Jonski said..
Ok so page 18 and I thought this would be a good time to join in . inflatedwingsails.com/en/category/video-en/ This thing makes me laugh and I would love to have one of these for a sail it wobbles around all over the place imagine the looks as you rocked up to the beach with one of these. As for the laser vs laser trial watch closely and you will see the winged sail can't point as well as the traditional sail so game over in my opinion. Even after 18 pages of reality I still would give a MW sail a go if it was rigged and ready for a trial I can't help but think it would behave in a similar way to a comparitive traditional sail of the same size

I hadn't seen the Laser vid - good find. It's a bit depressing since the vid shows the Laser being sailed so badly that these guys are either ignorant of the basics of tuning the world's most popular adult's dinghy, or they actually tried to be misleading by sailing the conventional boat slowly on purpose.

I'd love to give all of these sails a go, but still hate the overblown hype and the way so many of the press fall for it.

I don't speak French. But the real question is, does the author of that article know more about wingsails than people like the guys who design America's Cup wingsails, Boeing wings, and world record foils and who say that wingsails are not inherently more efficient?

No articles can make up for the fact that if the wingsails are as good as their manufacturers claim, they should just take the incredibly simple, easy, obvious and objective step of racing with their sails instead of talking about them.

Essentially, these sort of claims consist of someone claiming they are better at something (in this case, rig design) than everyone else in the world. And yet, they somehow refuse to prove their claims when all it would take is entering a bunch of races and beating conventionally-rigged craft of the same type. You wouldn't put up with it if someone was making that sort of claim about their own sailing ability, and then not proving it by racing. You wouldn't put up with it if someone was making the same sort of claim about a scientific breakthrough, and not proving it with proper tests. Why do we have to accept such hype from wingsail makers?

By the way, it's been five years now since the same magazine did an article on the Omer Wingsail. It's about 13 years since the creator of the Omer Wingsail promised to publish information about boat-against-boat trials. He's still just bragging and still hasn't published the info about the trials - probably because the wingsail didn't work well.

Paducah said..
5.6 Low Aspect? MW spent pages telling us that sailmakers were idiots for not making high aspect sails. What happened? Did his computer models change or did his less than fully developed design collide with reality? Wow, thank you, MW, for figuring out what the rest of us did twenty years ago.

"This is why wing tip on my sail is narrow, wider tip will induce more twist ( all been experimented). On my CFD blog sail is twisted at 20 degrees. I can provide projection from the top to prove it. By the way, i can see that only few people truly understand role of the twist on regular sail , I can explain but ,nah , don't want to inflame another unreasonable flame from my numb nuts critics . And you right , marketing is based on performance , this is why I feel free to slap them a bit. By the way, this is me been very nice."

Hey, I don't know what your problem is , but this is summertime! You can visit our sailing home spot at Seaside Park NJ 24 st IBP Marina to see and experience of what is wing sail is all about. We don't hold grange, we very friendly and we invite everyone to see and try, No need to guess. You will see that our sail is very different from other similar inventions and we are sure that in time you will become our customer. We also planning our second trip to OBX October 6-13 , Avon village island creek drive , we invite everyone to join us in this very exiting venture. We will demo our new prototype for 2019 , Everyone is invited!

FRPGear said..

MWsails said..
We also planning our second trip to OBX October 6-13 , Avon village island creek drive , we invite everyone to join us in this very exiting venture. We will demo our new prototype for 2019 , Everyone is invited!

MW Sails team is welcome at our OBX.
Are you planning to be at Canadian Hole or at Salvo? I will bring hydrofoils. I hope it will be less of sea grass to test the full potential of foils with better sails.
This event is in my calendar. Please feel free to remind at frpgear.com

Good work with successful reduction of the good idea into practice!

Dr. Lunin
(Participated in wings design and production for Boeing 777x, 747, 737max, Thin Wing, Phantom Eye, X45, F35, A350, A320 neo, ERJ190, MRJ, G650, F16FBW, Invent)

So XYZ is no more...

FRPGear said..

MWsails said..
We also planning our second trip to OBX October 6-13 , Avon village island creek drive , we invite everyone to join us in this very exiting venture. We will demo our new prototype for 2019 , Everyone is invited!

