Joseph Summers turboprop airliner (the Vickers Viscount) on 16 July 1948 and the initial flight of Britain's first four-jet bomber (Vickers Valiant) on 18 May 1951. By the time he retired, he had achieved 366 general types, second only to the Guinness world record holder Eric "Winkle" Brown who has 487. Summers still holds the world record of 54 "Prototype First Flights". On 15 December 2016, in a Boroondara Council meeting, Joseph Summers had the street formally known as Oliver Street renamed, to honour his work in the military. Summers married Dulcie Jeanette Belcher in 1922 in Sculcoates, Yorkshire. Summers died on
Vickers hardness test the material. The fin attachment pins and sleeves in the Convair 580 airliner were specified by the aircraft manufacturer to be hardened to a Vickers Hardness specification of 390HV5, the '5' meaning five kiloponds. However, on the aircraft flying Partnair Flight 394 the pins were later found to have been replaced with sub-standard parts, leading to rapid wear and finally loss of the aircraft. On examination, accident investigators found that the sub-standard pins had a hardness value of only some 200-230HV5. Vickers hardness test The Vickers hardness test was developed in 1921 by Robert L. Smith and George E. Sandland