Chris 249 said..

MWsails said..

Chris 249 said..

Mark _australia said..
MW still not understanding the definition of "proof"

I reckon am a way better sailor than all the PWA guys. You will all believe me without me actually showing anything, won't you?

I have hit 60kn on my speed gear, I'm sure I have.

The thing that magnetises the fuel in my car so the molecules line up and flow better is so good, it is only eclipsed by the thing that spins the air prior to induction.

I have a bridge for sale BTW........

It's strange, isn't it. If someone who had never proven their sailing ability said they were better than all the PWA star sailors, people would call them a wanker - quite rightly. But when someone who has never proven their sailmaking ability says they were better than all the PWA star sailmakers, they expect everyone to believe them and not to tell them they are being cocky.

It's an odd thing.

Did Koralev went to space? Did Boeing designers are best pilots? And Look at you, you are the champion of windsurfing and still promoting that rig from 1970 . Wingsail is not a new concept ,almost every company tried to develop it, It happens that I have enough knowledge ,skill, funds and patience to execute it properly . I don't have to be a champion to make rig for the champions.

You missed the point. The issue is that you are claiming to be better than all the other sailmakers, without proving it. It's just as if someone was claiming to be better than all the other windsurfers, without proving it. People would laugh and jeer at someone who insulted AA like you insult the top sailmakers, unless they had proven they were better.

Of course, we don't really see any great sailor insulting the best sailors like you insult the best sailmakers. The great sailors and sailmakers don't disrespect other sailors and designers like you do - they respect them and learn from them, not call them "foolish" and their designs "primitive". Bjorn didn't disrespect Robby, for example - he respected him enormously and learned from him.

If respecting others is good enough for the world's best sailors and sailmakers then it should be good enough for the rest of us.What you are doing is like someone inventing a new chair and claiming that all you furniture manufacturers came to "foolish conclusions" and made "primitive" chairs. Unless and until they proved they were right, they'd just be a blowhard.

And every good sailmaker I know of is a damn good sailor. If people are not very good sailors it's normally because they don't have a good intuitive understanding of what really matters in sailing and in sails. The lack of understanding Is not only caused by them being mediocre - it's often a cause of their mediocrity. An intermediate sailor often blames their gear, when the real problem is poor technique.

I promote a rig from 1970 for some things, because it's very good in some ways. In other ways and for other uses, it's terrible. Just about every sail has its good points and its bad points, like good span loading, or light weight, or low heeling moment, or high lift at the expense of very high drag. I own four wingmasts and they are great in some respects, bad in others. I own a bunch of conventional masts and soft sails and they are great in some respects, bad in others.

Claiming that any sail is "100% better in all respects" is just plain silly, especially when your own website shows that you sail has lower lift in some situations and therefore according to your own PR it is NOT "100% better in all respects". It's like saying that one wing shape is better in all respects in a plane.

For you to call someone a liar because they say they only use three sails, like you did here, is just bizarre. Plenty of us have three sail quivers and although you ignore it, plenty of racers only have one sail to cover from zero to 25+ knots and they do it well.

Oh Dear Chris! I didn't read the whole thing, just a bits, but from what I picked up, I'm really sorry! Not me not my website didn't mean to insult you. Besides I like 70 es rig . Racers who I 'm in contact with have at least 8 sails and 5 boards.

NCUSAGUY said..
Most of us mortals change sails because the power/speed of the sail in increasing winds = too much board speed for the conditions. Yes, at some point in increasing winds, the COE may change and the sail becomes uncontrollable. That's most common with the larger sails (8, 9,10 meter). When I am on a 6.0 or smaller and change down to a smaller sail because of increasing wind, it's not because the sail is uncontrollable, it's because the board speed (at my skill level) is too much for the chop/conditions. On my race sails, I have adjustable outhauls that allow for a broader wind range, but changing down because the COE is moving back only happens on my bigger sails (8.4 - 11.0). I mostly rig down to regain board control at speed.

