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Messages - BayAreaKite
Pages: [1]
1
« on: July 29, 2022, 05:56:30 AM »
Thanks @SUS4Life. Asking for a standard test is a lot. I'm just asking for basic proper engineering, and no false marketing. It's not just the foil world. I'm sure many of us are mountain bikers, skiers, etc. How many people do you see walk into a ski shop and pull a ski off the rack and flex it between their hands and feet Another very subjective test. I did notice when I upgraded my MTB to carbon, I immediately felt the stiffness difference. And it was the exact same model bike, just different frame materials. A bit more complicated to measure stiffness in MTB frames, especially full suspension, but it's just as important. @headmount that video was shared to show a more representative testing loadcase for a mast. Pushing on the wingtips will induce a constant bending moment in the mast, and allow you to compare the true bending stiffness of the masts. Assuming the wings and mast length are the same of course. When you really get on the rail of your board and drive hard upwind, or roll your foil wings, this is the type of loading you are putting in the mast. Hanging a weight on the end and measuring deflection/strength is really good if you want to see how strong your mast/mount is when someone lands a trick improperly. It's a good "abuse load" test. That's about it.
2
« on: July 28, 2022, 10:56:36 AM »
hello all, Kyle with Project Cedrus here. I value forums and would rather spend my time clarifying confusion or answering questions, than my money on marketing or google ads. Regarding sealing the mast: I tried closed-cell spray foams and they did not last. I have also seen through experience that most aluminum masts will lose there seal, suffer from water ingress, and even worse, the water won't come out! So I made the decision not to seal the aluminum mast, unless I had a year+ to do proper R&D on a seal that lasts, and let clients address water ingress if it is important to them. Also keep in mind, adding $20 in labor/materials to seal would add 40+ to the final price. That's just unfortunately how it works when you get involved in retail. Finally, I couldn't open myself up to warranty issues by promising a sealed mast. I'm just being transparent. Most brands have reasonably high warranty rates, and thanks to a low cost, can afford to replace a bent aluminum mast or two. I can't afford to replace masts, aluminum or carbon, and fortunately I don't have to. I can tell you for certain that it actually costs more to install my stainless helicoils in the aluminum mast, than it would to buy a complete extrusion from China. But I believe in supporting our community with meaningful manufacturing jobs. As for stiffness, it is not in the eye of the beholder. It is 100% scientific, engineering, objective data. I have tried to explain the proper way to characterize stiffness of a mast, but Adrian at Axis will not listen. And I only use his name because he is open in his latest Blue Planet interview about his feelings of Project Cedrus. Hanging a weight at the end of the mast is not a proper test for mast stiffness. It is a good way to assess the strength/stiffness OF THE MOUNT. The mast is subject to a constant bending moment when being ridden, which if you are not an engineer, you may not understand. Here is just one link if you want to dabble in structural engineering: https://www.constructupdate.com/what-is-shear-force-and-bending-moment-diagram/ The cantilever test that Axis does puts a maximum moment at the mount, with a decreasing moment throughout the length of the mast. It will give you inaccurate direction regarding the actual stiffness of the mast. It's also the main reason so many brands taper masts, because they don't think it impacts stiffness. But it does. Properly testing is not complicated and does not require fancy equipment. I showed Devon at Wake Thief how to properly test bending stiffness of a mast here: We didn't address torsion at this time, but in other videos, he has. I can see how this would easily result in confusion and differing opinions on stiffness. If Axis is using a different test method, they will have different results. Anyone who's ridden a NoLimitz mast has told me it's not as stiff as Cedrus. Is it thinner? yes. Is it lighter? yes. But it is not stiffer or stronger, partly because they too test incorrectly, as evidenced by their own website. I started this project in large part because I was fed up with the marketing in sports equipment, when brands make false claims, especially related to Cedrus, it boils my blood. I am setting up a proper testing procedure and plan to be a guest on Blue Planet to continue showing the world how to design and build a stiff mast as I have on my blog since 2018... Thank you, Kyle @ Project Cedrus with lots of skin in the game
3
« on: November 29, 2020, 01:17:15 PM »
Good video with real-world testing of thick vs. thin axis masts. As expected, doesn't make a difference. In fact, he even claims the thicker mast is faster due to higher stiffness = more energy transfer to the wings. This aligns with everyone's feedback re: Project Cedrus as well.
