Author Topic: First time riding the Lift eFoil- video review  (Read 20418 times)

bing

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Re: First time riding the Lift eFoil- video review
« Reply #15 on: March 19, 2019, 01:36:14 PM »
Looks like Lift Foil has developed a prop to allow you to drop into a wave and cut the motor - the props fold back reducing drag.  See video and start at 3:35 min mark.

https://www.youtube.com/watch?v=7CUpbZGd6ss

Beasho

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Re: First time riding the Lift eFoil- video review
« Reply #16 on: March 19, 2019, 04:45:27 PM »
Super cool! 

We saw a guy riding a powered surfboard at Pedro Point the other day.  This is the outer-most point in Lindemar, CA.  The board was gas powered and appeared to get up to 25 or 30 mph. 

Wind was out of the South and it was big buoys were 19 ft @ 14 seconds.  Sets on the outside we >> 25 feet.  Mavericks would was working but too much south wind to be survivable.  The guy on the motorized surf-board was skilled and charging into the sets, making the drops and hugging the shoulder like a pro. 

The benefit of a powered foil would be to get into BIGGER waves easier.  Small waves move slow enough to catch with a paddle. 

My question is when this thing breaks off from getting hit by a wave will it float?  :o
« Last Edit: March 19, 2019, 04:47:20 PM by Beasho »

blueplanetsurf

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Re: First time riding the Lift eFoil- video review
« Reply #17 on: March 25, 2019, 06:05:40 PM »
That collapsing propeller is cool!


Robert Stehlik
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TallDude

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Re: First time riding the Lift eFoil- video review
« Reply #18 on: April 07, 2019, 01:16:02 PM »
I was out in the ocean this morning for a distance paddle and saw two E-foils out just cruising around. They weren't even close to the surf line. Just going straight and then in big circles. Both looked in control and flying smooth. I saw them heading back to the harbor and noticed the Harbor Patrol was watching them. As they were crossing into the 5mph only zone, I thought "can they even fly at 5mph?" It looked like they attempted to slow a little bit because they appeared to sink a little lower. It's kind of deceiving because there is no wake. I thought, if they have to drop at the 5 mph buoys that will be a long sucky prone paddle into the harbor.
With the boats and jetski's their wake makes their speed obvious. The Harbor patrol is all over the weekend jetskier's and yahoo power boater's. They seemed to let these E-foiler's slide this time. Honestly, just going straight or making big circles in the open ocean with no waves, looks a lot less fun than un-powered wave foiling.  ::) I could be wrong???  Don't knock it till you try it right!
It's not overhead to me!
8'8" L-41 ST and a whole pile of boards I rarely use.

PonoBill

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Re: First time riding the Lift eFoil- video review
« Reply #19 on: April 07, 2019, 08:06:25 PM »
I'm very interested in powered foils, just not 12K worth. What I'd like is enough boost to get me up on a swell, which then doesn't interfere with downwind foiling. I doubt the Lift foil is really that. Fortunately, the path to getting that seems fairly straightforward. Brett Likle has kind of confirmed it for me with his attempt at the same thing using the pod-based jetpump system. In our conversations, he said it's about half the power he needs to get up on a downwind swell. Since I only need thrust when the board is in the water the design is no more complex than adding an outboard motor to a rowboat. 50 pounds of thrust should be plenty and I only need power for a few seconds at a time. A simple trolling motor head, batteries and a switch. The complex bit is going to be making the shroud for the prop. The batteries don't need to be massive, they just need to supply the required current (I figure 250 Amps at 24 volts) in short bursts. Hang the thing off a finbox--the motor and mount will be well under twenty pounds. For batteries I'll use RC LiPos. Even just a little 5S 5000mah 18V high discharge spec Lipo can deliver &%) amps in short bursts. My homebrew portable Mig Welder uses just a few 4S 100C batteries in parallel to weld 3/8 steel. We got the tech.

