Dave Ezzy hit his head on a foil

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Dave Ezzy hit his head on a foil

Love the guy. Love the sails. But...

No, this is not a photoshop

source: https://www.windfoilzone.com/single-post/Ezzy-Hydra-a-truly-innovative-windfoil-sail

Edit: Ezzy UK has this image on their book of faces page

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Re: Dave Ezzy hit his head on a foil

Wait, this is the guy that won't give us inset clews for shorter booms?

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Re: Dave Ezzy hit his head on a foil

Thunk it was a joke😳

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Re: Dave Ezzy hit his head on a foil

TBH - it doesn't really look any more strange than foiling does already. I didn't even notice the weird bottom batten when I first looked at the picture. I thought maybe David Ezzy was in the hospital or something.

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Re: Dave Ezzy hit his head on a foil

Reminds me of something, not sure what

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Re: Dave Ezzy hit his head on a foil

Race LTD model....found on seabreeze

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Re: Dave Ezzy hit his head on a foil
Marek wrote:

Race LTD model....found on seabreeze

source: http://www.windsurfing33.com/forum/viewtopic.php?f=42&t=112233
use Chrome or Chromium to translate

Marek, you get to see one in the flesh. They have a couple at Windance.

I must say, I go with Bruce Peterson on this one. Started using a cammed sail on the foil and it's amazing in gusty wind.

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Re: Dave Ezzy hit his head on a foil

Lockheed's Skunk Works designed very advanced airplanes in the 50s & 60s (SR71 Blackbird is the most beautiful plane ever made). They were super techies of course, but one thing I heard they always adhered to was the idea that "to fly right, it had to LOOK right". For my money, this Ezzy jus' don't look right.

One of the things about the foot that he cites is the 'end plate effect'. All the hot shit A Cat guys have gone to "deck sweeper" sails that are what that sounds like, with just a notch at the leech to slither through when tacking. It makes sense for their very upright sails, where spanwise flow goes both toward the tip and foot. Not-so-much, imo, for our sails where the rig is raked back so far. I imagine all the drag inducing flow going right up toward the tip of windsurfing sails. I always thunk somebody ought to make some kind of tip treatment to reduce vortices and drag. Also, like STOL aircraft, fences along the span of the sail to reduce spanwise flow and direct air straight off the leech. They'd be a pain to roll up though Shok

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Re: Dave Ezzy hit his head on a foil
FoilDood wrote:

Lockheed's Skunk Works designed very advanced airplanes in the 50s & 60s (SR71 Blackbird is the most beautiful plane ever made). They were super techies of course, but one thing I heard they always adhered to was the idea that "to fly right, it had to LOOK right". For my money, this Ezzy jus' don't look right.

One of the things about the foot that he cites is the 'end plate effect'. All the hot shit A Cat guys have gone to "deck sweeper" sails that are what that sounds like, with just a notch at the leech to slither through when tacking. It makes sense for their very upright sails, where spanwise flow goes both toward the tip and foot. Not-so-much, imo, for our sails where the rig is raked back so far. I imagine all the drag inducing flow going right up toward the tip of windsurfing sails. I always thunk somebody ought to make some kind of tip treatment to reduce vortices and drag. Also, like STOL aircraft, fences along the span of the sail to reduce spanwise flow and direct air straight off the leech. They'd be a pain to roll up though Shok

I get the more area down low part but his execution really doesn't make sense as it ends in a point. I can't imagine that a whole lot of air is being deflected off there, ie it's not functional sail area. It would be like trying to make an early planing board by extending a long pointy bit aft.

