Archived

This topic is now archived and is closed to further replies.

wai

what is this

Recommended Posts

Funny how everybody seems to like wing things all of a sudden.

 

Terminology, I will post some annotated images tomorrow when I get to the office.

 

In the interim; we call our front section on our wings number one and number two. as that foil is made of two pieces, the trailing edge being a flap. Behind that we have #3, which is a discreet flap unto itself. We also call it and think of it as a leech.

 

Our wings also have an internal tube spar, which we call.... the spar. In our wing it is the primary structure holding everything up there.

 

Ribs, well yup, they are ribs.

 

We have hard bits and soft bits. Carbon or shrink film, tape and dyneema, thats what shes made of.

 

We have a hounds bulk head and a boom box, which contains structure and control systems. Inside the boom box we also find the rotator arm which control the #1 twist. We also have a leading edge fairing on #1.

 

This is all related to the Alpha, Orion, Rocker, Cogito style rig / wing.

 

In the basement I have a simpler rig under construction for me and my kids to play with. It simply has a main element (The leading edge foil section) and a flap. Its dead simple. you adjust camber, and sheet angle, thats it. It will not be great at deep angles but its simple and should tear around on a reach nicely.

 

On the Alpha wing, we can adjust Leading edge twist (Only use that downhill to deal with gradient) , Camber between the #1/#2 and #3 sections, and twist in number 3 (Delta control) and of course sheet which is angle of attack. Slot control is acheived by little fixed fingers called idlers, they affect the distance between the LE of #3 and the TE of #2, which in turn affects the extent to which #2 articulates. My little model wing will only have sheet and camber, no twist in either section unless it blows in and twists the foils, the model wing is simply shaped pink foam with a layer of carbon bagged on top and a bit of structure will be cut into it here and there.

 

The arms that stick out of our wing aloft, at the hounds, are called the yoke, they attach to the delta lines.

 

We call the top of the rig the tip.

 

So I guess we'll see soon enough what all those bits in SD add up to, and then someone can put some nomenclature to that when it appears.

 

Recap: #1, #2,#3, Camber, front twist, Delta, sheet, Idlers.

 

its all you need to know, well for a C-cat anyhow.

 

B

 

With images now...

post-1634-1255445867_thumb.jpg

Share this post


Link to post
Share on other sites

A couple of questions:

- If the wing is in two or three parts (verticaly), does it need an internal mast (round) around which the first vertical elements rotate?

- how many elements are needed to be able to form a curve, 2 or 3? If 3 we could have a total of 9 elements for the whole wing?

- if stays are still needed why ppl say the compression at the base of the "mast" will be less vs a conventional mast-sail combination?

 

My take: Too heavy, too complicated, too long a testing period, wont be ready for February, hey what about Valencia in May??....lol

Share this post


Link to post
Share on other sites
- if stays are still needed why ppl say the compression at the base of the "mast" will be less vs a conventional mast-sail combination?

Because you do not need to create and deal with headstay/leech tension - you just need to hold the thing up. Much less compression this way.

Share this post


Link to post
Share on other sites
Funny how everybody seems to like wing things all of a sudden.

 

Terminology, I will post some annotated images tomorrow when I get to the office.

 

In the interim; we call our front section on our wings number one and number two. as that foil is made of two pieces, the trailing edge being a flap. Behind that we have #3, which is a discreet flap unto itself. We also call it and think of it as a leech.

 

Our wings also have an internal tube spar, which we call.... the spar. In our wing it is the primary structure holding everything up there.

 

Ribs, well yup, they are ribs.

 

We have hard bits and soft bits. Carbon or shrink film, tape and dyneema, thats what shes made of.

 

We have a hounds bulk head and a boom box, which contains structure and control systems. Inside the boom box we also find the rotator arm which control the #1 twist. We also have a leading edge fairing on #1.

 

This is all related to the Alpha, Orion, Rocker, Cogito style rig / wing.

 

In the basement I have a simpler rig under construction for me and my kids to play with. It simply has a main element (The leading edge foil section) and a flap. Its dead simple. you adjust camber, and sheet angle, thats it. It will not be great at deep angles but its simple and should tear around on a reach nicely.

 

On the Alpha wing, we can adjust Leading edge twist (Only use that downhill to deal with gradient) , Camber between the #1/#2 and #3 sections, and twist in number 3 (Delta control) and of course sheet which is angle of attack. Slot control is acheived by little fixed fingers called idlers, they affect the distance between the LE of #3 and the TE of #2, which in turn affects the extent to which #2 articulates. My little model wing will only have sheet and camber, no twist in either section unless it blows in and twists the foils, the model wing is simply shaped pink foam with a layer of carbon bagged on top and a bit of structure will be cut into it here and there.

 

The arms that stick out of our wing aloft, at the hounds, are called the yoke, they attach to the delta lines.

 

We call the top of the rig the tip.

 

So I guess we'll see soon enough what all those bits in SD add up to, and then someone can put some nomenclature to that when it appears.

 

Recap: #1, #2,#3, Camber, front twist, Delta, sheet, Idlers.

 

its all you need to know, well for a C-cat anyhow.

 

B

 

With images now...

post-1634-1255445867_thumb.jpg

 

 

 

 

Cool. That is very informative. Thanks

Share this post


Link to post
Share on other sites
With images now...

 

Thanks!!!! I am still trying to find the book 'Cats and Tris for dummies', so this image makes me happy.

 

Now only a sketch how the wing pieces would look like on the BOR :rolleyes:

Share this post


Link to post
Share on other sites
A couple of questions:

- If the wing is in two or three parts (verticaly), does it need an internal mast (round) around which the first vertical elements rotate?

- how many elements are needed to be able to form a curve, 2 or 3? If 3 we could have a total of 9 elements for the whole wing?

- if stays are still needed why ppl say the compression at the base of the "mast" will be less vs a conventional mast-sail combination?

 

My take: Too heavy, too complicated, too long a testing period, wont be ready for February, hey what about Valencia in May??....lol

 

Our wings works with a vertical carbon spar inside that takes the main structural loads, E.g compression and bending.

 

Older style wings such as PL VI have a D-section, which is comprised of the leading edge hard bit, and a full face across the back of that inside the wing, so in section it makes a "D". This acts as a structural tube, which holds up the wing. the downside to this approach is you cannot twist that section, unlike using the tube spar approach.

 

How many elements to make a curve... How many do you want?, and how curved do you want it. Yellow Pages has 3 foils in line on one rig, and two foils in line on their other rig, so single or double slotted. The more slots you have, the more complicated and tricky the whole thing is to use. More slots are faster down hill, but probably more draggy uphill. More slots equals higher L/D ratios and higher Cl-max. If you look at the harbor wing boats, they have a single wing section with integrated TE flap, and they have no stays, as it is an un-stayed rig, a wing on a popsicle stick as it were.

 

Stays: Well sure you still want stays, it looks stupid when your beautiful wing just falls over. As to why it has less compression: Mainsheet loads are absent. Most conventional sails these days require very high main sheet loads to make the leech stand up straight, or do whatever you want your main to do. With a wing there is no leech tension per se, the mainsheet on a wing boat is actually more comparable to your traveller loads. All you are doing is pulling the wing sideways, not down. As such the loads are waaaay lower.

 

The wing still experiences compression and bending but not like a conventional rig would because again, you ditch all the sheet loading. That having been said, if you put a jib in front of a wing, you probaly want to put some forestay tension on and would use runners or shroud tension to do that, this would impart higher compression loads to the wing.

 

So on a C-cat for example, right now it would be a bad idea to put soft sail on as the back beam is not strong enough for the traveller loads, and the front beam would probably fold under the additional compression loading. So wing sail boats as a result of this can build lighter platforms that soft sail boats, this negates some of the weight disadvantage of wings vs soft sails.

Share this post


Link to post
Share on other sites

AC Anarchy IS fun again! :rolleyes:

 

The un-masking of MSP and Marian Rotten Crotch's rants were entertaining, but this thread is the best.

 

How could this match possibly not take place in February?

 

I would think everyone on both sides are fully intent on meeting on the water to see how these amazing yachts match up. If the fun is spoiled by the lawyers and egos, that would be a real shame.

Share this post


Link to post
Share on other sites
So on a C-cat for example, right now it would be a bad idea to put soft sail on as the back beam is not strong enough for the traveller loads, and the front beam would probably fold under the additional compression loading. So wing sail boats as a result of this can build lighter platforms that soft sail boats, this negates some of the weight disadvantage of wings vs soft sails.

 

So does Dogzilla have new (lighter) beams? Or will they test the wing with the old beams, and then make the switch if the wing pans out?

Share this post


Link to post
Share on other sites

could it be a coincidence that one Steve Clark has been absent from the forums for a while now? He could be busy with his new boat but he hasn't posted in the thread about his boat lately....

Share this post


Link to post
Share on other sites
Two closeups, to hopefully help sort things out. If the butt ends of these two sections are different, it would seem there are altogether 3.

 

It's late here and I have to fold. Look forward to seeing what you've derived tomorrow!

 

post-35861-1255393404_thumb.jpg

Looks tapered to me.

 

 

Yup, it's the same.

