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burchas said..

JB said..
And the Southerlies just keep blowing = Soo good!

Here's today's run from Brown water to Mona basin.

SE wind around 18-20kn.
Swell 1.5m ESE

Riding the Naish Hover 125, JET 1800HA/280HA on 64cm Fuselage and 75cm mast. Plate shimmed 3 degree and rear wing shimmed 2 degrees. Mounted an inch further forward than maximum.

enjoy,

Ride safe,

JB

JB = Jolly Bumps? Great stuff!

i know your brand but you run with such a talented crew there with access to some cool gear,
do you switch gear with others just to get a different point of reference? Since we're talking technical now.

Honestly I haven't changed up gear for quite some time now. I am constantly working on my gear, milking every advantage point I can. There is so much to learn from very run. Sometimes best not to confuse things. As conditions are hard to come by, I often just want to get out there and use what I know. Maybe as summer kicks into gear more and I get more runs under my belt, I will swap up a bit with others more.

Great idea though!

JB

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Dpap said..

JB said..

JonathanC said..
Awesome JB
Can you please go through the rationale for the shimming of the mast and the stab. Why you are changing them and what you are looking to achieve with the changes. Great to see you achieving this with pretty 'standard' gear and not custom DW boards etc

Thanks

Hey Jonathan,

Shimming in a way or increasing/decreasing a set AoA (Angle of Attack).

Rear Wing is like the flaps on an aeroplane. Increasing the AoA will apply more down force aiding the front wing to rise/lift. Sometimes this can be too much when surfing and the added drag can be counter productive, so you have to be careful. I have 1 & 2 degree shims. I have found using the smaller rear (280cm2) and the 2 degree shim works quite well at DW speeds as I guess there's no real pitching sections or when there is, they're only momentary.

Base plate shim is changing the entire angle of attack when the board is in the water. This way when I am paddling for a bump just want as much lift as possible at a slow speed to break the hull free, I can achieve it, then as soon as the hull is free the plate shim does not affect the AoA theoretically. It will affect my flying angle a little bit by making me fly nose down a tiny bit, but that's a small price to pay for an easier paddle up (I actually do not notice it). But the key thing is it theoretically gives me a 5 degree rear wing AoA increase and a 3 degree Front Wing AoA increase before lift off and then 2 degree rear wing and 0 front wing increase at lift off.

To get this much kick (like shimming the rear wing at 5 degrees) would have way too much rear wing pressure once you got up speed. I love front foot and lift, and this is a great way to achieve it so it's massive at paddle up and just big when flying.

I hope this makes sense?

Ride safe,

JB

What you explain here is like trying to liftoff with an airplane at lower airspeed than indicated by forcing the elevator up...think about it .thank god it is not an airplane you would stall and die damaging the runway....
Another food for thought about shimming to change the AOA at the takeoff... while you pump the AOA of the foil is going from about +20 degrees to -20 degrees until you reach a decent speed so what exactly does a +-2 deg !!???
Just my 2cent..

You'd be surprised how much rear wing shim you can ride with. My 2019 gear with the adjustable rear wing I used to grind the tab and double the maximum angle considerably. Lots of kick and no stalling.

Something to get your heads around is to get your heads out of linear. It is how we try and rationalise what is going on, but under the board and round the foils there is a lot more going on than you'd think. Theory sometimes means nothing with foiling unless you;re comparing it to something you've already done. Feel is everything.

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PeterP said..
I find that the shimming of the plate, which allows the board to release easier, has more to do with the effect on the board moving through the water. Without the shim and LE of foil pointing further down, the board is being pulled down as one tries to increase forward speed, increasing drag (until sufficient speed allows the foils lift to release board). In this set-up board feels glued to the water

Get LE to point upwards towards board and any forward motion is working to release the board.

Shimming the plate increases the AoA, this increases the up lift proportionally whilst the board is being levelled (in contact) by the water. SO yes, it helps with paddling as it does to a degree help float the board a little as you move forwards.

