#helix#constant curvature curve#orthogonal frame#Frenet#Belyaev#movable
Date of design: 1934Designer: Belyaev (futher details unknown)Price: 30 rubles
For a regular space curve $\gamma$ at each point one can define a triple of vetors: a tangent vector $\tau$ (tangent to $\gamma$), a normal vector $\nu$, and a binormal vector $\beta$.
These vectors together make an orthonormal basis that is called a Frenet (orthogonal) moving frame.The model shows a Frenet moving frame along a helix-like curve. A helix is the only spatial curve with constant curvature and torsion.