4
« on: October 17, 2020, 07:10:59 AM »
Admin, thanks for the comments. You are reiterating one of my key points, which is that the wing contributes to a much larger portion of total drag than the mast. With wings you have wetted surface/skin drag, and lift-induced drag. Many of the wings now have a longer span than the length of the mast, which is insane considering where we were only 2 years ago! So yes, shaving 1-2mm from the thickness of a foil wing can have a bigger impact than shaving the same thickness off the mast because the wings are responsible for a larger portion of the total drag. And if we're going to talk about take-offs, you have to consider the drag of the board, which is 100x more draggy than the mast so I'm just going to forget about comments regarding Cedrus and takeoff;) I could certainly do a tapered and even thinner version of Project Cedrus. This is the natural evolution of optimized product design; remember this is only gen 1. One of the things I have loved most about engineering at companies like Boeing and Apple is working with other engineers to converge on a solution that satisfies everyone involved in the design. In the case of Cedrus, I am trying to balance manufacturing constraints (remember, this is the only hollow carbon mast!), compatibility with different wings(!!), environmental concerns (using re-purposed aerospace prepreg), cost, structures, hydrodynamics, and weight. I was also a bit conservative with my first version, because I would rather someone pass on the product because of drag concerns than see pictures on forums of broken masts. Thankfully I was conservative, because the size of wings and boards people are riding these days could not have been predicted 3 years ago when I started this. So if/when there is another iteration, I could certainly taper or reduce thickness. But would reducing drag 10-20% result in a sales increase enough to cover the cost of new molds and tooling? I don't know... not a gamble i can afford to take at this time. Phils, thank you for posting the quote from my blog. I'm glad people read the contents of my site, it has taken a lot of time and effort. As mentioned previously, yes this rider was riding faster Moses wings (633) AND using an older style adapter which made the increased drag more noticeable. One of the many things I have learned on this project over the past couple years is that the adapter design actually has significant impacts on performance and drag. If you look at my Lift and Axis adapters for example, you don't see them... they are recessed in the fuselage. But with Moses, there is a lot going on to get the surfaces to mate in an area that is already experiencing turbulent flow. I have refined all of my adapters over the years to reduce drag... in fact going a little too far with Moses so read that blog if you want a lesson in structures/FEA. The quote regarding thinner masts causing higher lift induced drag is on my FAQ: https://projectcedrus.com/faq/ Basically, if the mast is too wing-like, you can generate lift (drag) which may be undesirable. This statement is from the gentlemen who designed the foils for Team Oracle (America's Cup) and SailGP. I worked closely with him to optimize my mast section. I am not an aero/CFD engineer, I am a structures guy. I cannot explain the voodoo science that's going on in the waters around a foil, in fact even the experts still don't entirely know. But his point was simply that thinner isn't always better depending on the objective. Thanks again for all the discussion. I did not intend to high jack a post on Axis foils, but appreciate the topic came up. Project Cedrus is not perfect, and it never will be. That's the fun part of design and engineering:) I am however thankful that enough people think it's the right product for them to justify its existence and my investment of time and capital. It's been an unbelievable learning experience, and I am honored when someone forks over their hard earned money and nothing feels better than that first ride report which is usually very positive. Thanks again for the discussion and at risk of upsetting mods & admins I will refrain from any more sales pitch, if you can even call it that:)
5
« on: October 16, 2020, 03:49:25 PM »
Thanks for the questions, a couple things:
For sure the loads on the mast will be different if you are under a kite, powered by a wing, or on a SUP. I actually think the highest loads are under SUP, because they are the widest boards, and therefore the biggest moment. The kite results in the lowest forces, because it actually adds lift to the rider (therefore reducing his weight) and also boards are generally smaller. So good points brought up.
Thank you AGK for the feedback on Cedrus.
