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 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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