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mcrt said..

Dpap said..

What you explain here is like trying to liftoff with an airplane at lower airspeed than indicated by forcing the elevator up...think about it .thank god it is not an airplane you would stall and die damaging the runway....
Another food for thought about shimming to change the AOA at the takeoff... while you pump the AOA of the foil is going from about +20 degrees to -20 degrees until you reach a decent speed so what exactly does a +-2 deg !!???
Just my 2cent..

I am not sure if you are referring to the mastplate shim or the tailshim?.

Anyway,i do not think our foils will travel through a -20*/+20* AOA range
My guesstimate would be more like around -5* (zero lift,as it is an asym foil) to +20*/25* stall AOA?.

Mind you,i have never seen a C.lift graph for any of the foils we use but those figures should be in the ballpark.Probably very big stall angle differences between thin HA shapes like an Armstrong 1125 and thicker ones like a LOL or Gong Allvator.

For wingfoiling takeoffs i have not noticed any major effect from screwing around with the tail size or shim.Once in flight yes,a lot.

But if JB says it makes a big difference in SUP DW takeoffs i will take his word as gospel.He can DW really good.
And DW or flat water SUP takeoffs are the most demanding by far,with little power available for very little time.

The effect of the mastplate shim can be quite dramatic with med or hi aspect foils.They can change the takeoff from frustrating to really friendly.This is easy to test with a DIY shim, 6mm on the thick side tapering to 1mm should give about a 3* angle.Try it if you haven't already,might surprise you.

To me, and everything I have studied with my data and video. Getting up DW foiling all comes down to about 2-3 seconds and within 1km/h. Everything is in this magic little zone. Maximizing the punch in this zone is key without overly disturbing/affecting your flight once up.

I really want to try a 5 degree shim next. Waiting to get one printed.

Best things is get out there and try it. Don't mind test it. I get an idea and try it. It is the best way to work things out. Not everything works as you would imagine with foiling, and often there is side-affects you didn't consider when you do.

Ride safe,

JB

Warning - this video is 20mins long

Yesterday we had an awesome southerly buster hit just on sunset which lit up Pittwater to one of the best runs I've had. Epic bumps all the way down to the point I over shot my house and went further resulting in a walk home (lol, not that I minded).

This is the entire run, start to finish. The end is when I go over the sand spit and the bumps get small and I have to paddle pump at 90 degrees to the wind to cut back to shore.

Conditions, 25 - 30kn from the South. Zero swell, this is an inland run in the bay.

Gear, Naish Hover 125 and JET 2140HA/310HA on 64 Fuse and 75cm mast.

Super fun run and about as good as it gets on small bumps and inland runs except for maybe the gorge .

Enjoy.


Some stats,







Ride safe,

JB

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JB said..
Warning - this video is 20mins long

Yesterday we had an awesome southerly buster hit just on sunset which lit up Pittwater to one of the best runs I've had. Epic bumps all the way down to the point I over shot my house and went further resulting in a walk home (lol, not that I minded).

This is the entire run, start to finish. The end is when I go over the sand spit and the bumps get small and I have to paddle pump at 90 degrees to the wind to cut back to shore.

Conditions, 25 - 30kn from the South. Zero swell, this is an inland run in the bay.

Gear, Naish Hover 125 and JET 2140HA/310HA on 64 Fuse and 75cm mast.

Super fun run and about as good as it gets on small bumps and inland runs except for maybe the gorge .

Enjoy.

Some stats,







Ride safe,

JB

Great stuff JB, now I see where a big HA like the 2140 is suited !

Select to expand quote

JB said..
Warning - this video is 20mins long

Yesterday we had an awesome southerly buster hit just on sunset which lit up Pittwater to one of the best runs I've had. Epic bumps all the way down to the point I over shot my house and went further resulting in a walk home (lol, not that I minded).

