swap)??


To clarify, my two element wing is 60/40

#75 SimonN

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Posted 03 May 2012 - 05:21 AM

The aspects of this I find most interesting is the different philosophies between Thilo's wing and Ban Hall's wing. Ben had the ability to twist the front element but could only alter the slot off the water, while this mast seems to have no twist capability in the front element but a controled flap at the back of the first element in order to control the slot.

What I think is going on is a trade off between optimum wing performance and weight, and also looking at where there is a need to optimise performance. Not having the front element twisting should save weight compared with Ben's, although some is given back by the flap. I suspect that the flap will give better upwind performance, while the twist is only used downhill. It looks like Thilo's wing is moded more towards upwind. Having the rear element twist is common to both and really doesn't have a significant weight penalty.

When comparing this with other wings, both are a comprimise when compared with a C Class wing, which combines all the ideas in the 2 wings. Of course, that would add weight. Adam May's Moth wing had no twist in the first element, no flap and only twist in the rear element. It was, however, super light and despite that, super strong.

As said before, weight is a real key to a wing project and everything is a trade off - the more efficient you make the wing, the heavier it will be. I cannot remember exactly, but I beleive that Ben's wing was about 4kgs heavier than what he took off the boat, but because that includes traveller, mainsheet blocks, rotator etc., it wasn't just heavier but also had a far higher CoG. I am sure that if you could build a wing the same weight as a conventional rig, it would be a no brainer. I also suspect that with development, a wing will prove faster in almost all conditions on flat water. The challenge is going to be upwind in any conditions that causes the boat to pitch. It could be that curved foils help deaden that pitching, and I have a little idea to deaden pitching to try next season. Even then, I think we need to make a wing that is at least 5 kgs lighter than Ben's, which I believe makes the target sub 20kgs. Some would say that is impossible. Some would say a wing will work heavier than that. Time will tell.

Exciting times!

#76 Catnewbie

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Posted 04 May 2012 - 10:38 AM

Simon,

Thanks for your analysis.

According to the picture of the wing's bottom,at the painting stage, I though the first elet could twist on Thilo's wing??

With regards to the main issue: The pitching moment, I though a good trade-off could be a lower wing with a lower aspect ratio, but speewing the trampoline for the end-plate effect to offset the performance give-up due to lower aspect ratio.

Also, according to pitching moment formula, everything else equal, a 10% lower rig achieves the same result than a 21% lighter rig; that is the rational behind a shorter rig, as long as you can manage induce drag with end plate effect.

The problem is: lower span for the same area, means larger wing chord, and therefore less space on the trampoline to tack
or jibe behind the sail, even if your sailplan involves a maximum chord at 2.20 meter above the trampoline, (a bit like a windsurf sail with max chord at the wishbone height).

Doing so, with a 8.40 Meter wing, it could be possible to lower CoG by 50cm compared to Ben Hall's wing, but it still remains far above from soft rig's CoG.

That is why a lighter stuff is mandatory.

By the way, you seems to have seen all these wings, so I would have a question;

Do you know if the Clysar is double-sided tape on each ribs, or only on the "frame".

Thanks in advance

Cheers
W

#77 blunted

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Posted 04 May 2012 - 11:27 AM

Simon,

Thanks for your analysis.

According to the picture of the wing's bottom,at the painting stage, I though the first elet could twist on Thilo's wing??

With regards to the main issue: The pitching moment, I though a good trade-off could be a lower wing with a lower aspect ratio, but speewing the trampoline for the end-plate effect to offset the performance give-up due to lower aspect ratio.

Also, according to pitching moment formula, everything else equal, a 10% lower rig achieves the same result than a 21% lighter rig; that is the rational behind a shorter rig, as long as you can manage induce drag with end plate effect.

The problem is: lower span for the same area, means larger wing chord, and therefore less space on the trampoline to tack
or jibe behind the sail, even if your sailplan involves a maximum chord at 2.20 meter above the trampoline, (a bit like a windsurf sail with max chord at the wishbone height).

Doing so, with a 8.40 Meter wing, it could be possible to lower CoG by 50cm compared to Ben Hall's wing, but it still remains far above from soft rig's CoG.

That is why a lighter stuff is mandatory.

By the way, you seems to have seen all these wings, so I would have a question;

Do you know if the Clysar is double-sided tape on each ribs, or only on the "frame".

Thanks in advance

Cheers
W


for the 100th time, clysar is not taped to each rib, that would prevent the wing from twisting.

