Calculating Prop Shaft Diameter
 

Hi,

I'm making a large scale (13ft) model submarine and am currently designing
the propulsion unit for it.

If I told you I have a 2hp driving a 3 bladed prop would someone here be
able to tell me a suitable prop shaft size?

Cheers,

Michael

Calculating Prop Shaft Diameter
 

No, but if you told us what submarine, what scale you were using, (what prop
diameter), then max torque could be figured. It is torque and prop shaft
length that determines shaft diameter, not HP. I would hazard a guess at
..625 to .750 inches.
Steve

"Michael" q.quqkq wrote
in message .uk...
Hi,

I'm making a large scale (13ft) model submarine and am currently designing
the propulsion unit for it.

If I told you I have a 2hp driving a 3 bladed prop would someone here be
able to tell me a suitable prop shaft size?

Cheers,

Michael

Calculating Prop Shaft Diameter
 

Michael wrote:

I'm making a large scale (13ft) model submarine and am currently designing
the propulsion unit for it.

Try going to psubs.org. They're building manned ones, but as small as
your model. Someone there can lead you to the answer.

M

Calculating Prop Shaft Diameter
 

Are you designing the sub. to meet performance specifications?
Does weight matter or does it interfere with the indented performance.
Some time, you may have to cut the weight down from the start.
If this is the case the weight and size of the shaft will matter and you may
have to select the proper material to maintain the weight requirement.

wrote in message
ups.com...
Michael wrote:

I'm making a large scale (13ft) model submarine and am currently
designing
the propulsion unit for it.

Try going to psubs.org. They're building manned ones, but as small as
your model. Someone there can lead you to the answer.

M

Calculating Prop Shaft Diameter
 

wrote in message
...



Are you designing the sub. to meet performance specifications?
Does weight matter or does it interfere with the indented performance.
Some time, you may have to cut the weight down from the start.
If this is the case the weight and size of the shaft will matter and you
may have to select the proper material to maintain the weight requirement.

wrote in message
ups.com...
Michael wrote:

I'm making a large scale (13ft) model submarine and am currently
designing
the propulsion unit for it.

Try going to psubs.org. They're building manned ones, but as small as
your model. Someone there can lead you to the answer.

M




Thanks Guys,

M,

I'm a member of the Psubs mailing list but I must admit I didn't think to
ask them.

Marierdj,

I've worked out the sub has to weigh around the 2000kg mark before it will
sink, and generally speaking you have to add lots of ballast to get 'em to
dive so not too worried about weight.

Steve,

I've done the math, and using the data on the motor, I've calculated that
the max torque is 0.78Nm (7 pound inch) and with a shaft length of 1m max.

Cheers,

Michael