 

Look at the protrusion starting about a foot down from the top on the butt end. The same.

 

Also look at the first set of 'case binders". The nearest one curves down over the edge further than the one immediately behind it, which stops abruptly. The same.

 

Drat, only two pieces.

 

I'm starting to agree. I think I can see the red flag at the mast tip. If I draw a line from the red flag on the tip to the corner of the "base" and compare to the same line drawn on the blue truck photo I cannot swear to some taper, no taper, or same taper. When you look at the truck on the left with the untapered section, it looks like there is a curve on the top edge .... lens distortion I think.

 

I'll wait until it gets assembled. Three sections makes sense if they are going to have a top section that twists off, it also allows the shrouds/forestay to attach at the 50m point where there is already a reinforced bulkhead. It puts all the compression load in the two lower sections and would allow the "tip" section to be as light as possible.

 

If it is "only" two and the parts were made from molds, that puts a limit on the length at 25m so "only" 50m total. 60 - 75m makes more sense from my guesses at area needed. But if I knew all that much, they would have called ... and they didn't ... :)

Can't prove it yet, but if you count on two 30m sections then you will be very close.

 

The best argument for this is in the grainy shot showing the two trucks almost alongside one another, by triangulating with the buildings behind and with where Mo must have been standing. My sketch got to looking crazy so I discarded it, but then after posting that number - miracle of miracles - I got an apparently well informed PM 'confirming' 60m.

 

The trailing assembly, once added, will about double the width we see here. Those truck trailers are 8'6" wide, so.. what do you think for SA?

If that is all the area they will have, my first answer has to be "Not Enough" ... :(

 

But I'm still plugging away ... 60m is close enough to 200 and the height of the CE will be somewhat less than 50% of that, the wing is tapered ... so for very rough estimates sail power has to equal 50% of boat weight to be fully powered up and up on one hull ...

 

200 x 30 (average chord) is only 6000sq ft what they have in the mainsail alone now. With the full upwind sail area we have seen IIRC the genoa was 4500 sqft so figure 10000 sqft at like 1.6 CL ... to get that power out of less are the CL must be higher than 1.6 and much higher than the 1.2 that a simple wing can produce.

 

Not saying those are good figures, just a frame of reference.

 

It would be nice to just adjust the displacement down to make the small area work but there is a limit to how low it can possibly be ... and if it was that light, they would never have needed M3 and 10,000 sqft + sail area.

 

Quite a puzzle!

 

Nothing like new technology to steepen the learning curve ...

 

I stopped worrying about flying the damn hull and trying to get enough force out of the wing ...

 

Bottom line is that even with CL equal and Cdo equal (wing should lower) the big difference is Aspect Ratio. On a 200 foot (~60m) rig with 10000 sqft Area AR = 4 The same 200ft wing with only 6000 sqft AR=6.67

 

Even with only 60% of the area the wing provides 37% more forward drive in 4 knots true. That is more than enough to make up for any drag penalty from not flying the centre hull. No jib needed upwind even in 4 knots true.

 

WoW were my first assumptions wrong. I would have bet that you could not get more drive out of less area at the same true wind speed.

 

This is a game changer for sure. :) ... if it all works!

Share this post


Link to post
Share on other sites
[quote name='RHough'

But I'm still plugging away ... 60m is close enough to 200 and the height of the CE will be somewhat less than 50% of that, the wing is tapered ... so for very rough estimates sail power has to equal 50% of boat weight to be fully powered up and up on one hull ...

 

200 x 30 (average chord) is only 6000sq ft what they have in the mainsail alone now. With the full upwind sail area we have seen IIRC the genoa was 4500 sqft so figure 10000 sqft at like 1.6 CL ... to get that power out of less are the CL must be higher than 1.6 and much higher than the 1.2 that a simple wing can produce.

 

Not saying those are good figures, just a frame of reference.

 

It would be nice to just adjust the displacement down to make the small area work but there is a limit to how low it can possibly be ... and if it was that light, they would never have needed M3 and 10,000 sqft + sail area.

 

Quite a puzzle!

 

Nothing like new technology to steepen the learning curve ...

 

I stopped worrying about flying the damn hull and trying to get enough force out of the wing ...

 

Bottom line is that even with CL equal and Cdo equal (wing should lower) the big difference is Aspect Ratio. On a 200 foot (~60m) rig with 10000 sqft Area AR = 4 The same 200ft wing with only 6000 sqft AR=6.67

 

Even with only 60% of the area the wing provides 37% more forward drive in 4 knots true. That is more than enough to make up for any drag penalty from not flying the centre hull. No jib needed upwind even in 4 knots true.

 

WoW were my first assumptions wrong. I would have bet that you could not get more drive out of less area at the same true wind speed.

 

This is a game changer for sure. :) ... if it all works!

Cool! Yep, big IF..

 

6000 sqft sounds about right so far, what happens at 10 knots true?

 

Blunted, thanks for the labels, good we all learn the same language

Share this post


Link to post
Share on other sites
could it be a coincidence that one Steve Clark has been absent from the forums for a while now? He could be busy with his new boat but he hasn't posted in the thread about his boat lately....

Been busy

post-738-1255456149_thumb.jpg

SHC

Share this post


Link to post
Share on other sites
Nothing like new technology to steepen the learning curve ...

I stopped worrying about flying the damn hull and trying to get enough force out of the wing ...

Bottom line is that even with CL equal and Cdo equal (wing should lower) the big difference is Aspect Ratio. On a 200 foot (~60m) rig with 10000 sqft Area AR = 4 The same 200ft wing with only 6000 sqft AR=6.67

Even with only 60% of the area the wing provides 37% more forward drive in 4 knots true. That is more than enough to make up for any drag penalty from not flying the centre hull. No jib needed upwind even in 4 knots true.

WoW were my first assumptions wrong. I would have bet that you could not get more drive out of less area at the same true wind speed.

 

This is a game changer for sure. :) ... if it all works!

Amazing to read this train of thought you have in these posts RH.

If you alter the calculations, just to find at which boat weight the center hull would fly...

How much weight would it be?

 

Because that center hull will sure enough be flying!

Share this post


Link to post
Share on other sites
could it be a coincidence that one Steve Clark has been absent from the forums for a while now? He could be busy with his new boat but he hasn't posted in the thread about his boat lately....

Been busy

post-738-1255456149_thumb.jpg

SHC

 

Nice workshop. Wish I had one.

Share this post


Link to post
Share on other sites
WTF? Do you know who Blunted is?

Yes, Blunted is a key player in Fred Eaton's C-Class efforts. They are the current holders of the I4C trophy and he I believe sailed on Off-Yer-rocker the foiling C-Class that in it's new configeration as Orion. When Blunted speaks about wings, he knows what he is speaking about. Hope this clears up his credentials.

Share this post


Link to post
Share on other sites
Nothing like new technology to steepen the learning curve ...

 

I stopped worrying about flying the damn hull and trying to get enough force out of the wing ...

 

Bottom line is that even with CL equal and Cdo equal (wing should lower) the big difference is Aspect Ratio. On a 200 foot (~60m) rig with 10000 sqft Area AR = 4 The same 200ft wing with only 6000 sqft AR=6.67

 

Even with only 60% of the area the wing provides 37% more forward drive in 4 knots true. That is more than enough to make up for any drag penalty from not flying the centre hull. No jib needed upwind even in 4 knots true.

 

WoW were my first assumptions wrong. I would have bet that you could not get more drive out of less area at the same true wind speed.

 

This is a game changer for sure. :) ... if it all works!

 

Hi RHough, I enjoy your analysis a lot. I have a few questions:

 

Could they use alternative ways to lift the center hull? For example, we saw some pics where they left the windward banana board down (or it stuck?). Could that provide any significant lift to help to get on one hull? Also, there were those experiments with the fairing on the aft crossbeam. Would it be possible to have a wing-like thing there, which would be angled down for take off, then, once the tri is on one hull, it could go back straight to minimize drag?

 

Is getting on one hull similar to getting on a plane - so is it reasonable to assume that there would be some initial setup with sails / wing, which gives max lift and heeling force, then once the center hull is out of water and speed+AWS increases, they would trim for max speed / min drag?

Share this post


Link to post
Share on other sites
WTF? Do you know who Blunted is?

Yes, Blunted is a key player in Fred Eaton's C-Class efforts. They are the current holders of the I4C trophy and he I believe sailed on Off-Yer-rocker the foiling C-Class that in it's new configeration as Orion. When Blunted speaks about wings, he knows what he is speaking about. Hope this clears up his credentials.

 

 

Thanks for pointing that out to us. I think he deserves a big welcome as the more wing experience we have here the easier it will be to figure things out & have a great time at it. Welcome Blunted & cheers from Lotusland :)

Share this post


Link to post
Share on other sites

Quick random thought....

 

Would it be possible to engineer the center hull such that it (the hull) could be raised above the water surface when sailing, then lowered to make a pivot point for effective turns? Also in the lowered position for measurement, naturally.

Share this post


Link to post
Share on other sites
Nothing like new technology to steepen the learning curve ...

I stopped worrying about flying the damn hull and trying to get enough force out of the wing ...