Okay, on this tip vortex thing. One thing I've learned in my many trips down the rabbit hole is that sail twist helps the top of the sail approximate an elliptical shape aerodynamically (even though it doesn't look like it to us). Thus, to the wind the top of the sail looks more like that classic and lovely Spitfire wingtip. It has to do with some big words like spanload, etc that my little reptile brain doesn't grasp very well. If you want, you can struggle through page 7 here with me: https://northsails.com/sailing/wp-content/uploads/2016/09/4-NS-HowSailsWork_7.28.16.pdf

Time will tell. I understand where he's coming from - a short, punchy sail would make a good foil sail. That's why I bought a quiver of Naish Choppers. I suspect that the Kona 5.0 I'm trying to sell would make a pretty good foil sail, too, because of the fuller foot for a sail that size.

Edit: Bill Hansen briefly alludes to it on his old windwing site:

He talks about why windsurf sails are made to twist

Quote:

Reason III - Circulation-Induced Tip Stall

The discontinuity at the head (sail and then nothing) causes 3-dimensional circulation flow at the tip. A component of this flow is in a direction which serves to increase the angle of attack. At high (near critical) angles of attack, the circulation flow is increased resulting in tip stall. In aircraft, this phenomena is reduced by 'washout' (twist), a more stall resistant foil section, a winglet, or a combination of all three. In a sail, twist serves to decrease the angle of attack at the head thereby reducing tip stall.and improving efficiency and performance.

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Re: Dave Ezzy hit his head on a foil

I don't see why he didn't just make the sail shorter and stubbier like the (I think) Naish Boxer.

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Re: Dave Ezzy hit his head on a foil

IMHO, I think the aerodynamics of windsurfing sails have more in common with birds and insects than aircraft. The airfoil section has no thickness and is flexible in all directions, the Reynolds numbers are low, and the operating environment is highly unsteady, and being in the earths boundary layer the velocity changes with distance above the surface. Yes, endplate effects and idealized elliptical spanwise lift distribution could improve sail efficiency, and are fun too talk about, but for most of us, ease of use, cost, and durability are probably more important sail aspects.

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Re: Dave Ezzy hit his head on a foil

Gotta defer to the WINDLORD. I know words like "Reynolds Numbers" and I used to know what they actually mean, but I ran out of space in my tiny brain and had to replace them. "Kim Kardashian" now occupies that position. Shok

Agree that low speed wings are more akin to bird design. Also seeds. There was (might still be) a hang glider company called Seedwings. Their signature design feature was a tip shape that looked like a maple seed.

My older Ezzy Infinity has what seems like a uselessly floppy tip. Newer ones are not nearly so limp. I imagine that tip working like the splayed out tip feathers that vultures and hawks have when they are in low speed/high lift mode... sort of like a diffused transition from 'wing' to 'not wing' that fools the air into not making vortices?

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Re: Dave Ezzy hit his head on a foil

I don't think aerodynamics has nearly as much to do with windsurfing sails as marketing. "New" and "Improved" are the keywords. The problem with sails is they all look pretty much alike. To make one obviously different is a bold and risky move, but it might pay off. Anyway, I've been told this sail works great even w/o a foil if you use the right fin:

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Re: Dave Ezzy hit his head on a foil

I think most companies work pretty hard at it. Sometimes the changes are hard to see but they are there. Ezzy does a two year product cycle which seems pretty realistic.

Timely: https://point-7.com/blog/sail-development-work/

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Re: Dave Ezzy hit his head on a foil

Okay, after staring at this thing for an hour and reading his design objective I'm understanding why he did this although I feel (internet idiot in the armchair that I am) like he made some compromises.

Quote:

The extra long foot provides the needed low-end power to get up on the foil without using cambers or an extra batten below the boom, saving close to a kilo in weight. Being able to ride a smaller, lightweight sail makes foiling more fun by giving you the sensation of flying with nothing in your hands. You want a sail that β€œgoes away.”

To get the foot on the deck like that without an extra batten, you end up making a triangle and you can't avoid that shape. An extra batten or not quite hugging the deck as much would eliminate the simple geometric shape that otherwise requires the bottom batten to extend that far.

