The inlets are very shallow so I made a buck to form fiberglass ducts from shaped balsa wood, coated with CA and then epoxy resin, each of which was sanded smooth. Then a mold release
was brushed on. When dry polyester resin was applied, and then while it was wet two layers of 2/3 ounce glass cloth was wrapped around the form. As the buck was made symmetrical in
the horizontal plane and with the engine end offset toward the center of the fuselage in the vertical plane, the same finished part could be used for either side just by turning it over.