Bottom line is that even with CL equal and Cdo equal (wing should lower) the big difference is Aspect Ratio. On a 200 foot (~60m) rig with 10000 sqft Area AR = 4 The same 200ft wing with only 6000 sqft AR=6.67

Even with only 60% of the area the wing provides 37% more forward drive in 4 knots true. That is more than enough to make up for any drag penalty from not flying the centre hull. No jib needed upwind even in 4 knots true.

WoW were my first assumptions wrong. I would have bet that you could not get more drive out of less area at the same true wind speed.

 

This is a game changer for sure. :) ... if it all works!

Amazing to read this train of thought you have in these posts RH.

If you alter the calculations, just to find at which boat weight the center hull would fly...

How much weight would it be?

 

Because that center hull will sure enough be flying!

 

How important it is to fly the centre hull is all about how much drag you really reduce. At upwind angles that allow the boat to finish a 40 mile race in less than 7 hours, if the 10,000 sq ft soft rig could do it, the 6000 sq ft wing can also do it. At that upwind in 4 knots combination of sailing angles, boat speeds, AWA, and AWS ... The smaller area wing has like 25-40% MORE drive. Much more than needed to overcome sailing on two hulls.

 

I'm expanding the spreadsheet to produce a graph that shows the relationship of Drive to AR ... then I'll take a look at max safe wind speed and CL limited by RM ...

 

too much fun! :D

Share this post


Link to post
Share on other sites
WTF? Do you know who Blunted is?

Yes, Blunted is a key player in Fred Eaton's C-Class efforts. They are the current holders of the I4C trophy and he I believe sailed on Off-Yer-rocker the foiling C-Class that in it's new configeration as Orion. When Blunted speaks about wings, he knows what he is speaking about. Hope this clears up his credentials.

 

 

Thanks for pointing that out to us. I think he deserves a big welcome as the more wing experience we have here the easier it will be to figure things out & have a great time at it. Welcome Blunted & cheers from Lotusland :)

Dude, he's been here since 2004. Not sure he needs a welcome.

Share this post


Link to post
Share on other sites
Funny how everybody seems to like wing things all of a sudden.

 

 

 

Recap: #1, #2,#3, Camber, front twist, Delta, sheet, Idlers.

 

its all you need to know, well for a C-cat anyhow.

 

B

 

 

Sorry if I'm late in saying this but fuck you.

 

I've learned so far in life it's never too late to say "fuck you". So don't be sorry, you fucking idiot.

 

post-1634-1255466374_thumb.jpg

Share this post


Link to post
Share on other sites
could it be a coincidence that one Steve Clark has been absent from the forums for a while now? He could be busy with his new boat but he hasn't posted in the thread about his boat lately....

Been busy

post-738-1255456149_thumb.jpg

SHC

Well what would SA be with out pure speculation? I'm excited to see the finished project, thanks for the boat porn.

Share this post


Link to post
Share on other sites

Blunted

It appears that the leading edge of the moveable section (flap) is thicker than the trailing edge of the fixed portion (main wing). Its done on competition aerobatic airplanes to keep the flow attached at higher levels of deflection. Same principal?

 

post-1634-1255445867_thumb.jpg

Share this post


Link to post
Share on other sites
I'm inclined to believe that wai's picture was the official "unofficial leak" ;) ;) ..released to satisfy all AC anarchists who had been asking about what was happening at Anacortes. The folks at Anacortes obviously listen, so a polite "Thank you!!" would be in order...

 

 

Yes, I agree.

 

The Anacortes guys are also tired of the BS.

 

So, when they have something to stir the pot, why not have some fun?

 

But now I am thinking. On race day, which boat breaks first?

Share this post


Link to post
Share on other sites
Blunted

It appears that the leading edge of the moveable section (flap) is thicker than the trailing edge of the fixed portion (main wing). Its done on competition aerobatic airplanes to keep the flow attached at higher levels of deflection. Same principal?

 

post-1634-1255445867_thumb.jpg

 

I don't entirely follow your question but I think the answer is ,.... no.

 

The whole main element is a pretty fair curve to the TE. The only bumps in there are the fairing flaps, which by definition are not too good if they read as bumps.

 

Have a look at this and see if it answers your question...

 

post-1634-1255468436_thumb.jpg

Share this post


Link to post
Share on other sites
Nothing like new technology to steepen the learning curve ...

I stopped worrying about flying the damn hull and trying to get enough force out of the wing ...

Bottom line is that even with CL equal and Cdo equal (wing should lower) the big difference is Aspect Ratio. On a 200 foot (~60m) rig with 10000 sqft Area AR = 4 The same 200ft wing with only 6000 sqft AR=6.67

Even with only 60% of the area the wing provides 37% more forward drive in 4 knots true. That is more than enough to make up for any drag penalty from not flying the centre hull. No jib needed upwind even in 4 knots true.

WoW were my first assumptions wrong. I would have bet that you could not get more drive out of less area at the same true wind speed.

This is a game changer for sure. :) ... if it all works!

Amazing to read this train of thought you have in these posts RH.

If you alter the calculations, just to find at which boat weight the center hull would fly...

How much weight would it be?

Because that center hull will sure enough be flying!

 

How important it is to fly the centre hull is all about how much drag you really reduce. At upwind angles that allow the boat to finish a 40 mile race in less than 7 hours, if the 10,000 sq ft soft rig could do it, the 6000 sq ft wing can also do it. At that upwind in 4 knots combination of sailing angles, boat speeds, AWA, and AWS ... The smaller area wing has like 25-40% MORE drive. Much more than needed to overcome sailing on two hulls.

I'm expanding the spreadsheet to produce a graph that shows the relationship of Drive to AR ... then I'll take a look at max safe wind speed and CL limited by RM ...

too much fun! :D

Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

Share this post


Link to post
Share on other sites

Sorry guys my previous report of the wing parts arriving at the Dog Pound was incorrect. My operative informs me that they were in fact frames required to extend the tent. As they say if you pay peanuts you get monkeys. Here is his latest report:

 

First, I think what I saw last night on the truck was the aluminium framing to extend the tent! Not the 9 sections of the wing.

 

Second, they are extending the tent as we speak, presumably to work on the mast/wing.

 

I just went for a walk along to the dog pound and they are busy making the tent bigger - I'm guessing to work on the mast and/or wing under away from prying eyes. Dogzilla is on the hard in the compound (i.e. not in the tent). In fact I stood just 10 metres from the steering wheels. It's hard to see too much as they have black stuff on the wire netting fence, which is about my head height. And then around the perimeter of the 'pound are all the containers that serve as their offices, workshops, storage, etc. If I walk out onto the jetty by Joe's I might get a better look at the front end of the tri - I'll do that tonight.

 

As for the shed/tent, if you imagine it runs in a north-south direction. The north end is the front. It is longer down the sides (east and west) than it is across the front. When I was talking to you last night, I was at the south end (which faces my hotel but my room in the hotel also faces south), which is what they were starting to open up while we talked. Right now, the entire south end has been removed but they have a big curtain half way along the tent on the inside to stop you seeing all the way in, i.e. from the back all the way to the front. They are busy bolting together alum frames (the parts for which they have unloaded off the truck) to extend the tent. But the extensin will only be for half the width of the tent and not quite the full height - which is why i think it is to accomodate mast/wing work. I can tell this from the framing they have lying in the parking lot ready to stand up and add on to the tent.

Share this post


Link to post
Share on other sites
Blunted

It appears that the leading edge of the moveable section (flap) is thicker than the trailing edge of the fixed portion (main wing). Its done on competition aerobatic airplanes to keep the flow attached at higher levels of deflection. Same principal?

 

post-1634-1255445867_thumb.jpg

 

I don't entirely follow your question but I think the answer is ,.... no.

 

The whole main element is a pretty fair curve to the TE. The only bumps in there are the fairing flaps, which by definition are not too good if they read as bumps.

 

Have a look at this and see if it answers your question...

 

post-1634-1255468436_thumb.jpg

 

Yes it does. Basicly its two seperate airfoils and not one articulating blended airfoil.

Share this post


Link to post
Share on other sites
Sorry guys my previous report of the wing parts arriving at the Dog Pound was incorrect. My operative informs me that they were in fact frames required to extend the tent. As they say if you pay peanuts you get monkeys. Here is his latest report:

SNIP

I think what I saw last night on the truck was the aluminium framing to extend the tent! Not the 9 sections of the wing.

...

In fact I stood just 10 metres from the steering wheels. It's hard to see too much as they have black stuff on the wire netting fence, which is about my head height.

......

Please tell the monkey to climb up in the tree, and sit there until he finds something more fruitful... :lol:

 

...And if he sees a coffee cup, to hold on to it until the owner returns.

Share this post


Link to post
Share on other sites
Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

 

LOL ... that there is funny ... at 5.5 tons "unladen" WTF? No rig, no sails, no crew?

 

That puts USA well under the most credible estimate of A5's weight I've ever seen ...

 

SYDE is a design guy and has a feel for weight of carbon structures ... if he has seen that he'll have a heart attack!

 

I would love to find that to be a credible number, but sorry, no one in history has ever built that light.

