STABILITY RESEARCH AT THE NATIONAL PHYSICAL LABORATORY

“No Longer an Island” was the phrase that characterized the attitude of British citizens after the Wrights’ European demonstration in 1908 and Louis Bleriot’s successful flight across the English Channel in the following year.2 Immediately responding to this rapid technological development, the British government set up an Advisory Committee for Aeronautics (АСА) consisting of representatives from universities, industry, and the military. The committee’s function was defined as “the superintendence of the investigations at the National Physical Laboratory and… general advice on the scientific problems arising in connection with the work of the Admiralty and the War Office in aerial construction and navigation.”3 Accordingly, an Aeronautics Division was founded in the Engineering Department of the NPL in Teddington, and Department Superintendent Thomas Stanton and his assistant Leonard Bairstow started to measure aerodynamic forces in a new wind tunnel.4

In formulating their research program from autumn of 1911, Stanton and Bairstow were influenced by George Bryan’s new book, Stability in Aviation. Bryan, an applied mathematician, proposed a general theory of stability, suggesting it as a basis for NPL wind tunnel experiments.5 To utilize Bryan’s theory, Stanton and Bairstow had to measure not only lift and resistance but also rotative moments of an airplane model caused by wind from all directions. Bairstow devised original instruments different from those suggested by Bryan and had them constructed by instrument makers at the NPL and the Cambridge Scientific Instrument Company.

Experimental data were produced by the spring of 1913. When the data were plugged into Bryan’s theoretical equation, they produced a measure of the model’s stability. From these calculations, Bairstow offered practical suggestions to airplane designers on the position and size of tail planes to maintain stable flight. Bairstow’s experimental results were summarized in several technical reports and used by Edward Busk, an aircraft designer at the Royal Aircraft Factory in Famborough. Based on the data and the suggestions from the NPL, Busk succeeded in designing a very stable biplane, the B. E.2c, which was mass-produced during World War I. In this intermediary role between Bryan the theoretician and Busk the practitioner,

Bairstow served as a “translator” between scientists and practical engineers, a role described by historian Hugh Aitken and others.6 Bairstow was aptly called “an aeronautical form of the ‘scientific middleman.’”7

Bairstow’s stability research was taken very seriously by aeronautical engineers in Britain and abroad. On the eruption of the First World War in 1914, the British Advisory Committee for Aeronautics decided to classify all technical reports. Neutral Americans lost access to on-going aeronautical research in England. Edwin Wilson at the Massachusetts Institute of Technology became reluctant to continue his stability research for fear of duplication. When the United States entered the war in 1917, the National Advisory Committee for Aeronautics (NACA) in the United States officially requested the АСА to permit access to technical reports. The АСА discussed the matter at its main meeting and decided to open its technical results except for one subject – stability. The stability research of Bairstow and other workers was regarded too important to share even with the Americans.

Bairstow had thus achieved a remarkable prominence for a young man. Bom in 1880, he had studied at the Royal College of Science and entered the Engineering Department of the NPL in 1904. In 1917, he was elected a Fellow of the Royal Society. In the same year, Richard Glazebrook, NPL Director and АСА Chairman, asked him to assume the new post of Superintendent of the NPL’s Aerodynamics Department, which had evolved from the former Aeronautics Division. Despite this favorable offer, however, Bairstow decided to work instead for the Air Board as a scientific researcher and consultant.8 It was in this role that he would become a controversial advocate for a certain kind of aeronautical research.