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Aluminium vs Carbon Mast - Cost vs Benefit

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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby Flyboy » Thu Jun 24, 2021 7:42 pm

grigorib wrote:
Thu Jun 24, 2021 7:34 pm
There’s difference in riding lighter foil in at least two aspects:
- jumping with a foil (I don’t jump with a foil, but folks say jumping with heavy is not good)
- inertia of heavy setup. Getting hit with heavy foil hurts way more. Felt this one personally
Agree. I can't imagine jumping with an aluminum foil ... & the heavy foil feels like more of a threat if you hit/get hit by it. This is also partly a function of the wing size too. The LP foil I had was super light & had a very thin, light front wing. I had no concerns about being hit by it. So jumping foilers have carbon mast & smaller, lighter wings.

I think the justification for spending extra for carbon is that if you're spending a lot of time foiling, the extra expense is worth it. But carbon isn't a performance game-changer by any means.

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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby grigorib » Thu Jun 24, 2021 7:57 pm

I was trying to sit down on one with aluminum mast and got my butt kicked so hard… :)

I’m sure if I appear in San Francisco race and would be the only person on carbon mast I’ll still come the last. But would the other riders be wishing to get off the aluminum all the time they’re winning - likely yes

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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby Kamikuza » Fri Jun 25, 2021 10:00 am

Flyboy wrote:
Thu Jun 24, 2021 6:52 pm

I already posted a picture of the two masts. The alu mast cord is 4 1/8", the carbon mast cord is 6" up by the plate, tapering to 5 1/8" above the fuselage.

Another session yesterday. Again light wind. I'm a little less convinced that there's much of a difference in stability. The foil still makes little wobbles in the water, which makes me think this has more to do with pressure difference under the water than the composition of the foil.

Bottom line: it seems to me that the cost vs benefit is an open question. It's nice to have a lighter foil, but in practice the weight is barely noticeable when riding. More important is to get a decent foil & just get riding.
Yes, but I'm not going to make the effort of determining chord from a photo :lol:

Ugh, inches. Ick. That's what, 150mm? The orange LF mast is 100mm so I'm guessing the Axis one is no more than 150mm...

When I had the LF and the Axis kite foil, I did a bit of jumping but DAMN all that weight hanging off my knees hurt. Didn't even bother trying to jump with the Alien Air and HoverGlide :lol: and now I'm strapless because I like my ankles as they are, and not in separate pieces...

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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby BayAreaKite » Sat Jun 26, 2021 3:04 pm

I wrote a pretty extensive blog entry on the properties of various materials (carbon, aluminum, steel) and how design affects the stiffness of a mast: https://projectcedrus.com/general/solid ... sites-101/

In short you cannot talk about materials and the performance of a mast independent of design. Carbon is far superior to aluminum by every metric (stiffness, strength, and density) and that is not an opinion, it is a fact based on engineering data. However with poor design, those characteristics can be rendered worthless.
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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby BayAreaKite » Sat Jun 26, 2021 3:23 pm

Kamikuza wrote:
Mon Jun 07, 2021 2:29 pm
nothing2seehere wrote:
Mon Jun 07, 2021 11:35 am
Might have missed this but why is it a myth? Is it the light AND stiff bit? I'm sure I read one of the project Cedrus blog posts where he measured the stiffness of a bunch of aluminium masts to understand what he was up against in terms of competition. I notice that the Cedrus masts are not dramatically lighter than aluminium masts though they are claimed to be substantially stiffer.

I gather the Axis kit is good (difficult to get where I live) but I'm sure the numbers (for weight) I saw looked about the same as the Shinn foil gear. Having picked up the carbon Shinn mast, you can feel the difference in weight and I'm willing to believe that the carbon version is stiffer.
Yeah, light AND stiff is a myth for masts. You can have one or the other but not both at the same time...but apparently the flex is tuned for optimal something something. I'm not convinced ... yet.
I'm sorry but I have to comment on this statement too. Light and stiff is not a myth, in fact there is a material property called specific stiffness which is young's modulus/density. Carbon has a much higher specific stiffness than aluminum. Also it's very easy to have light and stiff, but not easy to add low drag to the mix. This is the tradeoff I made with Cedrus 3 years ago, it was the first mast with increased thickness and therefore theoretically higher drag. It's the same thickness as the Axis aluminum mast, but 30% lighter. It is much stiffer than their carbon mast, but also thicker (hence increased drag). Axis is my #1 selling adapter right now, and every customer says it's as stiff or stiffer than Axis aluminum, and way stiffer than their carbon mast but also lighter than both. So that's not a myth, but a fact. If it would be helpful to see some test data, here's a video from wakethief: https://www.youtube.com/watch?v=auJ2WlxNMfA
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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby Kamikuza » Sun Jun 27, 2021 8:21 am

BayAreaKite wrote:
Sat Jun 26, 2021 3:23 pm
I'm sorry but I have to comment on this statement too. Light and stiff is not a myth, in fact there is a material property called specific stiffness which is young's modulus/density. Carbon has a much higher specific stiffness than aluminum. Also it's very easy to have light and stiff, but not easy to add low drag to the mix. This is the tradeoff I made with Cedrus 3 years ago, it was the first mast with increased thickness and therefore theoretically higher drag. It's the same thickness as the Axis aluminum mast, but 30% lighter. It is much stiffer than their carbon mast, but also thicker (hence increased drag). Axis is my #1 selling adapter right now, and every customer says it's as stiff or stiffer than Axis aluminum, and way stiffer than their carbon mast but also lighter than both. So that's not a myth, but a fact. If it would be helpful to see some test data, here's a video from wakethief: https://www.youtube.com/watch?v=auJ2WlxNMfA
That's not a 100% carbon mast though is it, but I applaud the milking of the best properties of each material. The Axis carbon mast is 100% carbon, though not as stiff and barely lighter than the aluminum version.