For what it's worth, I would take a twisting main element over lower CG, end plate, and double D's with jugs of beer waiting for me at the finish line.

#78 SimonN

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Posted 04 May 2012 - 11:48 AM

According to the picture of the wing's bottom,at the painting stage, I though the first elet could twist on Thilo's wing??

I might be wrong, but I really don't think it does twist. First off, I don't believe you would use a D secion for the nose unless it is structural. The closed back edge would make it too torsionally stiff. The conventional way to build a twisting front section is with a spar that the ribs pivot around. If there is a spar and the D, the mast is heavier than it needs to be. I also don't see the control lines needed.

With regards to the main issue: The pitching moment, I though a good trade-off could be a lower wing with a lower aspect ratio, but speewing the trampoline for the end-plate effect to offset the performance give-up due to lower aspect ratio.

Also, according to pitching moment formula, everything else equal, a 10% lower rig achieves the same result than a 21% lighter rig; that is the rational behind a shorter rig, as long as you can manage induce drag with end plate effect.

Yes, I have thought of that but get very worried about the amount you get stuck in bad air, which you cannot avoid however good you are because you cannot win every start and lead every race from start to finish, and also what happens on the start line. A lower mast will also mean a lower centre of effort, which means you fly a hull later.

Do you know if the Clysar is double-sided tape on each ribs, or only on the "frame".

I hope I understood your question right but the only way I have seen the wings covered is to put the double sided tape around the outside edges and not on the ribs. I think if you had it on the ribs, you would have problems heat shrinking it.

#79 Catnewbie

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Posted 04 May 2012 - 03:42 PM

Thank you Blunted for your answer and also for your precious advice regarding priorities, I will make a good use of it.

Simon, I have these issues in mind, but it is a trade-off, and if you can use the end plate effect, the windward story in light breeze could be pretty different.

A different optimum lift/drag ration could lead to a different windward strategy.

Cheers

W

#80 SimonN

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Posted 05 May 2012 - 09:55 AM

For what it's worth, I would take a twisting main element over lower CG, end plate, and double D's with jugs of beer waiting for me at the finish line.

The problem isn't just a lower CG. It is also absolute weight and it also makes a huge difference which class we are talking about. In a C Class, i am sure you are right. In an A Class, where I am already horrified at the inertia/pitching problems caused by the weight of the rig upwind in a chop, an extra 5-8kgs plus a higher CG is, IMHO, unacceptable. therefore, we need to look at where to make sacrifices in order to save weight. Ben Hall got rid of the flap on the back of the first element. It seems that on this rig, there is no twist on the front element. In the Moths, Adam May did away with bothg twisting on the front element and a flap, but built a waing significantly lighter yet far stronger than Bora's all singing, all dancing but more fragile wing. Not having twist in the front element saves a significant amount of weight. Thoughts?

#81 blunted

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Posted 05 May 2012 - 12:26 PM


For what it's worth, I would take a twisting main element over lower CG, end plate, and double D's with jugs of beer waiting for me at the finish line.

The problem isn't just a lower CG. It is also absolute weight and it also makes a huge difference which class we are talking about. In a C Class, i am sure you are right. In an A Class, where I am already horrified at the inertia/pitching problems caused by the weight of the rig upwind in a chop, an extra 5-8kgs plus a higher CG is, IMHO, unacceptable. therefore, we need to look at where to make sacrifices in order to save weight. Ben Hall got rid of the flap on the back of the first element. It seems that on this rig, there is no twist on the front element. In the Moths, Adam May did away with bothg twisting on the front element and a flap, but built a waing significantly lighter yet far stronger than Bora's all singing, all dancing but more fragile wing. Not having twist in the front element saves a significant amount of weight. Thoughts?


For the record I think the lightest wing built for Bora's team was less than 2 lbs more than Adams wing. Still, full credit to Adam, he built a fine wing. Granted the O2 wings took a beating and ended in tears but, that's life in the "Zero time to test lane"

As for the tab or #2 as we call it in the C-cat. You can conceivably get away without it, with the right kind of set of for the hinge mechanism on the flap that maintains a certain geometric condition. You can conceivably have the slot control required to get the most bang for your buck downhill. That or you want to sail in decent to strong breeze all the time and not be too worries about stupidly low reynolds numbers downhill in light air.

At the end of the day I believe you need a fully cambered wing with twist matched to the gradient twist of the AWA all the way up the rig, to be in the game. The soft sails do it, so the wing has to as well. You can get twist that allows the wing to look right, just with planform tweaking and with a twisting flap, but if you have traded away camber to do it, you are pissing away horsepower. Also, don't be looking to those AC 45's or 72's for answers, totally different problem as they get to fly more sails and slots ahead of their wing, so it's apple's and oranges there.