This is the entire run, start to finish. The end is when I go over the sand spit and the bumps get small and I have to paddle pump at 90 degrees to the wind to cut back to shore.

Conditions, 25 - 30kn from the South. Zero swell, this is an inland run in the bay.

Gear, Naish Hover 125 and JET 2140HA/310HA on 64 Fuse and 75cm mast.

Super fun run and about as good as it gets on small bumps and inland runs except for maybe the gorge .

Enjoy.

Some stats,







Ride safe,

JB

What's the smallest wing you think you could ride successfully in those conditions ? Allowing for a wing or tow in

Select to expand quote

kobo said..

JB said..
Warning - this video is 20mins long

Yesterday we had an awesome southerly buster hit just on sunset which lit up Pittwater to one of the best runs I've had. Epic bumps all the way down to the point I over shot my house and went further resulting in a walk home (lol, not that I minded).

This is the entire run, start to finish. The end is when I go over the sand spit and the bumps get small and I have to paddle pump at 90 degrees to the wind to cut back to shore.

Conditions, 25 - 30kn from the South. Zero swell, this is an inland run in the bay.

Gear, Naish Hover 125 and JET 2140HA/310HA on 64 Fuse and 75cm mast.

Super fun run and about as good as it gets on small bumps and inland runs except for maybe the gorge .

Enjoy.

Some stats,







Ride safe,

JB

What's the smallest wing you think you could ride successfully in those conditions ? Allowing for a wing or tow in

Actually riding the bumps, the 2140HA was perfect, but maybe 1800HA or 2000. There's no point going faster than the bumps as you just end up pumping.

In that wind with the wing, I would likely use the 914HA. If I wanted to freewing a bit and carve, maybe the 1040HA or still the 914HA. but if you're aiming to surf the bumps soley, you've got to match the foil speed with the bump speed.

Don't think it would be worth towing into bay chop. Just paddle up.

That run looked Soooo good JB! and cool sound track to boot

Thanks JB.. What a great vid..

Awesome video JB you're a very lucky man to have the BEACH in your front yard and a Downwind Run in your back yard. "I'd Love It." When I first discovered Maliko on Maui I would always daydream how good would it be to have a Maliko Run in my backyard while I have Burleigh Heads to Snapper Rocks in my front yard. "The World Would Be My Oyster" You'd never have to Travel.

I be downwinding tomorrow but it won't be anywhere exotic but it's still going to be awesome!

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PeterP said..
I find that the shimming of the plate, which allows the board to release easier, has more to do with the effect on the board moving through the water. Without the shim and LE of foil pointing further down, the board is being pulled down as one tries to increase forward speed, increasing drag (until sufficient speed allows the foils lift to release board). In this set-up board feels glued to the water

Get LE to point upwards towards board and any forward motion is working to release the board.

Really inspiring videos JB..
PeterP's point makes sense to me. The shimming is not putting more energy into the setup as that is derived (mostly) from the rider. The 2 forces lift and drag opposing each other is changed. The drag induced by movement is being lowered more consistently due to the relative angles.. so the likely candidate would be surface contact area if you break surface tension by lifting the board into the air = massive while it lasts. The other may be along the lines of angle of attack changes on the lifting plane of the wings so creating stall conditions then driving the angle of attack down with the pumping movement before the drag overcomes the forward movement so leaving a powerful lift effect..(image it as walking up stairs).

In Hang-gliding we used to occasionally do spot landing contests (bomb-out paddock days) the silly angle of attack changes to try and nail it where something to behold.. massive angle of attack changes = a series of mini-stalls and with some head wind parachuting. The height changes where often quiet large that powerful lift effect..

Take-home shim to optimise your stance on the board to get the board wet surface off the water once you start pumping (- mimicking what a nice wave face gives you) in likelihood your vertical movement so opportunity to get more foil thrust.

G8 to see people experimenting and passing it on..
Cheers
AP

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AquaPlow said..

