Sir Frank Whittle, English aviation engineer and pilot, who invented the jet engine, was born on the 1st of June 1907, in Coventry, Warwickshire, England. The son of a mechanic, Whittle entered the Royal Air Force (RAF) as a boy Apprentice and soon qualified as a pilot at the RAF College, Cranwell. He was posted to a fighter squadron in 1928 and served as a test pilot in 1931 - 1932. He then pursued further studies at the RAF Engineering school and at Cambridge University in 1934 - 1937. Early in his career, Whittle recognised the potential demand for an aircraft that would be able to fly at great speed and height and he first put forth his vision of jet propulsion in 1928, in his senior thesis at the RAF College.

The young Officer's ideas were ridiculed by the Air Ministry as impractical however, and attracted support from neither the government nor private industry. Whittle obtained his first patent for a turbo-jet engine in 1930 and in 1936 he joined with associates to found a company called Power Jets Ltd. He tested his first jet engine on the ground in 1937. This event is customarily regarded as the invention of the jet engine, but the first operational jet engine was designed in Germany by Hans Pabst von Ohain and powered the first jet -aircraft flight on August 27, 1937.

The outbreak of World War 11 finally spurred the British government into supporting Whittle's development work. A jet engine of his invention was fitted to a specially built Gloster E.28/39 airframe and the plane's maiden flight took place on May 15th, 1941. The British government took over Power Jets Ltd, in 1944, by which time Britain's Gloster Meteor jet aircraft were in service with the RAF, intercepting German V-1 rockets. Whittle retired from the RAF in 1948 with the rank of air commodore and that same year he was knighted.

The British government eventually atoned for their earlier neglect by granting him a tax-free gift of £100,000. He was awarded the Order of Merit in 1986 and in 1977 he became a research professor at the U.S. Naval Academy in Annapolis, Maryland and his book Jet: The Story of a Pioneer was published in 1953, but he had a breakdown and died in 1996.

Also in America at the same time, the government did not want Pratt & Whitney to get into the jet engine business, but to concentrate instead on the production of piston engines. In the meantime in 1940 General Electric, Westinghouse and Allis Chalmers were set up in business with the aid of US. Government contracts and went into turbine production using Cyclops 17w for both the wheel and blades. The blades which were being assembled on the wheels in keyhole slots around the rim had to be machined all over. During 1942 and 1943 production was shifted to a Timken alloy wheel and Vitalium turbine blades and the blade production was now changed to a Dental investment lost wax casting process which only required a very minimum of machining. At that time the Vitalium alloy was made by Hanes Stellite Company for the Austenal Dental Laboratories, who owned the Vitalium Trademark.-

With grateful thanks to - Jack Connors - U.S.A.

CONCLUSION

The major difference between the industrial lost wax casting process and lost wax casting for jewellery and ornaments is that the engineer is looking firstly for precision, tolerances of +/- 5 thousandths of an inch which can easily be achieved and even beaten in many circumstances. This precision necessitated that the moulds for the wax pattern production, had to be produced in steel, instead of rubber which allowed a lot of distortion to take place, although for ease of production, weight and cost saving, aluminium is much more frequently used. In this the most modern and up to date form of Precision Investment Lost Wax Casting, a metal mould was devised with which it is possible to mass-produce wax patterns in high column.

Although being metal and not flexible, as with the rubber moulds for the production of jewellery, varies sophisticated techniques had to be developed to cope with some of the more complex external and internal shape, that over the years industry has demanded. There are several different process operated in the industrial field, Ceramic Shell, Ceramic Shell combined in a block mould centrifugally cast, Shell moulding and block mould for Aluminium casting. It also possible to cast small castings on a bottom pouring, Vacuum suction casting machine as used in Jewellery production.