Given a curve $r(s)$ with constant positive curvature and constant torsion, we consider the curve $r'(s)$. If $k_r$ and $\tau_r$ are the curvature and torsion of $r(s)$, what are the respective curvature and torsion of $r'(s)$ in terms of $k_r$ and $\tau_r$?
My answer isn't very rigorous but here goes:
We have a helix curve. The tangent curve of a helix curve is a circle. A circle has no torsion so the torsion of $r'(s)$ is $0$. A circle has constant curvature and since $r'(s)$ is tangent to $r(s)$ they share the same curvature $k_r$.
Does this make sense?