Dave, one thing that is clearly misunderstood is that a carbon mast should be lighter and stiffer than an aluminum mast. If it's not lighter and stiffer, than it's a crappy design. I didn't say it, cnski did. But he's right. Carbon is 2-3x stiffer than aluminum (120GPa vs. 68GPa) and 40% of the density (1.8g/cc vs. 2.6). There's a reason high performance cars, airplanes, and bikes are all carbon. For some reason the foil industry hasn't really figured out how to make a light, stiff, strong carbon foil. I believe it has partly to do with the fact that they make everything in Asia and spend their money on marketing and not engineering. I am not faulting them for this, it's just the reality of the sporting goods industry. I would not buy any of the carbon masts on the market because as you point out, there is no benefit over the aluminum! Unless you are racing, in which case the thinner masts reduce drag. But this is a small population, which is why I developed Project Cedrus.
I can't compete with aluminum on price. I bet you that $117 Axis mast cost $20 to extrude out of aluminum material and another few $$ to anodize. Project Cedrus is handmade in WA and OR by very skilled technicians who earn an honest wage and work for companies that have high environmental standards. The only way I can even sell it for the price I do is to reduce the distribution chain (no importers, distributors, or retail shops taking a cut). Sadly this impacts volume, but again I can't afford the markups or the mast would cost $4k. If volume were higher, I could certainly bring the cost down. Another story. So when you buy Cedrus you're not just buying a lighter weight mast. You're buying a stiffer mast, a mast that should last a lifetime (I think AGK purchased his in 2018 and has ridden it with Stringy, Cloud IX, and Axis). So it's an investment that can pay off quickly if you like to change your wings around. Is it worth it? I don't know, that's a personal question. I have customers who buy 3 (each a different length no questions asked) and I have guys who tell me it's overpriced and laugh at me. If you spend a lot of time on the water, hate being forced into a new wing attachment ecosystem every season, want something unique, appreciate American made products, then I think it's a steal. If you are happy with your aluminum mast, then stick with it and enjoy the ride! Spend money on things that make you happy:)
Thanks again, Kyle
6
« on: October 16, 2020, 06:06:58 AM »
Pretty much all the carbon masts offered by these companies are crap.
Slight tangent here, but have you tried the https://projectcedrus.com/ masts cnski?
These masts are noticeably draggy
Not to be rude but is that statement coming from personal experience? Sorry I have to chime in on threads like these because my marketing budget is $0. I'd like to make a few comments regarding stiffness. First, 90% of my sales this summer have been to wingfoilers who all greatly appreciate the stiffness. They are able to go with longer masts, ride wider boards, and use bigger wings thanks to the stiffness of Project Cedrus. Secondly, not one of those customers has complained of "noticeably more drag." You can ask any of my Axis customers, which is not surprising because as you point out the mast is a very similar profile. But even my Lift customers (quite a few of them) say they notice no decrease in speeds either despite the mast being thicker than the Lift mast. Again, it is quite a bit stiffer (and actually lighter) so maybe their brains are fixating on the positives vs. the potential negatives I don't know. But the reality is, the mast is ONE component of total foil drag. Most comes from the wings, a large component comes from the mast/fuselage interface, a large component comes from the water piercing section of the mast, and the rest from the laminar (hopefully) flow around the main portion of the mast. The bigger and slower the wings get, the less likely you are to notice drag from the mast. Some of my test riders a couple years (!!) ago riding small Moses wings on kites noticed more drag vs. the Moses mast. Maybe it's time to update the website to more relevant feedback. I am an [honest] engineer, not a sales/marketing guy. Thirdly, beam stiffness varies with the cubic of thickness. So a 19mm thick mast can be 50% stiffer than a 16mm mast. This is why Axis has two different thicknesses for their carbon masts, because the thinner carbon is not nearly as stiff as the thicker aluminum. Drag increases linearly with thickness. The point is, with a small tradeoff in drag you can have massive stiffness improvements. This is how Project Cedrus is able to achieve strength, stiffness, and low weight... all for a few mm of thickness. I made this decision 3 years ago, and a lot of FEA, CFD, and thought/analysis went into it. Quite a bit ahead of the industry, and am glad I did. Because wing foilers now are demanding stiff masts for their wider boards, bigger wings, ability to pump, and bigger loads. Thank you for your discussion and interest, Kyle
7
« on: July 25, 2020, 07:21:34 AM »
I'm sorry I'm out of town this weekend and can't weigh the exact setup you'd like me to give a number for, but most component weights are on my website and my estimate based on them is about 1.6kg for the mast + axis adapter + lightweight plate.