Yes Simon, 5 KG more on an A cat seems like an enormous penalty, way more than it need be. The lower rig will make for bigger chord lengths improving Re numbers and in turn efficiency, which is a virtuous circle.

The twisting front element has a weight cost and is tricky to build at this scale. just to find materials light enough for the LE on the main element is hard enough on the c-cat, much less something like an A or a moth, and it doesn't work so well with an operating condition known as inversion. We sometimes appear on the C-cat to not be pushing it too hard at times, which is true, and it's also proportional to how much we can keep the wing upright and out of the wet which is good for it's health.

Personally I think Thilo has done a fine job and it both makes me laugh but also makes me a little disappointed at the mild hysteria this seems to incite in people about the health of the class. I appreciate that people over time work hard to build a strong healthy class and that its a struggle to deal with change some times, but come on, this is in fairness, not mind blowingly ground breaking, let it race, see what happens, then form an opinion, or, as you do Simon, build your own better mouse trap. I think it's totally disingenuous to be working on a better foil and then to turn around and slag a guy for building a wing, total hypocrisy.

Happy sailing

#82 Steve Clark

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Posted 05 May 2012 - 01:24 PM

The fun thing about development classes is that the problems are so tricky.
The better mousetrap sometimes takes your finger off.
Chances are that each of the so called advances actually requires a rethinking or redesign of multiple other systems before it can full developed or exploited.
Then there is the stuff that is just hype, but which many believe because it seems to explain things it actually doesn't affect.
It is this intellectual challenge that differentiates development classes from the manufactured cookie cutter classes and why I sail in them.
The carbon masts and beams we now take for granted didn't spring fully formed from the lyons of Zeus.
They spent some time being wicked expensive, tricky, hard to acquire and "bad for the class." The same can be said of cored carbon hulls and one piece platforms, but the class seems to be growing through, and even prospering as a result of these negative developments.

The aerodynamic advantages of the wing are pretty well known, but there is baggage that makes it hard to adopt. Over time people will try to capture the advantages and mitigate the other issues and develop stuff that is more practical. The A Class is the remarkable boat it is because it has allowed development to roll forward. There are costs associated with continuous development, but being the clever monkeys that we are, I trust we will figure it out and acceptable solutions will result.
SHC

#83 Scarecrow

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Posted 05 May 2012 - 10:49 PM

Steve, given you've more history with wings than all but one (Simon) A class sailors put together, what would be the trigger that would make you build a wing for your A?

#84 SimonN

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Posted 06 May 2012 - 02:05 PM

Steve, given you've more history with wings than all but one (Simon) A class sailors put together, what would be the trigger that would make you build a wing for your A?

Just to correct something. I don't have a direct history with wings. I have friends who do have and i have a wing on the drawing board based on their work. I have spent more hours than I care to mention in analysis. I hav eeven sailed with weight up the rig to get an idea of what the problem would be, but removed it after only a short time because I thought it might break the mast and it scared the hell out of me! In A's, I would suggest that there are actually more people than you realise who really do have a pretty good idea, not least because of the number of AC design team members who now have A's but aren't (yet) seen on the circuit. I am hoping one of them will come up with the answer to the challenge of getting a wing to work on an A.

And i live in hope we might get a few hints from Steve and Blunted. I guess that blunted has made one comment that has made me reconsider certain aspects of the design.

#85 Steve Clark

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Posted 06 May 2012 - 08:37 PM

The trigger would be the decision to take A Class racing seriously.
SHC

#86 Scarecrow

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Posted 07 May 2012 - 01:09 AM

SimonN you're not the only Simon in the world. I was referring to last year's Australian of the Year.

#87 SimonN

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Posted 07 May 2012 - 01:13 AM

SimonN you're not the only Simon in the world. I was referring to last year's Australian of the Year.

OK, but as the only Simon on here, you can understand why I thought that you were refering to me and I doubt many (if any) others would have worked out who you meant either. It ,might have helped if you had been a bit more specific :)

#88 juniordave nz

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Posted 07 May 2012 - 06:48 AM

I hav eeven sailed with weight up the rig to get an idea of what the problem would be, but removed it after only a short time because I thought it might break the mast and it scared the hell out of me!