 

800kg in crew? er ... all eight grinders average 220 lbs?

Share this post


Link to post
Share on other sites

so true. usually lethal to the own user :unsure:

 

It is definitely shaping to to be one hell of a Match. The kit is shocking!

 

Absolutely - we are back to the Herreshoff era, I'm delighted! [but "The Widow Maker" in airplane lingo traditionally describes crafts that are inherently unsafe, not lethal to the opposition :D ]

That's why I feel the urge to comment, even knowing that 90% will turn out to be rubbish

 

The root certainly seems VERY thick if this is a wing element, doesn't it?

Yes! That is the most intriguing detail.

 

OK, it appears to be a wingsail (how "hard" we'll see). The square section would be the spar - large indeed (and you do pay a weight penalty for that, Randy).

 

In front, there'll no doubt be a separate, leading edge fairing - but what 's aft? The triangular elements are far too short to indicate the trailing edge, even with a large flap. By all rights they could either be the flap hinge points, or the supports for the cambering mechanism in a D-mast / double luffed, battened soft sail combination!

 

The large spar section can be justified for both alternatives: with a large flap, it comes in handy to resist torsion - you have quite a bit in the high-lift configuration, as the center of effort moves aft a lot. With a double luffed sail, it allows the cambering mechanism to stay inside even in the max. camber shape (low Reynolds Numbers do not agree with thick airfoil sections, though).

 

Right now, I see three possibilities:

 

- a low-lift D-mast used alone going upwind, supplemented by the customary reaching soft sails. The advantage would be marginal in terms of reduced drag (the bulk of that being induced drag, which is just a function of sail aspect ratio), but could be substantial in being able to sail at minimal AoAs where a soft sail would backwind. Max. lift coefficient would be somewhat lower than that of a wing mast main, though

 

- a large-flap, not-so-big hard wing (i.e. using "just" the two structural elements we've seen so far), plus reaching soft sails. It would retain a portion of the upwind advantages, while downwind it could exploit the 2.5 vs. 1.5 advantage in lift coefficient over a wing mast main

 

- a monster, three-element hard wing, period :blink:

Share this post


Link to post
Share on other sites
Rennmaus is a fucking gerbil? I thought it was a bat for some reason.

 

bat is fledermaus.

Share this post


Link to post
Share on other sites
final setting could be like this... :blink:

 

 

Well, Minus the SailDrive hanging out.... but DaYUM!!!!!!!!! Zillla go Zooooooooooooooooom!!!!!!!!!!!! :P

 

13

Share this post


Link to post
Share on other sites

...and minus the draggy self aligning air rudder thingies.

Think wing like a BIG f-ing C-Cat like Blunted posted.

 

I like the sail drive though! :lol:

Share this post


Link to post
Share on other sites
Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

 

LOL ... that there is funny ... at 5.5 tons "unladen" WTF? No rig, no sails, no crew?

 

That puts USA well under the most credible estimate of A5's weight I've ever seen ...

SYDE is a design guy and has a feel for weight of carbon structures ... if he has seen that he'll have a heart attack!

I would love to find that to be a credible number, but sorry, no one in history has ever built that light.

800kg in crew? er ... all eight grinders average 220 lbs?

Perhaps it is about half what you are guessing BOR90's weight to be?! I'd also guess that you are closer to the actual figure, but these New Zealanders aren't so dumb either.

Who has ever spent so much money to lose weight as these contestants? Maybe it gives some results.

So how much would you have to reduce your weight estimate, for the center hull to fly?

Share this post


Link to post
Share on other sites
Looking through my pics to see if there is something else. This one shows the surface, facing down, as it is being loaded.

 

Is that video cameraman wearing an Alinghi hat?

 

post-29220-1255319414_thumb.jpg

 

 

Looks like a Sailing Anarchy hat to me.

 

do you guys have a hat in that colour?

 

same to me.

Share this post


Link to post
Share on other sites
Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

 

LOL ... that there is funny ... at 5.5 tons "unladen" WTF? No rig, no sails, no crew?

 

That puts USA well under the most credible estimate of A5's weight I've ever seen ...

SYDE is a design guy and has a feel for weight of carbon structures ... if he has seen that he'll have a heart attack!

I would love to find that to be a credible number, but sorry, no one in history has ever built that light.

800kg in crew? er ... all eight grinders average 220 lbs?

Perhaps it is about half what you are guessing BOR90's weight to be?! I'd also guess that you are closer to the actual figure, but these New Zealanders aren't so dumb either.

Who has ever spent so much money to lose weight as these contestants? Maybe it gives some results.

So how much would you have to reduce your weight estimate, for the center hull to fly?

 

That is a big ask! It's not like I have a VPP or anything ... :( I have (now) 7 dull pencils and a slide rule that is warm to the touch ... ;)

 

Way back when DZ was first launched we(the forum) looked at the centre hull and based on probable prismatic of .68-.70 (IIRC) and a 90 ft LWL ... we estimated volumes etc and came up with a number that was more in line with what most builders have done on the ultra light end of things.

 

A D/L of 11 is extreme, 10 is possible? but .. 7!

 

A D/L of 7? I'd like to think they hit that ... but I've never seen that number on a sailboat before.

Share this post


Link to post
Share on other sites
Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

 

LOL ... that there is funny ... at 5.5 tons "unladen" WTF? No rig, no sails, no crew?

 

That puts USA well under the most credible estimate of A5's weight I've ever seen ...

SYDE is a design guy and has a feel for weight of carbon structures ... if he has seen that he'll have a heart attack!

I would love to find that to be a credible number, but sorry, no one in history has ever built that light.

800kg in crew? er ... all eight grinders average 220 lbs?

Perhaps it is about half what you are guessing BOR90's weight to be?! I'd also guess that you are closer to the actual figure, but these New Zealanders aren't so dumb either.

Who has ever spent so much money to lose weight as these contestants? Maybe it gives some results.

So how much would you have to reduce your weight estimate, for the center hull to fly?

 

That is a big ask! It's not like I have a VPP or anything ... :( I have (now) 7 dull pencils and a slide rule that is warm to the touch ... ;)

Way back when DZ was first launched we(the forum) looked at the centre hull and based on probable prismatic of .68-.70 (IIRC) and a 90 ft LWL ... we estimated volumes etc and came up with a number that was more in line with what most builders have done on the ultra light end of things.

A D/L of 11 is extreme, 10 is possible? but .. 7!

A D/L of 7? I'd like to think they hit that ... but I've never seen that number on a sailboat before.

Don't be so modest. If you posit that the center hull does not fly at a given weight, surely your slide rule knows what you need to shave off to get the hull up, ceteris paribus?

This boat weight subject is mysterious and fascinating. I did a breakdown of the weights given in the D35 class rules. There you have a boat built like a tank in some respects, and fitted with a fair amount of gear which could be radically lightened if cost was no object.

The percentages of total weight (1200kg) were interesting to look at. Amas accounted for 33%. Center hull 12%, mast 12%, beams 10.5%, daggerboards 6.3%. It was a bit different from what I was expecting.

 

Wish we had a thread on the subject which could carry on and on unpolluted - like those ACT guys have got going! :)

Share this post


Link to post
Share on other sites
This sure beats the legal threads!

 

truer words have seldom been spoken.

Share this post


Link to post
Share on other sites
Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

 

LOL ... that there is funny ... at 5.5 tons "unladen" WTF? No rig, no sails, no crew?

 

That puts USA well under the most credible estimate of A5's weight I've ever seen ...

SYDE is a design guy and has a feel for weight of carbon structures ... if he has seen that he'll have a heart attack!

I would love to find that to be a credible number, but sorry, no one in history has ever built that light.

800kg in crew? er ... all eight grinders average 220 lbs?

Perhaps it is about half what you are guessing BOR90's weight to be?! I'd also guess that you are closer to the actual figure, but these New Zealanders aren't so dumb either.

Who has ever spent so much money to lose weight as these contestants? Maybe it gives some results.

So how much would you have to reduce your weight estimate, for the center hull to fly?

 

That is a big ask! It's not like I have a VPP or anything ... :( I have (now) 7 dull pencils and a slide rule that is warm to the touch ... ;)

Way back when DZ was first launched we(the forum) looked at the centre hull and based on probable prismatic of .68-.70 (IIRC) and a 90 ft LWL ... we estimated volumes etc and came up with a number that was more in line with what most builders have done on the ultra light end of things.

A D/L of 11 is extreme, 10 is possible? but .. 7!

A D/L of 7? I'd like to think they hit that ... but I've never seen that number on a sailboat before.

Don't be so modest. If you posit that the center hull does not fly at a given weight, surely your slide rule knows what you need to shave off to get the hull up, ceteris paribus?

This boat weight subject is mysterious and fascinating. I did a breakdown of the weights given in the D35 class rules. There you have a boat built like a tank in some respects, and fitted with a fair amount of gear which could be radically lightened if cost was no object.

The percentages of total weight (1200kg) were interesting to look at. Amas accounted for 33%. Center hull 12%, mast 12%, beams 10.5%, daggerboards 6.3%. It was a bit different from what I was expecting.

