Direct drive outrunner with direct water cooling


#168


#169

Finally found some time to make a little progress. I covered all the iron and magnets with epoxy hope this is enough. Looks like a lot of people trying to run a outrunner direct underwater. Any good results yet?


#170

What motor & housing is that?


#171

Well, i reached 16.5km/h with a cut down 7.5X8" Yamaha propeller on my windsurfboard with a battery power of 2.1kW using the 6384 PG 100Kv with 12s and a VESC 4.12 with modified cooling with heat pipes and forced air.
At 16km/h it is gliding, becomes little instable and the turnes are tighter.
I have the possibility to swap props now without disassembling the motor and another prop with 7.5X7" is on its way.


#172

Were the STL files helpful?
Does anyone else need them, i can provide them per mail?


#173

Yes, that would be really helpful, thanks!

Btw, has anybody the Solidworks files from the user tunnelvision? He uploaded it on Dropbox but the link expired.


#174

Hi powerglider, still tuning the 3d printer and waiting for few props. Will update once will run in water. Great news. I think with a foil it will get much faster.

Do you know your current at start and 16.5km/h?


#175

The motor current i can actually only measure with my computer and the VESC connected to it. I am not sure, if there was a motor current limitation with the 8" pitch prop. I am very sure there was no current limit with the 5" pitch prop. So i wait for the 7" to test. In the meanwhile i am building a 5 blade guide vane from PLA. Additionally i am rebuilding my battery holder which was made of carbon now with glass fiber. The carbon is highly conductive and i already had two small incidents leading to small fire. Luckily without much damage. This time i am using GFK plate and nylon threads, no more steel rods. There are such a lot of cables everywhere, one small plug on the Tf02 was shorted when i turned the whole board upside down to mount the old drive system, when the battery holder out of carbon was pressing right in the middle between the contacts for B+ and B-.:roll_eyes:


#176

I appreciate that you share so many details. This really helps out others to not make the same mistakes.


#185

Where are you getting this equation from? Are you converting 5.25" in your computations? RPM/V = Kv? V = volts? Kv = ?


#186

Hi MaB,

Did you ever post your results from these props? I’m interested how the pitches of the 2 props compared

thanks!
MIke


#187

Its a Rotomax 80

I only need to install it on my board, so soon i`ll get some results.

IMG_4160IMG_4161IMG_4162IMG_4163


#188

Not enough, the 143 x 200mm pitch seems to push well but shaft failed too soon. I’ll try again this weekend


#189

sounds good. I’m waiting on parts and then will start testing as well.
Fooling around with javaprop this weekend and hopefully printing out props next week.
Good luck!


#190

136mm diameter, cut down from 7 or 7 1/2"
5" pitch was 13-14km/h at 1.7kW
8" pitch was 16.5km/h at 2.1kW
old setup with 6384 130Kv i ran last weekend
~170mm diameter, pitch 5" estimated 16km/h at 2.4kW


#191

This looks beautiful, tell us, how did you test it?


#192

Thank you,

Build goes a little bit slowly, because of work, but maybe a couple of hours away before testing. First I want to test how the motor holds up, when running underwater, and if the esc stays cool. Esc is mounted on the aluminum 5 mm plate that I also use for mounting the foil on the board. I also bolt I trough the board. I quite heavy 90kg, so I’ll hope the Chinese sup foil has enough lift?
Maybe the prop is still to big, but I can always trim it down. The motor is 195 kv, and my esc is 200A running on 8s 45Ah, so I hope this will work. In my old setup, without foil, My throttle is a bike brake, and the cable is connected to a linear potential meter inside the board, this has proven to be a solid waterproof throttle. Let’s see what happens, I’ll keep you updated


#193

Is that a drive shaft that runs through the mast and connect to the prop?


#194

no guess same board same motor , just put on the foil :wink:

@Johannes: this is a very nice built, do you have any problem with water and your bike throttle?

i think with you KV your propeller might be a little big , but you can always switch for the torqeedo ultralight 8*8 … waiting for the test !


#195

Awesome looking setup, but are you going to put a duct around that Sushi maker? :slight_smile:Open props are so deadly and its SO easy for a wrong fall or accident to happen. Just be EXTRA careful Johannes!