I have brought this point up before and you haven't addressed the issue. No matter how stable the sail, too much speed for the conditions is a limiting factor. So if you are on a 110 L board on your 5.8 and planing in 15 knots of wind in small chop, and then the wind builds to 35 knots and the chop increases 2, 3 or 4 times, most of us will be beat to death on your rig assuming we haven't crashed a dozen times. THAT'S why we rig down to a smaller sail and board. And by the way, I started windsurfing in 1984 so I have a few hours on the water.

NCUSAGUY. Change in wind speed 30 kt is not that much of energy change in modern aerodynamics. Light plane taking off in 40 kt and cruising speed @ 100 kt not a flinch in stability and performance including unpowered aircraft, it is just normal operating range. So what is such a big deal with holding relatively small airfoil in windsurfing ? Sail change during secession is very common practice. You are right, most noticeable decline in performance is on big sails, it is because big sails has more camber. Camber makes these sails more efficient, but when ground speed increases angle of attack decreases accordingly. At small angle of attack , curved plate profile (cambered sail ) develop leading edge stall, this is why you experience back hand pressure before the whole thing collapses . You right, once you outhaul, camber becomes smaller and leading edge stall will be postponed as well as decline in efficiency. Even if you outhaul hard to the point when sail becomes flat, than another problem will surface, turbulence on outer surface from leading edge. So, your large sail at this point becomes sorry to say, useless. ( Not my words, taking from JR Smith , Zenith aircraft designer. ) So ,what you do, you change for smaller sail. Smaller sail is extracting less power from wind and by its nature, it has less camber and less RE( reynolds) number and less of everything... . Smaller sail has less surface less efficiency but , more wind range. Than, if wind becomes much stronger again , same story. If first sail was 7 , your next sail will be 5.5 , now we talking 4.5 ,sometimes 3 and much smaller board. Each of these sails have comparatively low wind range and very pure performance on transition, wind gusts and lulls . It doesn't matter how you slice it , results are same. At some point your sail stops working , that's it. Wing sail on other hands has no above mentioned problems, Zero! I don't advertise my sail as a high chop or wave sail, however been on high chop I was more successful than others , do I like it? No. I don't like high chop with any sail . But my heavy 200 more pounds customers love it.
Now , high speed sailing that we see on flat water , lets say Luderitz. Despite high downwind angle around 38 degrees ( I was in contact with luderitz organizers) no large sail makes speed record , why? First of all, all sailors there are using very high cambered sails. They need efficiency and speed. Look at the pictures and videos, there is no lose leaches of flat sails , everything is heavily cambered and tight, boards 45 cm and less. With curved plate profile , to go high speed, sail needs to be at high angle of attack all the time due to its nature. If angle of attack decreases, leading edge stall occurs and sail will loose its power and stability. Large sail will propel board to the speed when angle of attack becomes small and leading edge stall will take effect . So, on luderitz , PROPER PROPORTIONAL combination of board wetted surface ,sailors weight and sail efficiency is winning recipe. All of this because curved or flat plate profiles have very limited capabilities. It will be ether leading edge turbulence on outer surface for flat, or stall for curves. Wing is completely free of these defects. Wing sail does what it designed to do, generate lift, and mega-range has been developed not by me , but by the leading airfoil designers. I just invent method how to successfully reverse and enforce shape under load. When you arguing with me about wingsail vs traditional, you only guessing. But I know what I'm talking about. I've been riding, making , testing , fixing and testing again for 5 years. I've built a large database of knowledge during this time. And now, nothing related to you. I think your posts are wise. But it was very surprising for me the level of skepticism and aggression in here, that goes beyond of level of common decency. Why don't they just ask , and I just answer.. wouldn't that be nice.

Mark _australia said..

MWsails said.. I've been riding, making , testing , fixing and testing again for 5 years. I've built a large database of knowledge during this time. And now, nothing related to you. I think your posts are wise. But it was very surprising for me the level of skepticism and aggression in here, that goes beyond of level of common decency. Why don't they just ask , and I just answer.. wouldn't that be nice.

There is the problem. I tell you why the scepticism - no facts.

