I've been using cm2 / rider weight to gauge the ratio of foil size for me of other riders.
For example I ride a 1130cm2 foil and weigh 98kgs, and comparing to a team rider of 84kg
1130/98 = 11.53
1130/84 = 13.45
The 84kg rider could drop down to a smaller foil to have the same ratio as me on a larger foil.
980/84 = 11.67
I use this method to determine what foil size to buy for my weight comparing to other riders.
I see 75kg guys down winding on axis 1201 and they have a ratio of 1318 / 75 = 17.57
For me the 1401 is close at 1647 / 98 = 16.81
Is this a viable method, is there a better way without demoing or are there too many other variables involved?
The numbers mean nothing between brands and lines of foils. Just look for small medium and large between the foil line. Judge that way instead of based on numbers. You using one size larger is a decent starting point.
Select to expand quoteHdip said..
The numbers mean nothing between brands and lines of foils.
And even between models of the same brand!
This is because the profile, the foil, is of utmost importance.
For instance, thickness should be a very important factor in comparing foils... but even thickness can vary a lot between the center and the tips.
Gong tries to provide three surfaces for their foil wings:
[1] the projected surface (the "shadow" of the wing), I guess what you were speaking of, the less useful one
[2] the extrados (or "developed"): imagine a cloth wrapping the curved side of the wing that you flatten and measure. It thus takes into account the profile in an objective manner
[3] the feeling: similar to the "apparent temperature", this tries to summarizes how much actual lift you will experience, feel. It takes into account all the wing parameters, but in a subjective manner. This is the one you should use to compare foils.
To give an idea, here are the numbers for a beginner wing:
And for an expert one:
And for a pumping/downwind one:
As you can see, depending on the wing shape, the "feeling" surface may be smaller or larger than the projected one.
Yeah foil section matters and high aspect foils behave different than low and your other gear matters and your conditions matter and yadda yadda yadda. At the end of the day there is a very finite and not terribly wide range of lift coefficients you can get out of various foil sections. So area still matters and comparing areas is still relevant, just know that it is subject to an increasing amount of uncertainty as foil designers push harder into diverging corners of the foil design solution space. I really appreciate brands that publish foil volume in addition to area. That gives a good read of average thickness. Combined with some photos you can start to see thickness and area distribution and, to a lesser extent, camber. At that point you have a pretty decent idea if you are comparing apples to apples or not.
All that said, investing in a completely new system is so bloody expensive and preferences so individual that I've concluded demoing is the only way to make such a big investment in a well informed manner.
I recall a podcast with Axis designer Adrian Roper from a while back where he lists the most important design aspects of a foil. In order of importance he put wingspan first, then apsect ratios/ average chord, then foil section, then thickness. He puts surface area right down at the bottom of the list of importance.
I think this is pretty accurate. If you compare a low aspect design from a couple years ago to a mid aspect design today you will see you get a much bigger wing with the same surface area. For instance if I compare my old Axis Surf Performance 860
( wingspan) with my current Axis Spitfire 1030 ( wingspan) both have a projected area just under 1300cm ( SF has a little more area). The 1030 SF is in every way a much bigger ( and better) wing. Lift, glide, pumping are all much more on the SF. ( I didn't mention turning because the 1030 SF turns ridiculously well for a wing that size.
As a bigger rider ( 100kgs) I definitely feel like wingspan is key to getting the pump and glide that I want. Anything under 950mm starts to get a lot harder to pump and link waves. Higher aspect wings, especially in good conditions, I can carry enough speed and glide to make them work well even with lower surface area.
I definitely wish there was a better way to measure lift ratio for rider weight. A friend I foil with a lot is 70kg and whenever he sees what I'm riding he says " Oh that's a big foil". When factoring in my weight and the increase in board size I would need to take at least 30-40% off for us to be at a similar lift ratio.
Select to expand quoteYoungbreezy said..
I definitely wish there was a better way to measure lift ratio for rider weight. A friend I foil with a lot is 70kg and whenever he sees what I'm riding he says " Oh that's a big foil". When factoring in my weight and the increase in board size I would need to take at least 30-40% off for us to be at a similar lift ratio.