Why don't you sail with an alloy rig if you wana see what it's like with the extra weight up there. That'll add another 10kg to your rigging weight.
Loving this wing by the way. I'm not sure if every boat in the fleet will ever end up with one, but it would be cool if some boats did. Be nice if each the soft and wing sail had their own strengths in different conditions although it could just be that the wing ends up outright better than a soft sail in all respects. Time will tell.

#89 piv

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Posted 04 September 2012 - 11:39 AM

Any more news on this wing Thilo? Did you sail it much this season?

#90 Silver Raven

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Posted 05 September 2012 - 06:24 AM

SimonN you're not the only Simon in the world. I was referring to last year's Australian of the Year.


Gooday 'crow' SimonN is not the only Simon that I know either - so why do you keep - this is now at least the 4th time - not mentioning the correct Simon by some title that will alow all the rest of us to know which 'Simon' you are talking about. Everyone else in here is trying to carry on a constructive - communication experience - why can't you do the same , Please Thanks - caio, james.

#91 Scarecrow

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Posted 05 September 2012 - 06:45 AM

Wow who pissed in your weeties this morning? You've dredged up a 4 month old post to complain that I didn't use Simon McKeon's full name. Very constructive.

My question got to the person it was meant for, Steve Clark and he answered it in a clear and concise fashion. To be honest the original post was done from my phone in 30 seconds and I didn't even consider who else had been posting. I asked Steve a question (sorry Steve Clark) and in re-reading it realised that he wasn't the only A class sailor with a lot of C-class experience and so added the quick exception. If you can ever find it in you heart to forgive my lack of thought I would be forever grateful.

#92 Silver Raven

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Posted 05 September 2012 - 06:54 AM


SimonN you're not the only Simon in the world. I was referring to last year's Australian of the Year.

OK, but as the only Simon on here, you can understand why I thought that you were refering to me and I doubt many (if any) others would have worked out who you meant either. It ,might have helped if you had been a bit more specific Posted Image



SimonN you're not the only Simon in the world. I was referring to last year's Australian of the Year.

OK, but as the only Simon on here, you can understand why I thought that you were refering to me and I doubt many (if any) others would have worked out who you meant either. It ,might have helped if you had been a bit more specific Posted Image


Gooday SimonN Dodn't respond to him - he is a Victorian & to top it off he's from Mlbrn - Don't respond to such small people - 'crow' was refering to "last year's Australian of the Year" - What a load of twasddle-

Back to learning about & sharing information about wing-mast & other sailing related important matters & leave the 'stupid' behind, Please.

It's very rewarding to see all the really 'high' quality people in here - sharing their hard & long earned knowledge with all of us.

When sailing with a wing-mast - when it is fully powered up - there is another gear of power that comes into play & is a tad like - an extra special overdrive or something akin to 'brute-force'. At least - there was - with the 'B' class & a few 'C' class wings I've worked on & sailed on - - it translates to - - when the hulls get totally over-powered & both berry & start to 'go-down-the-mine' then DO NOT ease off - pull everything on very very hard - then that extra 'o-d' pops into gear & the hulls will run parallel to the surface - until the maximum buoyancy of the compressed hulls takes over & the power - from the wiing - is still increasing - until the hulls - pop-out & the boat accelerates like all heck. You've sure got to believe in what you're doing because if you get it wrong - then - - POW - you're 'air-borne' like from a giant sling-shot & OUCH - very ! !

Hope some of that makes some sense - if not ask Cunningham, Buzaglo Hollier, Leverton or Stevensen. ciao, james

#93 Silver Raven

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Posted 05 September 2012 - 07:08 AM

Wow who pissed in your weeties this morning? You've dredged up a 4 month old post to complain that I didn't use Simon McKeon's full name. Very constructive.

My question got to the person it was meant for, Steve Clark and he answered it in a clear and concise fashion. To be honest the original post was done from my phone in 30 seconds and I didn't even consider who else had been posting. I asked Steve a question (sorry Steve Clark) and in re-reading it realised that he wasn't the only A class sailor with a lot of C-class experience and so added the quick exception. If you can ever find it in you heart to forgive my lack of thought I would be forever grateful.