5 yrs of making a database - show us the results. Speeds/ wind strengths. You make motherhood statements about everything being better but you don't back it up with anything tangible. There is no aggression here, just that he who makes the big claims needs big proof.

I doesn't matter how many available proofs I provide , for you glass is always half full . You already asked me this question, answer is same.

Here is one of my CFD simulations study , Low pressure distribution (lift, blue ) on outer surface for both airfoils looks the same , but different on windward surface . Leading Edge stall dramatically changes high pressure distribution on inner surface. This is what makes curved plate profile unstable and inefficient.

MWsails said..

Mark _australia said..

MWsails said.. I've been riding, making , testing , fixing and testing again for 5 years. I've built a large database of knowledge during this time. And now, nothing related to you. I think your posts are wise. But it was very surprising for me the level of skepticism and aggression in here, that goes beyond of level of common decency. Why don't they just ask , and I just answer.. wouldn't that be nice.

There is the problem. I tell you why the scepticism - no facts.

5 yrs of making a database - show us the results. Speeds/ wind strengths. You make motherhood statements about everything being better but you don't back it up with anything tangible. There is no aggression here, just that he who makes the big claims needs big proof.

I doesn't matter how many available proofs I provide , for you glass is always half full . You already asked me this question, answer is same.

Man, if we are always glass half full, your glass is overflowing it seems.

You have 4 testimonials saying they "like" it (which is subjective) and a handful of videos on people sailing along (which in itself proves nil) and that has you frothing and us supposed to be impressed. I love what you have done, the sail and your loft setup looks amazing. You have done a great job. BUT you claim it is a holy grail and have no proof.

Make a video of 3 or 4 GPS enthusiast folks swapping the sail for their 5 - 7m sail repeatedly and showing their speeds on their gear and your 5.8 sail. With good editing that could be oooh, 30 or so comparos in a 5min video?

Have people race slalom on unfamiliar stuff, it then swap it for your sail over and over. If it truly is so much more stable, people will take to it much more easily and sail must faster and more comfy?

I repeat - I love what you have done, the sail and your loft setup looks amazing. You have done a great job. But if you just tell everyone it is better you have to expect scepticism and be prepared for it. You have not provided any proof

BSN101 said..

Mark _australia said..

MWsails said..

Mark _australia said..

MWsails said.. I've been riding, making , testing , fixing and testing again for 5 years. I've built a large database of knowledge during this time. And now, nothing related to you. I think your posts are wise. But it was very surprising for me the level of skepticism and aggression in here, that goes beyond of level of common decency. Why don't they just ask , and I just answer.. wouldn't that be nice.

There is the problem. I tell you why the scepticism - no facts.

5 yrs of making a database - show us the results. Speeds/ wind strengths. You make motherhood statements about everything being better but you don't back it up with anything tangible. There is no aggression here, just that he who makes the big claims needs big proof.

I doesn't matter how many available proofs I provide , for you glass is always half full . You already asked me this question, answer is same.

Man, if we are always glass half full, your glass is overflowing it seems.

You have 4 testimonials saying they "like" it (which is subjective) and a handful of videos on people sailing along (which in itself proves nil) and that has you frothing and us supposed to be impressed. I love what you have done, the sail and your loft setup looks amazing. You have done a great job. BUT you claim it is a holy grail and have no proof.

Make a video of 3 or 4 GPS enthusiast folks swapping the sail for their 5 - 7m sail repeatedly and showing their speeds on their gear and your 5.8 sail. With good editing that could be oooh, 30 or so comparos in a 5min video?

Have people race slalom on unfamiliar stuff, it then swap it for your sail over and over. If it truly is so much more stable, people will take to it much more easily and sail must faster and more comfy?

I repeat - I love what you have done, the sail and your loft setup looks amazing. You have done a great job. But if you just tell everyone it is better you have to expect scepticism and be prepared for it. You have not provided any proof

+1
Get one over here and WE will get that info for you by guys that have huge reputations on the water. Sailing in their fav locations with others that can assist with performance comparison. if it works then there is the data and reviews by recognised sailors.
I too love what you have been able to achieve. awesome

Of course! It would be great , but we already set this in the motion, I guess you guys just have to wait for few months. But ones it verified, ( and it will) our money back offer will expire. And we might hand over our sails to retailers . So far this forum was very..... interesting.
Cheers mates!

