This calculator (and plotter) helps you to design the wing planform. You should enter the input parameters:
wing area (use wing calculator to estimate the area required)
quarter chord sweep
The default values are for Piper Cherokee's rectangular wing (taper ratio = 1 and sweep = 0). Usually the optimium lift distribution requires an elliptical planform. You can get close to that using taper ratio 0.4 at zero sweep.
Press the calculate button to calculate the output values and to draw the planform.
The script does not clear the drawing between new calculations so that you can compare the different forms. Press the clear button to clear the drawing when desired.