Ryan NYP Center of Gravity Calibration in Level Cruising Attitude (1927)

Three-quarter rear view of the Spirit of St. Louis elevated on tail stand showing level cruising flight line. — Ryan NYP Center of Gravity Calibration in Level Cruising Attitude (1927) · Donald A. Hall Estate Collection

A definitive engineering photograph capturing the Ryan NYP Spirit of St. Louis positioned on Dutch Flats in exact level flight attitude. With its tail skid supported on a vertical trestle, the aircraft mirrors its in-flight cruise profile. This perspective allowed Chief Engineer Donald A. Hall to calculate aerodynamic center-of-lift alignment and verify longitudinal balance against shifting fuel weights.