 

Wish we had a thread on the subject which could carry on and on unpolluted - like those ACT guys have got going! :)

I tried to get something like this going over at boatdesign.net and got very few takers. I agree a sailing geek thread might be fun. ;)

Share this post


Link to post
Share on other sites
......

Wish we had a thread on the subject which could carry on and on unpolluted - like those ACT guys have got going! :)

I tried to get something like this going over at boatdesign.net and got very few takers. I agree a sailing geek thread might be fun. ;)

We must have had scores of interesting posts over the past months, just on the subject of the weight of these two boats.

Now nobody knows where all those remarks are any more. If you browse down through the thread titles it offers practically no help at all.

If there were some kind of tag function, allowing posts to be categorized by the author as belonging to one of a few central issues, it might be better? Supposing those posts could be separately called up in chronological order...

 

As it is now, the site is well tailored to the attraction of starting new threads, but that constant deluge has the drawback of always burying a lot of relevant content.

Share this post


Link to post
Share on other sites

A well designed wing (not sail) will have an elliptical lift profile to minimize drag. The ideal sail will be a slightly distorted elliptical profile. The CE will be well less than 50%.

 

Not.

Show me any high performance glider with an elliptical profile.

 

What about this one?

 

post-19692-1255415684_thumb.jpg

 

And the lower performance gliders have them too.

 

post-19692-1255415720_thumb.jpgpost-19692-1255415739_thumb.jpg

 

Elliptical lift profile and elliptical plan form are completely different things. You have some semi-elliptical plan forms here, no friggen idea if the lift profiles are elliptical ... ;) I doubt they are.

 

Dont be a fucking smartarse RHough, elliptical planforms and elliptical area distributions are different things too. It's pretty obvious these wings are using close to elliptical area distributions with some sweep to the quarter chord line, and their lift distributions are likely not far off elliptical as well.

Share this post


Link to post
Share on other sites
Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

 

LOL ... that there is funny ... at 5.5 tons "unladen" WTF? No rig, no sails, no crew?

 

That puts USA well under the most credible estimate of A5's weight I've ever seen ...

 

SYDE is a design guy and has a feel for weight of carbon structures ... if he has seen that he'll have a heart attack!

 

I would love to find that to be a credible number, but sorry, no one in history has ever built that light.

 

800kg in crew? er ... all eight grinders average 220 lbs?

 

Randy,

 

I put my name on every post I make, or it least I have since I stop working for somebody else. You can use it, I really don't mind.

 

Not putting any more confidence in the veracity of the 5 tonnes platform idea than before and definitely not having a hard ... er ... heart attack. Thanks for the concern.

 

I think RG must be reading the same questionable posting based on a shipping request. I was thinking out loud how light could the whole thing be if that 5 something tonne figure is true? But, I was talking about possibly 5 ish tonnes stripped of everything.

Share this post


Link to post
Share on other sites

A well designed wing (not sail) will have an elliptical lift profile to minimize drag. The ideal sail will be a slightly distorted elliptical profile. The CE will be well less than 50%.

 

Not.

Show me any high performance glider with an elliptical profile.

 

What about this one?

 

post-19692-1255415684_thumb.jpg

 

And the lower performance gliders have them too.

 

post-19692-1255415720_thumb.jpgpost-19692-1255415739_thumb.jpg

 

Elliptical lift profile and elliptical plan form are completely different things. You have some semi-elliptical plan forms here, no friggen idea if the lift profiles are elliptical ... ;) I doubt they are.

 

Dont be a fucking smartarse RHough, elliptical planforms and elliptical area distributions are different things too. It's pretty obvious these wings are using close to elliptical area distributions with some sweep to the quarter chord line, and their lift distributions are likely not far off elliptical as well.

 

Brian, was waiting for that...

Share this post


Link to post
Share on other sites

I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

Maybe an ORACLE database together with BMW CAN-Bus?

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

 

Ironically enough it is due to the rule changes from SNG that we will likely see something pretty special here. Something that could not be managed by manual power and less computers.

 

We'll likely see some pretty cool real-time sensors reading out to the trimmer. Trimmer presses one of dozens of buttons to move element X this way or that.

 

Without power, there is no way they could manage anything as complicated. Thanks to SNG rule changes it will happen.

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

 

Ironically enough it is due to the rule changes from SNG that we will likely see something pretty special here. Something that could not be managed by manual power and less computers.

 

We'll likely see some pretty cool real-time sensors reading out to the trimmer. Trimmer presses one of dozens of buttons to move element X this way or that.

 

Without power, there is no way they could manage anything as complicated. Thanks to SNG rule changes it will happen.

 

 

 

I can't see why the trimmer would have more than two buttons, 'port and starbord' with an acelerometer monitoring the heal of the boat, you'd just want max drive for a given max heal the whole time. It will be very cool to see, but I don't see a human being significantly involved :( It is likely to be like F1 racing prior to some of the newer rules. The driver/helmsman steers the car / boat, the computer does the rest. My bet is that this will be a runaway race for the challenger unless they break it or SNG also has a similar system. I don't even think they will have to get this system close to optimal to win. Note that the software for this exists in the wind turbine field ...

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

 

Ironically enough it is due to the rule changes from SNG that we will likely see something pretty special here. Something that could not be managed by manual power and less computers.

 

We'll likely see some pretty cool real-time sensors reading out to the trimmer. Trimmer presses one of dozens of buttons to move element X this way or that.

 

Without power, there is no way they could manage anything as complicated. Thanks to SNG rule changes it will happen.

 

 

 

I can't see why the trimmer would have more than two buttons, 'port and starbord' with an acelerometer monitoring the heal of the boat, you'd just want max drive for a given max heal the whole time. It will be very cool to see, but I don't see a human being significantly involved :( It is likely to be like F1 racing prior to some of the newer rules. The driver/helmsman steers the car / boat, the computer does the rest. My bet is that this will be a runaway race for the challenger unless they break it or SNG also has a similar system. I don't even think they will have to get this system close to optimal to win. Note that the software for this exists in the wind turbine field ...

The controls we use on soft sails are actually very crude. We can adjust leach tension, angle of attack, and mast bend.

 

With a hard wing, powered by electronics, the angle of attack, camber, and slot at every point up and down the sail can be adjusted independently. There are a lot of interactions between airflow at different parts of the sail (wing). The wind actually changes fairly dramatically every second. Those changes are different at different heights. A sail (wing) that quickly adjusts its shape at different heights will be a more efficient sail.

Share this post


Link to post
Share on other sites
Did you see this remark by Gladwell, back on Sept. 23rd?

 

"Eight grinding crew are expected to made redundant in the change, which will affect the Load Waterline calculation which required, under the rules published by SNG, for the crew to be on board the yacht at the time of measurement. While some weight will be added by the engine and hydraulics, over 800kgs are expected to be taken off in crew weight, substantially affecting the float position of the multihull which is estimated to weigh around 5.5 tonnes in her unladen state."

 

http://www.sail-world.com/europe/Gladwells...lden-Gate/61555

 

LOL ... that there is funny ... at 5.5 tons "unladen" WTF? No rig, no sails, no crew?

 

That puts USA well under the most credible estimate of A5's weight I've ever seen ...

 

SYDE is a design guy and has a feel for weight of carbon structures ... if he has seen that he'll have a heart attack!

 

I would love to find that to be a credible number, but sorry, no one in history has ever built that light.

 

800kg in crew? er ... all eight grinders average 220 lbs?

 

Randy,

 

I put my name on every post I make, or it least I have since I stop working for somebody else. You can use it, I really don't mind.

 

Not putting any more confidence in the veracity of the 5 tonnes platform idea than before and definitely not having a hard ... er ... heart attack. Thanks for the concern.

 

I think RG must be reading the same questionable posting based on a shipping request. I was thinking out loud how light could the whole thing be if that 5 something tonne figure is true? But, I was talking about possibly 5 ish tonnes stripped of everything.

Hey Doug, I didn't remember you ever hazarding a guess that low, even w/o rig/sails etc. How stripped you the boat have to be to make 5.5 tonnes a believable number? IIRC you said that USA could bee 8-9 tonnes and A5 6-7 tonnes? I've never been able to convince myself that either one could be below 11 tonnes ready to race.

 

You are much more qualified than I am to make an educated guess.

 

Cheers

Share this post


Link to post
Share on other sites
The controls we use on soft sails are actually very crude. We can adjust leach tension, angle of attack, and mast bend.

 

With a hard wing, powered by electronics, the angle of attack, camber, and slot at every point up and down the sail can be adjusted independently. There are a lot of interactions between airflow at different parts of the sail (wing). The wind actually changes fairly dramatically every second. Those changes are different at different heights. A sail (wing) that quickly adjusts its shape at different heights will be a more efficient sail.

What a concept!

That makes me think of when I got my first 16-track sequencer synthesizer, and how it put my piano in a state of neglect.

Share this post


Link to post
Share on other sites
The controls we use on soft sails are actually very crude. We can adjust leach tension, angle of attack, and mast bend.

 

With a hard wing, powered by electronics, the angle of attack, camber, and slot at every point up and down the sail can be adjusted independently. There are a lot of interactions between airflow at different parts of the sail (wing). The wind actually changes fairly dramatically every second. Those changes are different at different heights. A sail (wing) that quickly adjusts its shape at different heights will be a more efficient sail.