It's going to be a busy summer. I want to downwind foil so bad I can taste it. Short of amputation I'm not going to get to the point that my geezer body will be light enough. strong enough, and flexible enough. Gotta cheat. 
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: First time riding the Lift eFoil- video review
« Reply #20 on: April 07, 2019, 10:58:29 PM »
Oops, it's really not &%) amps, it's 750. It's hard to believe that's true until you screw up and melt a wrench with one.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Dwight (DW)

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Re: First time riding the Lift eFoil- video review
« Reply #21 on: April 08, 2019, 04:39:11 AM »
Bill,

I think it will be easier and more fun to just get yourself a wingfoil. Duotone and Slingshot are saying ETA June.

deepmud

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Re: First time riding the Lift eFoil- video review
« Reply #22 on: April 08, 2019, 11:54:15 AM »
I'm very interested in powered foils, just not 12K worth. What I'd like is enough boost to get me up on a swell, which then doesn't interfere with downwind foiling. I doubt the Lift foil is really that. Fortunately, the path to getting that seems fairly straightforward. Brett Likle has kind of confirmed it for me with his attempt at the same thing using the pod-based jetpump system. In our conversations, he said it's about half the power he needs to get up on a downwind swell. Since I only need thrust when the board is in the water the design is no more complex than adding an outboard motor to a rowboat. 50 pounds of thrust should be plenty and I only need power for a few seconds at a time. A simple trolling motor head, batteries and a switch. The complex bit is going to be making the shroud for the prop. The batteries don't need to be massive, they just need to supply the required current (I figure 250 Amps at 24 volts) in short bursts. Hang the thing off a finbox--the motor and mount will be well under twenty pounds. For batteries I'll use RC LiPos. Even just a little 5S 5000mah 18V high discharge spec Lipo can deliver &%) amps in short bursts. My homebrew portable Mig Welder uses just a few 4S 100C batteries in parallel to weld 3/8 steel. We got the tech.

It's going to be a busy summer. I want to downwind foil so bad I can taste it. Short of amputation I'm not going to get to the point that my geezer body will be light enough. strong enough, and flexible enough. Gotta cheat.

Bill - you don't think the collapsing prop will do the trick? vs a jet?

I totally agree with you that a foil that will get itself into waves then let you ride the waves will be the best thing ever. I suppose the downside is that it will get a novice like me out downwinding way out where I could not get on my own. I or someone like me could get in real danger and then run out of juice or break down.

jondrums

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Re: First time riding the Lift eFoil- video review
« Reply #23 on: April 08, 2019, 09:24:22 PM »
Pono, I was thinking it would be easiest to take the same torpedo/motor/prop, but attach it to the mast just barely under the board.  High enough that its out of the water once foiling, but a little under the board so it keeps pushing all the way until the board is coming out of the water. 

And where are you getting 750A @ 24V?  That's 18kW electrical, which sounds like way too much.  I'm thinking 1-2 kW sounds about right.  The best road bikers in the world can output 2.5kW for 5-10sec and pretty top notch guys can do 1kW.  I'm thinking that full body paddling and pumping up from flat water should be somewhat similar to a road bike sprint.  Maybe even less is needed if we consider to get a little push from a swell and a little more from a paddle and a leg pump.  Come to think of it, we might be able to get by with a pretty small motor/battery given that it would be only for really short bursts.

PonoBill

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Re: First time riding the Lift eFoil- video review
« Reply #24 on: April 08, 2019, 11:57:11 PM »
Really I was talking about what is feasible in a small package for short bursts. The best graphene LiPos currently are 150C, meaning they can discharge at 150 times their rated capacity. A five amp 24V battery can be discharged at 150 X 5 = 750 amps. Not bad for a battery about the size of a pound of butter. Who needs that much? No one, it's just illustrative of the difference between building something that needs to put out a bunch of power for a short time and something that needs to power a board for an hour or so.

It's too much work to integrate it into the mast. I'm going for simple and brutal. I need something that can get me off the water perhaps twenty times, assuming I suck at staying in the energy of the swells. Five seconds of push to get the board up. Say something like 100 amps at 24V = 2400watts times 5/3600=3 watthours per five second hop. A 24V 5AH battery is 120wh = 40 five second hops. I think we're in the ballpark with something like a pound of battery.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

blueplanetsurf

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Re: First time riding the Lift eFoil- video review
« Reply #25 on: April 09, 2019, 12:20:31 AM »
Bill, it sounds great in theory, get a little boost to get up on the foil when downwinding.   In my experience, getting up is just the first challenge.   Keeping the momentum and connecting bumps is very challenging as well and I would be concerned that the extra weight will make it more difficult to stay on the foil between bumps.  I think adding 20 lbs will make it significantly harder to pump the foil between bumps.
Robert Stehlik
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PonoBill