Your last paragraph is what I'm talking about, there are lighter guys at my spot pumping for days, so if you take rider skill out of it, what I'm looking for is a way to measure what is a comparable foil size in the same brand for my weight to see if the brand has one big enough. But, I know I won't have the same experience as the foil will be bigger, wider, thicker, bigger chord and slower, but it's a good place to start from.
The only way I know how to do this is the cm2 / rider weight to get a ratio.
Select to expand quotenoepoxy said..Youngbreezy said..
I definitely wish there was a better way to measure lift ratio for rider weight. A friend I foil with a lot is 70kg and whenever he sees what I'm riding he says " Oh that's a big foil". When factoring in my weight and the increase in board size I would need to take at least 30-40% off for us to be at a similar lift ratio.
Your last paragraph is what I'm talking about, there are lighter guys at my spot pumping for days, so if you take rider skill out of it, what I'm looking for is a way to measure what is a comparable foil size in the same brand for my weight to see if the brand has one big enough. But, I know I won't have the same experience as the foil will be bigger, wider, thicker, bigger chord and slower, but it's a good place to start from.
The only way I know how to do this is the cm2 / rider weight to get a ratio.
I think it you add in wingspan and surface area you could get a more concise ratio for rider weight.
Another thing the smaller riders don't consider is that a heavier rider can get alot more performance out of the same wing. If you put a 70kg guy and a 100kg guy on the same wing the 70kg guy will get alot more lift and stay up a lot easier but the heavier rider will get alot more speed and better turning ( more leverage).
well all I know is you don't see many big guys 90-100 kg downwinding or pumping around like the light weights, by the time you add the weight of the board, foil, gear, paddle and rider e.g.
98 + 6 + 4 + 2 + 0.5 = 110.5 kg with dw board + 20-30L = 130.5-140.5L
75 + 6 + 4 + 2 + 0.5 = 87.5 kg with dw board + 20-30L = 107.5-117.5L
The foil needs to lift 110 kg, whereas a lighter 75 kg rider the foil would need to lift 87.5 kgs which is 23 kgs less, all things considered. Very rough numbers used above for gear weight.
Not many brands support foils with that lift profile or boards for that matter for my weight, guess I have to choose my brand wisely and find the best scale ratio etc
Select to expand quotenoepoxy said..Not many brands support foils with that lift profile or boards for that matter for my weight, guess I have to choose my brand wisely and find the best scale ratio etc
Thats why demo is important. At 100kg I cannot believe the biggest foil I need is 980cm2 until I demoed a Code foil. Heaps of lift and glide. They make bigger ones as well.
Waiting on the 860r for downwind which is meant to have more lift than the 980. Previously had to ride 1400cm2 foils at least.
Foils in general have come a long way in a short time. Code sure seems to have some secret sauce going. Nuts hearing 100kg guys riding a 770 cm2 foil saying it has glide for days and good low end. So itching to get an adaptor for my Cedrus mast and try one out. But I know that could lead down a costly spending spree.
All that math about wing loading leaves out speed. More speed equals more lift.
A heavier loaded wing might take a bit more speed to get up, but once it's up the heavy loading means it's going to glide faster, potentially glide further (because the rider has more speed to play with), and still be able to slow right down because once the flow is attached then you can go very slow and still generate lift.
Part of the appeal of downwind boards is you can get more speed on the surface so it's easier to get up on a smaller foil and do it with a smaller wing. Once up you can rip along at high speed and sip more power from each wave you pass.
Select to expand quotehilly said..noepoxy said..Not many brands support foils with that lift profile or boards for that matter for my weight, guess I have to choose my brand wisely and find the best scale ratio etc
Thats why demo is important. At 100kg I cannot believe the biggest foil I need is 980cm2 until I demoed a Code foil. Heaps of lift and glide. They make bigger ones as well.
Waiting on the 860r for downwind which is meant to have more lift than the 980. Previously had to ride 1400cm2 foils at least.
I sup the 1130S in waves it's good for sure, and the 980s but not enough glide etc, have the 1300S too, but on the east coast of aus, have taken both out with a tiny wing and they don't work downwinding at my weight. I use no foil assist, and trying to drop the wing, most 80kgs guys have a ratio of 13+ at a minimum and above and the biggest foil I have is just 13.
