Hello Australia,I hope you don't mind this post as we begin detailed design of the next generation Project Cedrus foil mast. Australia has been a big market for us, and we are very grateful for the support and feedback over the years. One of our biggest goals is to make a mast or ecosystem of masts that serves the entire range of foiling from kite to wing to surf and others. If you are interested in influencing Evolution Cedrus, please feel free to complete this google survey and put any additional comments in the end about what is important to you in a mast. We've gotten a lot of great feedback from the hundreds of current edition owners, but we really would love to hear from everyone! Many thanks, Kyle
forms.gle/QhV75FLRdgg5dXRo8

Stiff (S)
light (L)
low drag (D)
Pick 2

you should have three masts. SL, SD, and LD. You already have the SL. Don't worry about infinite adaptability.
Keep it up. Love what you are doing. my $0.02 from the cheap seats.

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Velocicraptor said..
Stiff (S)
light (L)
low drag (D)
Pick 2

you should have three masts. SL, SD, and LD. You already have the SL. Don't worry about infinite adaptability.
Keep it up. Love what you are doing. my $0.02 from the cheap seats.

Pretty much this.

But also I'd rather you move away from just bolting the adapter onto the flat end of the mast, that's not a great system.

Thanks @velociraptor. Yes, tradeoffs are necessary and not everyone understands that. We will see if we have the bandwidth to address all combinations of the above, or if it's best to just stick with he current combo we have chosen. You did forget "strong", which is critical to us. Many big riders riding big wings on high volume boards depend on strength. Or just normal riders not wanting to lose their foils to the deep blue... So of the 4, pick 3...

@grantmac hundreds of happy clients without issues, survey speaks for itself. A butt joint on a 19mm wide surface is incredibly strong, requires no shims, is fully repairable, and cost effective. Would love further input as to why this is not a great system and what you propose as an alternative.

I think the butt joint is good. I've got a Takuma stringy fuse that is a butt joint to the Cedrus and I kind of wish I could have this connection for all my foils. It's simple and solid (if the bolts are big enough) and you don't need to deal with tolerances adjusting over time. I haven't had any issues.


Are you going to be able to keep the bolt size in the narrower profile "evolution" mast? The bolt is part of what makes me trust the butt joint.

You like it, I hate it. We've been over this before. I believe it's a poor system but if the rest of the mast was brilliant I could look past.

So maybe the new version will have the characteristics to make me a buyer. It would have to be much lower drag.

As emailed in the survey:I really like my Cedrus and benefits of being able to switch brands without the mast is still awesome, but I tried the same foils with thinner masts like the F-one HM, SAB and the Cabrinha carbon (that one was admittedly too soft) and the drag difference was for me quite noticeable in slower weaker waves.

Being 188x 95kg (I think i,m a heavy weight?) winging mostly 1000-1200cm2 foils with aprox 90cm span, but in an for me ideal product I would sacrificie some weight and even some Stiffnes for less drag and being able to sail under a wider range of angle (and I think that is partly width related). Good stuff is expensive so willing to pay for it.

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Jeroensurf said..
As emailed in the survey:I really like my Cedrus and benefits of being able to switch brands without the mast is still awesome, but I tried the same foils with thinner masts like the F-one HM, SAB and the Cabrinha carbon (that one was admittedly too soft) and the drag difference was for me quite noticeable in slower weaker waves.

Being 188x 95kg (I think i,m a heavy weight?) winging mostly 1000-1200cm2 foils with aprox 90cm span, but in an for me ideal product I would sacrificie some weight and even some Stiffnes for less drag and being able to sail under a wider range of angle (and I think that is partly width related). Good stuff is expensive so willing to pay for it.

I feel exactly the same.

I have the Cedrus, but I now that I mostly ride faster foils the NoLimitz is my go to because the drag difference is noticeable. Whenever I ride my slower foils I'm on the Cedrus because the difference in stiffness is noticeable.

