Hall X-1 Low-Wing Monoplane In-Flight Fuel Consumption Test (Plate #5898) (Circa 1928)

Low-altitude flight photograph plate 5898 showing the Hall X-1 low-wing monoplane airborne during fuel tests. — Hall X-1 Low-Wing Monoplane In-Flight Fuel Consumption Test (Plate #5898) (Circa 1928) · Donald A. Hall Estate Collection

An archival master engineering negative print (plate #5898) capturing Donald A. Hall Sr.'s proprietary low-wing tandem monoplane (Hall X-1, registration X7621) airborne during low-altitude flight evaluations in San Diego. Flying level across an unpaved airfield, the aircraft demonstrates its wire-braced low-wing configuration, radial engine installation, and tandem cockpit layout. Chief Engineer Donald A. Hall conducted these flight trials in 1928–1929 to measure rate of climb, airspeed calibration, and fuel consumption under operational load.