Isotropic Helicoid

thingiverse

# isotropic-helicoid Lord Kelvin's hypothesized shape, as described in Thomson, W. (Lord Kelvin) 1871. Hydrokinetic solutions and observations. Phil. Mag. Ser. 4, 42, 362-377. >"An isotropic helicoid may be made by attaching projecting vanes to the surface of a globe in proper positions; for instance, cutting at 45° each, at the middles of the twelve quadrants of any three great circles dividing the globe into eight quadrantal triangles. By making the globe and the vanes of light paper, a body is obtained rigid enough and light enough to illustrate by its motions through air the motions of an isotropic helicoid through an incompressible liquid. But curious phenomena, not deducible from the present investigation, will, no doubt, on account of viscosity, be observed." Inspired by recent papers investigating Kelvin's hypothesis, e.g. https://doi.org/10.1103/PhysRevFluids.6.074302 (see also article, https://physics.aps.org/articles/v14/s89) https://github.com/chadfrost/isotropic-helicoid Note, if printed in PLA, must be at least ~80% infill or it will float in water (PLA density ~1.25 g/cm^3). 2021-07-29: Added fin angle parameter. Fixed fin location to scale with sphere diameter. 2021-07-29: Added example .stl with fatter fins, at 30 deg (instead of default 45 deg)