Working out the numbers as a first time efoil builder

Hey guys, I’ve been lurking in this forum for quite a while now and I’m slowly getting ready on building my first efoil. I’ve built FPV drones and a couple of hobbyist-level microelectronics in the past (working as a software engineer), so the process is not intimidating. However, I got a few questions that I couldn’t answer by googing.


It seems that building an efoil is pretty straight forward; there’s only 1 motor and a big battery.
Please correct me if I’m wrong, but It should go like:

  1. Calculate how much weight (your body)
  2. You need to push, for how much time
  3. Under what kind of conditions

… and start working out your build

Well,

  1. I’m at 95kg
  2. I hope to get around an hour ± 15m of good time
  3. And I’m located at Greece. So there might be a few < 0.5m waves, nothing crazy (for now… we got a lot of kitesurf spots which I think I’ll avoid) I’m just doing SUP until now.

So, now that we got those requirements, it boils down to selecting a capable board w/ foil, then selecting a motor capable of producing enough burst thrust to get us up in flight mode and that can sustain enough load to keep us going for about an hour. Building/Picking a battery should be pretty straightforward. Cells in series to meet the power output X cells in parallel to meet capacity. (And hopefully 5kgs won’t destroy the dynamics of the rest of the system).

So, is there any recommendation on what kind of board w/ foil to use for those circumstances?

  • gong allvator rise (XL) that I’ve seen getting mentioned a lot doesnt support >85kg if you look at the infographic, but provides a lot of thrust for just wing foiling.
  • I’ve also read about rules of thumb like “> 1750cm^2” wings for >95kg surfers, so It’s just hard to select some thing for sure. Not having any formula involved makes the thing way complicated and empirical
  • Plus, how big of a mast?

Okay, let’s say that we’ve selected our surfboard and our foil. Got to select a motor and everything else would follow. I see that there are a lot of flipsky builds around here so I took a look around that. I see people using 130-200+ KV motors and I got a few questions:

  • For the very big 200+ KV motors that some of you guys use, WHY do you do it? It’s nowhere near the max voltage range of the fattest 14-15-16s battery packs and you should be unable to go above 60-70% sustainable load!
  • For the very small 130ish KV motors (down to 6s! 4s was my drone, man!), I understand that it’s sufficient for assistance (to get up) or sup. Why is it mounted higher up on the mast on some builds though.
  • Let’s say you get like the 65111 160KV motor. It’s IP68 rated! They’re being sold as waterproof, but are there any steps to take vs. waterproofing and salt corrosion?

That’s a big thread already, and I should be able to make enough progression towards picking every component after getting those questions answered! Thanks In advance guys :pray:

PS. Those maytech remotes are kind of expensive, aren’t they? I’m surprised there’s no easy-to-make open source (software+hardware) alternatives out there…

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