Forums > Windsurfing Foiling

Racing Foil Boards PWA 91cm

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Created by berowne > 9 months ago, 17 Apr 2019
CJW
NSW, 1718 posts
20 Jan 2020 5:19PM
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Very interesting, thanks for posting WoH. They sure do have a very square front! I wonder what their thought is aero wise and if they have really looked at the AoA's of the apparent wind, particularly upwind in breeze, or there are other reasons? Gut feeling to me, without seeing the rocker line it looks draggy. I think this is an aera where some gains could be made if you were serious about it, nice to see the mast track is super recessed to maximise the end plating on rigs like the HG2 and others which have an extremely low foot.

WhiteofHeart
762 posts
20 Jan 2020 5:47PM
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The square nose increases lift in light wind and upwind angle, has to do with wind travelling underneath the board, which kind of "unweights" the foil. I've heard there were tests sith the very pointy shaped windfoil boards compared to these and that these had an upto 10 degree higher angle upwind!!

Also interesting to mark is the second set of strap inserts for the backstrap further forward on all the race boards. I asked why, and they said that in light winds some riders like to put their foot there (i do too), and because of that they have the inserts to run 2 sets of backstraps at the same time. I don't think i would use it, since im not really hanging in the strap anyway, but could be a nice addition for some!





CJW
NSW, 1718 posts
20 Jan 2020 10:43PM
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Yeah I assumed that was the theory which is why I wondered what the rocker was. I'm pretty sceptical though, it's a very draggy way to do it and would maybe only work in a particular wind range (super light), a certain foil rake and with low amounts of windward heel.

In 15kts of true wind, board speed of 18+kts upwind, with a fair windward heel which you run in these ranges, you're talking an apparent wind angle of about 22Deg, tacking through 100Deg or so and wind over the deck of +30kts. There's no way a board shape like that is efficient in those conditions. In my opinion of course and I've not tested it obviously. Starboard talked about a similar thing with the first F177, I was sceptical of it then and still am now....and they've gone away from that concept somewhat.

AUS169
NSW, 58 posts
20 Jan 2020 11:01PM
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CJW said..
Yeah I assumed that was the theory which is why I wondered what the rocker was. I'm pretty sceptical though, it's a very draggy way to do it and would maybe only work in a particular wind range (super light), a certain foil rake and with low amounts of windward heel.

In 15kts of true wind, board speed of 18+kts upwind, with a fair windward heel which you run in these ranges, you're talking an apparent wind angle of about 22Deg, tacking through 100Deg or so and wind over the deck of +30kts. There's no way a board shape like that is efficient in those conditions. In my opinion of course and I've not tested it obviously. Starboard talked about a similar thing with the first F177, I was sceptical of it then and still am now....and they've gone away from that concept somewhat.


This looks thinner through the nose.

www.facebook.com/616040088418393/videos/777880462710607/

CJW
NSW, 1718 posts
20 Jan 2020 11:55PM
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Yeah also an interesting concept, cool to see a video of it finally flying, not really too many shots of it touching down though and super light wind performance. I know the NZ lads tried something similar a few years ago and it was a no go, although that obviously looks a lot more refined.

A lot has to do with how it performs through the manoeuvres though, particular tacks/touch downs. Lets say it's 2% faster around the course due to lower aero drag, big call but lets go with it. Average foil race in Aus is about 18 minutes, so that means it's about 20 seconds faster over a race. However a few dodgy touch downs or a few bad tacks and that advantage is gone (if one exists). A lot to consider. On the other hand the patrik might be 2% slower but 3 seconds faster on average per tack. Lets say 8 tacks in a race = 24 seconds. This is all pie in the sky stuff but has to be considered to some extent.

Paducah
2546 posts
20 Jan 2020 10:16PM
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As a lightweight, I feel vindicated by those back strap inserts.

WhiteofHeart
762 posts
21 Jan 2020 2:16AM
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CJW said..
Yeah I assumed that was the theory which is why I wondered what the rocker was. I'm pretty sceptical though, it's a very draggy way to do it and would maybe only work in a particular wind range (super light), a certain foil rake and with low amounts of windward heel.

