I have noticed many advanced (Pro) riders using aluminum fuses. Just wondering if the change from carbon and added stiffness is noticeable and worth it?
For Ketos they don’t recommend using their carbon fuse for pumpfoiling.
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Gong has Aluminium, Carbon and Titanium fuse.
Their pros (and if you’re using their biggest foils) use the Titanium version.
Stiffness/drag = SS or TI
Stiffness/weight = carbon
In between and cheaper = Alu
Max performance for surf foil would probably be f one/lift style, max performance in speed is probably more like levitaz/omen
Price/performance Alu is the clear winner.
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Im riding a north setup - i think the only brand with both aluminum and carbon fuses - and i was able to test both.
I found the aluminum much heavier - and also much stiffer than the carbon. For me, in my riding, i find stiffness to be very important and weight to be almost irrelevant. I’ve also found that as we make some parts stiffer (masts, boards) it puts more pressure on other parts of the equation. I think carbon fuses were fine a few years ago but now that masts have improved they’re the weak link.
I’ve also cracked alot of carbon fuses so i really prefer aluminum for durability. The corrosion with aluminum can be in issue for alot of people - particularly how it reacts with carbon - but i have strategies for this. I don’t really change wings ever and i leave my setup assembled with marine sealant on all connection surfaces.
Design is also a factor. There are better and worse designs for both materials. I wouldn’t have guessed it a year ago but the north bolt on front wing is a fantastic design. There is a sight concave where the wing attaches and that allows the carbon to pre-load with bolt tension eliminating all connection movement on the aluminum fuse. Its honestly the stiffest setup i’ve ever put hands on. (And i’m agresive when i put my hands on foils). I’m also riding a custom mast that i potted into the fuse. I don’t think you could expect the same performance out of an aftermarket mast’s adapter. If i was riding a cedrus i’d be spending alot of money on custom stringy fuses (to run without adapter)
My recomendation is to put hands on alot of foils. Be agressive, push and pull on the frontwing (throw a foot up on the board for leverage!) FEEL how the thing moves - you won’t break it - foiling loads are HUGE compared to what your hands can do. Feel a bunch of setups and make your own call.
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Thanks for your response. I’m currently on Unifoil, which offers both carbon and aluminum. (Kited on Slingshot and eventually started my prone journey on them as well. Aluminum mast and fuse) I’ve been on their gear (Uni) for over a year now. (Tried Cloud 9, didn’t like it) I’ve progressed to the point where the stiffness of the fuse will probably make a difference. Pumping along with aggressive turns.
I’m fine with a few extra $ here and there to improve feel and performance.
I’ll probably pick up the Aluminum fuse.
Thanks again
Oho I was really talking about the mast to front wing part of the equation. In this particular scenario I’d go carbon just from a corrosion perspective. It’s not an area where the stiffness of the aluminum is an advantage and something tells me the fit of the carbon part is superior.
Gotcha. The mast to front wing would still be carbon. Fuse goes into the back of the front wing. I know I used to always break down the Slingshot setup, for fear of corrosion. Slingshot: Aluminum mast to carbon front wing, Aluminum Fuse to rear of front wing. Stainless hardware. Always broke it down, most would be 3 days in a row.
Correct me if I’m wrong, but marine sealant is an adhesive right? So you’re gluing your aluminum parts?
I had trouble finding Tef-Gel so I’ve been using silicone based faucet grease for my Unifoil aluminum mast and fuselage. Seems to work great but needs more frequent application than Tef-Gel, about once every week or two.
For some parts I’ll used a polyurethane sealant (like 4200) if in planning on disassembling on a 6 month timeline and it’s something that isn’t going to get stuck (like a long tapered connection like gen 1 Takuma). There’s a product that is used to help dissolve polyurethane sealant called marine De-bond that makes breaking things apart and cleaning old sealant easier. 4200 is going to secure and stiffen wiggly connections as well as keep water out by displacing any gap it might fill.
For those long tapered connections like that Takuma I’ll use silicon sealant. I’ll also used silicon sealant for things I might want to take apart more frequently. Silicon is soft and not so sticky and comes apart easily. It does however leave a persistent residue that can make future repairs impossible so don’t ever use it on a board. Silicon sealant is just going to keep water out and displace any gaps it might find its way into
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I just started using the aluminum fuse for Unifoil and I have found that it adds a little extra snap in top turns. Personally I will most likely use aluminum over carbon in fuses going forward too. A little extra weight I suppose but if it gives a little more snap in action I am in.
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Holy smokes! I only ever thought of aluminum’s stiffness as being a factor on the front wing but I guess it can be a factor for the stab as well! What’s the fit like on the aluminum? I found my uni carbon fuses to be not great for fit(always had a little wiggle even with fasteners)
That’s an interesting observation, are the aluminum and carbon versions identical in profile/thickness? Can you feel any difference in stiffness if you push hard on the fuse? The loads on the stabilizer can be surprisingly high, 100lbs of downforce is well within the expected range so flex does come into play at least at the top end. I’m curious if the feeling you have has to do with flex or the shape/profile
I have never had issues with fit on the stabs and certainly no issues on my aluminum
I have a short aluminum and a medium carbon to compare thickness etc so they are different anyway. Again I just notice it in the last section of a s turn. Kinda like comparing a Carbon surf fin to a glass surf fin. Just a different feeling release.
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I’ve been dreaming of the perfect fuselage lately. Titanium machined to connect to an AXIS or AFS style mast and either AXIS Black or AFS Enduro wing connection. Then behind the mast glued on carbon tube for the tail mount. I want the ultimate in stiffness with the least drag and Ti should get that for the front wing, but for the tail being unable to make a Ti fuse hollow is going to be a massive weight hit (and super costly). Carbon tube would bond very well to the Ti.
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I thought carbon fibre was stiffer than metals, hence the move to carbon in planes and high performance cars.
Carbon is far better than metals per weight, and better than Aluminum per thickness, but worse than steel per thickness. Most published properties are based on pure fiber but all carbon parts have around 40% epoxy, so the properties are already reduced by that much. Additionally, since carbon is anisotropic, you need to have layers that are in the direction of expected loads - a mast for instance will be around 50% 0 degree for bending loads and 50% 45 degrees for torsion. So if you have HM carbon that is ~300 gpa tensile modulus along the fiber direction, you lose 40% of that to the matrix (@ 60% fiber fraction) and another 50% to the off axis plies. this means that in bending you only get around 30-40% of the theoretical stiffness if you applied the pure carbon properties. That’s still stiffer than aluminum at 69 gpa, but nowhere near steel at 200 gpa and of course much lighter
That’s not a perfect calculation, but it points to the issue, particularly with a part that has complex bending and torsional loads like a fuselage. Steel or aluminum are isotropic and don’t care about loading direction
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Kane posted a great summary above. On the relative advantages of each material. It’s all about trade offs and there is no clear “winner”.
In general, it makes sense to use as much carbon as practical on aircraft since it has the highest stiffness to weight ratio. On a foil’s fuselage it is not so straightforward since rather than rely on a skinned airframe we are dealing with a solid part that is flowing through water.
Although a solid carbon fuse would be stiffer than a solid Al/SS/Ti fuse of the same weight, the carbon fuse in this example would have a great diameter and therefore create more drag.
So the material choice is ultimately determined by a designer’s priorities.
This is how Adrian from Axis has explained why they won’t produce a full carbon fuselage. It would need to be thicker to take the loads and thus result in increased drag and performance loss.
Reading between the lines there is experimentation regarding the use of a titanium front section and carbon rear. Titanium is light weight and corrosion free but too expensive to make a complete fuselage out of. Time will tell if we ever see an offering like this.