Project Cedrus is designed like any other airplane wing. Wings typically have a front and rear spar, sandwiched by upper and lower wingskins. These create the primary loadpath in all box structures. Foil masts don't need ribs, and in airplane wings they are there to support fuel loads and prevent the skins from buckling. But they are considered secondary structure, as if one fails it is not catastrophic. Even on large commercial jets, leading/trailing edges are non-structural. They serve aerodynamic purposes, creating high lift for takeoff and landing (slats + flaps) or controls (ailerons). The primary structural box has been the basic premise for wing design since the earliest aircraft.
There might be subtle differences between a mast designed for surf/sup vs. wind-powered, but I wouldn't say significant. The wind powered masts definitely see higher speeds and angles of attack in the water and therefore must have a more refined shape. As a kiter heals over and heads up wind, the mast actually becomes a lifting body. It is critical that flow separation (stalling) does not occur and also that the shape not be prone to ventilation. If any of you remember the original orange LF mast, that had a tendency to ventilate under an aggressive rider. Based on my experience and feedback, the surf/wing/SUP riders actually put higher loads into the mast due to wider boards, pumping, and quick changes of direction. They also don't go as fast as the kiters/windsurfers, and typically ride bigger wings, so one could argue drag is much less critical. I designed Project Cedrus for all activities, and feel that it is a good balance. Unfortunately the market is not big enough to offer custom tapered lengths or profiles for specific sports. I have yet to pay off my one set of production molds for one design, but if someone would like to commission molds for their perfect mast I'd be happy to quote the project;)
8
« on: July 24, 2020, 09:38:38 AM »
Thanks Admin. Yes, I was referring to the Axis aluminum mast. Their carbon mast is solid, so they can get away with less chord/thickness. I understand weight may not be an important factor for all. For me (and my 105lb wife) weight is really important and thus it was the primary optimization variable. We have longer walks to the beach, flying to MX with kite gear, and general ease of use improve dramatically with a lighter weight mast. Of course as a kiter on a small board this is a very different scenario than a big SUP.
9
« on: July 24, 2020, 08:54:52 AM »
Thanks everyone, I appreciate the kind words, positive feedback, and good discussion. Forums are really valuable tools for me to discuss and market Project Cedrus, and I appreciate your willingness to let me comment. Regarding drag... the mast is 19mm thick with a chord length of 120mm. This is coincidentally the same profile as the Axis mast. I worked with an America's Cup foil designer (I am a structural engineer, and not a CFD/aero expert) to optimize the section shape for stiffness, strength, weight, tendency to ventilate, and drag, in that order. The only people who have noticed the increased drag are kiters coming from small and fast wings (typically Moses) mounted to my mast. But at the same time, they are grateful for the increased stiffness so the tradeoff was worth it to me. My lift customers notice no reduction in top end speed, as those wings are a slower than Moses. So it's definitely wing-based, which makes sense as mast drag is only one component of total foil drag. 3 years ago I saw the direction of the sport towards bigger, slower, high lift wings, for which I designed Project Cedrus. Now the other brands are trying to catch up with stiffer masts, which will come at the expense of speed. I have a post related to drag here: https://projectcedrus.com/cedrus-development/aero/Regarding stiffness, this is an area that I consider myself an expert in. You give up very little stiffness/strength by going with non-structural leading/trailing edges. That material is closest to the neutral axis of the beam, and therefore not contributing much to torsional or bending stiffness. I am confident, based on benchmark analysis and testing of various masts that Project Cedrus is the stiffest mast on the market. The Axis aluminum mast is up there as well, but 2x+ the weight. The safety aspect of the non-structural edges is only one. The primary reason for soft plastic edges is damage tolerance and durability. I got tired of repairing foils and fairing the edges after rock chips or damage due to flotsum. In larger quantities there would be more of a cost savings as well, but because I'm small batch production it's not really a $$ thing. A similar post on structural sizing can be found here: https://projectcedrus.com/cedrus-development/sizing-analysis/Happy to answer any additional questions and thanks again for the positive feedback from my customers. This is a labor of love for sure, thank you for your interest and openness. Kyle
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