Hello again;
Retrieved the years old plans and sketches from the deep dark depths of the back closet.
Yes, another rubberband powered submarine, this one inspired by Jules Verne's
Nautilus.
There is a long and widespread tradition of people designing subs to varying degrees of faithfulness to what Verne describes in his 20,000 Leagues Under the Sea text.For instance,
https://www.vernianera.com/Nautilus/Catalog/The model I have drawn up can be considered more-or-less 1/72 scale. Roughly 38 inches long with a 4.5 inch beam.
Construction will be frames, stringers, skin; with interior free-flooding. After all, rubber band motors get along with water somewhat better than electric motors do.
Working lights are desired.
The big question of the moment is the propeller/propellor(I prefer the less common -or spelling)
Way back in early 2000s when idea originated I had acquired a 3-blade pusher prop meant for .049 airplane motors. At this point on the calendar I am not sure where it is or even if I still have it. Or what condition it would be in. At a previous residence it served to differentiate the ceiling fan chain from the light bulbs chain. I know it was taken down when I moved but that was 3 residences ago. Am also not yet sure whether such a prop is currently available, haven't searched yet.
But ...
I am pondering, well, just barely beginning to, what other propellor might be serviceable.
Decades ago, the 1970s, I built some simple wooden boat and sub models which used regular rubber band airplane props. Being underwater with rubber band power they turned fairly slowly. The RC deep-vee prop, which is nylon with metal hub insert, on PRS-1 does turn fast enough at beginning to cavitate a bit, but it also pierces the surface at start of run.
Unless the prop on this Nautilus model is something like 4 inch diameter it likely will not pierce the surface.
If a regular boat prop is to be used it will need to be fairly lightweight so as to make pitch trimming of the sub simple, and especially important, have a shaft hole all the way through so as to allow rigging a loop for the motor winder to use.
And that is as far as my brain has got for now.