Problem with lateral stability with my first diy efoil despite extensive foil experience

efoils – Electric Hydrofoil Surfboards
1

hello I just made my first efoil flight (200-300m, first turns) on my first DIY efoil, (flipsky VESC 75200, flispky 65161 motor 120KV, fliteboard propeller, lipo 6S turnigy 20A in serie= 12S 20A, foil gong curve LT 1500cm², stab kite 45 , gong mast V1 80cm, board: gong zuma 6.6 120L), but I find the lateral stability (in roll axis) very destabilizing and difficult to manage, with the impression of having a left/right oscillation all the time. (yet I am an experienced foiler, 5 years of kite foiling, 1 year of wingfoil, + dock start).

could this be due to a V1 gong mast that is too flexible? or maybe the board too long (Gong Zuma 6.6 120L)?

The good news is that my first diy efoil is flying well with only 1100W in flight mode, and 2200W to get it flying. (my weight 70kg)

Thank you for your wise advice

2

I have the 65cm v1 mast and it sways a lot just in the mast but in addition to this the mast plate used to have play in it. I glued it tight with epoxy glue, that made my setup rideable. With an 80 mast i’d guess it’s a lot more flex so i think those are your issues! My board is 150x56cm and your larger board size will probably also have some effect but i don’t think it’s the main problem for you.

3

thank you for confirming my intuition
I also saw that there was a lot of play in the mast plate, I’ll try to fix that

For those who have a gong V2 mast, do you have the same sway problem?

4

The main problem (90%) is the slop in the mast plate if you have this. The flex is there but doesn’t bother me since i fixed it on my setup.

5

The V2 mast is defenitly better, but you kite stab seems to be the bigger problem

this stab will give you much better roll stability

6

not sure if the stab is the problem, my issue is more the sway (very distrubing when riding) than the stability. I also have rise 45cm stab, but for wing foiling i really prefer kite 45 cm which glides more, and doesn’t seem less stable than rise 45cm. For efoiling I think that kite 45cm stab is much more efficient.

Maybe I will try rise 45 cm for the next efoiling session

Thanks

7

thank you very much Larbs for the relevant advice. I will try to stiffen at the top plate level. I don’t have any epoxy glue, I was thinking of trying to put a thin strip of metal between the mat and the plate, or very hard plastic, do you think that can work?

If I manage to find epoxy glue, what is the procedure ? (remove mast from top plate, insert 10ml of glue inside the plate, insert the mast quickly before the glue dries. Or add the glue on the mast and then insert the mast in the top plate ?)

8

I think the epoxy is the easiest. Cover the mast outside and base plate insides with glue, push mast in, wipe off the excess glue that’s pushed out. Mask all parts you want to keep free from glue, like holes, threads etc. I like electrical tape for that since it can be stretched to follow shapes.

My two epoxy seal jobs have eventually started to crack a bit but there is still no play. It could probably be fixed with a metal strip in between the parts also but i would be concerned that it jams before mast is inserted fully.

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