Per his post on the forum:
I didn't know how I would accomplish it at first, so I penned it out as frilly and loopy as I thought I thought could fly it. It had to be big enough so I could make some pretty quick turns, but doable at lower speeds in the Ercoupe. I had to figure out how big to make it. So, I just started out creating a flight plan adding way points in the AvMap GPS, spelling out the letters. I kept the spacing far enough apart that I thought it would work.Click here to access an interactive version of the GPS track.