Pitch for a 3d hyperbolic spiral

[trustthrust]

Hi, have worked out the formula for a hyperbolic spiral space curve to be r(t)=1/t X cos(alpha)+1/t X sine(alpha) + t and obtained the tangent vector T, normal vector N, and curvature (kappa) with the z axis being the central axis of the spiral. Am having trouble finding the formula for the pitch at any point of this spiral. What I have so far is pitch=arctan(axial speed/tangential speed).

Questions:
1. Is the axial speed the normal vector? Seems to me should be the z component of the normal vector. Is this correct?
2. Is the tangential speed in the above pitch formula the tangent vector T?

Thanks in advance for any help,

 

[Quinzio]

What "alpha" is ?
What "X" is ?

 

[trustthrust]

Alpha is the angle typically in the range from 0 (zero) to 2 phi.
X is a multiplication symbol