Computer Stabilized Foil PWC Concept

Hi everyone!

I had gotten bit by the eFoil bug last year when I saw a lift foil gliding down the beach and ever since then I have been on a mission to create my own version of a foil PWC. I am starting with a scale model to develop the design and test how some of the control systems work. Right now the model is just 3D printed and I am using a Pixhawk flight controller to stabilize the craft.

I am making videos showing the design and progress of my work and posting them to my YouTube Channel Intuitive Engineering

There are of course many details involved so please do not hesitate to ask about anything! Want to keep this post simple for the casual observers :slightly_smiling_face:

My most recent video shows the model working quite well actually, and supporting a heavy load as it flies through the chop!

Thanks for your time and happy foiling!


This is really incredible stuff. I think a lot of folks have been toying around with this idea for foils. You’ve made a great model. It be super to know more about the control methodologies and ideas you might have into implementing this on a mast with the proper actuator.


Nice, but i think you should change concept and put those rearwing elevons in the front. This way you coul as well controll speed and height more easily

Great stuff. Both the engineering and documenting.
Packing grease into electronic components works for a short while. Heat and humidity make water ingress everywhere - especially in moving parts.
Implementing rubber bellow seals in the design is quick and easy - even in poor surface finish found on 3d printed parts.

The rear wing can definitely control the pitch of the craft and actually act as a way to increase the maximum front AoA during lift off or compensate for less than ideal feedback when going over waves or other surface disturbances.

The main thing is that I do not want too much going on in the front and to keep as much of the electronics in the rear as possible.

Thanks for your comment and interest!


Yes it definitely only works for a while, I realized that the servos needed to be waterproof after I bought them! At least they were really cheap if they break!

The bellows are certainly a good idea and I will keep them in mind for using with 3d prints!

Hi IntuitiveEngineering.

Do you have any height sensor for active height control? Do you plan to build a bigger model?

PLS see my other topic - I think you need a bit more sophisticated fly control algorithms here…

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Hi Lingvo!

Currently I am using a mechanical surface follower in the front - the red foam thingy. It works reasonably well at the moment but of course active pitch control is the goal.

For the 1/5 scale model I did not believe the effort of the sensor is worth it, the flying height is quite low and most sensors are relatively slow reading, which would make it more difficult to stabilize. I also did not want to modify the pixhawk code yet to remove a complicated variable.

I do plan to build a life size version of this, with some basic specs of:

1.8 m rear wing
1.2m front wing
2kW battery
35km/h top speed
200kg load capacity

Full size version I will modify pixhawk autopilot code to change the “takeoff” and landing procedures, as well as other nuances of using the boat craft. Hope to design and insert a decent state space model into the pixhawk code in place of the PID so I can use multiple inputs and outputs for control. I do need to look into whether my hardware has enough cpu power but all that is down the road a ways.

As for your topic/objective, it may be difficult to just find some hardware to glue on electronics. The nature of the moving control surfaces, especially for roll control is something that needs to be designed into the wings. Just thinking about how you will create strong bearings and actuators is one of the main design areas that I had to work on for my project. Foils also usually do not have cavities in the wings for wires or cables which makes things more difficult that air planes.

Looking forward to chatting with you about this, funny we have similar ideas about taking these craft to the next level!

Also check out ray vellinga’s youtube channel from the international hydrofoil society

Thanks for reply. I actually chatted with Harry Larsen about his hydrofoil a little bit. He has a nice website with all data etc.

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Hey guys, new update to this build! I got all of the mechanisms built into the rear mast so now the drag is way less and the design is much more compact and integrated! Stoked to see how well it performs and what I can do with some more updates! Hope you enjoy the video!