Help with prop size?

[Farkel]

Need help sizing a prop on a Blackjack 42 running a TPPower 4070 motor with a Castle XLX2 ESC .Batteries are 2 14.4 100 c 5000 ma in series or 8s.8mm bullets and OSE 8 mm connectors.Is a 1.6 x 42 enough prop? All help appreciated.

[mappo]

Need help sizing a prop on a Blackjack 42 running a TPPower 4070 motor with a Castle XLX2 ESC .Batteries are 2 14.4 100 c 5000 ma in series or 8s.8mm bullets and OSE 8 mm connectors.Is a 1.6 x 42 enough prop? All help appreciated.

Check out the YouTube channel Ironclad rc has your answer.

[mappo]

What’s the kv on the motor? That would be helpful to know. If you’re using a Tp 4070 1520kv. On 8s then a 42 mm prop would make a good start, and check the temperature. download the Data Logging, then you can consider upsizing

[Farkel]

Yeah,sorry.the motor is 1520 kv.Thanks for the help.

[Fluid]

8S is far too much for a 1520 Kv motor. Even 6S is pretty high for a 43” boat. A 4070 motor is pretty small for a boat that large too, if he wants to upgrade the boat’s performance there are better choices. And a 42 mm prop is pretty small for much efficiency, a lower Kv will allow a better prop. The OP really needs to rethink his entire drive system.




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[Farkel]

I am having difficulty reconciling your comments with the Owners Manual for the Blackjack 42.The manual states that:
1) the factory installed motor is a 1350 Kv Spectrum;
2) the factory ESC is 160 A;
3)the batteries to be used for propulsion are 2 14.8V,5000 ma 4S1.6 100c packs in series as this is the way the boat is factory wired.
4)Stock propeller is 1.6 x 42.
With this S