PeterP said..
I find that the shimming of the plate, which allows the board to release easier, has more to do with the effect on the board moving through the water. Without the shim and LE of foil pointing further down, the board is being pulled down as one tries to increase forward speed, increasing drag (until sufficient speed allows the foils lift to release board). In this set-up board feels glued to the water

Get LE to point upwards towards board and any forward motion is working to release the board.

Really inspiring videos JB..
PeterP's point makes sense to me. The shimming is not putting more energy into the setup as that is derived (mostly) from the rider. The 2 forces lift and drag opposing each other is changed. The drag induced by movement is being lowered more consistently due to the relative angles.. so the likely candidate would be surface contact area if you break surface tension by lifting the board into the air = massive while it lasts. The other may be along the lines of angle of attack changes on the lifting plane of the wings so creating stall conditions then driving the angle of attack down with the pumping movement before the drag overcomes the forward movement so leaving a powerful lift effect..(image it as walking up stairs).

In Hang-gliding we used to occasionally do spot landing contests (bomb-out paddock days) the silly angle of attack changes to try and nail it where something to behold.. massive angle of attack changes = a series of mini-stalls and with some head wind parachuting. The height changes where often quiet large that powerful lift effect..

Take-home shim to optimise your stance on the board to get the board wet surface off the water once you start pumping (- mimicking what a nice wave face gives you) in likelihood your vertical movement so opportunity to get more foil thrust.

G8 to see people experimenting and passing it on..
Cheers
AP

An interesting explanation. This great getting different insights (assuming I am reading it correct, quite intense).

In practice, here's what I have found.

The plate shim definitely helps in getting up off the water. It kind of makes your pump and bounce that little bit more powerful IMO. It also primes your back leg giving it a larger range for less effort IMO.

The rear wing shim creates an environment where the foil is artificially in a higher lifting mode. Simulating being more powered up. This results in the rider requiring to use more pressure to keep it down. Foils love being pushed down, this creates thrust. Now as AP mentions, there is a by-product = drag! Drag effectually is lift (more lift = more drag) but they also oppose each other in the force digram. You can go too far too.

Without a power source we fly on a few principles, 3 of which that are very important are; 1. Stall Speed, 2. Minimum Sink Speed, 3. Minimum Glide ratio. Stall speed is when you push your angle of attack too far generally at lower speeds too, and break your flow loosing lift and splat you come down. Minimum sink speed/rate/ratio is the slowest speed you can glide at before losing altitude, generally a little faster than stall speed but less than minimum glide ratio. Minimum glide ratio/speed is where you will cover the most distance for the least amount of energy. We try to avoid stall speed. Trimming and tuning your foils personalised to your size, weight and conditions can try and lower all these factors which is key for downwinding. Minimum Sink affects bigger riders earlier as weight/mass is one of the opposing forces to lift and hangliders I believe use this to climb in thermals etc, travelling as slow as possible to stay in a micro system up draft and climb, kind of like us pumping up. Stall we all want to stay away from and Glide speed is the goal, sit in that magic realm were we effortlessly cover the most distance for the least amount of energy (planes learn this for emergencies like landing/flying after engine failure). All these are ever changing and personal to each setup and rider. For a given setup a heavier rider (assuming fully powered) will make a foil go fast but have a higher sink speed than a lighter rider on the same gear. But a heavier rider can change their setup to effectively produce more lift (shim) which does result in slowing down a little because of the drag but increasing some of these factors. But in general a bigger rider just needs to use a bigger foil.

As I am always playing and tuning. I try to understand things from a theory stand point then put it into practice, as it is not always as the calculator says it is.

Here is a run I did on Sunday. This is using the 1400HA (smaller than I usually use), no shims at all (plate @ 0, Rear wing @ 0). The outcome was very interesting.



Whilst it felt nice and nimble, I did have to pump a lot of the way. I used a lot of energy and interestingly enough, didn't actually go any faster really. Unfortunately I did come down in the middle, but I always seem to. Below if 3 runs splits which I found very interesting. Ignoring the crappy bits where I was not going well, the good km's numbers are surprising.


