Modified Slingshot for FoilDrive (first build)

[drcubes]

Here is my first build for a DIY efoil add-on to my existing slingshot foil and board. This first post will be a bit sparse but in the next week or so I hope to include all the details of the build.

In summary:

Board: Slingshot Wizard 103L
Foil: Slingshot Hoverglide 90cm mast, Switch Fuselage, Infinity 76cm front wing, 42cm rear wing
Motor: 6384 (I changed the factory bearings with ceramic and put a little bit of conformal coating on some spots in the winding I was worried about shorting as well as filled the cable sheath at the motor connection with marine epoxy to make sure the winding leads at the cable junction wouldn’t short)
Propeller: Propeller King Fold
ESC: Flycolor FlyDragon Lite 150A
Battery: 12S 22AH (2 x 6s 22AH Lipo batteries in series)
Waterpump: 5V 1.3L/min
Buck Converter: 8-60V to 5V 5A
Waterproof box: TICONN Waterproof Electrical Junction Box IP67
Remote: Maytech V2 Fully Waterproof Remote

I also designed and made some custom 3D printed parts to attach the motor, route cables, and a few other minor things. I certainly got a lot of inspiration from folks on this forum and in the next few posts I will attempt to credit everyone correctly!

Attached here is a picture of my setup.

I have taken it out once as of writing this post. It was…fun!! But certainly need to adjust the balance of the setup as it was pitching up extremely strongly with what I would expect is normal foot placement. I was able to easily take off on foil when i sat or stood at the front of the board. It was very silly looking but it worked! However, as you may guess, once I was up foiling but standing so far forward I had much less ability to control the board in turning - at least compared to how I normally do while windsurf/windfoiling.

I am open to all advice on the issue of extreme pitch up as the back of the board drags like a parachute unless I stand at the front. My plan for next step is to move the electrical/battery box to the nose (utilizing the sail mast track to secure it) as it is heavy and will help put some weight forward, as well as adjust the rear wing angle of attack to be neutral or even positive lift (to causing a downward pitch torque to the whole setup.

Thank you to everyone on this forum and I look forward to posting and learning more!

(I will include links to the items I purchased and a repository of the CAD files for the 3D printed parts)

[hangloose]

I’m currently on my first build for my Slingshot Hoverglide.

DIY 6384 Foil Drive Assist from South Germany

Hello everyone. My name is Markus and I am 43 years old. I live in the south of Germany, BlackForrest. I’ve been kitesurfing since 2004. This year I’m also traveling with a kite foil board. First of all, many thanks to the great contributions here in the forum. But now to my first build. Everything should go to my Slingshot Alien Air Kitefoilboard. [IMG_5593] [IMG_5592] For the Hyperglide I have three Frontwings. Apollo, SpaceSkate and Quantum 100.

I often read that the backwing of the hoverglide needs a different angle of attack. Are there any empirical values ​​by how many degrees the backwing needs to be trimmed?

@Bzhwindtalker: Have you already trimmed your backwing? Can you show us pictures?

THX

[Bzhwindtalker]

I had better results with a 2-3mm shim under the front of the wing. It gave better low speed performance (planning on foil with less power) but was unstable at higher speeds. then I ordered the 48cm rear wing, 120 euros from spain, and this one glides much better with a more neutral stance. However I noticed I needed a 3-5° shim under my board to get a neutral planing angle. I think the shape of the board : “area where the USBOX rests compared to the deck plane” has an effect there.

[hangloose]

Thank you for your information. I also think it comes from your Boardshape btw US Box.
It’s not normal

[Bzhwindtalker]

I think the board rocker is causing some of the issue, but I dont think anything is wrong with the board.

Those foils have a Big tendency to pitch up. it is better with the 48 rear wing than with the 42

[drcubes]

Thanks for the feedback!

@Bzhwindtalker , I notice that your rear wing is attached to the bottom of the fuselage with the dihedral pointed down (at least when the board is on top). My rear wing currently is set how I use it windsurfing with the dihedral facing up. Do you suggest I flip it over before trying to shim? Or maybe shimming how it is first? Or both?

[JFoiler]

Is it worth trying moving your foil mount to the back of your tracks?

[Bzhwindtalker]

The 42 rear wing mounts on top, while the 42 mounts to the bottom. I tried thé 42 reversed and it was not working great.