Clarin said:
Hi Waterfox,
How many Kv is your SSS56104? I have ordered the same gearbox has you, but was wondering if I should order the 500Kv or 700Kv?
Thanks to all of you for sharing your amazing build
Clarin, I bought the 500kV SSS56104. Given that pacific meister succeeded with a 500kV SSS, 7:1 gearbox and 10S battery. I wish we had more data than someone's youtube video..
3.7V/S * 10S * 500RPM/V * 1/7 = 2643RPM
Using 12S with a 8:1 gear ratio should be safe at 2775RPM.
My previous attempt used 6S with 260kV = 5772RPM. Had a pretty low pitch prop.
I was looking at marine outboard motors: Mercury Optimax 150hp: motor spins at ~5500RPM with a 2:1 gear reduction: 2750RPM prop
Some interesting considerations are the max input RPM of these Neugart gearboxes are 18000RPM and the recommended input is 5000RPM, so I would be exceeding that at 22000RPM (12S * 3.7* 500kV). I'm planning to heat sink the gearbox.
Also, the 8:1 gearbox has a much lower torque rating than the 5:1. 6Nm vs 14Nm nominal output Torque.
I bought the 8:1 because it was available.I might have selected a 5:1 if I could have due to the max torque and the ability to spin a smaller prop faster. That would be less efficient, but maybe a little safer.
I am hoping to end up using the 126mm ducted prop here.
https://www.aliexpress.com/item/Dia-126mm-3-Blades-Kort-Nozzle-Ducted-Propeller-Assembly-for-Electric-Motor-Underwater-Thruster-Robot-ROV/32823114033.html
Logical, it looks like that is approximately the size you are using. Has that been working out for you?