Gooday Mr. Scarecrow, the only one - I hope. Ha ha - I'm so glad you've got a great sense of humour - THANKS - I'm sure you care what I think or even would be bothered with it - again ha ha - but I think not. that said - I was not 'dredging-up' what was said 4 months ago - I was going back over the whole subject - from the very beginning so I could learn & get all that Steve Clark, Tom Speers & Mr. 'blunted' have had to say - for there is much to learn from their knowledge - as least for me - as I've only been messing around in wing-boats for a few year. (ha ha - said the guy - jumping into & through the dinghy - in the TV ad)

If I can make it long enough to get back into 'A' class - I'll try some wing stuff & see if I can remember what made them work - but I'll knot hold my breath, for there are many 'smarts' around closer to the answer than I. Wish I could write a list of items in the order of importance so that everyone could solve 1 or 2 problems - from the bottom up & in order, but that just 'ain't' going to happen, not soon anyway. Ciao, james Oh & tnx Mr. S-C ! !

#94 Silver Raven

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Posted 05 September 2012 - 07:12 AM

The trigger would be the decision to take A Class racing seriously.
SHC


Gooday 'Steve Clark' Stick with that beautiful - long skinny - RED ROCKET-ship of yours - I've got to think that - that would be more fun food & on a bigger plate than an 'A' class. Some yacht mate - I'm green with envy, for sure. ciao, james

#95 Catnewbie

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Posted 05 September 2012 - 09:33 AM

Hi Silver Raven,

Just a remark first:

If you mention you have a lot to learn from all the CFD & Wing guru's posting on the forum (I agree with you on this pointt at 100%)

then I don't understand why you mention you are afraid :"there are many smarts around closer to the answer than I"

You put your ideas on the forum as seeds, your ideas will trigger remark & critics and will provide some new ideas for other guys, reciprocicly you will harvest something, not always what you were expecting, but usually good stuff to fuel your brain.

Are you more CFD or structural engineering proficient?

Do you believe that an A-Cat wing prototype requires 15 000 hours of labor and 300 000€ budget as suggested by Tillo Keller interview (catsaingnews.com I think ???), or do you think it is just a joke to discourage new comers?

Cheers all,

W

#96 Silver Raven

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Posted 05 September 2012 - 11:38 PM

Hi Silver Raven,

Just a remark first:

If you mention you have a lot to learn from all the CFD & Wing guru's posting on the forum (I agree with you on this pointt at 100%)

then I don't understand why you mention you are afraid :"there are many smarts around closer to the answer than I"

You put your ideas on the forum as seeds, your ideas will trigger remark & critics and will provide some new ideas for other guys, reciprocicly you will harvest something, not always what you were expecting, but usually good stuff to fuel your brain.

Are you more CFD or structural engineering proficient?

Do you believe that an A-Cat wing prototype requires 15 000 hours of labor and 300 000€ budget as suggested by Tillo Keller interview (catsaingnews.com I think ???), or do you think it is just a joke to discourage new comers?

Cheers all,

W


Gooday 'W' - 'C-N-B' - Not sure where to start with your comments. Let's just stay with the subject - may we please.

What I think about someones figures in regard to cost of development has nothing to do with the subject as far as I can figure.
Your idea that 'I'm afraid' of something is equally - off subject & deserves the same - non-answer - I M H O

Subject is wing mast - sub-subject is - successful wing-masts for 'A' class cats. Yes/No ???

It seems that there are some big hurdles to overcome: weight, twist control, CofG, inertia moment (if I've got the term correct) bend & a few I've not mentioned - I'm sure.

I'd like to know what the leaders think about the construction methods are concerned or is all that to secret these days ???

Is a 'box' beam superior to a 'round' tube if both are built of the same materials & weigh the same as a single structure - which can be developed from that initial structure into a full or partial wing ???

I'm just looking for some 'high-end' basic starting point - that I could develop into a working wing.

ciao, james

#97 Catnewbie

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Posted 06 September 2012 - 11:22 AM

You have it SR, the COfG Weight are by far the main concerns, according to Ben Hall comments, the wing COfG is 2 meter higher than a soft rig. I am sure you are aware of this point.

So if minimizing pitching moment is the key,
If you assume you will not have access to the Hall's technology, the alternative is to be shorter (ie:8.20m instead of 9m)
and to be lower, I mean the foot sail will swep the trampoline, in addition it will provide an improvement in induced drag.

If you have a shorter rig, you will have longer wing chords, but you need a shorter chord at the trampoline for the crew to move behind.

Consequently, the largest chord of the wing cannot be at the bottom, it will be around 2.20 meters height.

Incidentaly it is a better place to have area according to the shape of the wind gradient above 6/8 knts true wind.

Regarding your question about "box" structure vs round tube, I think Inertia equations can provide an idea, I am far from structural engineer, so I d prefer more skilled people to answer.