It's ironic in that he's not shy about sticking a second batten in the foot of a Cheetah (pic below)

Sailworks takes a different approach: doesn't worry about the foot batten so much and uses cambers. With my super limited experience, if I were to buy a foil sail, I'd get the Flyer. It doesn't close the gap quite as much but I would expect the camber induced shape to provide adequate power before taking off. Also, the Flyer can be easily be used on a conventional board. I'd bet they could sell a ton in a 7.5 for summer long board cruising (7.0 is the biggest).

Also, I don't buy the "extra batten adds a kilo" argument. The 5 batten Zeta 5.2 weighs 0.14 kg more than the 3 1/2 batten Taka 5.3.

He's earned the privilege of pushing the design envelope. It'll be interesting how much this pushes the foot aspect of foil sails in the next couple of years.

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Re: Dave Ezzy hit his head on a foil

Back in the early 90’s had a NP speed sail.

The bottom went straight down below the boom at least a foot, maybe more.
That design would be interesting to try on a foil board (if the sail had a modern twist head).

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Marek

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Re: Dave Ezzy hit his head on a foil

1989 at Van Pugh. l-r Garrison Smith, Kevin Osburn and ? RAF Speed

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Re: Dave Ezzy hit his head on a foil
Marek wrote:

Back in the early 90’s had a NP speed sail.

The bottom went straight down below the boom at least a foot, maybe more.
That design would be interesting to try on a foil board (if the sail had a modern twist head).

Monty Spindler (Loft Sails) heard you. 5 batten, 3 cam

IMAGE(<a href="https://www.loftsails.com/uploads/image/595005942dcddc5d5b1602a7.jpg" rel="nofollow">https://www.loftsails.com/uploads/image/595005942dcddc5d5b1602a7.jpg</a>)

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Re: Dave Ezzy hit his head on a foil

Now that's interesting - the exact opposite concept to get the same effect. Sorry to be skeptical, but I am.

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Re: Dave Ezzy hit his head on a foil
Randy wrote:

Now that's interesting - the exact opposite concept to get the same effect. Sorry to be skeptical, but I am.

I'm not clear of what your skeptical? Loft or Ezzy? Loft is very much akin to the Sailworks solution with a more speed oriented vs freeride of SW. They are also more square keeping the power low as you alluded to previously. I think the biggest aesthetic difference between SW and Loft is the Loft's inset clew. I'll bet there isn't much area difference below the boom and the Loft is more vertical because of the inset.

btw, the weight of the Flyer in a smaller size is pretty much on par with an Ezzy 3 or 4 batten sail. The loft appears to be about a kilo more but has an additional batten, camber; and deeper luff sleeve.

Am I misunderstanding you?

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Re: Dave Ezzy hit his head on a foil

Well, Loft wants to bring the foot of the sail inside the clew, while Ezzy wants to make it outside of the clew. I'm thinking one of them must be on the wrong track. Yes - both want to "close the gap" which is a concept that it seems was found to be unimportant a couple of decade ago. But, I'm not against progress. If one of these designs will turn all of these 5 mph days into something a lot more fun, they will get my vote for the Nobel Prize in Windsurfing.

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Re: Dave Ezzy hit his head on a foil

This is what you need then: Gofoil Maliko 200. It's what the guy in the video I posted this morning was foiling on in 10 kts with a 4.3

https://windsportatlanta.com/content/wave-windfoiling-10kts-43-61418

Found some videos of a guy sup foiling that fin in California. Pretty unreal rides.

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Re: Dave Ezzy hit his head on a foil

Guess I should go back to my Paypal Mine (Ebay) and keep robbing stuff from my eventual Estate Sale while I can still spend the money. At least I already have the sail I need.

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Re: Dave Ezzy hit his head on a foil
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Re: Dave Ezzy hit his head on a foil

It's here! http://www.windance.com/Ezzy-Hydra-Foil-Sail-4.0/44296/

6.0 $804.95 Shok

6.0 Cheetah or Lion is less. Early adopters, amirite?

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