I found out that my current problem is more about a shortcut between to power chords .
But the ESC needs defenetly cooling for Summer. But to keep the overall concept as easy as possible. I am actually Planning to add a passive Cooling Plate on top of the Box similar to @sat_be s Build: Daniels (un)geared inflatable (slowly built) - #72 by sat_be
I think this could be enough cooling for my < 2,2KW mechanical Output power.
I made some progress on the folding prop thematic. I have now a working version that gives me ~60-70W/km at ~15-18 km/h foiling with the 6384 120Kv at 10S. And almost no drag when folded. Unfolding works almost perfect. But maybe i gonna need there some slight improvments. Also the durability is under investigation.
Its also pretty hard to balance the transfere from powered drive to glide without falling in the water ^^
I started also to make some simulations and optimize everything to low pressure and low turbulences:
There where some interesting findings in the Video:
I consume ~3kw from the battery with the camera underwater â so i defently need a Software limitation of the max current.
The unfolding is not perfect.
Folding works amazing
I have some Kavitation on the Proptips. But this seems to be quite normal compared to other Propvideos. But would be nice if some of you could make some own/post theyr Videos.
As promised here are the .STL files of my current Folding Prop design: KlapppropV4 BaseV3
I printed it with PETG and very thick outer layer. You need 35mm M4 Screws and M4 Nuts.
Very important: the Prop must unfold fold just my gravity when changing its orientation. So sand it as long as it runs freely! If opening goes even a little bit hard. Its not working properly in the water and gonna have a short life. Hard openings goes massively on lifetime!
In future i probably gonna make the angle of the folding props maybe a bit bigger. So drag is higher but it opens much better. This here is a try how far back it could foldâŠ
Itâs getting annoying.
Nobody wants your advice, we get along very well without it.
As always, there is no evidence that you can do anything but empty promises.
First, reveal a few facts about what you can do?
You promised me a 200% Eta profit without even having any data
Hey, I want that prop too, it creates thrust while also acting as a generator. The holy grail of perpetual motion has been found!
jokes aside, I see that you ran some simulations. How much drag are you getting from that configuration? I mean, how much does the drag increase compared to the clean (non-powerpod) configuration. I ask because I recall someone mentioning that the drag was important and gliding, even with the folded prop folder, was significant, was severily affected when the motor is touching the water.
I was wondering if a puller prop could provide a lower drag. I know itâs been discussed before, but could not find anyone experimenting with it. My point is, compared to the size of the wings, the motor pod is not a big fuselage, so if it was possible to keep the flow attached, the drag should not be that highâŠ
@pablo_foil i think i could simulate the drag coefficient between the motor gondel and the normal mast.
But that would be alot of work. And it does not make sens for my build at all. I gonna have it because its an efoilâŠ
So my only goal is to make it as efficient as possible.
Today i tested my FESC 6 for the first time. Its amazing it feels completly different than my YEP120A.
It starts the engine even with very low rpm. It feels like i have much more power in lower rpm. But it feels a bit slower. But there i have to check what my logs saying.
But it gets way to hot. So i urgently need some cooling concept. So i gonna plan to add a big aluminium passiv cooler to the top of my box. Lets see if this is enough. At least it limits its own heat. Thats so lovely
Surprisingly with the VESC the transfere between Efoiling to gliding and back is just easy. It works absolutely fluently. So it looks like i am on a good way with the folding prop. The current one has now around 2-3h of ridingtime. Lets see how much longer it holds. But since now no bad signs.
As i said i made some more simulations about the perfect folding angle. This time very thin simulationmesh. So every picture here took me 6h of simulation time:
This Is a 10° more out version of the V4 Folding Prop at 20km/h
So my conclution is: i already have the perfect angle for less Turbulences and good opening.
Going more outside woul make the flow worse. Maybe 1° more to the inside would be a try but before that i would like to know the current lifetime.
So i try now how long it last. And then optimize it for a long Lifetime.
Its snowing here so i thought this would be a nice time to start my cooling similar to @sat_be s Build: Daniels (un)geared inflatable (slowly built) - #72 by sat_be
This solution is much more easy because a water tube could disconnect when the radius is getting to small. The Summer gonna show if the aircooling is enogh .
