Its a big world and we all have good ideas just at different times
In reflections on my last posts i made, both the 50 mm and the 63 mm motor combos worked very well. At the time my experience with getting the foil OUT of the water in an efficient way was not up to spec and i was very much learning how to foil still.
I then progressed onto building 2 bigger motor combos down the bottom of the mast for constant foiling ( much like other normal e foil setup). I then gained a LOT of foiling experience and can now foil in the surf no problems.
if i revisit this small motor setup im sure i could get the boost i need to get out of the water and on foil now that i know how to finesse the foil into working and POP out of the water
After a 1h30min session the compartment was completely dry! The small droplets of water seen splashed in when I opened the lid, I’m pretty sure about that.
The first board was over $6k because I bought the Lift board and FR propulsion unit.
The second board was less then $4k.
These are rough estimates.
$1k battery
$1k board build
$1k foil
$1k for everything else motor, ESC, shitty maytech remote, enclosure, wires, miscellaneous stuff.
You could build a efoil for under $3k if you bought a cheaper foil, built a cheaper battery, and made a cheaper board.
But, I spared no expense! I have ridden with Lift boards and Fliteboards and I run toe to toe. I actually had to tow one back in. I wouldn’t trade either of my boards for a Lift board or a Fliteboard, so that’s saying something.
And with my bullet proof slingshot wings, I’m less concerned about hitting the bottom, and more versatile (3 different sizes).
Hey there, are you considering a folding prop for the foil sup / efoil mix? I have been thinking about using a oneway clutch (needle bearing based) in my shaft prop connection. Of course there will be some drag to spin the prop on the oneway clutch but I’m sure the folding prop has some drag as well. Sealing the oneway clutch will be the difficulty. I am using my 130L Gong Board for Wing surfing as well as efoiling. I just change the mast for this. I am also taking passengers along in the efoil setup. Currently the battery is still strapped on but i bought a rectangular hobie hatch which I am planning to install this fall. Hope this will seal sufficiently. Had some water intrusion into my battery suitcase this week and cooked some ml of water. No big thermal event unfortunately. I will for sure place some small common laundry room water detector in my battery case from now on to be sure.
Not a bad idea. Please let us know how it works.
Yes. I have a folding prop.
On sailboats the prop causes more drag if allowed to spin. So I the motors are designed where putting it in reverse with the engine off, locks the shaft.
And same thing with helicopters, and airplanes. A spinning prop causes more drag then a stationary one.
I was testing my new acrylic box with the marine connectors in the garage. Had little spark while connecting, I saw on an old post you were using an AS150 inline to complete the connection, were you still using that?
yes, I guess you are right about the drag while spinning. Same like the auto rotation sailing effect in helicopters. So wrong thinking about the free spinning prop. But regardless of all hydrodynamic solutions I see also the electric solution to have the controller regulate the prop speed to the board speed in order to spin just at the rpm which matches the current board speed for coasting. But this would require the speed information. So not really easy to achieve I would say.
You learn to do this with the trigger. That is the second best way if you don’t have a folding prop. The load on the motor is next to nothing when you catch a wave, and use the trigger to just match the prop speed to board speed, no thrust and no drag.
What have you done then ? Would you have a pict or two ?
I remember this method being first described by virus last July (2019). Not everybody understood at the time Does this method offer a totally invisible prop in terms of drag ?
This V_rot_mini might be automated with a micro wave sensor fixed on the mast or fuselage detecting the water flow speed. They do that on sailboats to send the speed to the board computer. For efoils, we need a proportionality table stored in the remote: V board (m/s) = K V rotation (rpm)
Does this method offer a totally invisible prop in terms of drag ?