Frank Whittle of Great Britain, along with Hans von Ohain of Germany, are credited with the invention of the turbojet engine (the two invented the engine independently). Frank Whittle is generally considered as the father of Jet Propulsion. Air Commodore Sir Frank Whittle, OM, KBE, CB, FRS, FRAeS (1907-1996) was an engineer officer at British Royal Air Force (RAF). At the age of 19 he was given the opportunity to attend the officer training course at the Royal Airforce College at Cranwell (1926-28) where he wrote a dissertation that contained the precursor to the idea of the turbojet engine. Whittle reasoned that to improve efficiency future aircrafts would have to fly faster and higher, for which a new prime mover was needed. (At that time the maximum flying speed of aircraft was about 150 mph and the maximum flight altitude was about 10000 ft.). On January 16 1930 Whittle filed for a Patent for the design of turbojet engine. He received discouraging response from the experts; a letter discouraging any further development of the idea and signed by some of the leading aerodynamicists of the time is displayed at the entrance to the Whittle Laboratory as an interesting memorabilia symbolizing the resistance and difficulties Whittle had to overcome. The patent however lapsed in 1935 when he, an undergraduate student at University of Cambridge, decided that he could not afford to pay the £5 annual fee. He was a member of the Peterhouse College, the oldest of all colleges at University of Cambridge, and graduated in 1936 with a First Class degree in the Mechanical Sciences Tripos. Whittle found that commercial development of the engine may be possible with money raised privately, Powerjets was formed in March 1936. The development of the engine began while Whittle was still finishing his degree program at Cambridge University. On June 30 1939 Whittle was able to run the engine for 30 minutes at 16000 rpm. This demonstration convinced the authorities, at last, that his concept was valid and worthy of substantial support. On 15 May 1941, the first British jet aircraft, the Gloster Meteor, powered by the Whittle engine, flew from Cranwell in Lincolnshire.

It is interesting to follow the development that was taking place in Germany. Hans von Ohain was a 33 year-old PhD student at Göttingen University in 1933 when he started developing the turbojet engine, apparently without knowledge of Whittle's work, being helped by his car mechanic Max Hahn and under the patronage of the planemaker Ernst Heinkel. The first engine prototype was fuelled with hydrogen and started successfully for the first time in September 1937. The First successful flight test in a Heinkel HE 178 test aircraft took place on 17 August 1938. Frank Whittle thus conceived and patented the idea long before Hans von Ohain, but the first successful test flight took place in Germany.

Frank Whittle was later involved with the development of Whittle Turbo-drill and SST (supersonic transport). He wrote "A strong desire to see a second generation SST come into service in my own lifetime became almost an obsession". Unfortunately, however, the only commercial (civil) supersonic aircraft Concorde, powered by the RollsRoyce-Snecma OLYMPUS 593 engines, that entered into service in 1976 had its last flight ever on 26 November 2003. Whittle did not survive to see this sad day, but the author of this article, standing on the roof of Queen's Building which is the home of the Engineering Faculty of Bristol University, witnessed the very last leg of its last historic flight, as Concorde flew very low as a mark of respect to the city - Bristol - which has been its birthplace. Whittle himself was a passenger in the CONCORDE flight to the USA on 4 September 1976. The thoughtful reflections on the development of the Jet Propulsion that went through his mind in reference to this flight are both historically invaluable and utterly inspirational for all of us. These reflections are part of the course lectures I used to give at the Aerospace Engineering Department of the University of Bristol and that I now give at  the Mechanical Engineering Department of the Indian Institute of Technology Kharagpur, I hope to include these here one day.

The invention of Frank Whittle, an engineering student of Cambridge University, has revolutionized human connectivity over the globe and is surely one of the most influential engineering achievements of the 20th century.
©Abhijit Guha