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Performance Charts T200/ which propeller


(Sven) #1

@adam @jwalser @rjehangir
Hello,
I looked at the performance charts for the T200 thruster here and I noticed, that there is a difference in full speed thrust in reverse and forward direction. Is this difference cause due to the motor because it has a preferred direction to spin or is it cause due to the propeller because it is designed to produced more thrust in one direction, then the other. If the difference in thrust is a result of the behavior of the propeller, then I would like to know which propeller you used for the measurement (clockwise or counterclockwise).

Thanks!
Sven


(Rusty) #2

@Sven - The difference between forward and reverse thrust is completely intentional. It is based on the propeller design and both the CW and CCW propellers have the exact same performance. Forward is when the thruster is blowing water out the back over the pointed tail cone. Reverse is when the thruster is blowing water out the front over the nose cone and cable.

For example, if you mount two thrusters side by side, one CW and CCW, and spin them both to push the vehicle forward, they will have equal thrust.

We did this because it has relatively little effect on most ROV applications but provides additional thrust for forward-only applications like surface vessels.

-Rusty


(Sven) #3

Hi Rusty,
Thanks for the fast answer and for providing this information for me.

Forward is when the thruster is blowing water out the back over the pointed tail cone. Reverse is when the thruster is blowing water out the front over the nose cone and cable.

This is only true I think, if you use a thruster with clockwise propeller mounted on it.
But anyway, if I keep in mind what you say, then you use a clockwise propeller for your performance chart measurement and the difference in thrust is a result of the shape of the propeller. That matches my measurement result.

Thanks!
Sven


(Adam) #4

Hi Sven,

This behavior holds true for both the clockwise and counter-clockwise propellers. The direction of the propeller does not change the shape of the blade to reverse the direction of thrust bias, it just mirrors to blades. Forward and reverse thrust are the same with both propeller types- the thruster is just rotating the other way, but water is flowing in the same direction. The nozzle shape also has a small impact on the thrust bias, but the propeller shape accounts for the majority of it.

-Adam