Maybe another brand maybe required to unlock it for me downwinding....I doubt the 860r or any of the r series will work at my weight, happy to be proved wrong, but no demo....
Select to expand quotenoepoxy said..hilly said..noepoxy said..Not many brands support foils with that lift profile or boards for that matter for my weight, guess I have to choose my brand wisely and find the best scale ratio etc
Thats why demo is important. At 100kg I cannot believe the biggest foil I need is 980cm2 until I demoed a Code foil. Heaps of lift and glide. They make bigger ones as well.
Waiting on the 860r for downwind which is meant to have more lift than the 980. Previously had to ride 1400cm2 foils at least.
I sup the 1130S in waves it's good for sure, and the 980s but not enough glide etc, have the 1300S too, but on the east coast of aus, have taken both out with a tiny wing and they don't work downwinding at my weight. I use no foil assist, and trying to drop the wing, most 80kgs guys have a ratio of 13+ at a minimum and above and the biggest foil I have is just 13.
Maybe another brand maybe required to unlock it for me downwinding....I doubt the 860r or any of the r series will work at my weight, happy to be proved wrong, but no demo....
I used a 0.5 shim with the 175 tail today but put it in backwards so giving more lift. Works really well. You might want to try that if you do not have enough lift which is surprising. I cannot imagine what the 1300 feels like lol. There is a 1075r now too.
yeah I go out at currumbin, out the back head out to sea and try and flag out with 1300S, 1130S and 980S and all don't stay with ocean bumps and give me lift, enough to catch a couple of swells and link but then always have to revert to wing for power. Will probably sell 1300 and go for axis dw setup as it's aimed for heavier riders and east coast of aus is s**t conditions compared to wa
Select to expand quotenoepoxy said..
yeah I go out at currumbin, out the back head out to sea and try and flag out with 1300S, 1130S and 980S and all don't stay with ocean bumps and give me lift, enough to catch a couple of swells and link but then always have to revert to wing for power. Will probably sell 1300 and go for axis dw setup as it's aimed for heavier riders and east coast of aus is s**t conditions compared to wa
Just went down the east coast of Australia the 980 was awesome over there.
there some local guys riding code, none over 80kg downwinding that I know of, most around 75kg. Certainly not bagging code but there's no chance with the 980cm2 at 100kg without a wing or foil assist, maybe if 30-40kn and blowing for a few days in open ocean to get some good bumps but average days 10-20kn it's not an option including the 1300s at my weight. Even in the broadwater at howard st in howling southerly against outgoing tide, can only link a few before lift gives out, same with wake thieving in broadwater off launches and fishing trawlers, just doesn't have the lift to glide on first or second wake at my weight.
Sup foiling and dinging is completely different from downwind when you only have a paddle, happy to be proven wrong by anyone who's 95-100kg
Anyway, back to the thread would be good if there was a consensus on the best ratio to compare foil size in a brand to rider weight
Small medium and large. The 1300 is a large foil. I have not ridden it though. Would love to see a big dog get on one.
The metric you are looking for is wing loading, so weight divided by area. I figure my foiling weight at 100kg and for winging I use an 800 so wing loading of 0.125kg/cm2 and a 1050 for SUP/prone so wing loading of 0.095. For someone at 80kg, equivalent sizing would be 640 and 840.
I agree that you can't compare directly across brands/models, but it's a rough guide and if you are sick of watching the local 70kg kid pumping all over the place on a lift 120 (70kg/775cm2=0.090) it's good to realize that you would need something around 1110cm2 of the same design to be near equivalent at 100kg.
Select to expand quotenoepoxy said..Is this a viable method, is there a better way without demoing or are there too many other variables involved?
There are too many variables demo is the best.
Yes the way I calculate is the inverse of weight divided by area, just gives a ratio easier to comprehend for me, but yields the same result
weight, cm2, weight/cm2, cm2/weight
70, 750, 0.0933, 10.71
100, 1071, 0.0934, 10.71
Select to expand quotehilly said..noepoxy said..Is this a viable method, is there a better way without demoing or are there too many other variables involved?
