Two front wing efoil: : best of both worlds?

EFOIL.builders Foils & Boards
#1

You have dreamt about reducing your take-off amp drawn by a two factor, but it seemed impossible.
You want to use an APS63100 but as you are over 80kg (160lbs), you will never have enough power to “unstick” from water,
You want to ride with a small and inexpensive ESC like a 40A cont and 60A peak from Flycolor, (@JetboardCologne ?)
You want to use a fast kitesurf wing but the surface is too small and the take-off speed is too high, (@Vicdes2 ?)
…
Why not using a second wing that “fades away” after the take-off ? Post your build here !
Credit and pictures: Platslagarn on kiteforum
Double Front wing 01

Building details:

Double Front wing 00detail
Double Front wing 00detail517×554 515 KB

Pro: your take-off speed is lowered so are the amps drawn.
Con: when you touch down, there is some noticeable drag so you tend to stop more quickly.

Drag can be reduced to a minimum with a small fuselage attached to the mast (and not a second mast on the board as above):

Double kite wing

4 Likes
#2

Wow, what a great idea!

#3

I’d be curious to see how smooth it transitions from 2 wings to 1 wings… It can’t be that smooth…

#4

I can build it, I have 2 wings from. Liquid force rocket v. 2 :joy:
But, when it not run, I habe lost holes in my Box.:disappointed_relieved:

#5

That is just really a great idea. So cruising stable at low speeds at low height with low power, and if you want to go fast, you can mount a real high speed front wing so you can go superfast. haha wonderful !

1 Like
#6

I actually also have a liquid force rocket V2 wing set laying around! I would need to get a mast clamp fuselage though

#7

It seems that the optimum height is 15-25% of the mast length on the board side to give the bottom wing the freedom it needs.

During the first trials, the game would be to avoid any hole in the mast, one notch or two on the trailing edge maybe :wink: To feel the potential, even a slight wing wobble would be fine I think.

Example of hollowed split fuse that could be in wood (shovel or broom handle). Here a cut Gong fuse:
Hollowed fuse

#8

I am 90Kg and can get on the foil with the APS6384…
This just looks like something that’s harder to transport and and extra wing to hit you. All of this is solved by just riding a slower wing with more lift.

#9

Or something worth it that eases accessibility for beginners.

A possibility but when you’ve learned how to fall… is it really more dangerous ?

IMHO, that’s the trail we need to get away from.
The questions to investigate could be:
Q1 - For a 75/80kg rider, how low can you go in terms of surface area for a main wing: 500 cm2 ?
Q2 - Can a 60kg rider use a 400cm2 main wing ( @JetboardCologne ?)
Q3 - Which mast height ratio is optimal for the top wing ? 5, 10, 15, 20 or 25% up ?
Q4 - Is this height ratio depending on the rider level ?
Q5 - Which surface ratio is optimal between top and bottom wing ? 20, 30, 40% up ?
Q6 - Is 50% comfortable, say 500cm2 x 2 ?
Q7 - Which top speed with a 400, 500 or 600 cm2 kitefoil front wing ?
Hey @visor360, this could be a new territory for you, just scaling down your best efoil wings :wink:
I know Zeeko has this kind of wing surface range. Plenty of cheap ones on the second hand market.
Hey @Mantafoils, feel free to chime in :wink:
Q8 - … tbc

#10

We do have 550cm2 wings… But… Honestly what I see looks overcomplicating…

#11

That’s the most backward statement. High aspect foils have already proved themselves an advantage over the older wings. They are more stable and faster at the same time.
I am ±90kg and have ridden wings from 56mm to 1M wingspan. The high aspect wings have loads of stability for beginners. So much that they would never ever need another wing to complicate things.
Kiters tried this concept almost 10 years ago already and dropped the idea. Some idea’s dies for very good reasons!

#12

I was an early fan of the Carafino HF as early as 2007. I then followed carefully Spotz and Ketos breaking the Carafino monopoly in 2010 opening the way to a global market. I’d like to be proven wrong but I think there is a confusion. IMHO, of those 12 years of innovation, what is merely approaching is @Brucecreations boxwing in 2014 followed by Horue’s biplane in 2019.
Both of these designs cannot switch between two lifting surfaces.
Bruce, please feel free to chime in.

If you are fond of (very) long high AR wings, you should appreciate their short reduced drag version that turn even better :wink:

#13

My smallest wing that runs well is the Liquid Force Happy Wing.
Greetings Frank

#14

Ladder foils are interesting, like @Vicdes2 said the transition can’t be that smooth, it will definitely require more control. It’s probably not for beginners but if you want to try something new and fun why not !

#15

When few days ago you mentioned about second wing at that moment I already knew where I could use 20-30cm of profile if I will cut 90cm RLboards mast :slight_smile:

#16

Make the upper wing V shaped.

When it starts to make contact the surface area is low, so zero-> full drag. Then as more submerges the force is felt gradually, not all at once. At takeoff the area is all wetted.

You could make struts for your main wing that are lifting foils, and make the mount and mast stronger this way.

But the boss move would be to have single wing, that changes shape as you go faster :slight_smile: If I ever get it to work I’ll post a picture.

1 Like
#17

Good idea, a dihedral wing shape like for the dinghy hydrofoils of the early days to decrease the up kick during the touch downs. Safety wise, in case of contact, it is also (a bit) less dangerous.

#18

The problem today is to find a nice way to attach the top wing to the mast. So as not to drill the mast or your electrical box I think that the small fuselage could be attached to a sleeve surrounding the main mast. In the water, this sleeve only works in compression mode. It will be much thinner than on the pict below:

  • a folded sheet of aluminium.
  • a 3D printed sleeve reinforced with carbon
  • 100% carbon vacuumed around the mast or molded in a @Visor360 type of mold.

Two-wing efoil

#19

Swiss 2012 technology: http://www.supramar.ch/

image