Weight of the build in kg:
Board 6.715
Ropes 0.135
Battery 11.04
Esc 1.125
Mast + Motor 4.725
Foil 2.715
Total 26.455
Are there any experiences with a smaller motor?
For my built I’d like to have just a relaxed cruising speed, with a 120l board, an big beginner foil and 80 kg rider, so I’m also looking for a smaller motor .
Not yet, but I plan to test a smaller motor and ESC. I’m choosing between a 6384 motor with an FS 75100 ESC and a motor with an integrated ESC.
I have not really started my next build yet, later this year when the weather gets cold.
There are plenty of eFoil builds that have used the 6384 motors, it’s probably a safer choice compared to a 65121 if you want something small. I’m about 62kg and I usually use under 2kW to take off, so I think I can get away with the weaker 65121, but I have no experience with it yet.
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Thoughts on the 65111?
Had a super long day today! Charged the battery to 87% and rode for 2 hours and 45 minutes. Ended with the battery at 28%. Now I’ve got some serious foil skills and can ride for ages without crashing. So tired but got tons of data!
Here’s what I learned: max power use is 1400W at 23A against strong winds and 1250W at 20A without wind. For cruising, I’m usually at 1000W and 17A.
Swapped my ESC from a 75200 to a much smaller 75100.
Not sure why everyone recommends more powerful ESCs. Maybe they have smaller boards and foils. I could probably go even smaller, like a 7550, since my big board and foil need less power to glide and take off.
My water cooling broke, so I rode without it. Max MOSFET temp hit 38°C when my prop and foil got tangled in weeds, pulling max current of 40A. Normally, temps stayed between 30-36°C and dropped to 27°C when I landed on water. So, turns out I don’t need water cooling on a water-cooled ESC in a waterproof case because it’s massive and dissipates heat well on its own. Plus, the ESC doesn’t generate much heat at that current.
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A lot depends on your weight too. I assume you are relatively light for that current and power.
Yup, with the board, the total weight is around 100 kg.
If the total weight was doubled to 200 kg, the current could be around 50A, right?
Because of startup requirements and speed requirements.
No, not how it works at all. At 200kg that board would be a lot harder to get on the plane and you’d need a lot more thrust which means you’d probably need around 200A give or take.
Also the size of foil makes a massive difference.
You are running 16S which means less current while many tend to run around 12S so need extra current.
A friend of mine recently tested his assembly with a 65111 motor and a standard propeller, and he was unable to get on the foil. Its weight is 95 kg. He gave it to his daughter, who is half the weight, to test it, and she almost succeeded. He plans to experiment with propeller and wing sizes. In addition, its battery pack is located under the board on the mast, which makes movement difficult. In general, it is difficult to say for sure whether 65111 is suitable.
The stock propeller is mid. The Fliteboard prop slaps way harder.
Well, one more argument against 65111: 12 awg wires were installed on it. According to the specification, they can carry a maximum of 30 Amps. The 65121 is equipped with 8 awg wires, the same as the 65161.
Got it, thanks for the update. Since 30 amps is sufficient for my needs, I’m still fine with using this motor.
12awg seems to do on the foildrives but are really under the specs on current, motor current is normally up to 100-150A during starts, being sinewaves that’s 71-106A rms current.
Wires will heat up and steal some efficiency but the real problem is that being an inrunner the 65111 is too small to produce enough torque to reliably get up on foil. If you want a small motor then it’s better to pick an outrunner.
I agree with you. The wires are working under great overload.
Just printed a new nose cone with super tough resin because my old one bit the dust after a gnarly crash! And it’s in a stunning black color! I slammed into some rocks at high speed and got launched off my board like a stunt double. The carbon foil wing took a serious hit, but to my surprise, the board survived! (Perks of an inflatable, I guess 
)
A bit bummed about the wing not being pristine anymore, but now I can toss it on the sand without a care about scratches! 
Always study the depth chart carefully before you efoil, my friends. Shallow spots can sneak up on you in unexpected places, and it’s seriously dangerous! Stay safe out there!
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I recently noticed that when I foil at higher altitudes, air gets sucked into the mast and reaches the propeller, reducing thrust. It’s called the Anti-Breach System.
To fix this, I used a hot glue gun to seal the nose cone, and now there’s no more air affecting the propeller:
After improvement:
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Hello Pavel,
how is your cone fixed? I can not see any screw,is it only glued?
How thick is this sheet you used? 6mm?