1/8th-inch versus 3/16th-inch drive shafts: which is better?

[RazorAntilles]

Howdy all,

Been a while since I've posted, but I wanted to pick the brains of veteran builders as to the diameter of drive shafts for RC submarines, especially my 1/96th LA build. I see a lot of commercially-available propellers that are drilled for 3/16th inch shafts, but my past experience building a 1/144th Iowa-class battleship featured 1/8th-inch drive shafts. Is there really a major difference in terms of the shaft diameter in terms of performance or is it a strength of shaft aspect for better rigidity while spinning, is it because drilling a bigger hole in the propeller makes it easier to attach to a shaft, or something else entirely?

Before I get myself in trouble with propellers, any and all information would be greatly appreciated!

[He Who Shall Not Be Named]

Howdy all,

Been a while since I've posted, but I wanted to pick the brains of veteran builders as to the diameter of drive shafts for RC submarines, especially my 1/96th LA build. I see a lot of commercially-available propellers that are drilled for 3/16th inch shafts, but my past experience building a 1/144th Iowa-class battleship featured 1/8th-inch drive shafts. Is there really a major difference in terms of the shaft diameter in terms of performance or is it a strength of shaft aspect for better rigidity while spinning, is it because drilling a bigger hole in the propeller makes it easier to attach to a shaft, or something else entirely?

Before I get myself in trouble with propellers, any and all information would be greatly appreciated!

If the propeller shaft extends any considerable length from the stern tube -- typically running through a strut bearing just forward of the propellers hub... hanging out there for God and everyone else to see -- then shaft diameter is driven by the models scale. In such situations I'll go from 1/16" to 3/16" diameter, depending on subject.

If the propeller shaft does not extend outside of the hull (modern 'teardrop' hulls) I prefer 3/16". Not for strength -- always go with stainless steel -- but for convenience.

Here's how I handle a 1/96 LA boat and a 1/35 Type-23, both big enough to house the bigger diameter shaft:





3/16" propeller shafts.

And here is the 1/144 XIA SSBN that uses a 1/8" propeller shafts due to its small size and tight tappered stern:

[RazorAntilles]

Thanks so much for the info!

[Timothy L]

That was a question I also had. Thanks for asking. Dave, I always appreciate your photos and explanations so much. Thank you.
Tim

[redboat219]

So I guess "it's not the size that matters, it's how you use it".