There are too many variables demo is the best.
agreed, but knowing what size to demo is important too, if you are using someone as a comparison, otherwise you end up buying the wrong size for your weight 
another example is with the 1300S video with casey, he is 84kg I think, so a ratio of 1300 cm2 / 84 = 15.47 and he pumps it so easy, the 1300 doesn't pump as easy as for me
for me to have the same experience (taking skill out of it) I'd need a foil that is 1517 cm2 / 98 = 15.47 and they don't have a foil that is 1517 cm2
maybe he could wear a weight belt of 14kgs to come up to my weight and see what happens...be interesting
Select to expand quotenoepoxy said..
another example is with the 1300S video with casey, he is 84kg I think, so a ratio of 1300 cm2 / 84 = 15.47 and he pumps it so easy, the 1300 doesn't pump as easy as for me
for me to have the same experience (taking skill out of it) I'd need a foil that is 1517 cm2 / 98 = 15.47 and they don't have a foil that is 1517 cm2
You cannot take skill out of it 
I could have a 2400 foil and still not pump it. James Casey can pump a 615 where does that leave your formula.
Select to expand quotehilly said..noepoxy said..
another example is with the 1300S video with casey, he is 84kg I think, so a ratio of 1300 cm2 / 84 = 15.47 and he pumps it so easy, the 1300 doesn't pump as easy as for me
for me to have the same experience (taking skill out of it) I'd need a foil that is 1517 cm2 / 98 = 15.47 and they don't have a foil that is 1517 cm2
You cannot take skill out of it
I could have a 2400 foil and still not pump it. James Casey can pump a 615 where does that leave your formula.
lol only used casey as an example for weight, it's all about having the same platform.
at 615 it would be the 720s for me, which i use kite foiling, I can pump it a bit but not much as hard with a kite over head
Select to expand quotenoepoxy said..hilly said..noepoxy said..
another example is with the 1300S video with casey, he is 84kg I think, so a ratio of 1300 cm2 / 84 = 15.47 and he pumps it so easy, the 1300 doesn't pump as easy as for me
for me to have the same experience (taking skill out of it) I'd need a foil that is 1517 cm2 / 98 = 15.47 and they don't have a foil that is 1517 cm2
You cannot take skill out of it
I could have a 2400 foil and still not pump it. James Casey can pump a 615 where does that leave your formula.
lol only used casey as an example for weight, it's all about having the same platform.
at 615 it would be the 720s for me, which i use kite foiling, I can pump it a bit but not much as hard with a kite over head
Riding bumps takes years to learn along with being able to pump foils small enough to surf well. I am not a code guy but I think you have purchased the best opportunity you could. Now it's up to you to put in the years of practice.
@NoEpoxy
I am in agreeance with Any board. If you've already got the 1130S and 1300S these are probably some of the best wings on the market for a bigger guy to be gliding bumps and downwinding. The Axis art pro 1201 or 1401 would probably be the best other options but I don't know if you would he much of an improvement by going to these wings.
As you get into bigger and bigger wings I feel there is a point of diminishing returns where the wing becomes too slow and draggy to ride the bumps effectively.
I have done a lot of downwinding/ bump surfing with a wing ( no sup downwinding just yet but planning on getting into it once I have my dodgy hip sorted out). At 100kg the best pumping and gliding wing I have used so far is the Axis ART 1099 with a skinny rear. With this set up I can ride indefinitely with the wing flagged out. I have also made some long runs doing drop wallets in winds around 18 knots. I have probably made distances of around 1km unassisted so it's definitely do able for a big guy even in winds that aren't too strong. Sup foiling on the ART 1099 gave me my best pumping and wave connecting so far. I have also had a good go on the HPS 1050 with a wing and doing drop wallets. At 1500cm2 the HPS 1050 was a lot easier to get up on foil but the additional drag meant it didn't glide on the bumps nearly as well as the ART 1099.
if I were you I'd just focus on the 1130s and 1300s and just keep hammering away at it. They are probably some of the best options out there.