What a concept!

That makes me think of when I got my first 16-track sequencer synthesizer, and how it put my piano in a state of neglect.

 

More like the fuzzy logic programs that keep the B-2 aloft or the F-117.

Share this post


Link to post
Share on other sites
Note that the software for this exists in the wind turbine field ...

 

As well as in the various Fly By Wire aircraft Cos - anyone remember the prototype swingwing fighter that used a wing that rotated assymetrically? It was unflyable without computer trimming. Same would apply here.

 

Allowing electronic trim and powered trim was stupid of Erne$to - particularly given Ellison's connections with Silly Valley

Share this post


Link to post
Share on other sites

A well designed wing (not sail) will have an elliptical lift profile to minimize drag. The ideal sail will be a slightly distorted elliptical profile. The CE will be well less than 50%.

 

Not.

Show me any high performance glider with an elliptical profile.

 

What about this one?

 

post-19692-1255415684_thumb.jpg

 

And the lower performance gliders have them too.

 

post-19692-1255415720_thumb.jpgpost-19692-1255415739_thumb.jpg

 

Elliptical lift profile and elliptical plan form are completely different things. You have some semi-elliptical plan forms here, no friggen idea if the lift profiles are elliptical ... ;) I doubt they are.

 

Dont be a fucking smartarse RHough, elliptical planforms and elliptical area distributions are different things too. It's pretty obvious these wings are using close to elliptical area distributions with some sweep to the quarter chord line, and their lift distributions are likely not far off elliptical as well.

 

Brain, being a fucking smartass is half of my identity. :) I answered your smartassed reply "What about this one?" with a smartassed comment of my own, even included a ;) Perhaps I should have said, "Don't be a smart ass Brian?"

 

All in fun! :)

 

There is some debate over what the lowest drag spanwise lift distribution is for sail boats. The simple elliptical answer that is "common knowledge" works for symmetrical foils. At one time sails were considered as half wings and the elliptical spanwise lift distribution was thought to be best. Tom Speer and others have shown that this may not be the case. That the gap at at the bottom of a sail is significant enough to prevent considering a sail as a half wing. Certainly on these boats there is no "End Plate" effect from the water plane as thought to exist with a monohull and a genoa that seals at the deck.

 

In plan view a sail is like a single wing with large tip chord at one end and small tip chord at the other. Lift distribution is unlikely to be elliptical with such an area distribution.

Share this post


Link to post
Share on other sites
With a hard wing, powered by electronics, the angle of attack, camber, and slot at every point up and down the sail can be adjusted independently. There are a lot of interactions between airflow at different parts of the sail (wing). The wind actually changes fairly dramatically every second. Those changes are different at different heights. A sail (wing) that quickly adjusts its shape at different heights will be a more efficient sail.

 

No doubt true - and I'm sure the SW will have been tested, optimized and debugged - without causing major breakages along the way, remember the F-16's navigation SW, that would have caused it to go upside down if it crossed the Equator - by Nov 30! :rolleyes:

Share this post


Link to post
Share on other sites
Note that the software for this exists in the wind turbine field ...

 

As well as in the various Fly By Wire aircraft Cos - anyone remember the prototype swingwing fighter that used a wing that rotated assymetrically? It was unflyable without computer trimming. Same would apply here.

 

Allowing electronic trim and powered trim was stupid of Erne$to - particularly given Ellison's connections with Silly Valley

 

Yeh I see it as stupid, unless they have something similar.

 

The interesting bit about the wind turbine world is that the reynolds numbers are similar (and if I remember from earler threads the builders also build turbine blades) - the question is how many degrees of freedom the wing has and how long they have to tune the code. I'd guess you could get it within 95% of optimal within a few days ... you probably don't need that last 5% to win. Now they could easily get something wrong and end up with a nasty feedback loop which could put the whole thing in the drink, that would be my biggest worry (there have been plenty of examples of this in the A/C world. )

 

I'm excited to see this thing sail, but I suspect that the 'race' will be very sterile.

Share this post


Link to post
Share on other sites
With a hard wing, powered by electronics, the angle of attack, camber, and slot at every point up and down the sail can be adjusted independently. There are a lot of interactions between airflow at different parts of the sail (wing). The wind actually changes fairly dramatically every second. Those changes are different at different heights. A sail (wing) that quickly adjusts its shape at different heights will be a more efficient sail.

 

No doubt true - and I'm sure the SW will have been tested, optimized and debugged - without causing major breakages along the way, remember the F-16's navigation SW, that would have caused it to go upside down if it crossed the Equator - by Nov 30! :rolleyes:

funny I heard the same story but it was an airbus, sounds like an urban legend. I do know of cases where the SW has put a/c in the ground though. The thing is that the software should actually be fairly simple if all you want to do is win.

Share this post


Link to post
Share on other sites
I can't see why the trimmer would have more than two buttons, 'port and starbord' with an acelerometer monitoring the heal of the boat, you'd just want max drive for a given max heal the whole time. It will be very cool to see, but I don't see a human being significantly involved :( It is likely to be like F1 racing prior to some of the newer rules. The driver/helmsman steers the car / boat, the computer does the rest. My bet is that this will be a runaway race for the challenger unless they break it or SNG also has a similar system. I don't even think they will have to get this system close to optimal to win. Note that the software for this exists in the wind turbine field ...

Software exists in the wing sail field too; Harbor Wing was already mentioned above and elsewhere:

 

VIDEO: Concept Demonstration of the Harbor Wing AUSV (Autonomous Unmanned Surface Vessel)

http://www.harborwingtech.com/products_demo.htm

 

The narrator mentions a "trimaran hull", though the prototype in the video is obviously a cat.

post-10646-1255543184_thumb.jpgpost-10646-1255543204_thumb.jpgpost-10646-1255543228_thumb.jpgpost-10646-1255543245_thumb.jpg

Share this post


Link to post
Share on other sites

I'm not sure that computers are allowed to control sail shape - ie., you don't just let the computer automatically trim the sails. Now that's not to say that the trimmers won't have a screen telling them what optimal trim would be and then the trimmer pushing the right buttons to make it so. I think the rule still says a person has to push the button.

 

My point in my post above about power opening a world of possibilities was that we should open our minds as to what the wing MAY look like. We seem to be stuck in a rut thinking about a 2 element wing (like Ben Hall's A Class) or what the current C Cats are running (call it the Steve, Duncan, Dave wing) which is a 2 element wing where the first element also has a flap at the trailing edge which adjusts with idlers and also leading edge twist control.

 

Much of what the A and C guys can do is limited by people - on the C they also have to trapeze, navigate, adjust 3 control lines, move dagger board up/down, etc. Also, as much as Steve and Fredo have burnt on their programs the BOR budget is, shall we say, bigger.

 

So, what sort of wing?

 

Canting?

 

We can only speculate but why stop at three elements? And will they be three front to back?

 

I don't think we'll see this but it is an interesting thought... what about a membrane stretched over a very large number of actuators. Something like North's 3DL mold but as a sail, if you see what I mean. I don't think we'll see it but it is possible.

 

My point in raising this is that, ironically, it is the power that SNG has allowed which gives BOR even more choices when it comes to the wing.

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

 

Ironically enough it is due to the rule changes from SNG that we will likely see something pretty special here. Something that could not be managed by manual power and less computers.

 

We'll likely see some pretty cool real-time sensors reading out to the trimmer. Trimmer presses one of dozens of buttons to move element X this way or that.

 

Without power, there is no way they could manage anything as complicated. Thanks to SNG rule changes it will happen.

 

Isn't it conceivable that the entire trim process will be computer controlled and the trimmer will keep his hands off? If you're talking about adjusting multiple elements up and down the wing every second, sounds like a job much better performed by a computer than a human brain. Not sure they'd have enough time to program it all out, but as others pointed out, fly-by-wire is nothing new. Probably need controls for prestart, but once you're in straight-line mode, hit auto-trim and strap yourself in.

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

 

Ironically enough it is due to the rule changes from SNG that we will likely see something pretty special here. Something that could not be managed by manual power and less computers.

 

We'll likely see some pretty cool real-time sensors reading out to the trimmer. Trimmer presses one of dozens of buttons to move element X this way or that.

 

Without power, there is no way they could manage anything as complicated. Thanks to SNG rule changes it will happen.

 

Isn't it conceivable that the entire trim process will be computer controlled and the trimmer will keep his hands off? If you're talking about adjusting multiple elements up and down the wing every second, sounds like a job much better performed by a computer than a human brain. Not sure they'd have enough time to program it all out, but as others pointed out, fly-by-wire is nothing new. Probably need controls for prestart, but once you're in straight-line mode, hit auto-trim and strap yourself in.

 

Or don't strap yourself in. Run the whole thing by remote from shore.

Share this post


Link to post
Share on other sites
I don't think we'll see this but it is an interesting thought... what about a membrane stretched over a very large number of actuators. Something like North's 3DL mold but as a sail, if you see what I mean. I don't think we'll see it but it is possible.

