Custom built based on direct drive SSS 56114 with 3D printed parts

Hi Guys, we’ve been developing our own E-Foil propulsion setup for approx a year now. with big pause over the winter. I want to share this with you and I am curious about your thoughts.

We use:

  • 12s 16.000 Lipo (710Wh) in cheap Box from ebay
  • SSS 56114 350kV with DIY 3D Printed end caps, other bearings and sealing
  • DIY 3D Printed Duct and Jet
  • Self developed Alu CNC prop with 8cm Diam and 6cm pitch, 4 Blades
  • Cheap Seashark ESC or the Waterproof 200A Flipsky VESC
  • Data recording in the Video is split screen capture from my Phone running the VESC App with BT to the VESC
  • everything designed in Fusion 360 and printed in FDM (PLA and ABS) or in SLS out of PA12

Archivements so far:

  • 44 km/h topspeed with small wing
  • 5.7 kW in static thrust test
  • About 2300W in normal foiling 25 km/h
  • Prop is very well matched with the motor and delivers good eta on the motor
  • Safe design, impossible to get hurt by prop
  • no cavitation even at 13.000 rpm and 50kg+ thrust

Problems still:

  • 2300W seems too much. Some only need half
  • Motor still not 100% watertight even we have good sealing with lots of grease etc
  • 10AWG cables in box sometimes getting so hot that solder joints go apart

more infos will follow…

Cheers
David

8 Likes

10 Likes

Hammer!! Ich hab den Motor auch noch liegen. Gibst du die Stl’s raus?

Echt toll !

Great work. Love the design! The small prop will mean its less efficient, but its definitely the best performing “jet” style setup I have seen.
Which wings are you using, they can also make a difference to your efficiency…

Great design !
Looks like a big impeller design but nicely done !

1 lipseal (depending if it’s 1 lip or 2 lips) can take up to 200W more power consumption. If we assume let’s say 150w and if you are using 4 double lips seals it would mean you have around 600W of power lost in your seal system, which brings the rest of the system to 1700W. Still like 500W too high. However like Jezza said, it also depends on the wings you’re using.

EDIT : One legit question here. It sounds like a turbojet. Does it come from your unit ? Does it make so much noise ?

Danke, nein die STLs wollte ich nicht hergeben. Bringen dir eh nix ohne die Prop und einen SLS drucker.

Thanks
Small = less efficient? Don’t think so.
Wings are from Slingshot

Thanks. I will try to remove some lipseals and test the effect. They are really getting hot as we use up to 14.000 RPM
THe noise is quite low now as we have rubber between the motor and the mast to decouple the vibration. Before some people thought it’s powered by a combustion engine because of the noise :smiley:

You should be good if you use FKM lip material. SKF HMSA10V is rated up to 200°C and 14626 RPM. However, you’ll be reaching the limits if you ever go on 14S instead. Have you tried a mechanical seal ? They are often used in submersible pumps.

That’s exactly what I thought haha !

I calculated the conversion efficiency of the prop from shaft power to stream power and found it to be about 66%.
(data from the static thrust test at the beginning of the video)

Nozzle outlet is 66mm Diameter, 500N thrust -> 2942W Stream power
Motor shaft power is about 4450W (88% from electrical power of 5058W)

Which wings though? Is the bigger one the space skate or the infinity 76?

this one is the one we are using

I’ve got that. It’s not an efficient wing at all. The infinity 76 would be a much better wing to use. I have moved to high aspect wings now which have made a massive difference!