Fastest Sailboat on the Planet!

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Hard to say-maybe Tom Speer will take a look and comment.

 

That is not what that video shows at all, the colours are vorticity thresholds, not free stream velocities

 

ya I wasn't focusing on the vortex areas but instead on the those stream velocities indicated by the particles which clearly show the accelerations

my point about the whole thing is similar to the issue of drafting. By riding behind a fence the kiters are essentially riding in the dirty air stream and meeting less resistance. At the same time they are keeping there kites up in the accelerated air stream above the area of the vortexes. Neither condition represents "natura wind" if its coming off a fence or an artificial embankment

 

Actually I'm not trying to favor one vehicle type over another. Which is why I'm on about "comparable conditions" and "natural wind", little things mentioned in the rules.

Any boat of any configuration should have an "equal" shot at this tittle regardless of continent of origin based on "comparable conditions" and "natural wind" being available to all

What your saying is if they wanted the tittle they should have built a kite and raced at the venues which have specifically modified the wind and water to enhance the performance of that specific design. I didn't miss your point. What I'm saying is thats BS and the stipulations of the rules were not intended to favor any one type of vehicle by allowing the modifications we are seeing to natural conditions at Luderitz.

Listening is as much of an art as speaking

cheerio
B

 

The fact that they are running in such high windspeeds means there will be a turbulent boundary layer, the sand berm as you put it will have little effect on the rider and none on the kite itself

 

the higher speeds the longer the draft area and the greater pressure difference

the original video clearly shows an area of "dirty" air extending behind the car "berm" and clearly shows an area of accelerated air above and behind sweeping into this "drag". With the correct shape this is a common occurrence and is a well known phenomenon used regularly by stock car drivers to enhance there speed.

drafting explained
http://www.youtube.com/watch?v=Gj0mBGYcjdM

should make my point pretty clear
or at least one portion of my point the other being mechanically altered boundary layer conditions ( chop killer )

as for what happens up at the kite its a simple mater of looking at the air flow accelerating down and into the low pressure area behind the wind block

You might study up a bit on fluid dynamics. Granted its been a long time since I studied it but this is really basic stuff.

my point is that at Luderitz the players are working with an artificially created air stream that is unique to this venue and does not represent "comparable conditions" as specifically stated in the very first regulation IE Rule 1

the rider is drafting behind an artificial barrier
the kite is benefiting from an artificially accelerated air flow
and the board is benefiting from an mechanically moderated surface layer friction
none of which represents "comparable conditions" in my book nor is it in compliance with some number of other rules

cheers
B

 

http://www.youtube.com/watch?v=z-IlgOx6MoQ&feature=related

am looking for a video that shows the area where air accelerates downward and into the low pressure zone behind an obstacle in the wind. The video above this dip is clearly visible numerous times in the graphics display

it may not be sufficient to show some of dissenting opinion that is exists so I will continue looking however I assure you that this phenomenon exists

not that my assurance is going to mean much to anyone on this thing but hey
I'm working on it

cheers
B

there are several shots that depict it well in this one as well

http://www.youtube.com/watch?v=4hHGEjRcuVc&feature=related

ok this ones great at showing it

http://www.youtube.com/watch?v=sV_6E1Lh7yo&feature=related

the air stream is clearly showing a dip behind the vehicle
what happens is air stacks up a bit in front of the barrier increasing in pressure and then rushes over and downward behind the vehicle
the stream that breaks up is the slower "dirty" air that; in the case of Luderitz, benefits the riders, and the air influenced by the downward trend in the lower pressure "dirty air" exists just above that layer

even in wind speeds of only 30 or 40 knots the area of turbid air will extend quite a ways behind whatever the obstacle is blocking the wind
cheers and thanks for listening
B

 

I do understand what you are getting at, I just dont think that the effect on the kite will have any significance at all. For instance the video of the Merc the smoke is in a laminar air stream whereas the kite/rider will be in a turbulent boundary layer, well the rider anyway the kite may not this could depend on the land layout a long long way from the ditch.

 

They have an advantage anywhere they run with respect to being able to get the kite up away from messy surface air. They pay for this with the drag from the lines. This is just part of the game and they should be allowed to use it for all it is worth.