Low drag / stiff would be my first choice. I actually wouldn't mind the extra weight all that much, I believe it has it's advantages such as not as likely to flip up when crashing in high winds so maybe an ALU version of the new one as well?

I ride few systems and always try new ones so the modularity is a big advantage. I have no doubt I'll be buying the next generation. Keep up the good work!

Regarding the mentioned drag:
With my Kujira1210 (gen2 foils?) I don,t really notice drag at all and its feel perfectly harmonius matches the mast.

But with newer more optimised, faster (gen 3?) that are younger as the Cedrus mast design the drag is noticable more as when running them on the newer (thinner) more efficient masts. examples: Cab. Hseries, Fone7seas.
I still like my Cedrus, but where it was with the Kujira on all aspects simply better, with the newer foils it has it pro,s and cons.

I would love to get a Cedrus with Low Drag and reasonable stiffness (knowing that it wont be one of the lightest masts on the market).
(Regarding stiffness: With 90kg i want to push my foils with spans up to 90cm with confidence in fast and tight turns. I also ride 110cm span foils but i am not going for the stiffest mast on the market to also get the best performance out of these wide span front wings)

I'm one of those (many) people that can't feel ANY difference in drag between a 19mm aluminum Axis mast and a 14.5mm Go Foil mast but also don't go out in light conditions or underpowered. I think your mast would probably work great for me but am already perfectly happy where I'm at. Kudos though for what you're doing and posing the question

Thank you for taking the time to make a survey, hopefully many people fill it up.
Imo stiff and thin (ideally 13mm, or at least sub 16mm) is the go, aka high modulus racing masts. Only using that these days, there is no turning back. Mast thickness difference can be felt at all speeds, proning and winging, as it drastically decreases the glide of the setup. Loving the concept of universal mast, it would be super convenient!

Thanks everyone. The feedback regarding drag is fairly consistent and we will most certainly be addressing this in our next generation mast. Please don't forget, Project Cedrus was designed 5 years ago, likely before many of you were even foiling:) The sport has evolved and we while we were well-suited for powered forms of foiling like kite and wing, it does seem that the low speed prone/pump riders are more sensitive to drag than powered riders. This is counter-intuitive for us, because drag varies with v^2, meaning the drag forces are much higher at 20kts vs. 10kts.

One piece of feedback that is not consistent is related to weight. Some owners suggest to sacrifice weight for a faster mast, but then some feedback implies a potential customer did not buy Cedrus because it was too heavy. To be clear, Project Cedrus was the first hollow carbon foil mast and as far as we're aware, still one of the lightest masts on the market. It's hard because few brands post their weights on the site, but we do.

Finally, we want to again reiterate that we will be reducing drag, not just focusing on thickness. Chord length affects wetted area, which is the primary driver in drag. So some of these new "thin" masts are actually very draggy when low in the water or starting due to a long chord length. Sometimes we feel partially to blame for the industry and consumers being overly focused on "thickness" because we are honest on the site about our dimensions. So to those who suggest a single dimension for our next mast, there will be a lot more to it than that...

Hi Kyle,
I think the focus on thickness is because it is one of the very few things that are actually pretty easy and uniform to measure.
If you can make a very low drag 30mm thick mast that is plenty forgiving in a wide range of angles i,m equally happy as with an thin mast.

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BayAreaKite said..
Thanks everyone. The feedback regarding drag is fairly consistent and we will most certainly be addressing this in our next generation mast. Please don't forget, Project Cedrus was designed 5 years ago, likely before many of you were even foiling:) The sport has evolved and we while we were well-suited for powered forms of foiling like kite and wing, it does seem that the low speed prone/pump riders are more sensitive to drag than powered riders. This is counter-intuitive for us, because drag varies with v^2, meaning the drag forces are much higher at 20kts vs. 10kts.

One piece of feedback that is not consistent is related to weight. Some owners suggest to sacrifice weight for a faster mast, but then some feedback implies a potential customer did not buy Cedrus because it was too heavy. To be clear, Project Cedrus was the first hollow carbon foil mast and as far as we're aware, still one of the lightest masts on the market. It's hard because few brands post their weights on the site, but we do.