MW Sails team is welcome at our OBX.
Are you planning to be at Canadian Hole or at Salvo? I will bring hydrofoils. I hope it will be less of sea grass to test the full potential of foils with better sails.
This event is in my calendar. Please feel free to remind at frpgear.com

Good work with successful reduction of the good idea into practice!

Dr. Lunin
(Participated in wings design and production for Boeing 777x, 747, 737max, Thin Wing, Phantom Eye, X45, F35, A350, A320 neo, ERJ190, MRJ, G650, F16FBW, Invent)

It just confirmed today , we will be on OBX October 6 -13 at island creek drive Island Magic house right behind swimming pool. You can call me anytime for directions . It would be cool to meet you and try your foils.

MWsails said..

TurnBackTime said..

Pacey said..

As to the high aspect ratio, there are good reasons why modern slalom sails have tended towards lower aspect ratios, it would be a good idea to study and understand why this has happened, and why lowering centre of effort may give benefits that outweigh the increase in induced drag.

Lower you get COP(center of pressure or center of effort),more sail force you can hold .More sail force/thrust = more speed.Sail force is like your engine,300HP boat will allways goes faster then 200HP boat,normally if boats are same..

It is very simple to explain.
Y= Height of COP
X= how much sailor center of gravity is out

Sailor weight x X = Sail force x Y
righting moment=overturnig/heeling moment

now put numbers inside;

COP at 1.8m
100kg x 1m = Sail force x 1,8m
Sail force =55 kg x 9.81= 539N


COP at 3m
100kg x 1m = Sail force x 3m
Sail force=33kg x9.81= 323 N


remark
(This numbers 539N and 323N are resultant sail force,your real thrust is only drive component of resultant,maybe 15-20kg,depending on sail course and sail profile)

Absolutely true! This is what kind of posts this tread needs.

I feel a convergance in the force coming.

Sparky said..

MWsails said..

TurnBackTime said..

Pacey said..

As to the high aspect ratio, there are good reasons why modern slalom sails have tended towards lower aspect ratios, it would be a good idea to study and understand why this has happened, and why lowering centre of effort may give benefits that outweigh the increase in induced drag.

Lower you get COP(center of pressure or center of effort),more sail force you can hold .More sail force/thrust = more speed.Sail force is like your engine,300HP boat will allways goes faster then 200HP boat,normally if boats are same..

It is very simple to explain.
Y= Height of COP
X= how much sailor center of gravity is out

Sailor weight x X = Sail force x Y
righting moment=overturnig/heeling moment

now put numbers inside;

COP at 1.8m
100kg x 1m = Sail force x 1,8m
Sail force =55 kg x 9.81= 539N


COP at 3m
100kg x 1m = Sail force x 3m
Sail force=33kg x9.81= 323 N


remark
(This numbers 539N and 323N are resultant sail force,your real thrust is only drive component of resultant,maybe 15-20kg,depending on sail course and sail profile)

Absolutely true! This is what kind of posts this tread needs.

I disagree. I believe this thread needs LESS bullshyte theorising and more real world testing/proof. Sounds like that is what you are trying to work on by inviting others to try it. But that offer is local to the US and your posturing is global.

We posting plenty of data in forms of videos and peoples opinions. Please visit our website for more info MWsails,com . We are young company and already won best design trophy from WISSA also we have positive independent publications all around the world . And yes, we inviting real people to try our product in the real world. These days nobody believe in bul..... comparison data done by person of interest. Of course we would like to send out prototypes for testing to all windsurfing places on the globe, but we just can't afford it yet. So we do best we can at this time.

TurnBackTime said..

Pacey said..

As to the high aspect ratio, there are good reasons why modern slalom sails have tended towards lower aspect ratios, it would be a good idea to study and understand why this has happened, and why lowering centre of effort may give benefits that outweigh the increase in induced drag.

Lower you get COP(center of pressure or center of effort),more sail force you can hold .More sail force/thrust = more speed.Sail force is like your engine,300HP boat will allways goes faster then 200HP boat,normally if boats are same..

