Yes still riding takuma ( smaller then gong M ) , speed is not that low :29km/h and 60A is high for me , i think I can go 50A with the RL wing
It is already lower in amp than a gong L at 25km/h
For me any thing bigger than 1250cm2 will increase amp above 20km/h
What’s the lowest speed you can ride on the foil at?
If it’s the v100 it’s the slowest foil on the market, ie lifts out the water at the slowest speeds.
No , never really measured , I can tell you tonight , probably around 15km/h I think
Yes I have v100 from 2017
The v900 is the biggest
I tried the gong L which bigger and slower than the v100 , more stable and you can real push on it when turning
Yeah both foils are designed for low speed takeoff with the V900 taking off at only 3MPH. So I would guess the V100 would take off at around 6MPH.
More data !!
140mm diameter yamaha prop
Maytech 65162 100kv motor
ttps://www.aliexpress.com/item/Marine-Boat-Propeller-For-Yamaha-Outboard-Part-Aluminum-Alloy-2-Stroke-2HP-2-5HP-Outboard-Motor/33000170289.html?spm=a2g0s.9042311.0.0.63e663c0ni2ZVR
So kv announced is really wrong by 3x the value or am I missing something 12768/42=304…
Or the Swordfish data logger is totally off. Do you have a laser/strob tacho to check?
4,6kW at 77% Throttle,
3,8kW at 56% Throttle
Is there any speed Data?
That is really much Power.
In my opinion, not a efficiant setup, as far you are not going 40kph+
And 10-13k rpm sounds not plausible
That would be ~30m/s or over 100kph 
I may be wrong? also I am not familiar with the settings options of a Swordfish data logger however I would suggest that the RPM value is reading X3 the true value or to put it another way every time each phase is energised, the motor has no hall effect sensor to send back a signal so perhaps the data logging it readings another way of counting the RPM that may not be configured correctly? Can someone advise if this could be the case ?
The kV value is normally given unloaded.
For me at 408.7s, we have the medium value of all charts:
50% throttle, 75A, 9000rpm, 45v
Taking into account this is a test without load, with 40-50% rpm loss once loaded, it wouldn’t be that bad under load.
Original propeller 7.25 OD x 5" pitch reduced by 24% to 140mm = x 0.761
The Thales theorem says that pitch is reduced by the same ratio = 0.127m x 0.761 = 0.0966m per rot per minute
x 5000 rot/min x 60 min/h = 28.9kmh
Divided by pole pairs (3), guessing it is erpm not rpm, so it makes 100kv
You need to set the correct pole numbers in the logger to get the correct RPM data. It appears you have the poles set to 2.
If I remember correctly this motor has 6 poles so the RPM data needs to be divided by 3 still.
Therefore Max RPM in the graphs would be 12768/3 = 4256.
Considering the voltage is 42.4V I’d say your motor is more than 100Kv.
Isn‘t there a need for a „thrust bearing“ in this setup?
I only feel a little cavitation when start, the rest of the ride works well.
This is the video with 140mm prop 100kv motor
Fron The Graph above it looks your avarege current is around 70-80A.
Do you have comparison to your geared setup?
This looks like they are simply labelling the 120Kv motor as 100Kv!
At that RPM and assuming it is actually 120KV it would be giving an efficiency of around 88% which would be about right.
It will be very interesting to see what speeds you are reaching with this prop and whether it can handle 6" and 7" props well.
What OS are you using on your PC for downloading the logs? I had issues with my swordfish 300A, although I’m convinced it was defective anyway as it would only start up the first time and then not again until I powercycled it.
windows 7, this was my first test with 140mm I will update data gps next rides :guiño:
I use the same prop with less diameter (120mm) in my gearded propulsion tp power reisenauer with aprox 60-70A average
thank you @virus for the numbers, i used swordfish last year:
anyway this set up works
