80100 direct cooling

XSailor · June 12, 2019, 7:13am

Did not mean to be harsh and fully agree testing sheds some light but to interpret the results from bollard pull to useful data for flying with a foil, is a challenge.

Yes but the result is probably not applicable in the " real world" application, the achieved rpm might not be the same due to so different hydrodynamic conditions in a "static" situation. RPM and power requirement is depending on the load(heavy vs light rider) and

a bollard pull situation is not even close to foiling condition. The foil drag is a reality, and each propeller will react differently to each foil profile, do we really need the information given without the foil drag?

Again Yes, but that will be the strongest grunt in bollard pull, no guarantee this is applicable when the propeller is working on a actually moving object.

For sure testing is worthwhile, especially for the electronics much safer to test how it can take the loads. But can You really predict real world performance in this type of application based on bollard pull is another story.

Let me give an example. For simplicity using an 5hp outboard engine (Petrol or electric) on a light foil boat. You do 3 different bollard pull test’s.

using the high pitch prop: 7.5 X 9
using the high thrust prop: 8.4 X 6
using the high thrust prop: 8.4 X 6 but adding a rice profile nozzle around the propeller.

No doubt the best bollard pull result will be option 3 and the worst for option 1. Rpm I dont know, pending on cavitation, but will probably be different in each option. So now we have hypothetical test result.

For a slow going heavy sailing boat, option 3 will be best. For a light foiling boat, option 1 will be best, this for foiling speeds. To get the boat up on the foil, option 2 or 3 might be better but thereafter the 9 pitch prop works better.

So for lighter boats/boards a better bollard pull result might predict a worse actual performance, however this is not always the case, can be the other way around also…Just saying using bollard pull results for propeller optimizing to predict real world performance on light relative fast boats is a huge challenge. There is a reason why its called "black magic of propellers …

SoEFoil · June 13, 2019, 12:34pm

Thanks for your answer with use cases. I do not pretend to be a guru or to reinvent the wheel just trying to propose ideas, explore new paths (eg best motor timing) and more generally speaking how to make the best possible choice between a list of alternatives… confirm or refute a hypothesis within less than 5 minutes.

As electric foiling is a new subject, I would love to see this list of bollard pull pros and cons being enriched every day (new post ?). Lets imagine that, like a gearbox on a gas car we could highlight that EsC timing could vary with motor rpm … and ask the manufacturers to add a new feature called “Adaptative ESC timing”… just an example

XSailor · June 13, 2019, 1:36pm

Me no guru either but i do have practical experience of boats and related engines/propellers in range from 1-300 hp and still learning more every year. On one of my boats tested 7 different propellers, none of the results was logical compared to theory and specification on paper, you just have to test them in real condition to see how they work. Anyway it is always a compromise, are You looking for high top speed, torque or what. I am sure that certain aspect of the build can be tested stationary in a pool and have been thinking how to improve the result in bollard pull. One way (as also discussed here) would be to do it in streaming water, but again, then You will have less resistance for the propeller than in the real world so really don’t know what would be the right solution/ how to simulate with good correlation to actual condition.

My own idea of making life simple, if talking about propeller propulsion, would be to mimic torque and rpm of outboards and use their propeller, can not go much wrong. So many outboard manufacturers has been developing those for decades that think the design of those propellers must be relative good. The nozzle around propeller for safety reasons makes things more complicated but probably slightly cutting the tips would probably still work fairly good with a nozzle also.

SoEFoil · June 13, 2019, 2:18pm

Testing a set of efoil propellers with all the comfort of a sitting position in a small boat (the @Louis way) would be a nice test bench . Then there is this alternative, the surfboard fin (diY version to create) to install on a large and stable sup board… OK, there wouldn’t be the flying aspect but we would have the dynamic one the bollard pull does not offer…

Many people including Mat have been testing the 12usd Solas plastic and alu prop with great success.

Who’s going to make the first benchmark test (Gps speed vs Power) from a outboard between a Flying rodeo 125mm and a shortened solas prop ? or from a boat fitted with the Flying Rodeo mast and pod .

kaya_973 · June 16, 2019, 10:52pm

Hi guys

I discovered this forum recently.

I had in mind more than 2 years ago to do my efoil, I designed my stuff, first one based on an alien motor,

By discovering your smart approach to directly use apm engine with direct coolling, simplify th design to its minimum

Is there any chance to have a post with more details about the technic to isolate the motor, I read all your posts but it’s still not clear to me… I have esc flyers, alien engine same, I Baugh an alibaba baba prop, and 4batts 8s 5000mAmp/each +ender for 3d printing
Thks for feedback

Mat, where are U located?

Ben

Mat · June 17, 2019, 12:58pm

Welcome to the adventure!

For the motor preparation:
Check out the doc written by @Vicdes2
https://docs.google.com/document/d/1UosI2KZN9h9E4q1G0ikiLPxTUhX5FFuk09xoBxRoY_0/edit

it’s more details, and you can also have a look at my video : https://vimeo.com/291837634

regarding the battery, you’ll do 8s / 20Ah or 16s 10Ah ?
What Kv is your motor?

and… i’m in houston for a month or 2, and then probably abu dhabi…

Louis · June 17, 2019, 1:36pm

Watched the movie twice. Incredibe!
You also tried ceramic bearings? So many posts. I forget what you did and what you did not. The mounting 3d printing files are updated? Or can I use just the one in this topic?