In 15kts of true wind, board speed of 18+kts upwind, with a fair windward heel which you run in these ranges, you're talking an apparent wind angle of about 22Deg, tacking through 100Deg or so and wind over the deck of +30kts. There's no way a board shape like that is efficient in those conditions. In my opinion of course and I've not tested it obviously. Starboard talked about a similar thing with the first F177, I was sceptical of it then and still am now....and they've gone away from that concept somewhat.



Can see you've put some thought into it and I think for a big part you are right. In my talks with Kiran he said the differences were most notable in light winds, which seems logical ofcourse. The tacking you are talking about is already noticable comparing my formula (165L) to a 185+L wf raceboard! I have to do practically everything perfectly to "plane through" a tack. I've had a few goes on the recent wf raceboards, and because of the volume in the nose "planing through" tacks is so much much easier. Wouldn't like having to do that on that elix design.

Expanding a little regarding technique, look at the really fast WF racers like Kiran Badloe, Luuc van Opzeeland or the Goyard brothers! Independent of wind conditions they ride their board fairly high up, with the board being reasonably level! When I last sailed with Kiran it was gusting over 20 and we were out with 9.0's. He told me I had to sail my board way flatter and instead of using that for leverage should extend my upperbody way farther from my sail and stiffen up, being a straight plank from head to toe. That would allow me to "swivel" the board into a higher upwind angle. I tried, and it cost me a lot of strength but really works like a madman. When you ride your board flatter you also ride naturally a little higher, thus faster, and the upwind angle is insane if you put your preassure in the right place. If you tilt your board a lot you have a lot of preassure going into the tilting, while the preassure could go into upwind angle instead.

Kiran weights 75 Kgs, so you'd think he'd be overpowered earlier than me with my 88. If he manages to hold that bodyposition with a flat board upto 30 knots with a 9.0, we should also be able to hahaha.

Combine that fact with the things you already came up with on the wider noses and I think you have your answer.

CJW
NSW, 1718 posts
21 Jan 2020 5:36PM
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Yep 100% agree on the tacking, the first model 177 is very very good through the tacks and I don't think the new model is quite as good; shorter nose, less volume up there etc. My board which is a heavily modified JP135, and I'm talking fully cut and shut so it's 91cm wide, straight parallel rails etc, but it is still very short and low volume in the nose and now about 150L. It sounds like your board is similar in that you have to get everything perfect to get really nice tacks, far less forgiving.

The heel thing is interesting and I agree with you up to about 12kts, at my weight of 70kg after that I just loose way too much righting moment if I don't have a fair amount of heel. When I customised my board I heavily optimised the strap positions etc and even on the standard 115 fuse it gives a very powerful ride. Back to back with say a 177 is night and day in terms of front foot power. Because of this (and now with the plus fuse) and my weight I can get away with more heel. Also remember you can get height from heel too, you're letting the foil do the work for you, but you need a setup optimised for it. I also agree you have to fly the foil very high, particularly upwind. From all my testing there is a very small window where the thing absolutely lights up and it's fairly high on the foil. It's where you get maximum righting moment and minimum drag. That said I don't have the PWA guys to benchmark against so who knows haha, I can only go off my GPS logged data/analysis.

I run my 9.0 up to about 16kts, after that I've got enough power to not loose out downwind. After about 14 kts the 8.0 is actually faster upwind because i'm already way overpowered due to the very high apparent wind, but still under powered downwind.

Key to foiling imo is also how to mode the board, when to be low and fast, when to be high and slow, absolutely huge gains can be made if you are on top of it.

Paducah
2546 posts
22 Jan 2020 2:50AM
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speaking of Patrik - not for the squeamish

berowne
NSW, 1307 posts
29 Jan 2020 10:23AM
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jusavina said..
You'll have to come and race at the National with that


Just arrived... ready to race. If anyone else is out training Wed/Thu ahead of the comp let me know. I'm keen to know which sand bars to avoid!

CJW
NSW, 1718 posts
29 Jan 2020 11:43AM
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A few of the Wollongong lads should be up there today/Thurs for some training. Other thread might be more appropriate though as people might not necessarily read this one RE the nationals.

WhiteofHeart
762 posts
30 Jan 2020 4:30AM
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Patrik explaining their design decisions himself, and very indepth too!! m.facebook.com/story.php?story_fbid=2843140995752409&id=529688553764343

Funny thing is, he says they made the nose extra square to disrupt the airflow around the nose on purpose. This to make wind have less effect on the board and make the ride more stable in gusty weather. Its true that that is a problem a lot of beginning racers are struggling with. You have to get the rake of the foil (and so angle of attack of your board) just right for the conditions to have a stable ride and not get lifted or slammed down in heavy gusts! Just wonder how its working in light winds, but maybe a little more rake will still allow the hullshape to lift in light winds.

Paducah
2546 posts
30 Jan 2020 12:38PM
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WhiteofHeart said..
Patrik explaining their design decisions himself, and very indepth too!! m.facebook.com/story.php?story_fbid=2843140995752409&id=529688553764343

Funny thing is, he says they made the nose extra square to disrupt the airflow around the nose on purpose. This to make wind have less effect on the board and make the ride more stable in gusty weather. Its true that that is a problem a lot of beginning racers are struggling with. You have to get the rake of the foil (and so angle of attack of your board) just right for the conditions to have a stable ride and not get lifted or slammed down in heavy gusts! Just wonder how its working in light winds, but maybe a little more rake will still allow the hullshape to lift in light winds.


Amazing video - a ton of info not just about boards but foil racing in general.

Boston!
NSW, 249 posts
30 Jan 2020 8:34PM
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Impressed with the construction of the board. I would of loved to have seen the pummelling given to the nose of the board and, the repair technique following that. I feel a manufacturer that is are serious about providing value should produce a foiling board with adequate protection to the inevitable nose impacts that occur to foilers of all skill levels.

WhiteofHeart
762 posts
31 Jan 2020 2:09AM
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Boston! said..
Impressed with the construction of the board. I would of loved to have seen the pummelling given to the nose of the board and, the repair technique following that. I feel a manufacturer that is are serious about providing value should produce a foiling board with adequate protection to the inevitable nose impacts that occur to foilers of all skill levels.



They are working on a series on Youtube.



The next one is going to be on how they fix it again hahaha

Edit: Just noticed someone posted the same thing a little higher up!

segler
WA, 1623 posts
1 Feb 2020 12:18AM
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Making boards with a composite honeycomb "skin" is a good idea. John Doyle in White Salmon, Washington state, made hollow slalom and bump and jump boards this way before concentrating only on kite boards. He originally came out of the aircraft industry in Kansas, so he knows a lot about honeycomb structures. You still see his blue boards in use.

If honeycomb is good enough for aircraft and satellites, it is good enough for us.

duzzi
1066 posts
1 Feb 2020 1:33AM
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segler said..
Making boards with a composite honeycomb "skin" is a good idea. John Doyle in White Salmon, Washington state, made hollow slalom and bump and jump boards this way before concentrating only on kite boards. He originally came out of the aircraft industry in Kansas, so he knows a lot about honeycomb structures. You still see his blue boards in use.

If honeycomb is good enough for aircraft and satellites, it is good enough for us.



I remember Doyle boards! But I think he was using Divinycell? If I recall 1/4". I would love to have a detailed description of how to build a hollow board. Can't really find much on the net ... although there is plenty about how to build a hollow wood surf board ... e.g. woodsurfboardsupply.com/HowItsBuilt.html

Paducah
2546 posts
1 Feb 2020 1:58AM
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duzzi said..
... although there is plenty about how to build a hollow wood surf board ... e.g. woodsurfboardsupply.com/HowItsBuilt.html


Termites?

duzzi
1066 posts
1 Feb 2020 4:22AM
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Paducah said..

duzzi said..
... although there is plenty about how to build a hollow wood surf board ... e.g. woodsurfboardsupply.com/HowItsBuilt.html



Termites?


Or sea worms



515
809 posts
1 Feb 2020 9:10AM
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Composite honeycomb carbon hollow board is very impressive. Thinking they must use a inflatable bladder inside the mould!



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"Racing Foil Boards PWA 91cm" started by berowne