Finally, we want to again reiterate that we will be reducing drag, not just focusing on thickness. Chord length affects wetted area, which is the primary driver in drag. So some of these new "thin" masts are actually very draggy when low in the water or starting due to a long chord length. Sometimes we feel partially to blame for the industry and consumers being overly focused on "thickness" because we are honest on the site about our dimensions. So to those who suggest a single dimension for our next mast, there will be a lot more to it than that...

I don't have measurements to validate my theory but I have the feeling that a lot of what people feel as drag could also come from the mast resonating because it is hollow, and it might even feel a lot more on the carbon vs alu masts. Obviously the faster you go you will feel more drag but the mast will also vibrate a lot more so it might add up to the overall feel compared to a mast with a core inside. The reason behind my theory is because some days when the wind is coming from a specific angle or some strength, the ride feels really "draggy", but then other days it is perfectly fine (riding the same foils but different wind conditions)

I do agree with Grantmac in the sense that even if the current 2 bolt system is good, maybe a 3 bolt system would be safer or something with a foot/shoe type of connection would be good for those cases when the adaptors are not checked in a while and bolts might become loose.

In any case, I haven't had any issues with my masts and I am heavy and riding big foils. I made the right choice when getting them

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Jeroensurf said..
Hi Kyle,
I think the focus on thickness is because it is one of the very few things that are actually pretty easy and uniform to measure.
If you can make a very low drag 30mm thick mast that is plenty forgiving in a wide range of angles i,m equally happy as with an thin mast.

haha thanks Jeroen. I have had a heck of a time measuring thickness of masts that have up to 140mm chord length; my calipers don't reach! But I know what you mean. I am only suggesting we not forget about chord length/wetted area.

@mindhoc, Cedrus is known to actually have really good damping characteristics due to the rubber edges. Most find that it doesn't vibrate like other masts which can whistle or shimmy. While it is hollow, the walls are still thick enough to not "oil can" or resonate like speaker membranes. Some people must be more sensitive than others when it comes to the drag, which I believe could also be due to weight. Lighter guys need less lift, and therefore have less drag... they may be more sensitive to mast drag.

Anyway, feedback well received. Thanks all.

Actually I think the mast thickness to chord ratio has to be kept low to reduce drag, I am guessing that the current Cedrus would be less draggy with more chord, as it is with a ratio above 15% which is quite uncommon (most masts between 10 to 15%). Keen to hear thoughts/info on that.
Takuma alu masts v1 and v2 keep the same ratio, v2 being thicker, they increased the chord to preserve the same profile and ratio.

I would suggest a bit of a revaluation on the powered rider perspective, for wingers at least. Myself and the majority I talk to are looking for efficiency, doesn't matter if it is for blasting, racing, waves, or freestyle. Exactly where the tradeoffs against weight, stiffness and cost end up varies by focus, but everyone want efficiency.

I'm interested in the drag component as a total of the total drag of a setup. Specifically the mast contribution as a component of the total drag at varying mast heights, and especially curious for smaller very efficient low drag front wings.

Would it be possible to get a rough approximation of the mast drag component and the wing/tail drag component? The mast is solely drag where as the tail+wing is drag and lift.

It seems possible to determine a theoretical drag calculation for each profile/cord/thickness combination, and the same could be done for each tail+wing combination. Maybe necessary to ignore planform and other nuances as well as fuse and surface variations.
eg skill-lync.com/blogs/airfoil-simulation-plotting-lift-and-drag-coefficients-of-an-airfoil-at-different-angles-of-attack

@BayAreaKite this possibly something you have done or would know where to look? Seems likely to be well computed for sailing/kite racing.

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foilstate said..
Actually I think the mast thickness to chord ratio has to be kept low to reduce drag, I am guessing that the current Cedrus would be less draggy with more chord, as it is with a ratio above 15% which is quite uncommon (most masts between 10 to 15%). Keen to hear thoughts/info on that.
Takuma alu masts v1 and v2 keep the same ratio, v2 being thicker, they increased the chord to preserve the same profile and ratio.