This is my 1400cm2 on the run in the video. 18-20kn southerly. I imagined it being a loaded fast run, but it really wasn't.


This is the week prior on my 1800cm2. NE'er 18kn. again came down a bit, but generally a good run. A bit of pumping, but a pretty nice run.




This is two weeks ago on my 2140cm2. 15-18kn North easterly. Felt good most of the run, not a lot of pumping, comfortable.


Crazily the averages are very similar when in a good run. Interestingly the 2140 had the highest top speed!

1400 - no shims
1800 - 3 degree plate, 2 degree rear wing.
2140 - 3 degree plate, 2 degree rear wing.

Anyway, I am going to go back to my 2140 for a while and get some more comparisons. Interesting.

Ride safe,

JB

I remember with hang gliding , minimum sink was not the same as best glide, we used minimum sink in weaker thermals to gain the most height, but we covered the least distance.Best glide ratio or L/D was a speed faster than this and it covered the most ground.Both speeds were useful, for cross country flying but I wonder if knowing the best glide speed of a foil matters because in DW your really only trying to connect energy not glide DW as fast as possible.

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www.instagram.com/p/CU5eWLJv70M/

davekalama

Maliko was on fire yesterday. Got a new personal best, 32:25 for 9.2 miles, which works out to a average of 17.03 mph. Which also means you're motoring at 20+ a lot of the time because it also means you're at 12 to 16 a lot too. My board is 6'6"x lickety split and I was using the @gofoil RS 1150, 14" red fixed tail and 27" mast.


This is crazy fast !!

I'm surprised he is on a 27" mast, not much room for error. I guess DK dosen't make any mistake anyway...

With a wing but still very nice..

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DavidJohn said..
With a wing but still very nice..

Hey DJ, does the wing get in the way much dwinding ?
I'm contemplating getting a dwind set up but not sure to go wing or use a paddle.

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toppleover said..

DavidJohn said..
With a wing but still very nice..

Hey DJ, does the wing get in the way much dwinding ?
I'm contemplating getting a dwind set up but not sure to go wing or use a paddle.

I wouldn't say it gets in the way per se - but using a paddle feels more raw and pure. That video is a perfect example, he is getting nice long glides on foil with wing flagged out but every now and again you see him sheet in "yachting mode" to get propulsion to get the next bump.

With a paddle you have no such luxury, you have to be in the right spot, with the right speed, at all times, and as such it's much more technically, and physically, demanding.

I guess you could force yourself to not enter yachting mode on the wing, and make it a principle to stay off the strut handles - but they are right there, and I've to date found it impossible to not grab them, when you're about to go down.

Downwinding with a wing is extremely easy (unless you force yourself off the handles) in comparison to the paddle, and as such, maybe not as satisfying.

Ventura, CA, USA today. 50 mph + wind. Double overhead bumps? Matt Costa on a prone board. Lift ha120.

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kobo said..
I remember with hang gliding , minimum sink was not the same as best glide, we used minimum sink in weaker thermals to gain the most height, but we covered the least distance.Best glide ratio or L/D was a speed faster than this and it covered the most ground.Both speeds were useful, for cross country flying but I wonder if knowing the best glide speed of a foil matters because in DW your really only trying to connect energy not glide DW as fast as possible.

correct. I am still learning as lot about it all, but generally Stall Speed is the lowest speed, then Sink speed is literally as slow as you can go without losing altitude (as you mentioned, hangliders use this in thermals to raise up as the sink speed/ratio is obtained in static conditions). Snd glide ratio is basically the most efficient you can be given an amount of energy, you will travel the furtherest without other influences.

Where I feel glide speed is important in DW is because we need to connect from energy to energy. This is the hardest part of DW and where we use the most energy. What spun me out was seeing that going faster than your glide ratio is less efficient than at it. And when I check data, this looks right, generally every time you get a crazy bomb or huge spike in speed, you have a massive drop off also straight after, whereas maintaining smooth lower speeds is far more efficient and will produce higher averages overall.

