Smooth T produces turbine maps with the same number of points on each speed line. A net of equally spaced auxiliary coordinates called beta lines is used in the map smoothing process. The beta lines can be used in performance computer programs to locate the operating point in the map.

In Smooth T the beta lines are composed of parabolas. The beta line grid can be defined either graphically or by the input of the parabola coefficients.You get a proposal for the auxiliary coordinates on your screen, see below. The lower line is for beta=0, the upper is for beta=1.

When you are not happy with the shape of the beta lines as proposed by the program you can modify it easily. On both the lines for beta = 0 and beta = 1 you will see five squares which define two connected parabolas, one for the lower speed range and one for the upper speed range.

From school you will remember, that a parabola is fully defined by three points. If you change the position of a point then the shape of the parabola passing through that point will be modified. You can change the position of each of the ten points with the mouse easily.

A grid with 20 beta lines covers the data in the example below very well: