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Open Fuse

Here you can exchange your experience and datas about your home build boards
tomtom
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Re: Open Fuse

Postby tomtom » Thu Oct 29, 2020 12:42 pm

Why do you think are so few carbon fuses? Do think that mill fuse from solid alu block is cheaper than composite? It is very difficult to make rigid enough composite fuse.
Why do you think mast fuse connection is so important if there are low forces? Im speaking from direct experience with torsional noodle fuse it is borderline unridable. I was trying to make lighter composite fuse for moses.
It was very very stiff longitudinal and flexier than original alu in torsion.

fluidity
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Local Beach: Ngati Toa, Plimmerton, Titahi Bay, Waikanae, Petone, Seatoun, Lyall Bay, Eastbourne, Lake Wairarapa
Favorite Beaches: Plimmerton
Style: Wave, jump
Gear: Late model Switch kites element and nitros,
DIY CAD ultra-concave wave twintips 1500 and 130mm with my own fin designs. Easy upwind, awesome carving. Switch Nitro 10m V7, Naish 5.3m Wing. Now focussing on Wingsurfing to rise to a new challenge. Building my own foils from my CAD design and 3D prints, built a CNC machine last year and now cutting designs with CNC as well as 3D printing.
Up to 3 DIY foil designs built and getting the hang of wingsurf foiling as we switch into 2021.
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Re: Open Fuse

Postby fluidity » Thu Oct 29, 2020 6:19 pm

tegirinenashi wrote:
Wed Oct 28, 2020 7:34 pm
Torsion is proportional to the beam length. For fuselage we are talking about 20 cm or so of the length between the main wing attachment point and the mast. I have hard time believing that this fuse section, which is supporting the full rider weight, might be weak on torsion. Second, what is the cause of torsion on the fuse? The difference between the lift of the right and the left wing. Those are always balanced (or are closed to balanced during maneuvers). Because if they are not balanced, the foil would rotate wildly and rider will fall. Finally, the cross section of the fuse is typically more than 20 cm -- much thicker than typical thickness of the mast. I don't know -- you have to really make an effort to manufacture 20 mm wide torsion challenged rod.

To summarize: I have seen noodle masts. I have yet to see noddle fuse.
If using composites then layup of fibre direction is very important. Torsion is almost irelevent for the stabiliser as it is so rarely exposed to torque. and when it is, like bumping a rock etc, being able to twist away is a plus.

For the mast/front wing this is critical though. Tortional rigidity here results in a stable ride and ability to handle the inevitable high loads of tip breaches and landings. In composite layups you can get this tortional rigidity from braids, double bias, triple bias or custom hand layup of carbon tow.

fluidity
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Posts: 391
Joined: Sat Mar 19, 2016 11:20 pm
Kiting since: 2015
Local Beach: Ngati Toa, Plimmerton, Titahi Bay, Waikanae, Petone, Seatoun, Lyall Bay, Eastbourne, Lake Wairarapa
Favorite Beaches: Plimmerton
Style: Wave, jump
Gear: Late model Switch kites element and nitros,
DIY CAD ultra-concave wave twintips 1500 and 130mm with my own fin designs. Easy upwind, awesome carving. Switch Nitro 10m V7, Naish 5.3m Wing. Now focussing on Wingsurfing to rise to a new challenge. Building my own foils from my CAD design and 3D prints, built a CNC machine last year and now cutting designs with CNC as well as 3D printing.
Up to 3 DIY foil designs built and getting the hang of wingsurf foiling as we switch into 2021.
Location: Porirua New Zealand
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Re: Open Fuse

Postby fluidity » Thu Oct 29, 2020 6:36 pm

tomtom wrote:
Thu Oct 29, 2020 12:42 pm
Why do you think are so few carbon fuses? Do think that mill fuse from solid alu block is cheaper than composite? It is very difficult to make rigid enough composite fuse.
Why do you think mast fuse connection is so important if there are low forces? Im speaking from direct experience with torsional noodle fuse it is borderline unridable. I was trying to make lighter composite fuse for moses.
It was very very stiff longitudinal and flexier than original alu in torsion.
I'm not so sure that milling from solid aluminium is more expensive actually. I was checking out CNC operator and programmer wages and they are rather unexciting.
Cost of the aluminium vs carbon/epoxy is favorable.
And I'm a newb at CNC but even with my setup and inexperience I can already see that these can be fast cut operations in 2.5D if using trochoidal milling with auto tool change and a variety of bits to get the right curves, flats and holes.
Speed is also dependent on spindle motor power and steppper motor drive power, drive voltage. A large sheet of 25mm thick aluminium could be filled with fuselages nestled next to each other with tool changes only on completion of all that sheet's use of prev tool on that side.
If you haven't encountered trochoidal milling yet, it's like moving a saw around the work piece to cut at different angles, only it allows better tool insersion lengths, less tool heating and potential to work without lubricants.

tomtom
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Re: Open Fuse

Postby tomtom » Thu Oct 29, 2020 11:26 pm

Alu milling is cheaper but not that much than composite. That was my point. Nothing like alu mast extrusion vs composite mast. With composite is very hard to reliable and repeatable get real word isotropic properties which you need for fuse.

