Foil pumping using low power efoil

Hopefully the right category.

I’ve got a decent pumping setup with Axis1150 and a small kiteboard. Wondering if anyone could point me in the right direction regarding a lightweight efoil setup.

I’m envisioning not needing the power to get up and riding, rather doing dock-starts, thus the power rating need not be as high as the equivalent wet start, and the large high aspect foil needs very little to keep going.

Familiar with RC planes, e-skates etc, but I’m guessing I’ve maybe missed something. Perhaps a start would be the smallest power unit from the community?

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That’s a new track. @JetboardCologne has written interesting posts about efoil setups for sub 60kg riders: small and (really)cheap Flycolor ESC + 6374 outrunner motors.
If you want to collect data, a VESC might be useful.

This motor assist for SUPsurfing might inspire you. The battery should be bigger though.
'Mini motor for SUP surfing

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Ah thanks for the link, the mini motor project looks perfect.

Most appealing is that the components are so much smaller = cheaper!

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Any thoughts on this parts list? I don’t think I’ll need 50% of the power in Parts List A, but the price difference seems so minor between A and B that I feel like I could just go with A and have headroom for adding extra cells as necessary?

Parts list A

  1. Brushless Motor 6384 120KV - ~$92
  2. 5-12s 120A Brushless ESC Without BEC - ~$123+
  3. 6S lipo battery ?
    Comments: Same as this this “bolt on” thread, seems 120A ESC appropriate for the 6384 motor. Pulling 60A to get onto foil and 30A to sustain.

Parts list B: Atlernative spec, smaller motor and ESC.

  1. F5085 140KV 650W - $69.00
  2. FSESC 4.12 50A Based on VESC4.12 - $89.00
  3. battery?

Parts list C: Other stuff

  1. Tx+Rx - £30
  2. Prop - will need to modify I guess? Make it smaller? Pitch surely is fine for 100-140kv motors?
  3. Foil with all parts - £1300 2nd hand, currently using this.

Would greatly appreciate any feedback. Key struggle for me is to match prop/motor/esc/battery as I’m used to RC planes where you pop it into a calculator and it will give an estimation of compatibility.

This really caught my attention…

Did you ever make any progress with this? I was thinking of trying something similar. It seems like most of the full power builds once people are up they back off of the throttle significantly, so starting with a smaller motor and only 6S might work? It is certainly way cheaper than going 12S with a big motor.

I haven’t, hoping to do it into the winter. No longer near a river so the incentive is lower.

For example, here’s one interesting inspiration for low energy efoil https://www.youtube.com/watch?v=zyHxnw3pyBc Plus it has the added advantage of being quick release, instantly functional and versatile.

However, this type of jet propulsion (SCUBAJET) has very low efficiency, the e-foil will probably have very low speed and acceleration (or suitable for very light riders, up to 50 kg). Therefore a conventional propeller is ideal, but not an FR, Manta, Flite etc.

I am now also considering a similar propulsion system (with a battery capacity of 84 Ah or 105 Ah). So yesterday I sent a 3D CAD file with a modelled tube (with a better hydrodynamic shape than SCUBAJET has) to a company that makes fibreglass tubes (on a rotary winder) to offer me a price. If the price of the tube is affordable, I’ll get right to modeling the other parts.

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Interesting video from rctestflight showing APC RC plane props showing 100% improvement in efficiency on already very efficient propeller designs. I wonder if these would be a large improvement on the efoil props in circulation today for

3.5 m/s ~ 12.6 km/h at about 400w (I think, videos are long…)

That seems quite slow, but the world record pump foil speed pumped for 3.44 hours, covering a distance of 44.46 km, so ~12.9km/h. The interesting thing is that the power will be quite low, < 200W input from the pumping or less. New record slightly faster 54.8km/4hours = 13.7 km/hour

I wonder if these props would be interesting if the power curve was optimised for a slightly higher mid curve speed to improve the efficiency.

Is there any consideration for optimising efficiency for setups?

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