So i bought the biggest cooler i could find, around 30010020 and cut it down to 20010020.
After that I trimmed ~8 - 10 mm flat plane around.
Then I made a hole of the size of the cooling fins in the box.
The direction of the fins is going to be in the direction of surf. This should lead to a maximum air cooling.
Made some Isolation with some rubber from a bike tube. And placed all the components and made some nice cabeling. The placement of the components is pretty nice. If water comes in they stay dry a long time. But the batterys gonna melt .
The edges of the heatsink are really sharp. If i fall i directly fall over it. So i Made some PETG protection frame around it. There will come an aditional one for the screw of the VESC.
yes it did worked really nice at the time, never had a temp-cut and i was running 8S at a constant 120A (280a pics) on a 200A esc, it really depends on the esc or vesc and how long you ride close to its capacity (you can always check the thermal pad on the fets inside) , for me you should be fined
all data are on the post âslow build from franceâ
Thats great news thx for your experience
I should be far away of the ESC Limits ^^
Jeah just started to going trough your Builds.
I saw you also have an Takuma V100. I also have one and thought to make a bit faster build with this one.
How is your folding propellor going for durability and efficiency with PETG?
Iâm interested in which orientation you are using for printing, and how much infill/wall thickness? It looks as if you have sanded the propellor, so perhaps used supports and printed in the flat orientation?
I have a roll of ePLA-ST which Iâm planning to test with a folding propellor, just wondering if yours has been durable for many sessions.
Printed it like this with 6 top/bottom and 6 perimeter layers in esun PLA+, support overhang angle 65° (no support under the propeller blade). I had to offset and rotate:
Z offset 310.6
X rotation 90
y rotation 176
z rotation -26
Thanks michael and sat_be, both look like reasonable ways to print it. 6 walls/top/bottom seems a good idea.
Is KlapppropV4 the updated/fixed STL file, in a previous post above?
Iâve been sent a higher kV motor than I ordered (6374 170kV arrived, instead of 6384 120kV), so itâs going to be spinning at a faster RPM than I wanted. Itâll be with a 6s battery, for a foil drive, so Iâm after efficiency with low speed push.
Hi Achim I really like your build. Simple effective cool. Above all with a screwdriverpack as a battery. Wow.
Especially the folding propeller looks great for me, as like you, I want to cruise on our channel in front of the house and also hope to chase waves in the nearby sea, which most probably will be fantastic with your folding prop. Looking around I noticed that some people also took the 63100 because itâs a bit stronger, but I also like your setup because itâs a bit lighter which might be an advantage in the waves. Therefore my first question :
I weigh around 80 kg included my neoprene and my hipe 5.5 is a little bit heavier than yours. are you in the same weight range that It would be safe to assume the setup also works for me?
Which vesc do you actually have there?
Is it actually the motor that determines the choice for the vesc size or the battery?
Which manipulations did you actually make on your motor ? There seems to be a new model , âbattle hardenedâ, at Flipsky that I ask myself If it would maybe be ok to take it as it is, without adding epoxy and change bearings.
i weight around 70kg. But the System has plenty of thrust so i think it could handle your 80kg.
But the folding prop is actually not really reliable so i would not going out in the wafes with it.
But i have several plans how to improve that. I hope i have a reliable version till beginning of summer.
Great , thanks a lot Michael, the vesc is actually a great tip for this price! As for the prop I can go for the Normal version for the beginning.
But just to know, in wich way is the folding prop unreliable? It sometimes does not unfold?
So my investigations about the failure mechanism are right now:
The opening shock when turn up fast (Current controlled VESC) is way to hard.
I Already tried to make it with 100% Infill, it makes it even worse. Because the opening shock on a stiff part is even more stress for the material.
So the my current work is to develop a 2 phase opening of the Prop. Version 4.1 becomes a TPU printed dampening system to reduce the opening shock massively. I already did some dry tests. and it seems to work: https://youtu.be/szalWEe53GM
take a look to the gap between the base and the blades. Initially the Blades crash against the TPU dampers. And then at full speed/ Watertrust the blades going to press the dampers together and unfold completely. I am going to make now some Watertests and when the system survives some hours. you get the files for mass testing
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