Got some scales as I was curious about the total weight myself…
It is heavier than I whish, 22.2kg without batteries, so 26.2kg with the small 16000mAh Lipos and 27.4kg with 20000mAh Lipos. With 12s12p, it would be close to 30kg. The Pod and the mast/fuselage/wing are quite heavy, there is some potential. The contactor also adds 500g. Alu plate for passive cooling weights 1.3kg.
What do other setups weight? I know some are even over 30kgs.
Did two test rides, still learning but today I managed to fly while lying on the board, lots of fun. It seems I have an issue with my duct, it is probably too soft because the propeller scraped some layers of it off. It happened twice, I replaced the duct and happened again today. I didn’t hit anything, the duct must somehow deform and then touch the prop. It is 3D printed in ASA-X. Prop is cnc’d aluminum, trailing edges are quite thin/sharp. Distance between blades an duct is around 1mm.
Any idea why this happened?
Not sure how thick your duct is, but it could deform during a changing flow while manoeuvring (up/down left/right). 1mm is quite a tight tolerance. Out of the water it is free spinning?
If you have the duct, spin prop, and by hand can very easily warp it so it touches then it is not rigid enough.
I also have a pretty thin duct and placed a layer of fibreglass on the inside and outside. Made it very rigid. My gap is about 2 to 2,5mm.
Yes it’s free spinning, duct is about 6mm at the thickest spot. I can push it so it touches the prop but it takes quite som force. The question is wether the round hull around the prop deforms or the struts are too weak and bend. I think if I do as you suggested and cover just the tube inside and outside with glass or carbon it should be stiff enough. I guess its try and error.
Or print it in different material like petg or some carbon reinforced material.
I also put a layer of carbon on the outside of the duct and put 2 layers of fiberglass on the fins to stiffen them. This reinforced the duct well. I haven’t been able to test it in water yet.
To strengthen the ribs of the duct I have printed them hollow, with a through hole of 3.3mm. In this hole I’ve epoxied an carbon rod of 3mm, huge difference in strength. Next duct I will do the same and make the ribs thinner.
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Thanks for your suggestions, I’ll try to cover the outside with carbon and put 3mm carbon rods into the struts. Wasn’t that easy to get those holes into the struts in fusion (still easier than drilling them out).
It’s printing so I hope for a good result and that I don’t break the struts when removing the support.
Nice, good luck with the mods after printing
Very nice. We can see the NACA airfoil section for the six ribs. Which section did you use for the main shroud ?
I should have stated that the duct itself is not my work it’s @pacificmeister’s parametric duct, I just adapted it to fit my prop. I looked it up in the file, it’s a naca0012 profile, 6mm thick.
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Hey Daniel,
thats looking amazing!
I tried to find that inflatable board you are using from aliexpress, but could not find it.
Do you got a link to it?
Daniel. What is the size of the lid (the round one), and did you make this or is it a commercial one? The biggest commercial round lid I found was 8". Unfortunately way to small for what I need it.
It’s from alibaba, I got a prototype for 210$ plus shipping to CH (95$) plus tax = 350$ in total
Thank you a lot!
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It is 8” from ali express, opening is 180mm and it is 100% waterproof.
US $8.81 37％ Off | 4 Inch/6 Inch/8 Inch Anti-slip Hand Hole Plastic Round Marine Boat RV Hatch Cover White/Black Screw Out Deck Inspection Plate
https://a.aliexpress.com/_dXJxKRW
It was the biggest one I could find, you need to split the battery to fit in.
Thanks Daniel. Yes I’ve seen the 8" versions. Unfortunately they are to small for my jetboard. I’m now using a PVC draining cover. The hole is 9 1/2 ". It works perfect (100% watertight), but looks so ugly.
you could put some pva anti slip pad on it.
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Weight per part.
To see the potential for weight reduction, I weighted the separate parts.
You can see that the board, top plate/box plus front bottom plate are ok (weight is without batteries).
ESC box with Aluminium passive cooling plate/mast/fuselage pod are too heavy. Wings are on the heavy side too.
Potential for weight reduction:
AS150 as on/off switch instead of forklift relay: 500g
Direct drive instead of geared setup: 2kg for outrunner in wet, 1kg for 65161
Mast/fuselage/wing: 1.5 - 2kg
Replace passive cooling alu plate, and cool with water (no pump): 1kg
The heavy weight has one advantage: It won’t flip over easily so it’s less likely to fall on the mast or wing…
Looks good with the carbon inserts!