fluidity
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Posts: 391
Joined: Sat Mar 19, 2016 11:20 pm
Kiting since: 2015
Local Beach: Ngati Toa, Plimmerton, Titahi Bay, Waikanae, Petone, Seatoun, Lyall Bay, Eastbourne, Lake Wairarapa
Favorite Beaches: Plimmerton
Style: Wave, jump
Gear: Late model Switch kites element and nitros,
DIY CAD ultra-concave wave twintips 1500 and 130mm with my own fin designs. Easy upwind, awesome carving. Switch Nitro 10m V7, Naish 5.3m Wing. Now focussing on Wingsurfing to rise to a new challenge. Building my own foils from my CAD design and 3D prints, built a CNC machine last year and now cutting designs with CNC as well as 3D printing.
Up to 3 DIY foil designs built and getting the hang of wingsurf foiling as we switch into 2021.
Location: Porirua New Zealand
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Re: Open Fuse

Postby fluidity » Sat Oct 31, 2020 2:25 am

Pretty stoked with my new wing. Still needs a proper fill, coat and polish but there's enough foil under my weight now that it's properly responsive to pumping.
I've gone from approz 1820 sq cm to over 2600 sq cm and over the last few weeks I've also personally dropped from 110kg to 104kg with some pretty committed dieting. I was out today in around 20 to 35 knots, at times my wind wing felt clearly overpowered but standing up, even in big chop was again easier with the bigger wing and the nice solid mast, fuselage and wing connection. The windage on the big 6 foot 6 F-one inflateable and the squalls being past the Naish 5.4 wing's range added to the fun. I'm really looking forward to something more around the 16 knot range after polishing the foil to see how I handle it in calmer conditions. No handy lakes here.

The flexibility of the glass fibre rod to the stabiliser feels fine but I think I need another degree or two in the stabiliser to properly counteract the new bigger wing.
At the moment' it's very close to a level glide without me on the board. Because I'm doing all the designs fresh I don't have any commercial products to compare my setup to.

However... I want to change the design of the stabiliser support stalk and switch it out for a square cross section carbon fibre rod around 12mm to 14mm square.
The machining to fit a square rod is super simple.
Attachments
20201031_103758.jpg
20201031_103747.jpg
20201028_195324.jpg
Using 3D printer hot end heater to straiten fuselage socket.

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downunder
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Re: Open Fuse

Postby downunder » Sat Oct 31, 2020 12:25 pm

tegirinenashi wrote:
Wed Oct 28, 2020 4:18 pm
That's right: tubes; 6mm outer, 3 mm inner diameter. It is the common structural engineering wisdom that the inner part of the bar/tube/strut is useless for the bar strength. Then, you may ask why not to use just a larger diameter tube? This is because I can glue relatively short 500 mm rods in overlapping Lego fashion. The fuse at the picture is 700mm and its tail is just 2 by 2 rods wide, while the nose is slightly more substantial:

fuse2.jpg

fuse1.jpg

I admit that even though those 6 mm tubes alone seem quite bending resistant, I have no idea how good they are in respect to torsion. Keep in mind however that, first, they are glued together, and then wrapped into carbon sleeve with carbon strands doing about 45 degrees -- perfectly aligned against torsion. Besides, is torsion really a problem for the fuse (as opposed to mast)?
Overthinking?

On my pic above, the fuse is a wood wrapped in few 45/45 carbon layers, with slotted mast connection. And that connection again wrapped in few.

It is so strong when I stand on it, it does not bend.

I even tested torsion, and it is on par with Moses! There is a pic on this forum with exact figures.

So, wood all the way. Wrapped. Cheap, simple, easy to replicate.

fluidity
Frequent Poster
Posts: 391
Joined: Sat Mar 19, 2016 11:20 pm
Kiting since: 2015
Local Beach: Ngati Toa, Plimmerton, Titahi Bay, Waikanae, Petone, Seatoun, Lyall Bay, Eastbourne, Lake Wairarapa
Favorite Beaches: Plimmerton
Style: Wave, jump
Gear: Late model Switch kites element and nitros,
DIY CAD ultra-concave wave twintips 1500 and 130mm with my own fin designs. Easy upwind, awesome carving. Switch Nitro 10m V7, Naish 5.3m Wing. Now focussing on Wingsurfing to rise to a new challenge. Building my own foils from my CAD design and 3D prints, built a CNC machine last year and now cutting designs with CNC as well as 3D printing.
Up to 3 DIY foil designs built and getting the hang of wingsurf foiling as we switch into 2021.
Location: Porirua New Zealand
Has thanked: 29 times
Been thanked: 41 times

Re: Open Fuse

Postby fluidity » Mon Nov 23, 2020 5:25 am

Update:
I've been improving my uptime a lot over the last two big wing sessions. Enough to now be able to compare the ride quality from the small wing(where I was mostly riding only on my knees due to it needing to be nuking to get lift, then super choppy) and the big wing. Small wing has a glass fibre reinforced wood core. Overkill stiffness. Big wing uses my openfuse design with a 12mm diameter pultruded glass fibre rod. I can get up on the foil fine, glide fine but as my speed increases it feels like the stability drops off. I've had enough time up on it now that I'm certain this is the flexibility of the rod working against me. Likely it would be fantastic for pumping but I'm on a 7 foot 6 inch inflatable board, no foot straps, learning and there's no pumping happening yet! :lol: I'm more concerned about maintaining stability and height over waves of more height than my foil mast and close together.
The aliexpress 12mm x 500mm titanium round and square rods are in transit still, likely I'll see them in the next couple of weeks. I'm expecting around double the stiffness on the titanium round rod vs the pultruded glass fibre rod which should make a massive difference, it should take a lot more to flex with my (currently 103kg) weight. If the 12mm round rod in titanium isn't enough I can switch to the square rod and likely get about another 30-40% stiffness.
The square rod is actually preferrable for CNC cutting of the main fuselage module as it's a simple square cut socket.


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