DATCOM allows the designer to input both area, S, and radius, R, for each body station. If we assume R is equal to half the width and height of the input body the maximum area covered is given by:

2R * 2R or 4 * R2

This formula is closely related to the formula for the area of a circle:

pi * R2

We can add a third formula for the area of a diamond:

2 * R2

In the general case, a shape number, Sn, can be calculated by:

Sn = S/R2

Since the maximum value for S is 4 * R2 it follows the maximum value for Sn must be 4.

While there are many shapes possible for an Sn less than 4, I have dervived two formula to give a possible shape. Both formula converge at a circle with Sn = PI.

One formula, the blue line in the figure below is valid for PI <= Sn <= 4.0 and becomes a square at Sn = 4.0

The other formula, the red line in the figure below is valid for 2.0 <= Sn <= PI and becomes a diamond at Sn = 2.0. This formula yields result for Sn < 2.0 however, they are not accurate.


Chart of S = 1.0
Fig.1, Sn = 1.00

Chart of S = 1.5
Fig.2, Sn = 1.50

Chart of S = 2.0
Fig.3, Sn = 2.00

Chart of S = 2.5
Fig.4, Sn = 2.50

Chart of S = 3.0
Fig.5, Sn = 3.00

Chart of S = PI
Fig.6, Sn = PI

Chart of S = 3.5
Fig.7, Sn = 3.50

Chart of S = 4.0
Fig.8, Sn = 4.00

Chart of S = 4.5
Fig.9, Sn = 4.50

Chart of S = 5.0
Fig.10, Sn = 5.00