MWsails said..
Here is one of my CFD simulations study , Low pressure distribution (lift, blue ) on outer surface for both airfoils looks the same , but different on windward surface . Leading Edge stall dramatically changes high pressure distribution on inner surface. This is what makes curved plate profile unstable and inefficient.

May we ask;

What is your angle of incidence/attack?
How does the angle in the study compare to real life and where did you get the real-life angle?
What is the sail camber, and how does it compare to real-life camber?
What is the wind shear, and how does it compare to real life?

The diagrams that were used earlier appear to show cambers that are incorrect and angles that are too narrow, therefore they are not representative of real world sailing in overpowering conditions.

By the way, you didn't answer the question about what your "background in aerodynamics" is.

Paducah said..

Chris 249 said..

MWsails said..
Here is one of my CFD simulations study , Low pressure distribution (lift, blue ) on outer surface for both airfoils looks the same , but different on windward surface . Leading Edge stall dramatically changes high pressure distribution on inner surface. This is what makes curved plate profile unstable and inefficient.

May we ask;

What is your angle of incidence/attack?
How does the angle in the study compare to real life and where did you get the real-life angle?
What is the sail camber, and how does it compare to real-life camber?
What is the wind shear, and how does it compare to real life?

The diagrams that were used earlier appear to show cambers that are incorrect and angles that are too narrow, therefore they are not representative of real world sailing in overpowering conditions.

By the way, you didn't answer the question about what your "background in aerodynamics" is.

More questions - how does the "curved plate" correspond to a free ride sail with an sdm or rdm? How close/far is it to a deep luff race sail? What is the profile of the "curved plate"?

And the question only a few have raised. How is anyone supposed to sail this thing anywhere with other traffic on the water without a window?

To answer most questions I open blog on MWsails site where all issues will be addressed using CFD illustrations. Purpose of this blog is not only to compare , but better understand airflow around traditional sail and wing. www.mwsails.com/blog

Sparky said..
Good one Stan. I wish you the best in your quest to better understand airflow around traditional sail and wing.

In this post CFD study symmetrical profile cons and pros . These profiles done in past by windsurfing sail designers . www.mwsails.com/single-post/2017/12/30/Symmetrical-airfoils

duzzi said..

MWsails said..

decrepit said..

MWsails said..
>>>> I did not call him a liar . He just said that rig doest'n need to be changed with wind. This is a lie.

It's not a lie, it's interpretation of semantics. Just because people after absolute performance choose to change sails every 6kts, doesn't mean the average Joe has to!
This was my point much earlier on about efficiency. A sailor can only make use of as much power as they can counter balance, after that they have to sheet out, the excess sail area is then just drag. So it's not about sails being unstable out of their wind range, it's about different wind ranges for different weight sailors.

And no matter how good the wind range of any sail is, once the sailor is using all their weight to counterbalance it. With any increase in wind speed from there on, a smaller sail will be more efficient.
So I really can't see how your sails are any different in that respect, even if you only NEED 1 sail for the whole wind range, there's still going to be a fairly narrow band where it's most EFFICIENT, and this will vary with the riders weight, and to a certain extent height.

Everybody knows that if you use 7.0 at 14 kt it will fail at about 20 , Not because it generate too much power but because it become uncontrollable and useless. But before it fails it become slower, much slower, it doesn't generate more power it just center of power shifting rapidly and human can't react fast enough. The reason why wing has mega range it because center of power stays stationary disregard of wind speed, And this is why it faster, simply because it continuously generate lift while other sails fail.

This thread is hilarious: do you actually windsurf? A free race/race 7.0 works perfectly fine in 20 knots. I am no pwa level sailor, weight 68 kg, and I could take my 6.6/4 cams sail out when people were planing on 4.5 and be comfortable ... and I clocked my best speeds in those conditions: no becoming slower!

