Author Topic: E foil  (Read 3581 times)

Admin

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Re: E foil
« Reply #30 on: September 19, 2020, 08:54:17 AM »
Check the YouTube videos from Bali. This thing will get you over the hump. For me itd make a sub-5 prone paddle in possible, if I could live down the ribbing.

I have no pride left. 

Boost from a YouTube response, "We tested it in the pool with a 150lb guy paddling at the same time on a 9' surfboard - top speed was 11 mph"

You could easily attach one of those stick on foil mounts to the board right under the front wing with two of these linked Boost units in there.  It would be an easy way to test.  We have some little boards that are pretty solid there.  Might have to try this.

This young fella clearly has a more than we would need so it is certainly possible to get a nice small setup for what we are thinking.  It would be cool to ease yourself to the surface and then give it a good pop timed with your swell.

skip to 2:48

https://www.youtube.com/watch?v=QBKDYsAhiuc
« Last Edit: September 19, 2020, 09:18:33 AM by Admin »

Hdip

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Re: E foil
« Reply #31 on: September 19, 2020, 08:59:33 AM »

surfcowboy

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Re: E foil
« Reply #32 on: September 19, 2020, 07:36:47 PM »
Slatch, 100% it was classic. 20 mph wind had me pinned to the bow of a 60 cruiser while the maintenance guys watched.

Hdip, that account is fire. Everything they post kills me.


I never really report the good however (its never as funny.) When I crashed after my first run on foil one of the ladies on the dock clapped and cheered. Learning surfing is mellower since every foiler still remembers the early days.

Yo! Ill be in Carlsbad for a week in like 7 days. We gotta go to San O!

tarquin

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Re: E foil
« Reply #33 on: September 20, 2020, 01:10:54 AM »
https://e-surfer.com/en/liftfoils-efoil-2019/?cookie-state-change=1600588324366
 The folding prop has been around for a while now in efoils.
 Some of the efoil home builds are amazing as well. I am sure you could just attach one higher up the mast as others have said.
 It's all new still and I think things will develop as people develop. Companies will only make things if there is a market though.
 A company in France has just patented a propulsion system that is built into the bulb on the keel of sailing boats. No prop at all. Think The hunt for Red October!
That's what you want in the fuselage of the foil.
 Or a foil like a sting ray that flaps and does all the work for you!

tarquin

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Re: E foil
« Reply #34 on: September 20, 2020, 02:18:41 AM »
Just wrote something but I timed out and I dont think it posted.
 The short version. Foiling has been around for longer than a lot of people think. Eric Tabarly was making foiling sail boats in the mid/early 70's. 2 great quotes from mad French sailors.
 " I only made 2 mistakes, I thought I was the first and I thought it would be easy! They were very big mistakes"
 " The only way to know is too try it. We must try it!"
 Something along those lines.

tarquin

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Re: E foil
« Reply #35 on: September 20, 2020, 02:31:29 AM »
1920 was the first patent for a foiling sail boat.
 Yellow Pages that had the sailing speed record for a long time actually had tiny foils. They managed to keep it secret for years.

MLB

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Re: E foil
« Reply #36 on: September 21, 2020, 04:54:47 PM »
It most certainly is interesting on flat water and almost everyone is interested IN them.  ;)

I was speaking specifically of a propeller mounted up high on the mast where it is out of the water once flying.  Obviously lots of people are riding the efoils in flat water

ahh, of course.

tarquin

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Re: E foil
« Reply #37 on: September 29, 2020, 11:20:01 PM »

PonoBill

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Re: E foil
« Reply #38 on: September 30, 2020, 08:51:51 AM »
There have been some impressive designs of fuselage-based impellers, none of which have adequate thrust. I was working on a fuselage-based thruster with my typical delusions of competency telling me I could do it better but lost I interest when I took stock of the limitations and realized that no, I couldn't. Impellers (jet pumps) are limited by their intake geometry and location. The good news is that the fuselage location is good--the deeper the intake is, the less subject to cavitation the impeller is. Cavitation is a big issue with impellers since any intake restriction reduces the NPSH (net positive suction head) and lowers the boiling point. Anyway, even my primitive calculations demonstrated that intakes that were big enough dictate a fuselage diameter large enough to add almost as much drag as a folded prop. The other big limitation is that electric motors that produce enough power do so by spinning at high rpm (horsepower = torque X RPM X a conversion factor), like 20,000 rpm or more. The impeller needs to spin much slower, which means you need an expensive axial gearbox. It all continues to go to shit from there.
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.

surfcowboy

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Re: E foil
« Reply #39 on: October 11, 2020, 05:08:02 AM »
Rode an efoil today (custom prototype) it was really fun and really helpful. People were swapping out so I didnt want to take too long so I just did maybe 5-10 min but when asked, do you want to go a bit more. I said, no, that was a month of foil surfing right there. ;)

It was sized so I could start standing, so none of the hassles or knee starting, so my learning curve was shorter. My e-skate throttle experience transferred and so I got up on foil immediately and got little short 1 minute rides. By my 3rd or 4th ride I was able to slowly bank a turn and so it probably did save me a month of surfing as far as progression. I can see how and hour or two would put you in great position for foil surfing and (other than wave knowledge and managing the board and foil in and out of the water) I could see an efoil cutting months off your progression in 2, 1 hour sessions.

If you have the chance, definitely rent or demo one.

 


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