Hi all,
I was previously using a 2-blade prop with my 6374 motor and 10s batteries but having a lot of motor phase issues or something weird with timing that meant i could never apply more than 50% throttle on take off or it would make a horrible sound and cut out. Almost like it was shorting or missing a phase. Today i tried a friend’s Foil Drive 3 blade aluminium prop and hub and WOW what an incredible difference. So smooth and seemed to be way happier touching down than my 2 blade nylon props.
My question is would 3 blades that are significantly smaller than my 2 larger blades be pulling a lot more current? I also managed to fry my 160A Flycolor X-cross HV3 ESC today - which baffles me since i have a current limit and thermal limit set. But if trying the 3 blade system is what caused the ESC pop then i will stick to 2. thoughts?
I suspect your aluminium blades are lower pitch and higher mass, permitting more power output. Could be your battery to ESC wires are too long and you need capacitance to maintain smooth ESC input voltage under high loading. I’ve seen that listed as an issue in the RC industry and it could give similar symptoms.
Interesting. My battery to ESC cables are only about 40mm long. I compared my nylon blades to the aluminium ones and it appears the aluminium ones are about 25-30% smaller. But probably more surface area overall since there is 1 extra. Not sure about the pitch.
on closer inspection of the ESC there are 3 capacitors that have completely blown. the remaining 7 are fine and the system still fires up and works. Have ordered a replacement and will be improving cooling even further. Currently only cooling one side of the ESC mosfets with an external heat sink.
If everything is setup, so you achieve compareable thrust for start and compareable speed, my expierience is, a 3Blade needs about 15-20% more current during foiling.
In Advantage you usually have more thrust with the 3Blade.
3Blade: More thrust for start, less highspeed (If current is limtied)
2Blade: Less Thrust during start. Higher highspeed, If current is limtied, or 15-20% less consumption for same fixed speed (compared to 3 Blade same fixed speed)
Sorry to hear about your esc. I have the same model but haven’t pushed it hard yet as I’m on a sup foil using it to just assist into waves. I’m putting it into prone foil board currently and keen to learn from others on its limits. I have an external alu heat sink attached to it but can I ask what thermal and current limits you set on the yours that got damaged?
No worries, as it turns out it was just a few smd capacitors that exploded, so i was able to solder some new ones on and it now works again. I have also improved my cooling solution (hopefully) by machining an alu clamp to pull heat from both sides of the ESC - clamping both sets of mosfets. Yet to test but i am hoping this will be an improvement.
Thermal limit set to 70deg C, Current limit 75A. I have also changed my prop to smaller ones that are more in line with Foil Drives size. Hoping this will take care of the motor demag/timing issues i have been getting with the bigger props.
