I think I will end up doing that @PowerGlider , in this configuration the diameter is increased by 5.8mm, and it would probably enable more blade area closer to the shaft if the prop was mounted there, so it could be more efficient.
I made a new 2 blade propeller that I’ll do some tests on this afternoon, it fits much nicer and has more pitch than before.
These KEDA motors are very easy to work with, I basically have connected the bells of the motor by putting M3 screws through the propeller mounting holes, and pushing the shafts maybe 4mm through so the rotors are well aligned.
This will make it much more efficient than one propeller per motor, and it should be easily able to peak over 4KW reliably with 2 VESCS.
rpm and dutycycle control cannot override the maximum current setting in VESC, there is no need to use current control as input signal. I use dutycycle.
You will need two points to mount the stators, at least you need transfer of the torque? Than another thing becomes important: You need to align the stators AND the rotors, than it would work.
Be careful with two VESCs, they influence the bus voltage (and ground) of each other which can lead to voltage differences destroying some interfaces in the past.
6364 alone might be a little weak, never tried it, i only have experience with 6374 and 6384.
With 190Kv it is also a little weak in torque.
Try to build a prop with 4" pitch and same diameter for a single motor.
Yeah sure, for a single motor the difference is just acceleration or rpm drive.
But if you use 2 motors mechanically tied together you have to measure each motor independent and then use current control, so the power gets distributed equally. Otherwise minimal changes in motor design or model errors will wind up in the PID controller and cause unequal power distribution.
Thats good to know about duty cycle, i’ve never used it, what are the advantages?
I use 2 VESCS on my electric skateboard, and use CAN-BUS control so the master VESC controls the throttle of the slave VESC via CANBUS, it hasn’t given me any issues at all in this configuration
The stators will be connected with a 3d printed structure that locks them together, and the stator are aligned perfectly as the same shaft goes maybe 5mm through on and all the way through the other.
yesterday I tested a single 6364 in the pool with Pacificmeisters 2 blade propeller. It was amazing compared to the propeller that mounted by covering the rotor, i could hardly hold it back with my arm, and that was with a VESC pulling 35 amps from the battery, the motor was at 85 amps though! I’ll try it again this afternoon with a YEP120A HV, hopefully it will be able to run 2.5kw. I was surprised how powerful it was I am sure it could work with one 6364.
running on 6S it was extremely powerful, I can easily say over 25kg of thrust, when I was kneeling on the edge of the pool with both arms holding the front of the board, my whole body was almost sliding backwards on the concrete. When I tested it in the pool, It was not getting me up on the plane, but there wasn’t enough space… it clearly needed a bit more thrust, So i’m about to try it this afternoon with pacificmeisters 3 blade propellers.
I will be sure to post a video here if it works
I think this powertrain is definitely powerful enough if the board has more capacity so it doesn’t require so much power to get up.
Phantastic job! Might have better efficiency comparing to a single motor (the same principal as in multirotors).
What do you say @jakebarnhill1 to incorporate very cheap setup with 6-7s two batteries and 5065 motors, each 1500wt. As per links as follows, below.
With appropriate two blade prop?
I’m sure that has a ton of power but two open blades especially one that close to the back of the board where you are crawling up and likely to squeeze the trigger by mistake is deadly. You best find a way to enclose those blades or this could happen but much worse: Nice cut from propeller - Safety - FOIL.zone
@vefoil that is definitely a serious concern! I knew I should make a duct for safety but you’ve motivated me to do it for the next ride…
It just didn’t have enough power to get me up on the plane still… Do you think that a larger surfboard that is more buoyant can make a lot of difference? The small foam board I’m using is submerged when I lay on it in the water.
@Antonbit The motors I’m using are extremely cheap at $60AUD each. I don’t think that the motors you linked would have enough torque at 320KV, my 190KV motors are still to high…
But if it could work with cheap ESC’s like you linked that would be good for lowering the cost!
Great to hear! I cant stomach the thought of guts getting sliced open or private parts - shark bait! lol
With direct drive setups the proper foil and board it 50% of the setup, if those two are not matched for low thrust setup then your toast. A planning hull is critical, the wider the back of your board the better, and flatter the bottom as well. a surfboard that tapers in at the back won’t work with the direct drive.
Direct/Jet drives are safer and sleeker with much less drag than a large prop and duct, but the trade-off is a much wider board, little longer, and a flat bottom.
What size is your board, and what foil, also what is your weight?
And yes, if your RPMS are maxing out then you have left over torque to use and a 3 blade should provide more thrust.
@VeFoil The board I was testing on is a small foam surfboard, which i was testing with dual motors as you saw above but no foil. My new build which I’ve started already is with the parts below. The only thing I’m concerned about is the size and buoyancy of the surfboard that I’m using.
My board is a 6’2 surfboard, it has a flat bottom and is made of fibreglass but certainly isn’t very buoyant…
Hi Jake, I use also an old surfboard it’s even smaller and I am 10kg heavier. To start it’s a little harder (power and skills) but once your up on the foil it has less inertia.
One of the drawbacks is the lack of space for big batteries
I have no doubt you will need a board that is 28+" wide, and it must be wide at the back to get planing, that board will plow the tail through the water and prevent you from getting up on foil most likely. But if you have not tried it, test it out first, your only 72kg, thats lot lighter than me 115kg
