  Classical Faraday's law on electromagnetic induction states that a change of
magnetic field through a coil wire induces a current in the wire. A mechanical
analogue of the Lorentz force, induced by a magnetic field on an electric
charge, is the gyroscopic force. Here, we demonstrate a mechanical analogy with
a chiral elastic waveguide subjected to gyroscopic forcing. We study waves in
an infinite mass-spring `gyrocore helix', which consists of a helix and a
central line (gyroscopic elastic core). The helicoidal geometric chirality is
considered in conjunction with a physical chirality, induced by gyroscopic
forces. It is shown that the interplay between these two chiral inputs leads to
the breaking of symmetry of the associated dispersion diagram, resulting in a
unidirectional waveform with the direction of propagation being tunable through
the gyricity.