In the video there compared to the 19mm the only advantage seemed to be weight...? Which was what -- 600g for 8 time the price? I seen to remember that's relevant to the OP.

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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby Kamikuza » Sun Jun 27, 2021 9:43 am

BayAreaKite wrote:
Sat Jun 26, 2021 3:04 pm
I wrote a pretty extensive blog entry on the properties of various materials (carbon, aluminum, steel) and how design affects the stiffness of a mast: https://projectcedrus.com/general/solid ... sites-101/

In short you cannot talk about materials and the performance of a mast independent of design. Carbon is far superior to aluminum by every metric (stiffness, strength, and density) and that is not an opinion, it is a fact based on engineering data. However with poor design, those characteristics can be rendered worthless.
Well that's what I thought: carbon is a superior material but carbon masts most likely aren't because design and implementation compromises.

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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby BayAreaKite » Sun Jun 27, 2021 2:33 pm

No, it is not 100% carbon and for very good reasons. For example the edges being flexible PVC make them lighter, cheaper, and less prone to chipping and cracking than carbon. They are also safer, and the aluminum mount plate is stronger than the the top mount of any carbon masts (and lighter). So marketing a 100% carbon mast that is inferior to a hybrid design by nearly all metrics makes no sense to me. and 600g is not insignificant! People pay a lot more for less weight savings in a lot of other sports (cycling, sailing, flying, etc). When I used to race road bikes people would spend $2,500 on a set of carbon wheels which weighed 1200g vs. aluminum hoops for less than half the price at 1600g.

Definitely not here to try and convince the price is worth it. That's a very personal decision based on your finances and what makes you happy. But I do want to clarify obvious misunderstandings of mechanical properties, inaccurate data being shared, and the importance of recognizing design. The age old comparable is a Honda Civic will get you where you need to go just as fast as a Porsche 911 if you obey the speed limits, so is a Porsche worth it? For some people, clearly it is. The industry has gotten better at designing carbon masts, as I am working on an Armstrong adapter right now I'm fairly impressed with their mast. It's light and stiff, and I would say worth it over any aluminum mast on the market. Moses also seems to have solved their reliability problems, and the F-One mast has good feedback. Fortunately there are a lot of people who believe Cedrus is worth it, perhaps less because of weight/stiffness and more for the fact that it's 15+ masts in one and they don't need to get a new mast to change their wings, which actually saves a lot of money in the long run.
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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby Kamikuza » Mon Jun 28, 2021 1:45 am

BayAreaKite wrote:
Sun Jun 27, 2021 2:33 pm
No, it is not 100% carbon and for very good reasons. For example the edges being flexible PVC make them lighter, cheaper, and less prone to chipping and cracking than carbon. They are also safer, and the aluminum mount plate is stronger than the the top mount of any carbon masts (and lighter). So marketing a 100% carbon mast that is inferior to a hybrid design by nearly all metrics makes no sense to me. and 600g is not insignificant! People pay a lot more for less weight savings in a lot of other sports (cycling, sailing, flying, etc). When I used to race road bikes people would spend $2,500 on a set of carbon wheels which weighed 1200g vs. aluminum hoops for less than half the price at 1600g.

Definitely not here to try and convince the price is worth it. That's a very personal decision based on your finances and what makes you happy. But I do want to clarify obvious misunderstandings of mechanical properties, inaccurate data being shared, and the importance of recognizing design. The age old comparable is a Honda Civic will get you where you need to go just as fast as a Porsche 911 if you obey the speed limits, so is a Porsche worth it? For some people, clearly it is. The industry has gotten better at designing carbon masts, as I am working on an Armstrong adapter right now I'm fairly impressed with their mast. It's light and stiff, and I would say worth it over any aluminum mast on the market. Moses also seems to have solved their reliability problems, and the F-One mast has good feedback. Fortunately there are a lot of people who believe Cedrus is worth it, perhaps less because of weight/stiffness and more for the fact that it's 15+ masts in one and they don't need to get a new mast to change their wings, which actually saves a lot of money in the long run.
So as it stands at this point in time, carbon masts (as we typically understand them to be) that are lighter AND stiffer are still a myth, you won't notice a 30% reduction in weight while riding, and the answer to the OP's question is still probably "no, unless you like chasing ever diminishing returns."

The future looks promising though.
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Re: Aluminium vs Carbon Mast - Cost vs Benefit

Postby BayAreaKite » Mon Jun 28, 2021 4:42 am

@kamikuza for you carbon masts are not worth the cost. I respect that. But you can't speak for everyone. You can absolutely feel a 1lb weight difference in the mast when foiling... and walking on the beach, and flying commercial airlines with your gear, and starting strapless, and jumping. Weight is the enemy of everything.

I don't know why I have to repeat myself, but light and stiff is not a myth. What is your definition of light? My mast is 30% lighter than the Axis aluminum mast and just as stiff. I could trade more weight for stiffness, for example I could design the mast to be 15% lighter than Axis and 15% stiffer. That is lighter and stiffer. As a designer/engineer I simply chose to allocate more to weight savings than increased stiffness. But the mast is still much stiffer than many carbon and aluminum masts on the market. You will never see carbon masts that are more than 40% lighter than an aluminum mast of equivalent stiffness, so not sure what you mean by the future looking promising. Based on the mechanical properties of the materials it's simply impossible.

So again I respect your opinion that carbon masts aren't worth it for you. Not going to argue. But for some riders, a well-designed lightweight and stiff carbon mast is worth the premium, and they do exist.
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