There's a lot in it, and ideally on an amazing run with lots of energy, you're holding your ankles and just trying not to fall, but on the lighter days when technique is everything, this makes sense.

"generally every time you get a crazy bomb or huge spike in speed, you have a massive drop off also straight after, whereas maintaining smooth lower speeds is far more efficient and will produce higher averages overall."
That's really interesting,So you think a foil which is efficient at lower speeds is more important than one which can go fast and ride the big bumps ,so that would be a mid aspect type foil ? and connecting lots of smaller bumps is better than taking the bombs. It's interesting that you are shimming for lower speed performance as well ,I didn't expect that.So much to learn.......Great info JB.what's your favorite setup atm ?

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kobo said..
"generally every time you get a crazy bomb or huge spike in speed, you have a massive drop off also straight after, whereas maintaining smooth lower speeds is far more efficient and will produce higher averages overall."
That's really interesting,So you think a foil which is efficient at lower speeds is more important than one which can go fast and ride the big bumps ,so that would be a mid aspect type foil ? and connecting lots of smaller bumps is better than taking the bombs. It's interesting that you are shimming for lower speed performance as well ,I didn't expect that.So much to learn.......Great info JB.what's your favorite setup atm ?

It all depends on the ocean energy available.

On a dw run in a bay or any zone protected by the ground swell, ususally you go slower as the bumps are close together and are not fast so a super fast wing might not be not the best (except if you can keep up pumping catching bumps in front).

On an open ocean dw run with ground swell, you definetly need a fast foil, so you can go from small slow bumps to big long fast swell line.



On this run it was super windy (40nd) but no ground swell. The bumps were big and steep but not fast. Still I had to use a small wing to handle those bumps. I was using Unifoil Hyper 170 (1090 cm2).

To define this speeds* in a different way:

-Stall speed is where flow separation happens,you loose all lift and drop.

-Minimum sink ,just a little faster than stall.If you had 1m of mast above the surface slowing to minimum sink will give you the Longest Time possible before touching down.Could be used to wait for a chop behind you?.
Problem with anything below max L/D is drag increases very sharply so you better have some horsepower in your sleeve (wing,pump,chop) or you are toast.

-Maximum L/D or Best Glide: faster than min sink, with the same 1m of mast above surface this speed will give you the Longest Distance before touching down.I think when pumping we tend to stay at or above Max L/D as it feels lowest drag with good handling,anything below gets very hard to accelerate out of,like getting in a hole,and kind of mushy handling.
If you were towing behind a jetski this would be the speed at which you feel less pull on the rope

*All this speeds are in fact AOA's.They only are fixed speeds at a constant load on the foil.
Change the riders weight,carve a turn or add any up/down acceleration and the speeds will change...but the AOA's at which you get them remain the same for a given foil.

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mcrt said..
To define this speeds* in a different way:

-Stall speed is where flow separation happens,you loose all lift and drop.

-Minimum sink ,just a little faster than stall.If you had 1m of mast above the surface slowing to minimum sink will give you the Longest Time possible before touching down.Could be used to wait for a chop behind you?.
Problem with anything below max L/D is drag increases very sharply so you better have some horsepower in your sleeve (wing,pump,chop) or you are toast.

-Maximum L/D or Best Glide: faster than min sink, with the same 1m of mast above surface this speed will give you the Longest Distance before touching down.I think when pumping we tend to stay at or above Max L/D as it feels lowest drag with good handling,anything below gets very hard to accelerate out of,like getting in a hole,and kind of mushy handling.
If you were towing behind a jetski this would be the speed at which you feel less pull on the rope

*All this speeds are in fact AOA's.They only are fixed speeds at a constant load on the foil.
Change the riders weight,carve a turn or add any up/down acceleration and the speeds will change...but the AOA's at which you get them remain the same for a given foil.

