Engineering work involved a three-year commitment from the company and incorporated an extensive amount of wind tunnel testing at the California Institute of Technology (Caltech). The resultant design was a large but aerodynamically "sleek" airliner, incorporating the cockpit in a streamlined glazed "dome". The engines featured a unique nacelle tunnel cowl where air was ducted in and expelled through the bottom of the cowl, reducing turbulent airflow and induced drag across the upper wing surface. After a mockup was constructed in 1938, Curtiss-Wright exhibited the innovative project as a display in the 1939 New York World's Fair.