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New Laser Performance Boat?

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Sam.Spoons View Drop Down
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Topic: New Laser Performance Boat?
    Posted: 02 Mar 22 at 7:38pm
Like we had on the Raceboards, max size sub F2.5 and smaller once railing upwind.
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Post Options Post Options   Quote Oatsandbeans Quote  Post ReplyReply Direct Link To This Post Posted: 03 Mar 22 at 7:18am
Foils are just like sails. You can have fast or you can have easy to use-you can’t have both. Most people go for easy to use as they don’t spend the time mastering the tricky option.
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Post Options Post Options   Quote H2 Quote  Post ReplyReply Direct Link To This Post Posted: 03 Mar 22 at 8:57am
Next time I am trying to sail over the top of a Finn I will remember that it has a flat sheet of metal for a foil and that it really cannot point high at all........oh wait
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 03 Mar 22 at 11:55am
All else being equal, the effect of apparent wind is that the slower the boat the higher it can point. Given an inefficient foil the boat will also need to sail with the foil at a greater angle of attack, which will make the boat appear to point even higher (and go even slower). So a Finn will easily outpoint a foiling Moth, but the Moth will be round the windward mark before the Finn is halfway there...
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 03 Mar 22 at 1:00pm
I spent years studying fluid dynamics and foils, is it Bernouilli or is it AOA, and came to the conclusion that it's both, with Bernouilli perhaps having greater effect on slower flow.

It used to be quite important on Raceboards in the early days, because the relationship of the uderwater foil was a greater ratio in terms of size back then (5.4 - 6.3 sails). As sail sizes increased, 7.5, then 8.5, then 9.5 the speeds increased and the relationships changed.

Then fins became important as short boards raced off their fins, there was a Danish development I thought was cool called the Boe Stick, in which he put a deep narrow chord forward, then increased the size of the fin with an almost negative aft section curved to flat, so you had a bigger sideways area, but a reduced lift/drag surface. Like a Glider style hi aspect wing, with extra flat bits on the trailing edge to promote early sideways resistance during the AOA phase.

It's a field that is always changing, always developing, always fascinating, the search for the Holy Grail of maximum lift, minimum drag. Remember that Record Breaking speed machine, forget it's name, used half a foil, chopped the back off to let the turbulence create the aft section which finished the foil but had no wetted surface, that worked.
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 04 Mar 22 at 6:58am
Originally posted by iGRF

I spent years studying fluid dynamics and foils, is it Bernouilli or is it AOA, and came to the conclusion that it's both, with Bernouilli perhaps having greater effect on slower flow.

It used to be quite important on Raceboards in the early days, because the relationship of the uderwater foil was a greater ratio in terms of size back then (5.4 - 6.3 sails). As sail sizes increased, 7.5, then 8.5, then 9.5 the speeds increased and the relationships changed.


Foil size is a function of boat speed : wind speed ratio, with faster boats needing less area in the same wind.

Originally posted by iGRF

Then fins became important as short boards raced off their fins, there was a Danish development I thought was cool called the Boe Stick, in which he put a deep narrow chord forward, then increased the size of the fin with an almost negative aft section curved to flat, so you had a bigger sideways area, but a reduced lift/drag surface. Like a Glider style hi aspect wing, with extra flat bits on the trailing edge to promote early sideways resistance during the AOA phase.

Sounds interesting - got a picture? Hollow aft sections, if I understand?

Originally posted by iGRF

It's a field that is always changing, always developing, always fascinating, the search for the Holy Grail of maximum lift, minimum drag. Remember that Record Breaking speed machine, forget it's name, used half a foil, chopped the back off to let the turbulence create the aft section which finished the foil but had no wetted surface, that worked.

Sailrocket used a supercavitating foil section - essentially triangular (fat at back). In normal flow this isn’t effective - you need enough speed to get the water around the foil to cavitate.
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Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 04 Mar 22 at 12:37pm
Originally posted by JimC

All else being equal, the effect of apparent wind is that the slower the boat the higher it can point. Given an inefficient foil the boat will also need to sail with the foil at a greater angle of attack, which will make the boat appear to point even higher (and go even slower). So a Finn will easily outpoint a foiling Moth, but the Moth will be round the windward mark before the Finn is halfway there...


While I know this to be true it made me pause to think why it seemed odd. I think it is missing ‘for boats of equal efficiency’. A TP52 is super fast AND super high…..
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NickA View Drop Down
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Post Options Post Options   Quote NickA Quote  Post ReplyReply Direct Link To This Post Posted: 22 Mar 22 at 8:09pm
Sorry to return this thread to the boat its about 😃.

But would anyone buy any boat from LPE ever again?

Even in the unlikely event it's properly built, they'll stop making or supporting it as soon as sales dip.

Edited by NickA - 22 Mar 22 at 8:10pm
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fab100 View Drop Down
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Post Options Post Options   Quote fab100 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 22 at 2:10pm
Originally posted by NickA

Sorry to return this thread to the boat its about 😃.

But would anyone buy any boat from LPE ever again?

Even in the unlikely event it's properly built, they'll stop making or supporting it as soon as sales dip.

no chance
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Post Options Post Options   Quote tink Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar 22 at 2:40pm
Plenty of volume in club racers and holiday companies
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