It is very simple to explain.
Y= Height of COP
X= how much sailor center of gravity is out

Sailor weight x X = Sail force x Y
righting moment=overturnig/heeling moment

now put numbers inside;

COP at 1.8m
100kg x 1m = Sail force x 1,8m
Sail force =55 kg x 9.81= 539N


COP at 3m
100kg x 1m = Sail force x 3m
Sail force=33kg x9.81= 323 N


remark
(This numbers 539N and 323N are resultant sail force,your real thrust is only drive component of resultant,maybe 15-20kg,depending on sail course and sail profile)

TBT, that ignores the fact that the induced drag on the lower sail is much higher. Having more thrust does NOT equal more speed if drag increases too much.

Using your formula, you could design a sail much faster than your one with a COP at 1.8m. If you made a sail with a COP of .18m, according to your formula it would be faster. So why don't you do that and break the world speed record?

I'm with tbt here. Being a short light weight. I struggle with power too high in the sail. Obviously you can take that too far. There's going to be a sweet spot where the extra power outweighs the increased drag. And that sweet spot will probably be different for different height and weight sailors

decrepit said..
On second thoughts. If you've closed the gap there shouldn't be much extra induced drag at the bottom of the sail

I think chris249 thought on head induce drag.
narrow and floppy head ,reduce induce drag .

TurnBackTime said..

This is just basics wsurf concept.
But normally that lower sail has low aspect ratio where induce drag is bigger.But benefits of low COP is bigger than disadvantages of increase induce drag.Because most of drag caused by board not sail.
board 50%, sail 30%,sailor 10% and fin 10%

Wsurf is not sailboat,we have only our weight to counter balance sail power,low COP is crucial.

Then you make 15m high aspect sail,with COP on 8m and I will take low COP sail and we are going to Luderitz!
Who you think would win!!?? :)

Who who said everything about windsurfing has to do with Luderitz? A lot of the time you're not competely powered up so COP and righting moment are not the major factors.

If lowering the COP always gave you more speed then AA would go to Luderitz with a 20cm high sail. The point is that it's not just a situation where you reduce the rig height and the board goes faster. You have to balance the benefit of lower COP with the benefits of lower induced drag.

decrepit said..
No he said the induced drag on the lower sail would be higher. Because a low aspect sail is wider at the foot

The wider foot will have more surface drag due to the increased area.
You *may* also get increased drag because the extra length can allow for a deeper profile [ and thus more profile drag ].

But the key factor is drag-vs-lift.... if you have a wider foot and you get more lift than the increased drag, then it is a net win.
So stating that there is increased drag - without stating any other parameters - is misleading.

I apologize for the late comment.
My son (started windsurf last year) has tested MW Sail on OBX and he liked it because:
(comments from a child)
1. It feels like easier to handle. More smooth in gusts. More stable. Like a Cadillac compare to S-10 Pickup.
2. It pulls you forward, not on a side (regular sail).
3. It floats - much easier to pull it out of water. It will probably pull you out of water at stronger wind.
4. The board goes kind of smoother but could not explain why.
5. Easier to flip the sail on jibes.
Definitely wants to try it more at stronger wind.
Wind was 12 knots max for a short time.
70 kg. 80L 50 x 230 board.
Thank you MW Sails for the opportunity!
5'-9" tall, 173 lb weight :)

P.S.
There is a common misunderstanding about induced drag relation to aspect ratio:
Wing span, not aspect ratio effects induced drag. Longer span - less induced drag.
Aspect ratio effects the coefficient of the induced drag, not the actual value of the induced drag. To simplify: the same mast sails will have the same induced drag even if different aspect ratio. But, lower aspect ratio will have higher coefficient of the induced drag. Higher aspect ratio is better not because of lower induced drag, but because of lower friction due to less area. But the coefficient of the induced drag is less on a higher aspect ratio wing. Coefficient is not the drag - it is a value artificially used in fluid dynamics. Drag is real - this is what we experience, and it is induced by the wing span (mast length) and total lift, not by the aspect ratio.
Practically, for the same lift, the larger wing span and less area wing will be more efficient. Thinner wing is better and the planar shape is also important. In other words it is not just the aspect ratio. More variable are in the efficiency equation to optimize.
Try finding aspect ratio in the induced drag formula:
en.wikipedia.org/wiki/Lift-induced_drag#Reducing_induced_drag

Nothing new there, here's the same idea back in 1987 testing on the ADTR at El Mirage dry lake bed. During the day we would plug it onto the landsailor and chase dust devils and thermals around.


Anders Bringdal also tried a similar idea at Luderitz back in 2011. Bjorn also had a go around 2007.