Got me one of these from a guy in Naples, Italy:
I’m hoping to learn pump foiling in a decade or so, and it’s all about the gear, right😄
So, i need a sabfoil to gong fuse, first thought about making an adapter but the mast is right on top of the wing which makes it impossible. I think it’s designed like this to facilitate easier pumping so it’ll be a great opportunity to try a fuse build.
Started from some pics and sketches of the original fuse setup
Unfortunately they weren’t entirely correct so i had to make quite a few 3D prints and iterations before reaching a mature design.
Now i’m sketching the molds for it. Will take a few iterations to get the offsets right… it’s WIP:
Which mast are you planning on using? The gong alloy V2?
Yes… i know it’s not recommended with this kind of monster wing. We’ll see how it performs in the end.
Why not shift to axis masts and then just have a custom fuse for your gong wings?
I’ve actually done it this route. Means I have endless options too as I can run gong, axis and Unifoil wings very easily with the adaptors.
Lars, sorry but this will not work. I started pumping too, and have a sirus xxl (156cm span) and started with a gong V2 alu mast. Impossible! It was a 95 mast, so maybe a 70 might work, but these wings easily flex the mast, so that every steering input first flexes the mast, and then the wing slowly starts to bank. This is impossible to ride (at least for me)
No I have the HM CF mast
Thanks for the input. I will probably have to switch to Axis 19mm as Jezza proposed, anyway had these in mind for some time 
I have done the axis to gong fuse.
If you need more info on the dimensions let me know!
I used a cnc (manually operated) to get it right. But it might also be possible with hand tools
Sirus 136 works with alloy. Mast 75cm. My friend used it for quite a while. I read reports that the fuselage breaks with wings over 150cm. So a Toten fuselage is advised
If gong alu fuse breaks with wings above 150cm then my project is in danger. Maybe i’ll have to add a sleeve up towards the mast so that design is more like a fuse with integrated doodad
Trial molds are on the way, one left to do. I plan on making the structure like this:
-One bottom shell, UD fibre to 1mm
-One top shell, UD fibre to 1mm
-Demoulding and trimming of the edges
-Filling the internal voids of the halves with epoxy plus fibre
-Assembly of halves and wrapping the complete fuse in carbon braided sleeve.
-Drilling holes and assembly of inserts
-Additional layers of carbon
-Finishing
Did molds and a molding, unfortunately i got the fabric thickness wrong and this screwed up my upper/lower half concept. I tried to join it but the result wasn’t good enough, the recess for the doodad is tricky since angles there are so steep.
Yes Gong says you have to use the titanium fuselage for all those super wide wings that’s why they made it the alu one is not strong enough too much leverage on a super long wing if you hit something.
I read that, hard to believe. The gong alu fuse is overly thick so if that cannot take the load then either their doodad design isn’t good or my carbon fuse won’t have a chance to hack it. We’ll see. Anyway, these thin wide pump wings will break easily if they hit something too…
It is hard to generalyse but thin HA wings are made from prepreg and contain a high percentage of carbon, otherwise they would break during normal use. Therefore I don‘t think they break easily. My north sonar ha didnt break when I hit an underwater concrete block at low speed, but one stainless M8 bolt got bent.
I think the mast has to be stable with HA wings, especially with masts of 80cm and above.
It may be overly thick but its not a fantastic grade I don’t think. The other brands that use 7075 and 6061 grade don’t have problems with large wings. I cut my gong fuselage on my CNC and it cuts like butter.
True, could be some chewing gum grade of alu. I threaded one and it’s certainly softer than 7075T6
Just got an Axis mast, bought one from the UK and selected cheapest shipping possible, it took forever to reach me. If you can share the needed dimensions and modifications i’ll be forever grateful 
Some slow progress on this one, i started to modify a goong dodad to make it work with axis masts but the result seemed to become too much of a hackjob. I’ll order a CNC:ed Axis to Gong doodad.
3d-printed fitting after some design loops:
I don’t spend a lot of time in the sea now but hope to do so - wonder if anodising is mandatory for 7075 alu? Been reading up on it and for longer term definitely but these things don’t get a zillion hours of use. Does anyone have input? @jezza ?
