Conquering the Night through Research

Because of inadequate funding and official disinterest, night fighting became the responsibility of regular U.S. tactical squadrons during the interwar years. These units had enough problems preparing for day war, much less confronting the obstacles of darkness. Yet, despite minimal budgets, pioneering airmen still strove to conquer the night by developing blind-flying techniques, primarily at the Army Air Service’s Engineering Division at McCook Field, and later at the Army Air Corps’ Materiel Division at Wright Field, both near Dayton, Ohio. The research of 1st Lts. Muir S. Fairchild and Clayton Bissell in the 1920s showed that night operations required a specifically designed aircraft with great speed and maneuverability and an unobstructed view for the pilot. Test flights revealed that pilots became disoriented when they lost sight of the ground and the horizon. Human senses contradicted aircraft instruments, while vertigo magnified a pilot’s confusion. The biggest problems were how to land and navigate at night. U.S. airmen tested electric landing lights and flares without success, though the tests did reveal the need for illuminated instruments and flame dampers for engine exhausts.

In 1928 Edwin Link’s ground trainer made practicing for night missions safer and less expensive, but did not solve the basic problem of flying into inky blackness. Intrepid airmen such as 1st Lts. James Doolittle and Albert Hegenberger attacked the problem of blind takeoffs and landings in what the New York Times called the “greatest single step forward in [aerial] safety.” Newly invented illuminated instruments-a specially designed artificial horizon, directional gyroscope, turn indicator, radio beacon, and barometric altimeter (developed by the Pioneer, Kollsman, and Taylor Instrument Companies, the Sperry Gyroscope Company, and Bell and Radio Frequencies Laboratories)-allowed Doolittle and Hegenberger to make blind flights from 1929 to 1932 that opened the night skies to military operations. At the end of this critical period, 1st Lt. Carl Crane published the first U.S. treatise on night flying, Blind Flying in Theory and Practice (1932). Soon the homing beacon indicator and radio compass made possible night navigation, and flying the air mail across the country during the 1930s gave Army airmen practical experience in flying at night. Late in the decade, U.S. bomber squadrons were practicing occasional night missions, including mock interceptions in which fighter (pursuit) aircraft were guided by searchlights on the ground.

Obvious to aviators was the seemingly insurmountable obstacle of finding another airplane in the vast emptiness of the night sky. If the opposing crew took basic precautions to “black-out” their aircraft, the optimal range of an intercepting pilot’s vision declined to 750 feet or less, though on especially clear nights with strong moonlight three-mile visibility was possible. Night fighters needed assistance from the ground to bring them within visual range of their targets. Until 1938 this help came from searchlight crews lucky enough to illuminate an intruding aircraft and from acoustical locators using conical horns to focus incoming sound. There were also vain attempts to detect radio waves emitted by the spark plugs of aircraft engines or infrared radiation from engine exhaust gases. Tests at Fort MacArthur, California, in 1937 and in Hawaii in 1940 proved the futility of such efforts.

All this development seemed to make no difference. A new generation of bombers such as the Martin B-10 could fly higher, faster, and farther than any fighter in the world, convincing a whole generation of Americans to agree with erstwhile British prime minister Stanley Baldwin that “the bomber will always get through,” whether day or night. On its test flight the Boeing B-17 Flying Fortress set a world record, flying 2,270 nonstop miles at 252 miles per hour. Many airmen believed fighter aircraft could never intercept and shoot down such bombers in broad daylight, let alone at night. Since bombers could strike by day without peril, there would be no need for night missions and no need for a night-fighting capability. Only when the Second World War revealed these new bombers to be vulnerable to attack during the day and unable to “always get through” did the need for night fighters again become clear.

In the United States, air doctrine reinforced a disregard for night operations. At the Air Corps Tactical School, first at Langley Field, Virginia, and then at Maxwell Field, Alabama, the faculty developed daylight high altitude precision strategic bombing and advocated this concept as the offensive doctrine of the U.S. Army Air Corps. Large fleets of fast, well armed bombers would attack key chokepoints in an enemy’s industrial fabric by day-the most rapid, efficient, and least bloody means for defeating the enemies of the United States. The revolution in bomber technology represented by the four-engine B-17 made axiomatic the belief that no defenses could stop such an attack. Brig. Gen. Oscar Westover expressed the conviction of most U.S. airmen when he declared that “no known agency can frustrate the accomplishment of a bombardment mission.” Norden and Sperry optical bombsights could locate precise industrial targets from four or five miles up under the proper conditions, but only during the day and in the absence of high winds and excessive cloud cover.

This strategic bombing doctrine and its advocates overwhelmed any airmen still concerned with defense and fighter operations, and encouraged the building of an air force committed to daylight bombing operations. Thus, the Materiel Division redirected its research in blind and night flying to the problems of aiming bombs through overcast. Defensive strategies reflected this emphasis on daylight precision bombing, and more defensive- minded airmen began to focus on the problems of daylight interception. Even the conflicts of the interwar period, including the Spanish Civil War, gave U.S. airmen no persuasive reasons to alter their thinking.