Great! Using Ardupilot for logging makes sense as you know your way around that system. You can configure VESC stream data in the configuration app.
Regarding watercooling, you can check out my MakerX Hi200 temperature in the logs in previous posts. It’s housed in an aluminum box. No watercooling or conduction to mast etc. So maybe try without it and add it later if it’s really necessary.
I suppose my 75350 is completely overkill but I had some failure on RC plane due to low/limit capacity. For my safety, bigger ESC means bigger mofset means low temp when far to the high hard AMP limit. Probably I will loose some efficiency with this mofset not fully used but logger will give all I want to know/analyse. I’m working as a sofware engineer in Machine Learning area so it’s always a pleasure to digg in datas 
I agree with you that watercooling won’t be necessary, given the aluminum surface. To be seen. I also chose this ESC model because it is able to output more logs according to Flipsky’s specs. I think the material design is also more recent than the problems encountered on 75200s.
Does anyone know of an 18650/21700 li-ion battery organization simulator? (example 12s10p in square , rectangle , many row …)
I don’t think you’ll lose much efficiency with that controller. You could even gain some. The mosfets in your controller have a lower resistance, so there is less heat generated. On the other hand, they use more power to switch, and your current measurement has less measurement points in the eFoil current use range when compared to Hi200 for example. This may cause some noise in the motor output (losses). Ultimately I think that the lower resistance dominates and you will end up at the winning side in efficiency. Let us know when you get some tests done.
I’ll keep you posted. I’m starting to receive the elements I need to start building. Thanks 
New efficiency record, 47.9Wh/km over the entire session, so including a few takeoffs and some higher speed running in the end as well. Stable foiling at about 16A @ 14S, battery was at about 51V. So power consumption is about 800W. This was with Curve MT + Surf 40cm stab.
To get this improvement, I got my Gong V2 motor mount rear clamp MJF printed and removed the motor tail support. I made a tail cone without the support fin to retain the smooth motor to prop transition. I’ll release the new files soon in my motor mount thread. I added a cutout in the motor mount to reduce material where it’s not needed. This made the part a bit cheaper. The rear clamp part was 48 USD + tax and shipping from JLCPCB.
Congrats. Fun to improve your personal bests.
As I make alterations to my setup and my riding is improving I’m finding that I can travel further and my max session time is also increasing.
Do you credit the improvement to the reduced drag of removing the tail support or smoother more consistent riding?
I am pretty sure it’s the reduced drag that gave me the biggest benefit, since this was a drastic, about 15% efficiency boost with the Curve MT. Riding technique improvements have been more gradual.
I’ll test Veloce MT + Fast 40cm stab efficiency soon. First I need to learn to ride it properly, though. It’s significantly more demanding than the Curve MT setup.
Hi, try the Veloce with the surf stab first. It’s actually the stab that makes the biggest difference. I would assume that you will also gain some efficiency with the Veloce stab over the surf stab.
However, you will find that you will need more speed with the Veloce - it’s only comfortable from 25kmh up.
What is your all up weight? I have similar setups (Flipsky 65161 120kV; 14s with Curve MT+LT, Fluid LT, Veloce LT and both Surf and Veloce M stabs) and I am getting ~55Wh/km @25km/h average. FR and Hyperdrive Props. 130kg all up.
I would appreciate it if you could explain the logic behind the weight variable.
To my thinking weight is an issue during the “take off” part but once your foiling level and at a consistent speed does it make a difference to efficiency level?
In other words let’s say two people weigh 70kg and 90 kg and both riders have exactly the same riding skill and they take turns riding the same rig in the same weather conditions.
There is logically less power used to get the lighter person up and flying but from then on would the extra 20kg make a difference?
Don’t mean to hyjack your thread. Sorry.
My engineer brain thinks that given the same speed and foil setup, an eFoil will have some base current consumption to overcome drag and such losses + some current consumption that depends on rider weight in a nonlinear way. 20kg more will surely increase consumption, but not by +33% if you compare a 60kg rider to a 80kg rider.
I weigh about 67kg, my battery weighs about 8kg and the rest of my board I haven’t measured but it’s surely less than 20kg.
Thanks for the suggestion to try the Veloce MT with the Surf 40cm stab. I’ll follow the advice. The Veloce MT + Fast stab combo felt very nervous when foiling on my knees, but I probably also had pretty low speed. I am comfortable up to 30 km/h with the Curve MT but the efficiency greatly suffers. At about 30km/h it’s 55-60Wh/km, whereas at about 19 km/h it’s 40-42 Wh/km.
I don’t mind these discussions at all. Actually I greatly enjoy them, these are really a chance to understand eFoiling much better 
@Foilguy: The lift that needs to be created for each rider costs power
in a theoretic example a 80kg rider at 20kph needs 1000w to overcome gravity and drag, and a 100kg rider at the same speed and same wing angle would not fly - so wing needs to be tilted more to get higher lift. This increases the drag in the water so he needs 1200W (or something) to fly at the same speed.
@jkoljo: i have just gotten a veloce mt since they were on sale i find it somewhat less stable than my curve LT but not really a game changer for me - it’s a lot faster than the LT wing though (which seems to somehow bottom out at higher speed for me)
I like it but the falls are starting to hurt due to the higher speed!
Not being an engineer I don’t really have much of a base to comment on this, but I have a life long passion to learn.
That said it’s my perception that once the rider is up foiling in a level consistent attitude the pitch angle of the foil is also consistent. It is neither climbing or descending. Therefore the weight that is above the foil shouldn’t have much effect. If the pitch angle changes then the weight becomes a factor again.
I understand that the energy required to transition more or less weight to the level “neutral” position would vary. That part seems very logical to me.
It’s like i explained. Maybe easier to understand like this:
The lifting force is created by the flow around the wing: same speed and angle of wing gives the same lifting force.
If you load the wing more, then more lifting force is also needed - otherwise forces are not in balance and we will start to fall downwards
How to get more lift?
Either increase the speed or increase the angle of the wing. A force balance will be found with the higher lift, higher weight on wing so you won’t be going up or down.
A drag/lift curve of eppler 817 profile:
(which is a wing profile i think was used on older hydrofoils)
Cd is drag coefficient / Cl is lift coefficient
Alpha is angle of wing towards flow
You can see on the Cl vs Alpha plot that it starts to create positive lift already at negative wing angles and the lift peaks at roughly 7.5 degrees upwards angle. At higher angles than that the wing stalls.
Thank you that is very helpful. The charts help me get things that I struggle with in just txt.
Thanks for you patience. It was never your explanation but my ability to comprehend what you were expressing before.
Im thinking I should go on a fasting diet and lose some of the extra tonnage I’m dragging around😀
I’m on one right now since my gong YPRA wing has a hard time to lift me😄
I’m just beginning the tweaking - try different thing stage and I’m finding it amazing how much difference that changes in setup make.
I also totally get the faster you go the more interesting the crashes get. There was a point when I windsurfed a lot that top speed was everything. At some point along that path I discovered how hard water can get even when it’s not frozen😎
Windsurf record
I don’t know what the windfoil record is but I think it’s a bit less than with a fin.
I think the Efoil record is held by Flite at about 55 km/h.
The point is anything 25km/h or over starts to “leave a mark” when you crash 
That’s some crazy speed. I calculated that with full throttle I might reach +40 km/h. I’ll try to reach that some day, but about 35 km/h is my limit so far.
