A correct solution was also received from Bradley alum Brain Laughlin ('81), Philippe Fondanaiche, Robert T. McQuaid, William Webb.
There are numerous variations on the main equation to the problem. If we assume (as we may) that the radius of the porthole is 1 unit, then the area, A, swept out by a wiper of length L is given by the equation
Solving for A to be half the area of the porthole gives two solutions: L = 21/2, 31/2.
A little straightforward calculus gives you a maximum of about 52.45% of the area of the porthole with a wiper of length approximately L = 1.588.
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