Mat · June 17, 2019, 3:30pm

Thanks
I didn’t tried ceramic bearings… lead time to procure them was too long, and the open / stainless steel ones i have are doing great, i let the salt water in the pod for a week before opening it last time i went in and they’re brand new… only problem is the magnets that i can’t stop from rusting i need to look at them more seriously
If you go from the end of the topic up, you should find my latest 3d files… there were some improvements between the beginning and the end double check that the pod will fit your mast (mine is a recent Liquid force)

Louis · June 17, 2019, 4:16pm

Still using the corrosion x after a few runs ?The 2k epoxy spray in a can was not good enough to cover the magnets? Maybe some epoxy? If it is too tick maybe it will scratch off by letting the motor rotate? I will look up your files, thank you. I have a F-one foil mast. I think I will give your 3d files and my mast to a friend so he can draw a new file. Ill share that in a new topic if it worked.

Mat · June 17, 2019, 4:31pm

yes, regular corrosion X and i’m usually flushing the pod with fresh water… but i forgot the fresh water home last time…
I didn’t got around to try the 2k, it was just suggested to me… may be this time

kaya_973 · June 17, 2019, 8:11pm

Hi Guys,

Thks mat for your feedback.

I will try to quickly summarize my project. Started in summer 2017 before my second kids. Then time to time on the subject without huge motivation. Difficult Kids…sick…

My initial design targeted the use of APM alien engine. 6000Watt. Exactly : C8085 Outrunner brushless motor 170KV 6000W / xas Available in august 2017.

According to base designe d& personnal analyze : Low speed for engine and “Good” torque was the Key.

A 300A ESC boat module ; water cooling.

Key concern was the Cooling process for Engine & Controller. First idea was to create large container with lot of space and contact to cool Down the motor with cavity for water to go through.

With ESC Controller behind Engine with direct water Entry.

BMS charger is a Max 8S module with plenty options… A very nice stuff… I had some issue to identify a product able to charge more than 6S lipo. Up to 6 it is quite easy and upper quite boring to identify.

Battery is a 7S 5000MAmp from Turnigy 60C / 4 packs of this : 2 in series mounted in parallel to reach 14S /20000MAmp. Almost 4,5Grams of L

Propeller is something difficulty bought in Alibaba at this time / Quite a nightmare to find a propeller with for me appropriate characteristics of size, Shaft constraints & good Pitch.

After a while a couple of printed object I reviewd my “Container to something smaller and less complex.” / If with 3D printer it is quite easy to print / Making an aluminum structure is quite impossible.

==> See Internal “tube” to cool down internal cavity of Engine.

In terms of Static test : battery / esc , motor and prop out of Water ; it is quite Heavy in terms of ACTION… Propulsion. Quite dangerous to get this rotating stuff not far from me… I will try to share this Video once found back…

Now my second approach was to reduce container to strict minimum / Thinking “Now” that Heating won’t be too problematic / Which now seems finally the KEY problem. Or at least one the the Key issue. Right now my container is much smaller, just enough space to mount engine inside.

I loaded some picture to illustrate this.
But as beginners / Only 1 image… See Next Post…

Finally, NOW my plan is to move forward for my efoil this year; So back on line and checking news on it ; I found DIY video from Martin ; In fact I found it 2 year ago the first one and then I did not follow it anymore.
So by going deeper on the subject ; I understand that for smaller eFOIL tube you need to reduce the engine and it goes through a Reductor. I Thought about it long time ago but I could not imagine something doing this job with such rpm and torque and this “thin” size. I got Wrong for this approach.

Anyway, I may have now to conclude about what to DO , either I continue with all my gears available changing my approach to "Mat’s one ; Also in parallel try to start as PacificMesiter!
Let See

First I will check the way to isolate my motor. I will revert back to you. I have plenty questions on this method and also bearings…

benjamin.R

kaya_973 · June 17, 2019, 8:12pm

==> See Internal “tube” to cool down internal cavity of Engine.

kaya_973 · June 17, 2019, 8:14pm

Other Picture of All Gears / part 1

foiledagain · June 18, 2019, 3:07am

Hey Mat, are you still using your carbon prop? I’m throwing blades around every 5 hrs of ride time, so much so that I have two spares at anyone time! I need to find a better solution. I was thinking I might layer one in carbon, does it effect the performance? Speed, battery life etc?

Just · June 18, 2019, 4:24am

2 in series gives u 14S 5Ah, 2 more same series in parallel gives u 14S 10Ah.

kaya_973 · June 18, 2019, 6:20am

Other Picture of All Gears / part 2

Louis · June 18, 2019, 7:01am

170kv at 14s is almost 10.000 rpm at prop.

Another question Mat or anyone that can answer. Why the need to waterproof the phase wires at the motor? After 6cm there is a non waterproof connector. So the phase wires are in the water anyway. Would we loose energy by having the wires inside the water ?

When i build my jetboard I was tired of unscrewing the waterproof lid of the board to charge the batteries. So I just had a + and - sticking out of the board for charging. I did measure if there will flow any Milli amps of current with small distance of the poles inside the water. I could not measure any current at 58volt I think.

s9tim · June 18, 2019, 10:26am

I had a buddy sla print one. It is super strong and uses resin instead. I am trying to see if he can make some for a decent price.

Mat · June 18, 2019, 12:57pm

well, the carbon one broke when my mast fell on the ground when i was fixing the board
it was actually more efficient than the second version with the smooth transition from the motor OD, but i’m not sure of the reason yet (stiffness, smoothness of the profile, thickness of the profile…)

Mat · June 18, 2019, 1:01pm

I actually waterproofed the connectors between the motor wires and the mast wires with sealing electrical tape.
If the wires were far apart with no chance of touching and only used in fresh water, you might be able to get away with it, but i’m using it in salty water, and the wires are bundled together, so I preferred to not take a chance…