Air flow just above and downwind of the berm might be accelerated a little bit. To think it is still moving faster out at the kite is unlikely to the point of being incredible. I have been studing air foils & airflow for a while. If you actually went out there and made measurements, I would give you 20 to one odds, that the berm/trench either has no affect, or it reduces the average useful wind speed across the kite surface. Wanna make a bet?

They have shown the ability to hit record speeds away from the shore, just not over a full 500 meters with WSSRC approved timing stuff in place. Unless you can prove otherwise, you are twisting facts when you say that the berm and/or trench is the reason they go so fast.

Also, you are totally misrepresenting the chop killer. This started out as a fence that they used prior to digging the trench. There may be some amount of fence in the acceleration strip, but given that they are still accelerating as they cross the start line it a non-issue.

 

How can some smart guys come up with ideas that kiters like piles of sand upwind of the course?

"my point is that at Luderitz the players are working with an artificially created air stream that is unique to this venue and does not represent "comparable conditions" as specifically stated in the very first regulation IE Rule 1" - Boston

"By riding behind a fence the kiters are essentially riding in the dirty air stream and meeting less resistance. At the same time they are keeping there kites up in the accelerated air stream above the area of the vortexes. Neither condition represents "natura wind" if its coming off a fence or an artificial embankment" - Boston


Piles of sand and or obstructions up wind and even down wind creates big problems for the kite (sail). Kiters were increasing line lengths to deal with the dirty air. The sand piles or berm (obstacle) in Luderitz was shaped like a bus not a race car. Lets see the results of air flow over a bus with a near verticle windshied. Kiters had issues with the piles of sand upwind and used shovels to remove most of them....kiters like laminar flow.........piles of sand dont produce laminar flow....and it actually produces a downward pressure on the water that creates chop.

Where do you some of you guys come up with this stuff? Answer, Lack of experience and zero time spent on location.

 

Pot, meet Kettle

Share your wisdom about laminar flow at kite altitudes in 40 knots of wind ... hold on let me call Nasa first ...

 

wow
that was a very favorable response letter from the WSSR
apparently the mater is going to be reviewed although the ditchs themsleves are fair ground

exactly the response I believe is fair

cheers
B

oh and barring any objections I did fire off an unedited portion of our discussion to the race committee

best
B

 

Randy be careful before you dive into that one to deeply, The parameters that make for advantageous conditions are much narrower than those that might make for disadvantageous ones. This comment about the shape of the berm is spot on and some of these guys have hand on experience with this particular venue so it is always possible that my observations in this regard are incorrect. Its equally as possible that I hit the nail on the head though so I think a real honest review by the race commission is in order and they certainly seem amenable to that.

Basically the best way to make a point like this is to try and step up in front of the ruling body smelling like a rose. Best way to do that is to remain as reasonable and open as possible to a full range of findings, after all I'm betting an aerodynamic study has not been done at this venue ( few guys with cameras and a couple with foggers is all it really will take ). If it is found that a significant downward draft is pulled from clean air above down and into the low pressure ( dirty air ) and accelerating then they have artificially modified the air ( course them getting up there with shovels might also be considered artificially modifying the air ).

Flados
I'll take your bet any day
but lets keep it to friendly numbers or maybe a dinner out a few beers or something

I used to sail a lot and lots of things accelerate the air and none better than on shore topography if you hit it just right

ok thunder heads do a great job as well but they are way to unpredictable for practical use in a ditch

I have a friend up at NOAA who can model this for us given a real time topographical map in really fine detail
either that or someones got to physically get out there and do a smoke test under some pretty ugly conditions from what I can see

cheers
B

 

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Boston, way to go! Can you post your letter and their response?

 

I'll assume you now realize how odd and incorrect your statements were about the Luderitz berm........Just ask some questions next time before you assume. The WSSRC has been in Luderitz for 4 years and there has been plenty of discussion. People have been informed on what is being reviewed.

"the ditchs themsleves are fair ground" .....too bad for Boston and RHough.

Seriously, do you guys even sail?