But you would be surprised how light could be the main tube for an A-Cat wing (< 20% total wing weight), but as you already know, there is a lot of stuff around!

All the leaders you make reference to, are more evangelist than greedy with their secrets!

In order to minimize weight, may be it worth investigating some trade-off regarding the flap (#3) structure:
The Ben Hall wing has a 20 feet long slot between the bottom and the hound.

If you accept some extra drag with an intermediate "command strut" in the middle, the inertia required for the flap(#3) structure can be seriously downsized . I guess ?? and the global weight could be lower ?

Also the split ratio : relative chord of (element1 + element 2) vs element 3.

Assuming that to achieve the larger power downwind in light wind requires a 50% /50% ratio with a quite heavy flap (#3)
How lighter would be a 40% flap(#3) and heavier main elements at 60% (#1& #2) ?

I am guessing that the extra weight of the 60% (#1 + #2) will not offset the weight gain of the 40% flap(#3) ??

It is a trade-off, you would give up a little hp in some specific condition to gain weight which would improve performance in all conditions.

I am not a genious and have no ambition to market wings, just to build one or 2 maximum,
that is why I don't mind posting my ideas which are very basic.

It is not the "high end" basic starting point you were expecting, but it is all I have, if it can help I d be happy

Regards and my best wishes for your A-Cat wing project.

Cheers All

W

#98 SimonN

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Posted 07 September 2012 - 01:04 PM

About every 6 months I revisit the "how to make a wing competitive in an A" question in some way or another. And every tim eit comes down to one major factor, weight. The issue isn't getting the whole boat down to weight, although on most A's it would be very tight, but the fact that the weight goes from the platform to the rig. The centre of gravity moves up considerably as well. Imagine adding 5 kgs to the existing rig, somewhere near the hounds! It might work on flat water but as soon as there is any wave action, you will be dog slow upwind with significant excess pitching.

Having spoken to a number of people who have built wings and gone through all the potential options, I cannot find a way fo building a wing light enough, even with reduced functionality - no twist in the front element and no flap to control the slot. And it isn't hard to see why. Even if you make the front section not twist and the nose a one piece "D" shaped, that alone would weigh close to a mast to be strong enough to stand up. Then you add the ribs, trailoing edge and skin it, and then you add the rear element with a far lighter leading edge but still with more ribs, trailing edge and skin. Everything behind the "D", added together, would weigh more than a sail with battens. Let's be optimistic and say that the deltas for twist control and all the controls weigh the same as the boom (I don't really believe that). There is a small saving in mainsheet system (I use a really lightweight cascade already) but that weight is too low down to really matter, as is the removal of the mainsheet track.

Have I got that wrong? Add twist to the front element and a flap and the weight climbs higher again.

I should add that I call bullshit on 15,000 hours and 300,000 euros. That's getting into the realm of a full C Class campaign, never mind a wing (yes, I know people have spent more than that on C's, but some have spent less!)

#99 piv

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Posted 07 September 2012 - 01:37 PM

Any news Thilo?

#100 hump101

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Posted 07 September 2012 - 04:07 PM

About every 6 months I revisit the "how to make a wing competitive in an A" question in some way or another. And every tim eit comes down to one major factor, weight. The issue isn't getting the whole boat down to weight, although on most A's it would be very tight, but the fact that the weight goes from the platform to the rig. The centre of gravity moves up considerably as well. Imagine adding 5 kgs to the existing rig, somewhere near the hounds! It might work on flat water but as soon as there is any wave action, you will be dog slow upwind with significant excess pitching.

Is the rig weight issue so critical when you have lifting foils and movable ballast representing 50% of the weight? Raising the CoG increases the pitch inertia, which will reduce the pitching at periods below the natural period, and will increase the natural period, so can't you just tune the hullform to move the natural pitch period away from the expected excitation range? Easily done and would give a hullform better suited to foils in any case. You can't do much about pitching above the natural period, in any case, so there are potential advantages to raising the natural period by modifying the hullform accordingly, if pitch at the natural period really is the limiting motion.

I've sailed beach cats most of my life, including an A with a heavy alloy rig and light hulls (unicorn), and haven't had any pitch issues that couldn't be rapidly damped through crew movement in antiphase, hence not seeing this as a major issue. When I bought my Unicorn in 1978 (K35 from 1967, with original 5 batten main) it came with a sliding seat as well as a trapeze, so for fun we fitted the seat. Not being able to move longitudinally was a real issue because the pitch could not be controlled, but on the trapeze just rocking fore and aft was enough to damp out any periodic motion.




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