The attached Excel spreadsheet calculates the taper and station information from 3 user defined parameters (input in the green fields):
B Taper # - Any number can be entered, but Powell's best B tapers range from 8.0 to 9.0.
Rod Length (inches) - 7' to 9'6" is the recommended range.
0" Tip Diameter (inches) - This simply defines the starting flat-to-flat diameter at the 0" station. From there the 'calculated slope/inch' is used to fill in the taper and planing form data.
The data shown in the image below is for an B8.7 taper that is 8' long with a 0" tip diameter of .068".
Download the zipped Excel spreadsheet linked below to create your own EC Powell B taper.