You are confusing drag coefficient with total drag force. Thickness to chord ration (t/c) affects the drag coefficient, which you then multiply by reference area (surface area in the case of a wing) to get a total drag force (along with velocity). Two masts with the same t/c can have totally different drag forces. If we added 10mm chord length to Project Cedrus, it would become about 2% more draggy at 10kts. The drag coefficient would decrease slightly, but not enough to compensate for the increased wetted area (affecting drag force).

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cornwallis said..
I'm interested in the drag component as a total of the total drag of a setup. Specifically the mast contribution as a component of the total drag at varying mast heights, and especially curious for smaller very efficient low drag front wings.

Would it be possible to get a rough approximation of the mast drag component and the wing/tail drag component? The mast is solely drag where as the tail+wing is drag and lift.

It seems possible to determine a theoretical drag calculation for each profile/cord/thickness combination, and the same could be done for each tail+wing combination. Maybe necessary to ignore planform and other nuances as well as fuse and surface variations.
eg skill-lync.com/blogs/airfoil-simulation-plotting-lift-and-drag-coefficients-of-an-airfoil-at-different-angles-of-attack

@BayAreaKite this possibly something you have done or would know where to look? Seems likely to be well computed for sailing/kite racing.

My friend Cody @Inde foil did this a while ago: www.indefoil.com/foildesign/mast-thickness-drag

In short, wings contribute about 70-80% of total system drag. The mast is only a small portion of total drag, so the impacts of optimization are limited. But as suggested above, some claim to feel the 2-5% drag increase. Many don't. It's very personal, and I believe there is a bit of placebo affect too.

In my experience, mast drag is pretty noticeable. I just compared a 16.7mm thick mast with a fat NACA-style section to a 15.5mm thick mast with a more laminar-style section. The more optimized mast raised my average speed over 15km downwind by 1-2mph over 5-10 runs each. Average speeds are between 15-20mph. The reduced drag also allowed me to slightly decrease my tail wing angle, multiplying the effect.

That said, downwind foiling is very sensitive to changes in drag and this is not a very scientific test. I felt the most difference in drag above 20mph, and not much difference below 15.

I find the biggest difference between mast thicknesses is not speed but control. For example when winging through waves a thick mast will have a larger drag difference between low and high on the mast. Something like the mikes lab mast is much smoother through rough water because the drag spike through waves is less.

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FoilAddict said..
In my experience, mast drag is pretty noticeable. I just compared a 16.7mm thick mast with a fat NACA-style section to a 15.5mm thick mast with a more laminar-style section. The more optimized mast raised my average speed over 15km downwind by 1-2mph over 5-10 runs each. Average speeds are between 15-20mph. The reduced drag also allowed me to slightly decrease my tail wing angle, multiplying the effect.

That said, downwind foiling is very sensitive to changes in drag and this is not a very scientific test. I felt the most difference in drag above 20mph, and not much difference below 15.

I find the biggest difference between mast thicknesses is not speed but control. For example when winging through waves a thick mast will have a larger drag difference between low and high on the mast. Something like the mikes lab mast is much smoother through rough water because the drag spike through waves is less.

I also feel that on thicker masts, that's a great point, beyond the question of drag and speed. The thicker the mast, the more there is a difference of drag of the whole setup between mast low and high in the water, which makes it hard to control, because you have to constantly correct the pitch. Mast deep feels like pulling the breaks so all weight on the back to compensate the nose down, mast high feels dragless and weight has to be shifted forward to not breach. Thin masts don't really have this problem, or at least much smoother.

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BayAreaKite said..

foilstate said..
Actually I think the mast thickness to chord ratio has to be kept low to reduce drag, I am guessing that the current Cedrus would be less draggy with more chord, as it is with a ratio above 15% which is quite uncommon (most masts between 10 to 15%). Keen to hear thoughts/info on that.
Takuma alu masts v1 and v2 keep the same ratio, v2 being thicker, they increased the chord to preserve the same profile and ratio.