Good description, We just need a foil that can go slow and fast and glide !

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frenchfoiler said..

kobo said..
"generally every time you get a crazy bomb or huge spike in speed, you have a massive drop off also straight after, whereas maintaining smooth lower speeds is far more efficient and will produce higher averages overall."
That's really interesting,So you think a foil which is efficient at lower speeds is more important than one which can go fast and ride the big bumps ,so that would be a mid aspect type foil ? and connecting lots of smaller bumps is better than taking the bombs. It's interesting that you are shimming for lower speed performance as well ,I didn't expect that.So much to learn.......Great info JB.what's your favorite setup atm ?

It all depends on the ocean energy available.

On a dw run in a bay or any zone protected by the ground swell, ususally you go slower as the bumps are close together and are not fast so a super fast wing might not be not the best (except if you can keep up pumping catching bumps in front).

On an open ocean dw run with ground swell, you definetly need a fast foil, so you can go from small slow bumps to big long fast swell line.



On this run it was super windy (40nd) but no ground swell. The bumps were big and steep but not fast. Still I had to use a small wing to handle those bumps. I was using Unifoil Hyper 170 (1090 cm2).

Yes that makes sense, I guess with experience you can look at the ocean and decide which will be the best foil to use on the day.
Do you ever take out a bigger slower foil on a day when there is groundswell and smaller wind swell and just ride the smaller wind swell ,because the ground swell would be too big /fast for the larger foil?Is it better to gear up with a smaller foil for the Larger swell ,and sacrifice being able to ride smaller stuff.

Select to expand quote

kobo said..
"generally every time you get a crazy bomb or huge spike in speed, you have a massive drop off also straight after, whereas maintaining smooth lower speeds is far more efficient and will produce higher averages overall."
That's really interesting,So you think a foil which is efficient at lower speeds is more important than one which can go fast and ride the big bumps ,so that would be a mid aspect type foil ? and connecting lots of smaller bumps is better than taking the bombs. It's interesting that you are shimming for lower speed performance as well ,I didn't expect that.So much to learn.......Great info JB.what's your favorite setup atm ?

It is all a little trickier then that. But you want a foil with the largest range. Going flat out will only lead you to lots of pumping on your run. It is near impossible to stay on swells and at some point you have to peel off and connect to chops in between. James Casey always says, "Big bumps for the thrills but Small bumps pay the bills". The crazy thing with minimum glide ratio (the most efficient speed for maximum flight for a given energy) is your glide is actually less above and below this speed. Again I do not fully understand it, but have read this in multiple documents. But, high aspect foils generally have a fantastic range. They are more suited to DW than MA or LA in a lot of cases but not totally. Drag is always a component that kills runs. Rear wing size is a big one. You want enough kick and stability but big rears are drag machines. You also need enough down force to level out pitching moment when you do get loaded high speed runs or risk diving.

I think a really good way to look at it is. For me, 20kmh is a good solid average speed in the conditions I ride in. James and Zane are more like 24-26kmh, In Maui, Dave Kalama is like 30kmh or something crazy. Some is skill based, some is conditions based. Also a heavier rider will make the same foil go faster when loaded up. A lighter rider will make the same foil fly at lower speeds. It is all about trying to get consistent, use the climb of your peaks to glide you through the lulls as you peel off instead of charging down the swell into nothing and ending up pumping. It is a real art to DW "properly", you nearly have to leave the ride just as it's getting fun and go find another one (that's the way I think about it), if you fun the glide all the way til you begin dropping off, you've probably over done it and will need to pump now.

I am loving the 2140HA. This wing has such a good range. I pull 20kmh averages a lot on it, and it can handle 30kmh peaks with my weight as well as stay up as slow as 10-11kmh. Pretty bloody impressive. I am more the key factor of failure when it comes to this foil. I am keen to get some faster runs on the 1400HA, but find I spend too much time under cooked and pumping and still end up with similar averages. Another thing Casey says is always choose over foiled to under foiled. You will end up faster by being more consistent, letting big ones go but use that kick to get you to the next glide. So addictive and an awesome game. Worth every second of the learning curve and without a doubt the apex of foiling!