This is a great video on reading and riding bumps
Thanks for your feedback. I've tried the 1130S and 1300S in 15-20 knot a few km's offshore dinging and flagging out and I can ride a few bumps but the swell is moving a bit fast and not enough lift/glide for my weight. FWIW, I'm an advanced foiler, can do forward, backwards flips kite foiling, winging for a few years, and not too shabby at sup foil either. I would say for me to use any of these it'd have to be 20-25+ solid and bigger bumps, probably be fine if I was in Perth. I'm looking at 15kn+ open ocean conditions at it's the east coast which is very fickle. DW is hard enough let alone being under-foiled and tbh not looking at pumping all the time as I'll just burn myself out, need more glide and less pump. The 70-80kg guys have a great selection of foils, but if you're in the 95+ kg club options are definitely limited.
Funny you recommend that, I've sold half of my code setup and replaced with 1401 and 1100 spitfire, will get a 1201 for more powerful days, on paper these wings should give me more lift and speed to keep up with the bumps. I've seen a dave west video of him pumping the spitfire 1100 easily and he's 95kg. Have keep the 1130S for sup foil/ding until I dial in the Axis and decide which setup I'll keep
Select to expand quoteYoungbreezy said..
@NoEpoxy
I am in agreeance with Any board. If you've already got the 1130S and 1300S these are probably some of the best wings on the market for a bigger guy to be gliding bumps and downwinding. The Axis art pro 1201 or 1401 would probably be the best other options but I don't know if you would he much of an improvement by going to these wings.
As you get into bigger and bigger wings I feel there is a point of diminishing returns where the wing becomes too slow and draggy to ride the bumps effectively.
I have done a lot of downwinding/ bump surfing with a wing ( no sup downwinding just yet but planning on getting into it once I have my dodgy hip sorted out). At 100kg the best pumping and gliding wing I have used so far is the Axis ART 1099 with a skinny rear. With this set up I can ride indefinitely with the wing flagged out. I have also made some long runs doing drop wallets in winds around 18 knots. I have probably made distances of around 1km unassisted so it's definitely do able for a big guy even in winds that aren't too strong. Sup foiling on the ART 1099 gave me my best pumping and wave connecting so far. I have also had a good go on the HPS 1050 with a wing and doing drop wallets. At 1500cm2 the HPS 1050 was a lot easier to get up on foil but the additional drag meant it didn't glide on the bumps nearly as well as the ART 1099.
if I were you I'd just focus on the 1130s and 1300s and just keep hammering away at it. They are probably some of the best options out there.
Yep I agree with Youngbreezy and Anyboard it takes ages to be able to pump well and to learn to stay on bumps downwind.
I am still learning but can usually stay up for a few Km's
I have lost a fair bit of weight recently (through health reasons that I wouldn't recomend) but am usually around 92 kg (and 62yo) and for downwind Sup, my go to is the 1201 Axis but I use the 1401 when its under around 15knots and 1121 when over 20knots.
I live in WA and am a fairly experienced sup paddler and foiler but at 92kg I was able to paddle the Code 980 up and stay up relatively easy in good ocean conditions once I adjusted to the different feel from the art pro's, if I was to use your formula it would be 980/92 = 10.65.
If I was to buy one Code foil it would be that one, mainly as I already have light wind covered with my Axis wings.
I haven't tried the 1300 Code vs the 1401 Art Pro but I don't imagine it would be much different for a heavyweight to get up in light wind despite its smaller size.
The Codes are fairly lifty for their size and a good wing for learning dw.
As much as I love my 1401, I'd persist with what you have or at least try to demo a 1401 before I went out and bought one.
Edit: whoops No Epoxy you replied whilst I was typing that, it will be interesting g to see how you go on the Axis, they are good but there is no magic wing it will still take time.
ha ha, too funny!
I guess I'm looking at making my dw journey as easy as possible and I've owned all code foils from 720S to 1300S, they are great dinging but for my weight dw the glide is not there. My favourite was the 850 and 980 on the ding, but always needed to be fully powered.
As much as I like riding smaller foils as they're more agile and slippery through the water and just feel better, being a bigger guy, for dw they are not an option, anyway, hopefully the Axis foils will unlock it for me, time will tell
