Flight Test Performance Blueprint (1927)

An original blue cyanotype blueprint detailing the calculated flight test performance, fuel economy, and range of the Spirit of St. Louis, signed by Donald A. Hall on May 9, 1927. — Flight Test Performance Blueprint (1927) · Donald A. Hall Estate Collection

The culmination of Donald A. Hall Sr.'s rapid engineering. This original 1927 cyanotype blueprint details the calculated flight test performance, fuel economy, and range of the Spirit of St. Louis. It is officially signed and stamped by the Chief Engineer on May 9, 1927, just days before Lindbergh's departure.