 

You mean an adaptive wing? So far, it's a DARPA bottomless pit :ph34r:

Share this post


Link to post
Share on other sites
I don't think we'll see this but it is an interesting thought... what about a membrane stretched over a very large number of actuators. Something like North's 3DL mold but as a sail, if you see what I mean. I don't think we'll see it but it is possible.

 

You mean an adaptive wing? So far, it's a DARPA bottomless pit :ph34r:

post-10646-1255545386_thumb.jpg

"Shape Memory Alloys"

Share this post


Link to post
Share on other sites
I don't think we'll see this but it is an interesting thought... what about a membrane stretched over a very large number of actuators. Something like North's 3DL mold but as a sail, if you see what I mean. I don't think we'll see it but it is possible.

 

You mean an adaptive wing? So far, it's a DARPA bottomless pit :ph34r:

So what is khalas , anyway? :huh:

Share this post


Link to post
Share on other sites
I don't think we'll see this but it is an interesting thought... what about a membrane stretched over a very large number of actuators. Something like North's 3DL mold but as a sail, if you see what I mean. I don't think we'll see it but it is possible.

 

You mean an adaptive wing? So far, it's a DARPA bottomless pit :ph34r:

 

Something like that. Just wanted to push the idea to get people to think more openly about what we might see. Still don't think we'll see it but we also won't see a scaled up A or C class wing. Might just be lots of elements with a membrane stretched over them.

We'll see in a week or two.

Share this post


Link to post
Share on other sites
So what is khalas , anyway? :huh:

 

 

You also find that in the Urban Dictionary - but it's arabic for kaputt, finito

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

 

Ironically enough it is due to the rule changes from SNG that we will likely see something pretty special here. Something that could not be managed by manual power and less computers.

 

We'll likely see some pretty cool real-time sensors reading out to the trimmer. Trimmer presses one of dozens of buttons to move element X this way or that.

 

Without power, there is no way they could manage anything as complicated. Thanks to SNG rule changes it will happen.

 

Isn't it conceivable that the entire trim process will be computer controlled and the trimmer will keep his hands off? If you're talking about adjusting multiple elements up and down the wing every second, sounds like a job much better performed by a computer than a human brain. Not sure they'd have enough time to program it all out, but as others pointed out, fly-by-wire is nothing new. Probably need controls for prestart, but once you're in straight-line mode, hit auto-trim and strap yourself in.

 

The manual or automatic control of trim vs rules is a good question. Under manual power rules is wind vane steering allowed? Any well trimmed boat will sail herself to windward in reaction to the changes in the breeze, that is all a wind vane does.

 

Under manual power it is common to mark adjustments so all the manual crew does is use predetermined marks based on conditions. The computer is the powered equivalent of marks on sheets and jib leads. Manual trimmers rely on data from instruments to select settings, the computer on boat manual powered boats is part of that instrument system. I'd say that all you need is three buttons: Trim Auto Ease. When the trimmer is anticipating the boat, use the trim-ease buttons. When on a course, the computer provided the "trim to marks" and the "auto" button simply adjusts the wing to those preset targets. The trimmer looks ahead and can override with trim/ease is needed and then press "auto" to return to optimum settings.

 

The software does not have to be terribly sophisticated to be "self learning" in that if the trimmer applies an override and that setting is faster, the target for that conditions is updated.

 

All very cool stuff and all impossible at this scale if powered systems are not used.

 

This has implications for large cruising boats and mega yachts. Smaller crews needed and better performance possible with an integrated systems approach. Simply integrating sail trim with autopilot functions would be a first step.

 

Sail design was once an art, now it is more science. If it is acceptable to use the best tools for design, why not allow the best tools for trimming those designs? Computerized sail trim feedback is a step forward is it not?

Share this post


Link to post
Share on other sites
I'd like to get a look at the software thats going to auto-trim the wingsail with the engine taking into account wind readings at the bow :P

 

I'd think you would split the wing into segments have local pressure reading across the span within a segment and maximise the Cp profile. You'd also have to have a estmate of the effect of the spanwise flow on adjacent sections. I can't see them worrying about wind speed or direction, just set the tack and go for max Cp.

 

Ironically enough it is due to the rule changes from SNG that we will likely see something pretty special here. Something that could not be managed by manual power and less computers.

 

We'll likely see some pretty cool real-time sensors reading out to the trimmer. Trimmer presses one of dozens of buttons to move element X this way or that.

 

Without power, there is no way they could manage anything as complicated. Thanks to SNG rule changes it will happen.

 

Isn't it conceivable that the entire trim process will be computer controlled and the trimmer will keep his hands off? If you're talking about adjusting multiple elements up and down the wing every second, sounds like a job much better performed by a computer than a human brain. Not sure they'd have enough time to program it all out, but as others pointed out, fly-by-wire is nothing new. Probably need controls for prestart, but once you're in straight-line mode, hit auto-trim and strap yourself in.

 

The manual or automatic control of trim vs rules is a good question. Under manual power rules is wind vane steering allowed? Any well trimmed boat will sail herself to windward in reaction to the changes in the breeze, that is all a wind vane does.

 

Under manual power it is common to mark adjustments so all the manual crew does is use predetermined marks based on conditions. The computer is the powered equivalent of marks on sheets and jib leads. Manual trimmers rely on data from instruments to select settings, the computer on boat manual powered boats is part of that instrument system. I'd say that all you need is three buttons: Trim Auto Ease. When the trimmer is anticipating the boat, use the trim-ease buttons. When on a course, the computer provided the "trim to marks" and the "auto" button simply adjusts the wing to those preset targets. The trimmer looks ahead and can override with trim/ease is needed and then press "auto" to return to optimum settings.

 

The software does not have to be terribly sophisticated to be "self learning" in that if the trimmer applies an override and that setting is faster, the target for that conditions is updated.

 

All very cool stuff and all impossible at this scale if powered systems are not used.

 

This has implications for large cruising boats and mega yachts. Smaller crews needed and better performance possible with an integrated systems approach. Simply integrating sail trim with autopilot functions would be a first step.

 

Sail design was once an art, now it is more science. If it is acceptable to use the best tools for design, why not allow the best tools for trimming those designs? Computerized sail trim feedback is a step forward is it not?

 

Computer for sail trim might be great for sailing but not for racing as the technology has yet to see forward beyond it's physical reach (vanes). Until a computer has the eye sight of a human racing with computers is limited.

Share this post


Link to post
Share on other sites
Sail design was once an art, now it is more science. If it is acceptable to use the best tools for design, why not allow the best tools for trimming those designs? Computerized sail trim feedback is a step forward is it not?

 

Huge step forward (and also a big step back) cf. F1 car racing, I for one love the idea of a self trimming sail and I don't believe it to be hard to pull off, to win this cometition is don't have to be that complicated a design (assuming no wing from SNG) These guys certaunly have the money - the biggest unknown is whether the wing was designed prior to the ruling on power or not and what changes were made in the process.

Share this post


Link to post
Share on other sites
Software exists in the wing sail field too; Harbor Wing was already mentioned above and elsewhere:

 

from looking at their design they appear to have gone for a (IMHO ugly) dynamically stable setup, I don't see the need for a computer system there. With computers you don't need the two extra wings hanging off the back causing drag. Now that does assume you want to mix electronics and salt water ...

Share this post


Link to post
Share on other sites
Computer for sail trim might be great for sailing but not for racing as the technology has yet to see forward beyond it's physical reach (vanes). Until a computer has the eye sight of a human racing with computers is limited.

 

I don't get that, assume that the computer is always looking to maximise thrust from the wing. It can react far faster to changing conditions than a human, you don't need to guess when you can read. You still need a good tactician and driver though - I don't see them being replaced any time soon.

Share this post


Link to post
Share on other sites
Computer for sail trim might be great for sailing but not for racing as the technology has yet to see forward beyond it's physical reach (vanes). Until a computer has the eye sight of a human racing with computers is limited.

 

I don't get that, assume that the computer is always looking to maximise thrust from the wing. It can react far faster to changing conditions than a human, you don't need to guess when you can read. You still need a good tactician and driver though - I don't see them being replaced any time soon.

 

How does a computer see/read/sense up the course for a change in pressure or angle? Altering sail shape is one thing but how you position it on & thru the course is another especially when you are moving thru 2 fluids that are constantly changing.

Share this post


Link to post
Share on other sites
How does a computer see/read/sense up the course for a change in pressure or angle? Altering sail shape is one thing but how you position it on & thru the course is another especially when you are moving thru 2 fluids that are constantly changing.

 

Give it a doppler sensor input that uses microwave or laser to survey the windfield, and keep it auto stabilized. Isn't that what the "Goose" was used for?

 

:ph34r:

Share this post


Link to post
Share on other sites

I've never sailed a wing on water but I have a lot of experience with them dirt and iceboating. A few advantages take place when using a wing . One is there is way less compression on the boat due to the fact that the wing doesn't have to be sheeted in tight like a sail . Fat head sails are even harder to sheet in so they don't twist off.

