DAYTON, Ohio -- Late 1920s-era General Electric turbo-supercharger of the type tested by Lt. Macready in the XCO-5 on display in the Early Years Gallery at the National Museum of the United States Air Force. (U.S. Air Force photo)
Dr. Sanford Moss (left) with Lt. G.W. Elsey and Capt. Rudolph Schroeder in front of the special LePere LUSAC-11 equipped with an exhaust driven turbo-supercharger built by General Electric. Dr. Moss invented this supercharger and continually improved its design through data obtained during flight tests at McCook Field. (U.S. Air Force photo)
Schroeder's Altitude Flights, 1918-1920
During World War I, the Air Service began making test flights at high altitude. On Sept. 18, 1918, Capt. Rudolph W. "Shorty" Schroeder set a world record of 28,900 feet in a Bristol airplane from McCook Field. In 1919 he established three more world altitude records, and on Feb. 27, 1920, in a LePere airplane fitted with a General Electric turbo-supercharger, he reached a world-record height of 33,114 feet. When he removed his goggles to change oxygen flasks in order to continue breathing in the rarified atmosphere, the minus 63 degree air temperature immediately froze his eyeballs.
Schroeder passed out from the lack of oxygen and carbon monoxide poisoning and the LePere plummeted nearly six miles in two minutes; at the very last moment, he regained consciousness and pulled the plane from its dive. Although he was almost totally blind, Schroeder was able to locate McCook Field and land safely.
Macready's Altitude Flights, 1920-1926
Following the injury to Schroeder's eyes, the project for testing turbo-superchargers was assigned to Lt. John A. Macready. For the next six years, Lt. Macready flew all the tests, routinely climbing higher and higher, first in the LUSAC 11 and, beginning in October 1924, in the XCO-5, an improved high-altitude test plane.
During these tests, Macready set various world altitude records; the highest he flew in his open-cockpit plane was an indicated 40,800 feet. On practically every flight, he encountered some kind of emergency, such as the supercharger overspeeding and exploding, engine failure or cooling system freeze-up, or a propeller flying off its shaft. For courage and zeal in the face of unknown dangers and extreme hardships, Macready was awarded the Mackay Trophy for 1921.
It was not until World War II that the full benefits of these high-altitude test flights were realized, when planes such as the B-17, B-24, B-29, P-38 and P-47 were so successful in carrying the war to the enemy at high altitude. They all used General Electric turbo-superchargers based upon those primitive models tested and constantly improved in the 1920s and into the 1930s.
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