Diy e-foil!

[supuk]

 The guy smashed it so stoked he got it to work!
https://youtu.be/vQRO4glxExQ

[PonoBill]

Great. I'm doing the same thing. I've got a couple of 2400 watt inrunner motors that just arrived, and a 70mm ducted fan on the way. I'm not going to try to seal the motors for version 1, just stick them in the water. The only part that is water sensitive is the bearings, and they should last long enough for proof of concept. I'm going to use the existing impeller intended for air for the first tests while I print new ones. I've been searching for appropriate pitch and design, but I'm not finding much. I think just guessing at first will get me in the ballpark. Gear reduction would be a good thing, but for now I'll just fire it up.



The guy in the video is wise to use ammo boxes for his batteries. I have mine in an ammo box, a cheap home safe, and just outside on the concrete. If you start playing with hobby lipos, be careful. Losing a shop is a big setback.

[supuk]

Looks like all the e foils are ending up with more of a prop than a jet I guess to get the low end torque. This chap has used a 7:1 box. Maybe a out runner would be better. My prusa printer arrives this week so will have to start playing

[PonoBill]

Possibly, or maybe they're using a prop because it's easy. I can convert this to just a shrouded prop by pulling the flow straighteners out--as you can see, they're attached with Allen screws, though they are also the front shaft support. The guy in this video looks like he's printing an impeller that's a lot like the ones I'll be using, though probably fewer blades and higher pitch. 7:1 gear reduction would be great. I have some gearboxes that would work but they offset the motor and they are a single drive, so they generate a lot of side thrust.

[supuk]

he started with a shrouded version but thought it was creating more drag than anything and then went larger prop with more pitch. There are plenty of inline gearboxes available for rc stuff however you loos a fare bit of power In them so better to avoid if possible. I much prefer the idea of a shrouded jet but maybe there is a reason they have gone the prop route. Will be interested to hear what you find out.

[PonoBill]

Certainly would be easier, and yeah, the shroud is draggy--they're foiled to increase pressure on the impeller and make it more efficient. With an incompressible, 1000 times more dense medium that isn't a good strategy.

[container]

any idea what foil hes using? seems that it doesnt like slow speed too much. besides who needs a motor when you have a bro

[supuk]

any idea what foil hes using? seems that it doesnt like slow speed too much. besides who needs a motor when you have a bro

Liquid force kite foil I think it was? So yea wouldn't like to go slow.

Amazing you got yours up just running! How hard was that?

[container]

need a wider board for the take off but the loads are definitely paddle-able!

[clay]

Awesome to see all the creativity in the quest for foil.

A few weeks back we tried to recreate this:


What we learned is that wheels are very efficient, towing someone on water not as much.  1000 watt ebike without towing did 25mph on the beach, with towing and pedaling hard barely 10mph.  We tested first without the foil and the rope wasn't long enough to stay away from shore.  So we added a longer rope and that helped.  Then trying to get more juice out of the ebike the bike rider switched gears and the chain snapped, bringing our session to an end.  The bike rider was winded and we concluded that we could probably ebike foil and it would be short lived. Fun as a novelty but probably not very practical, much easier to go behind a boat.

[PonoBill]

Some local Hood River kiter kids have been towing a foil with a foil. one of the kids has a big light wind kite and a rope tied to his harness, the other grabs the rope and gets towed--both are on foils. What's interesting is that the drag of the towed rider lifts the other rider into the air--way up in the air. Probably thirty feet up one of the times. I was there with my drone, but ran the battery too low for it to take off. I held the drone to shoot video but forgot to hit record on the remote. Duh. Fun to see though.

[supuk]

Bill fig. 5-9 in the hydrofoil book for prop v jet

[DavidJohn]

Was that for me to read.. 

[supuk]

Sorry no idea why that is upside down but bill has the book

[Bean]

Was that for me to read.. 

Ha...the Oz edition