Ride safe,

JB

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frenchfoiler said..

kobo said..
"generally every time you get a crazy bomb or huge spike in speed, you have a massive drop off also straight after, whereas maintaining smooth lower speeds is far more efficient and will produce higher averages overall."
That's really interesting,So you think a foil which is efficient at lower speeds is more important than one which can go fast and ride the big bumps ,so that would be a mid aspect type foil ? and connecting lots of smaller bumps is better than taking the bombs. It's interesting that you are shimming for lower speed performance as well ,I didn't expect that.So much to learn.......Great info JB.what's your favorite setup atm ?

It all depends on the ocean energy available.

On a dw run in a bay or any zone protected by the ground swell, ususally you go slower as the bumps are close together and are not fast so a super fast wing might not be not the best (except if you can keep up pumping catching bumps in front).

On an open ocean dw run with ground swell, you definetly need a fast foil, so you can go from small slow bumps to big long fast swell line.



On this run it was super windy (40nd) but no ground swell. The bumps were big and steep but not fast. Still I had to use a small wing to handle those bumps. I was using Unifoil Hyper 170 (1090 cm2).

Wow, 1090cm2 is a tiny foil! What is your weight? 40kn is very windy though and definitely helped. 21.1kmh is relatively slow average too for such a small foil. Very interesting? I am really keen to DW on my 1040HA as it is super efficient, but I fear the difficulty in getting up.

Have you got some more stats on this run.

Awesome, thanks,

Ride safe,

JB

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mcrt said..
To define this speeds* in a different way:

-Stall speed is where flow separation happens,you loose all lift and drop.

-Minimum sink ,just a little faster than stall.If you had 1m of mast above the surface slowing to minimum sink will give you the Longest Time possible before touching down.Could be used to wait for a chop behind you?.
Problem with anything below max L/D is drag increases very sharply so you better have some horsepower in your sleeve (wing,pump,chop) or you are toast.

-Maximum L/D or Best Glide: faster than min sink, with the same 1m of mast above surface this speed will give you the Longest Distance before touching down.I think when pumping we tend to stay at or above Max L/D as it feels lowest drag with good handling,anything below gets very hard to accelerate out of,like getting in a hole,and kind of mushy handling.
If you were towing behind a jetski this would be the speed at which you feel less pull on the rope

*All this speeds are in fact AOA's.They only are fixed speeds at a constant load on the foil.
Change the riders weight,carve a turn or add any up/down acceleration and the speeds will change...but the AOA's at which you get them remain the same for a given foil.

Yep, it is very interesting. I look at the Sink speed giving you an idea of what foil you can get away with at what speed. Obviously we don't know the numbers or have the controlled environment to properly test. Glide ratio is definitely the speed were I think you foil is most efficient, add a tiny bit of power and you what I call "PRIMED" or as some call it foil plaining. Agree, once you go below Sink and towards the theoretical stall, everything gets heavy.

Rider weight, board weight, foilsetup all affect these, but it is an existing terminology to help understand what is going on. Particularly when picking foils. Would be good if foil brands listed the actual scientific Stall, Sink and Glide speeds so we could compare and understand further.

Funny went out to sea the other day with the boat to try some DW tow ins on the prone foil and the ocean was rough as guts ..3 days of NE wind swell mixed with SE ground swell plus some refracted bumps of the rock headlands......well couldn't stay on foil for more than 100m constantly crashing into big holes out of nowhere and ended up being as sick as a dog.I think we chose the wrong conditions.
Total disaster really , had great expectations but ended up getting our arses handed to us. Had much more success just pumping out from a point break on the prone in a NE swell and running down the beach ,or just using the ding.