Oh this is because you're superman! You are the greatest of the great and you can handle everything! But for the rest of us who have to use 4.5 while you enjoy your 7.0 or whatever , I have wing sail with proper aerodynamics to enjoy.

Subsonic said..

vortex said..

duzzi said..

MWsails said..

decrepit said..

MWsails said..
>>>> I did not call him a liar . He just said that rig doest'n need to be changed with wind. This is a lie.

It's not a lie, it's interpretation of semantics. Just because people after absolute performance choose to change sails every 6kts, doesn't mean the average Joe has to!
This was my point much earlier on about efficiency. A sailor can only make use of as much power as they can counter balance, after that they have to sheet out, the excess sail area is then just drag. So it's not about sails being unstable out of their wind range, it's about different wind ranges for different weight sailors.

And no matter how good the wind range of any sail is, once the sailor is using all their weight to counterbalance it. With any increase in wind speed from there on, a smaller sail will be more efficient.
So I really can't see how your sails are any different in that respect, even if you only NEED 1 sail for the whole wind range, there's still going to be a fairly narrow band where it's most EFFICIENT, and this will vary with the riders weight, and to a certain extent height.

Everybody knows that if you use 7.0 at 14 kt it will fail at about 20 , Not because it generate too much power but because it become uncontrollable and useless. But before it fails it become slower, much slower, it doesn't generate more power it just center of power shifting rapidly and human can't react fast enough. The reason why wing has mega range it because center of power stays stationary disregard of wind speed, And this is why it faster, simply because it continuously generate lift while other sails fail.

This thread is hilarious: do you actually windsurf? A free race/race 7.0 works perfectly fine in 20 knots. I am no pwa level sailor, weight 68 kg, and I could take my 6.6/4 cams sail out when people were planing on 4.5 and be comfortable ... and I clocked my best speeds in those conditions: no becoming slower!

Oh this is because you're superman! You are the greatest of the great and you can handle everything! But for the rest of us who have to use 4.5 while you enjoy your 7.0 or whatever , I have wing sail with proper aerodynamics to enjoy.

Dont get me wrong here, im quite interested in some of the concepts youve put forward with this sail.

Im a bit lighter again than duzzi, and a 7.0 race sail is manageable in 20knots. 4.5 even in a wave sail, i'd be under done.

Im looking forward to hearing how people who've bought one of your wing sails go with it. And how it stacks up against a traditional cambered sail, in a real world test.

Look I can tune up and handle large sail in very (relatively to sq m area) strong winds while others wandering how it humanly possible ? And actually many of us can. But call it user friendly ... I can't. It is amazing to me when people claim how stable racing sail is. In reality majority of windsurfers don't like race sails at all. Retailers say that it is difficult to sell them , so they don't sack them, Also some sail brand sites say user friendly 40% . Stability and performance of wing sail and what you can do with it, is no near in comparison with any sail on the market. I would like to get more people involved writing reviews and share experience, but we are in between seasons, so not in the cards now. In meanwhile we're posting CFD blogs on our website where people can learn facts and compare traditional and wing sails. www.mwsails.com/blog

All this theory and cfd both with absolutely nothing behind it as no one has actually determined the conditions this would operate under every technical post in this read is just meaningless. These are not facts of the wing sail but a sales pitch with a convenient interpretation.A race sail rigged right with the right fin and board is super stable once you get to a point of ability/ rig tuning/ confidence you have just fly over massive chop and swell with the balance of sail and board looking after everything it is amazing how locked in the whole set up is I can easily do 33 knots over the back of chop with only one hand resting on the boom. The race sail is the easiest style to sail at speed for a reasonably experienced sailor. I'm not claiming its more stable or easier than yours but please don't try and perpetuate the myths about them being heavy and hard to sail they do have amazing stability built into them which undoubtable is front the active twisting and flexing. All these wing profiles are the perfect shape for what they do the glider has the best l/d , the f1 has a huge c/l plus does alot extra in its job, the short take off plane has huge lift at the expense of drag the fighter jet has swpt wings because of pressure of high speed fligh( im sure there is more to that one but i have no idea) The propellor has alot of twist to allow for different apparent wind angles anlog its length.
There is not one best shape based on 2 dimensional simulation of and airfoil profile, the puzzle is far more complex than that.

