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Another application of molded plywood construction was used by Jack Northrop in the construction of the Loughhead S-1. For the S-1. They used a 21-foot-long concrete mold. In this mold were placed three thicknesses of spruce plywood strips, alternately laid, and well saturated with casein glue. Once the strips were in position, the mold was covered with a rubber bag and then a cover was bolted to the bottom mold. The rubber bag inside was inflated and pressure was maintained for twenty-four hours. The half shells produced could be joined, making clean, smooth, bullet like fuselages.
The S-1 was a distinct departure from pioneer and wartime aircraft. Northrop's experiments resulted in a unique cigar-shaped, streamlined fuselage that was of monocoque (French for "single shell") construction, in which strength comes from the outside skin rather than internal bracing. Northrop, Stadlman, and the Lougheads devised and patented a process to make molded plywood monocoque fuselage shells (US Patent #1,425,113, August 8,1922).