The second thing that happens with a wing is if you get the rotational axis's( Side hound attachment point and mast step location) close to being balanced but still sheet out on its own it will take less power to sheet in. Another advantage in light air is that the wings in general hike before a soft sail will. This will allow them to fly a hull in less wind. The wings taper profile ( vertical center of effort)and flap size will play into that role as well. In our case with dirtboats we can close the gap between the wing and the fuselage. This helps eliminate tip loss off(drag) the bottom. I have done testing and found closing the gap makes a big difference in performance. We have built identical wingboats for testing. Last week we found that endplates seemed to hook up faster than a non end plated wing . It also hiked more and would be an advantage to get a boat to fly hulls sooner in less wind.

Share this post


Link to post
Share on other sites

LIDAR:

Outlawed in the America's Cup rules in both 03 and 07'

Measures particles in the atmosphere and can accurately map the "wind field" either upwind or downwind or in a vertical axis....

Article

Share this post


Link to post
Share on other sites
How does a computer see/read/sense up the course for a change in pressure or angle? Altering sail shape is one thing but how you position it on & thru the course is another especially when you are moving thru 2 fluids that are constantly changing.

 

Give it a doppler sensor input that uses microwave or laser to survey the windfield, and keep it auto stabilized. Isn't that what the "Goose" was used for?

 

:ph34r:

 

ignore prediction and use pressure sensors in the wing, you are looking for better than a soft sail today, not better than an optimised computer controller hard sail... Of interest would be if there are too many hysterisis/non-linear effects, but since the wing (at low Re) is going to have a turbulent boundary layer it is likely not that bad. Optimise in software towards a maximum Cp along the hull direction (you may end up at a local maxima, but due to the unstable nature of the wind it is likely to be short lived), Failing that you could always put out a couple of A/C style sensors just ahead of the wing, much like an aircraft you only care about wind relative to the wing and nothing else - The other variable would be the time it takes to deform/rotate the wing, the assumption being that changes in wind velocity / direction are signifciantly slower than changes in wing position / shape (likely true once moving) you might need a set of heuristics to get you moving.

Share this post


Link to post
Share on other sites

http://www.boot.de/cipp/md_boot/custom/pub...ather_Team.html

 

America's Cup 2003

Weapons of the Weather Team

 

bbb.jpg

Infra red satellite image.

 

Image NZ MetService Russell Coutts has been quick to recognise the part played by the weather team in Alinghi’s success so far. “Jon Bilger and his team have achieved great things out there and taught Brad and me things about the Hauraki Gulf that we didn’t know.” In race three of the America’s Cup Match, with six minutes to go, just seconds before the communication lines are cut at the five minute gun, it was Bilger who relayed the vital call to the Alinghi afterguard to ‘go right’. That bold call helped tactician Brad Butterworth to plump for the right side of the race course and open a decisive 200 metre lead on Team Zealand in the first few minutes of the race.

 

Space age monitors have raised the game at predicting shifts

The wind was out of the north and Bilger says that up until a last minute change of heart, he liked the left and it seemed like left was the obvious call. “For once it looked an easy choice, we thought ‘left-handers’ on the left would be the only way to go, despite that fact that there looked like more wind on the right. But one of our weather boats saw the big right hander and radioed in immediately.”

 

Cold War on the Weather Front

Bilger orchestrates a flotilla of eight Alinghi weather boats, placed strategically to monitor the wind on each side of the race course. Data from each boat is networked together and displayed before Bilger and meteorologist Jack Katzfey on their flag ship or nerve centre. Armed with fast intranet access and scrambled communications Bilger can also monitor a myriad of shore stations as well as view sophisticated radar to track shifts and wind patterns. Team New Zealand has seven weather boats. Three weeks before the Cup, they increased their team from four to seven to match that of the Challenger. Roger ‘Clouds’ Badham remarks, “it is a cold war out there and we decided to match Alinghi’s weather flotilla a few weeks ago. Financial constraints would not allow us to have that many six months ago, but we have some great sailors out in our boats who all contribute a massive amount.”

 

aaa.jpg

LIDAR utilises laser technology to predict the wind

 

Great tools for building scientific pictures

One of the most impressive of the America’s Cup forecasting monitors is the ‘wind profiler’, which is a huge 16 metre square array on Motutapu Island on the eastern side of the Hauraki Gulf. It is designed to monitor the lower layers of the atmosphere (up to 2000 metres) and help forecasters and air traffic controllers warn pilots of wind shear on the approach path to an airport. Utilised by NASA for wind information for the landing of the space shuttle, the massive aerial transmits vertically giving wind speed and direction at varying heights to enable a three dimensional picture to built up with time. Atmospheric Radar Systems Ltd (Atrad) CEO, Rob Silva explains, “the wind profiler is a great tool for building up clear scientific picture of the wind over a small area. The data feeds into a meso-scale computer model and the computing power is usually the limiting factor given that with our transmitters we can achieve a definition of 75 metres with our UHF transmitters.” The transmitter on the Hauraki Gulf is VHF and achieves a definition of 150 metres and costs in excess of US$100 000.

 

Syndicates share the huge costs

The huge costs of some of the weather monitors have meant that the weather teams have clubbed together to share expenses. Team New Zealand and Alinghi share the information of the wind profiler (Prada and OneWorld also bought in). Likewise the weather buoy information was bought by all of the teams, whilst a ‘secret SODAR’ monitor, (again discreetly placed on Motutapu Island) is again a joint programme between the top teams.

 

How to find out about turbulences in the air

Sodar (Sonic detection and ranging) systems are used to remotely measure the vertical turbulence structure and the wind profile of the lower layer of the atmosphere (usually below that of wind profilers). Sodar systems are like radar (radio direction and ranging) systems except that sound waves rather than radio waves are used for detection and cover an arc of around fifteen degrees. Other names used for sodar systems include echo sounder and acoustic radar.

 

Almost like submarines

A more familiar related term may be sonar, which stands for sound navigation ranging. Sonar systems detect the presence and location of objects submerged in water (e.g. submarines) by means of sonic waves reflected back to the source. Sodar systems are similar except the medium is air instead of water and reflection is due to the scattering of sound by atmospheric turbulence and can replace the conventional ‘weather balloon’. Most sodar systems operate by issuing an acoustic pulse and then listen for the return signal for a short period of time. Both the intensity and the Doppler (frequency) shift of the return signal are analysed to determine the wind speed, wind direction and turbulent character of the atmosphere.

 

‘Scary’ Lasers

A discreet, but exciting development for this America’s Cup has been the use of lasers by the OneWorld weather team, early in their programme. Known as Lidar (Light Detection And Ranging) uses a similar concept to Sodar and is normally positioned vertically at airfields to give wind data. However when used horizontally, they can be used as a powerful weapon to predict the wind on the race course. A lidar is similar to the more familiar radar, and can be thought of as laser radar. In radar, radio waves are transmitted into the atmosphere, which scatters some of the power back to the radar's receiver. A lidar also transmits and receives electromagnetic radiation, but at a higher frequency. Choosing different types of scattering processes allows atmospheric composition, temperature and wind to be measured.

 

No high-tech tool can replace Murray Jones up the mast

To harness such sophisticated wizardry takes a hugely powerful meso-scale computer model and Alinghi have harnessed the help of the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) and significantly have signed an exclusive deal with them to help with their ‘weather modeling’. Inputs include ‘runs’ or GRIB files, from the worldwide weather super computer models as well as satellite images and shore side observation points around the Hauraki Gulf. Despite all the ‘high tech’ weapons, it is still the original ‘mark one eyeball’ that is the best sensor of picking wind shifts. In light conditions we regularly see Murray Jones onboard Alinghi scaling the mast to give him better a view and call the wind further up the race course. Even the ‘mark one eyeball’ gets expensive assistance in the America’s Cup. Oracle BMW’s well publicised ‘Formula One sun glasses’ developed for Ralph Schumacher, allowed crewman Eric Doyle to have wind data projected onto his lenses like a fighter pilots ‘head up’ display.

 

The most highly monitored stretch of water worldwide

Weather wise, the Hauraki Gulf must be the most highly monitored race course in history. Despite the multi million dollar budgets, it is still that mark one eyeball that is the most potent weather weapon, carefully honed and trained in tiny Optimists and P Class sailing dinghies.

Share this post


Link to post
Share on other sites
Computer for sail trim might be great for sailing but not for racing as the technology has yet to see forward beyond it's physical reach (vanes). Until a computer has the eye sight of a human racing with computers is limited.

 

I don't get that, assume that the computer is always looking to maximise thrust from the wing. It can react far faster to changing conditions than a human, you don't need to guess when you can read. You still need a good tactician and driver though - I don't see them being replaced any time soon.

 

How does a computer see/read/sense up the course for a change in pressure or angle? Altering sail shape is one thing but how you position it on & thru the course is another especially when you are moving thru 2 fluids that are constantly changing.

 

Hence the manual override function I suggested. All the wing can do is react, a human trimmer can anticipate. There are times like when the boat is pitching in a swell that you don't want the wing to be chasing optimum trim it might well become a destabilizing factor and once a pitch cycle is started it would amplify and continue as the wing is behind the the local condition by the response lag time.

 

The neat thing would be that given a trim command, the software moves the right bits in the right order in response to the command. Just like a good crew maintains boat balance during trim adjustments.

Share this post


Link to post
Share on other sites