You are confusing drag coefficient with total drag force. Thickness to chord ration (t/c) affects the drag coefficient, which you then multiply by reference area (surface area in the case of a wing) to get a total drag force (along with velocity). Two masts with the same t/c can have totally different drag forces. If we added 10mm chord length to Project Cedrus, it would become about 2% more draggy at 10kts. The drag coefficient would decrease slightly, but not enough to compensate for the increased wetted area (affecting drag force).

Makes sense, thank you for the clarification

Lower drag
Longer
Stiffer
Retain the Clydesdale strength

I am definitely not a fan of the butt joint, especially since my fuselage strength has already been compromised with a mortise (phantasm) . Feel like I would be getting the worst of both worlds.

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BayAreaKite said..

cornwallis said..
I'm interested in the drag component as a total of the total drag of a setup. Specifically the mast contribution as a component of the total drag at varying mast heights, and especially curious for smaller very efficient low drag front wings.

Would it be possible to get a rough approximation of the mast drag component and the wing/tail drag component? The mast is solely drag where as the tail+wing is drag and lift.

It seems possible to determine a theoretical drag calculation for each profile/cord/thickness combination, and the same could be done for each tail+wing combination. Maybe necessary to ignore planform and other nuances as well as fuse and surface variations.
eg skill-lync.com/blogs/airfoil-simulation-plotting-lift-and-drag-coefficients-of-an-airfoil-at-different-angles-of-attack

@BayAreaKite this possibly something you have done or would know where to look? Seems likely to be well computed for sailing/kite racing.

My friend Cody @Inde foil did this a while ago: www.indefoil.com/foildesign/mast-thickness-drag

In short, wings contribute about 70-80% of total system drag. The mast is only a small portion of total drag, so the impacts of optimization are limited. But as suggested above, some claim to feel the 2-5% drag increase. Many don't. It's very personal, and I believe there is a bit of placebo affect too.

This is perfect, thank you. Two observations leading to questions:

1. The foil analysed is quite a conservative design, a1100 not sure what the span is but I'm guessing quite large? It looks really big. I would imagine as you drop down to a more popular prone foil wing, the % will increase quite dramatically? Or have I got the specs wrong on this wing? How does it compare to say Cabrinha H1050- 1050cm?, WS 1000, AR 9.52, Chord 140mm
a1100 Chord length: 110mm - www.instagram.com/p/CWJIG1ivyTN/

2. The 50% mast immersion I think is possibly misleading (not intentionally). I think that when the drag really matters is when you are low on the mast and trying to recover speed and height. If I understand it the increase in immersion means linear increase in drag, meaning that at the critical moment you have more like a 4-10% increase in drag? Caveat that it seems lower drag % at low speeds, so maybe less.

"""At 0 degrees yaw and 50% mast immersion, a 2-5% increase in overall drag can be expected in the 10-25knot range when using a 19mm mast as compared to a 12mm mast.
As more of the mast is immersed, the percent of the total drag will also increases linearly for a constant section mast"""

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cornwallis said..

BayAreaKite said..

cornwallis said..
I'm interested in the drag component as a total of the total drag of a setup. Specifically the mast contribution as a component of the total drag at varying mast heights, and especially curious for smaller very efficient low drag front wings.

Would it be possible to get a rough approximation of the mast drag component and the wing/tail drag component? The mast is solely drag where as the tail+wing is drag and lift.

It seems possible to determine a theoretical drag calculation for each profile/cord/thickness combination, and the same could be done for each tail+wing combination. Maybe necessary to ignore planform and other nuances as well as fuse and surface variations.
eg skill-lync.com/blogs/airfoil-simulation-plotting-lift-and-drag-coefficients-of-an-airfoil-at-different-angles-of-attack

@BayAreaKite this possibly something you have done or would know where to look? Seems likely to be well computed for sailing/kite racing.