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Re: First time riding the Lift eFoil- video review
« Reply #26 on: April 09, 2019, 01:09:20 PM »
Yup, it might not work. I won't know until I try. Part of the plan is more efficient wings and stabilizers--I'm going to punch them out like shortbread cookies. Fundamental desperation--I got into foiling to do downwinders, the surfing looked lame to me. It still does, it was a pleasant surprise to find out how much crazy fun it is. I did more than 40 sessions in the Columbia last summer trying to downwind foil. I sucked so bad at it that I snuck away from my friends to do it without all the "encouragement". My longest flight was about 50 feet. I could get up, but by the time I did I was so exhausted, I'd just stand there. Adding twenty pounds to my current 230 plus board and foil weight is not as big a deal as it would be for others.

I might be able to get the thrust I need to get up without adding 20 pounds, but whatever weight I wind up with can be distributed and located to minimize the negative effects. One of my experiments will be to push brushless DC motors well past their design spec. I don't care if they toast as long as they stay together for a while.
« Last Edit: April 09, 2019, 01:13:04 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

blueplanetsurf

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Re: First time riding the Lift eFoil- video review
« Reply #27 on: April 09, 2019, 03:07:40 PM »
Sounds good Bill, I find the same thing, getting up on the foil takes so much energy that it's hard to focus on actually flying.   Your plan sounds good, it's definitely worth trying and I'm looking forward to hearing about the results.   I'm tried to set up a DW foil with a scubajet I just received (after waiting for two years) to see if I can fly it in flat water but the wireless control does not have any range underwater so I'm waiting for them to send me a wired controller, I'll keep you posted.




Robert Stehlik
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supthecreek

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Re: First time riding the Lift eFoil- video review
« Reply #29 on: April 30, 2019, 06:35:35 AM »
That's pretty wild. He's going to want to do something about that big prop. Drag increases as the square of velocity, and an oversped or feathering prop has huge drag at any speed above 0--they wouldn't work as a propeller if they didn't--the amount of power a propeller can deliver is directly proportional to the area of water it intercepts. Close the throttle on a high performance boat and it stops like a chute was deployed. Even in air, a thousand times less dense than water, it's a problem. That's why airplanes don't glide for shit if the motor seizes. at the very least you need to feather the prop, and even then it's a lot of drag. A folding prop at minimum, though they still induce a lot of drag and it's more challenging to shroud them.

I've been considering doing a jet pump in the fuselage. The primary problem is that jet pumps work better in larger diameters, and you need either a torque-y motor, which means a large diameter outrunner (think leverage--small diameter motors have less and so are better for high rpm) or a gearbox to reduce the RPM--expensive and overcomplicated. My possible solution is a long stack of smaller motors connected end to end. Torque is additive. In theory I could get to the thrust I'm looking for with a 1.5" tube and five motors with a two stage pump. In theory. I might take a swing at that this summer.

Another solution is to have the drive attached to the board or high on the mast. It could get you into the wave and then get out of the way. But if you dipped the motor for a second you'd be off the board and tumbling in a heartbeat.

I built as wireless motor controller last night for fun. Two ESP32 boards, an ESC and a brushless motor I had kicking around from one of my dead drones. The ESP boards I'm using have 6 touch control pads, so I didn't even have to use a potentiometer. the speed control is in six steps. Just screwing around, and I wanted to watch the new netflix series on F1, so I didn't spend time on it, but it's simple stuff. I didn't even have to write most of the software--I found a sketch on the web that worked fine with a few little changes. Of course this is the most expensive way to do it, much cheaper to use WR boards, but I think I have about 30 bucks in parts there.

Pono: to your point on drag:
when I was at Nazera' watching a big, perfect session, I was amazed to see a surfer racing in on a motorized surfboard.
One of the short boards with a tethered throttle (from what I could see from a distance and old eyes)

It was extremely fast catching waves and he could take off before they got steep. (see pic of him on a tiny wave that day)

BUT, once on the wave, I noticed that it was much slower than the other tow-in boards.
The drag was even very noticeable to my cataract eyes (operation in 3 weeks)   

He rode conservatively and got out early.... zipping right back outside, which was pretty cool to watch.
His safety ski shadowed him at all times, I can't imagine that it was an easy board to rescue in critical situations.

 


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