MWsails said..

Simon100 said..
All this theory and cfd both with absolutely nothing behind it as no one has actually determined the conditions this would operate under every technical post in this read is just meaningless. These are not facts of the wing sail but a sales pitch with a convenient interpretation.A race sail rigged right with the right fin and board is super stable once you get to a point of ability/ rig tuning/ confidence you have just fly over massive chop and swell with the balance of sail and board looking after everything it is amazing how locked in the whole set up is I can easily do 33 knots over the back of chop with only one hand resting on the boom. The race sail is the easiest style to sail at speed for a reasonably experienced sailor. I'm not claiming its more stable or easier than yours but please don't try and perpetuate the myths about them being heavy and hard to sail they do have amazing stability built into them which undoubtable is front the active twisting and flexing. All these wing profiles are the perfect shape for what they do the glider has the best l/d , the f1 has a huge c/l plus does alot extra in its job, the short take off plane has huge lift at the expense of drag the fighter jet has swpt wings because of pressure of high speed fligh( im sure there is more to that one but i have no idea) The propellor has alot of twist to allow for different apparent wind angles anlog its length.
There is not one best shape based on 2 dimensional simulation of and airfoil profile, the puzzle is far more complex than that.

Simon, please explain all pros about race sail to vast majority of windsurfers and windsurfing sail retailers. Also please tell race sail producers to put user friendly 100% not 40. Than you can have legit voice here. FYI my cfd simulation is 3 d . I just started cfd blog . Keep watching, there will be more information to boost your knowledge. I assure you , at the end you will gain some wisdom of modern subsonic aerodynamics , and you will never post jet plane on windsurfing forum. www.mwsails.com/blog

What are we comparing the race sail to ? Compared to a free ride sail >The pros are they are faster and more stable to the retailers the benifit would be having a product to compete with the race sails sold by other retailers to make money off.

Your simulation is 3d but its a sail with no twist and a wind with no gradient this does not represent the actuall conditions of a sail in use, you dont even know what angle of attack should be simulated at or what the wind speeds are or quote lift or drag a picture with lines means nothing what if one sail makes double the lift at half the size there are so many variables which cant be ignored. Why would some one not post a pic of a fighter jet its part of an example that there is not one right wing shape and the deign is specific to the conditions, broad asumptions of good vs bad design cant be made without first knowing what is required in use.

John340 said..
MW, your comments about race sails may be valid for your sailing spot but not for mine. Yesterday we had 40+ windsurfers on Moreton Bay Brisbane. 80% of them were on race sails and recorded their speeds etc on GPSTC. I weigh 88kgs. I used a 7.9. The wind slowly built from 13 to 20kts. I sailed comfortably all afternoon.

I don't know how things in Australia but in Europe and USA race sails not really popular. I had 2 of them , give it away for free. Don't tell me how great they are because you have no idea what you are talking about. By the way my CFD simulation have all variables, I can specify angle of attack wind speed surface condition, air pressure temperature, density etc. Watch more blogs where simulation will be around two profiles, these profiles will have twist as you requested. www.mwsails.com/blog

MWsails said..

John340 said..
MW, your comments about race sails may be valid for your sailing spot but not for mine. Yesterday we had 40+ windsurfers on Moreton Bay Brisbane. 80% of them were on race sails and recorded their speeds etc on GPSTC. I weigh 88kgs. I used a 7.9. The wind slowly built from 13 to 20kts. I sailed comfortably all afternoon.

I don't know how things in Australia but in Europe and USA race sails not really popular. I had 2 of them , give it away for free. Don't tell me how great they are because you have no idea what you are talking about. By the way my CFD simulation have all variables, I can specify angle of attack wind speed surface condition, air pressure temperature, density etc. Watch more blogs where simulation will be around two profiles, these profiles will have twist as you requested. www.mwsails.com/blog

Race sails are awesome