My friend Cody @Inde foil did this a while ago: www.indefoil.com/foildesign/mast-thickness-drag

In short, wings contribute about 70-80% of total system drag. The mast is only a small portion of total drag, so the impacts of optimization are limited. But as suggested above, some claim to feel the 2-5% drag increase. Many don't. It's very personal, and I believe there is a bit of placebo affect too.

This is perfect, thank you. Two observations leading to questions:

1. The foil analysed is quite a conservative design, a1100 not sure what the span is but I'm guessing quite large? It looks really big. I would imagine as you drop down to a more popular prone foil wing, the % will increase quite dramatically? Or have I got the specs wrong on this wing? How does it compare to say Cabrinha H1050- 1050cm?, WS 1000, AR 9.52, Chord 140mm
a1100 Chord length: 110mm - www.instagram.com/p/CWJIG1ivyTN/

2. The 50% mast immersion I think is possibly misleading (not intentionally). I think that when the drag really matters is when you are low on the mast and trying to recover speed and height. If I understand it the increase in immersion means linear increase in drag, meaning that at the critical moment you have more like a 4-10% increase in drag? Caveat that it seems lower drag % at low speeds, so maybe less.

"""At 0 degrees yaw and 50% mast immersion, a 2-5% increase in overall drag can be expected in the 10-25knot range when using a 19mm mast as compared to a 12mm mast.
As more of the mast is immersed, the percent of the total drag will also increases linearly for a constant section mast"""

It is pretty easy to approximate the drag of the submerged part of the mast but hard to figure out how sections and thicknesses behave differently when near or piercing the surface. There may be additional drag due to surface-piercing that could raise the total percentage of drag contributed by the mast. I'm interested in learning more about this.

Increased water pressure with depth may have an effect as well.
The Cedrus foil section having flat sides for a significant portion of it's chord isn't doing any favors for drag either. I expect that is an area where the new mast could be optimized.

Relating to this topic:
docs.google.com/document/d/10WBFH_4EdQAH116QgkvfjTx6ZNM8SqTgRcJ89zFfjAg/edit

I have nothing to do with the study, just found it interesting. Takeaway is that Cedrus is considerably lighter and stiffer than the Gong aluminum and carbon masts tested, with loading methodology similar to foiling.

Im surprised so much hate for the butt joint. Has anyone ever had a failure? Its simple, stiff, light and reliable. I have some complaints with Cedrus (although the benefits usually outweigh the shortcomings for me), but the butt joint isn't one of them and I fail to understand what the actual issue is.

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Velocicraptor said..
Relating to this topic:
docs.google.com/document/d/10WBFH_4EdQAH116QgkvfjTx6ZNM8SqTgRcJ89zFfjAg/edit

I have nothing to do with the study, just found it interesting. Takeaway is that Cedrus is considerably lighter and stiffer than the Gong aluminum and carbon masts tested, with loading methodology similar to foiling.

Im surprised so much hate for the butt joint. Has anyone ever had a failure? Its simple, stiff, light and reliable. I have some complaints with Cedrus (although the benefits usually outweigh the shortcomings for me), but the butt joint isn't one of them and I fail to understand what the actual issue is.

I haven't had a failure from it but I've had the screws come loose maybe 3 times in 2 years maybe? when it happens the plane becomes a bit unridable as it starts yawing and I've had to end the session (always a good thing when wife is expecting you to be home half an hour earlier ). having said this , I can now just buy the PC multi tool and take out with me and can get passes that issue whenever it happens again.

bare in mind, it has only happened after a few days of pumping hard on super big wings for several days straight and I believe a third screw could help holding the line

My only contribution is that I really like the feel of my Cedrus mast in the waves and at speed on flat water. Compared to 1st Gen Armstrong, axis alu and hi mod carbon. 90kg winger riding 1000 and 800 area foils in medium sized waves off Margaret River. don't have any opinion on drag except I don't feel I need any more speed when coming down some of these wave faces and I feel if I need more speed on the flat or to catch waves I should look at my foil.