[ASK] 2 blade or 3 blade

[chazter]

which better? thruster with 2 blade or 3 blade?

[olegodo]

I think there are a lot of factors that needs to be defined before anyone can answer that question correctly.

Stuff like Motor RPM, Motor torque, Motor power, blade size, blade pitch/angle and much more.

I have no knowledge to calculate or determine this. But there is quite a few people here on the forums and elsewhere on the interwebs that have done quite a lot of testing on motor and prop combinations for our style of use.

Just an observation though. Most smaller commercial ROV's use either two or three blades in different shapes or sizes.
The larger and more powerful ones often have bigger 3 or 4 blade thrusters.

[TigerShark]

Most of my testing and that of others here has shown that three blades seems to work best with small brushless motors. It will really be your particular combination of motor, voltage and current you want to run at that will determine the best propeller though.

[chazter]

thanks for the answer,

i'm gonna use rule 1100 GPH as the thruster, is 2 blades with 40 mm diameter good enough?

[TigerShark]

thanks for the answer,

i'm gonna use rule 1100 GPH as the thruster, is 2 blades with 40 mm diameter good enough?

I have similar pump motors (which I am now replacing with brushless) and they worked best with the Graupner 50mm three blade props from my testing.

[SSN626B]

From my days in the submarine service, I believe that the higher the number of blades on a prop, the lower the ideal blade speed.
Regards,
TCIII/SSN626B