MILITARY
AERO ENGINES
The HYPE & THE
HYPER
Today, practically all the frontline fighters of the world use turbofan jet engines. For tomorrow, one concept fast gaining momentum is that of ‘HYPERSONIC’ flight.
PHOTOGRAPHS: ROLLS ROYCE, PRATT & WHITNEY, SNECMA AND EUROJET
W
right brothers Orville and WilJET PIPS THE PISTON By Air Marshal (Retd) bur are credited with making By the middle of the 1950s, jet engines had V.K. Bhatia, New Delhi the first controlled, heavierbeen propelled to centre stage as power than-air flight. To power the plants of choice for all combat aircraft. aircraft, they had specially commissioned Piston-engines were confined to powertheir bicycle workshop mechanic, Charlie ing transport, liaison and other special Taylor, to build a matching low-weight enduty aircraft. Even here, improvements in gine, mostly of the light metal aluminum. the turboprop (jet engine with propeller) On December 17, 1903, with the first flight pushed the piston out of the mainstream. of Wright Flyer The speed advan1, they not only tages of the jet F135 made aviation engines were so history but also alluring that by set the trend the next decade, for designers all large civilian and manufacaircraft were also turers of aero jet powered. But engines to it was not till the build products late 1970s, when, in sync with the with the advent requirements of high bypass jet EJ200 TP400 of the aircraft. engines, fuel effiSensibly, this ciency was so optrend has continued during the entire timised as to herald the era of fast, safe and span of the rapidly changing aviation sceeconomical travel for the general public. nario, but most unfailingly, in the field of Meanwhile, eruption of Cold War resulted military aviation. in an unprecedented arms race, which also AE3007 ENGINE FOR GLOBAL HAWK Aero engines per force have to be exgave catalytic push to ever faster airplanes tremely reliable, lightweight, powerful, flying at high speeds at the extremes of atmofuel-efficient, easily maintainable and caspheric boundaries. Who can forget the highpable of operating at high altitudes as also at high speeds. ly complex Pratt & Whitney J58-P4. A pièce de résistance, the Initially, automobile engines were suitably modified and used J58-P4 was especially designed to power the US spy plane, the on aircraft, but soon a new breed of aero engine manufac- trisonic SR-71 Blackbird. Sharing the limelight was its counturers sprang up to cater for the specific needs of designers terpart, the Tumansky R 15(B) engine extraordinaire, used to and manufacturers of aircraft. Various types of piston-engines power the matching Russian MiG-25 Mach 3 high-altitude airwith different cylinder positions, such as inline, rotary, radial craft for both interception and strategic reconnaissance roles. and v-shaped, were tried out. But in their quest to fly faster and higher, especially the fighter aircraft, designers hit a CUT TO THE PRESENT dead end with the propeller-driven, piston-engined aircraft, While jet engines continued to evolve and were perfected as the because with the propeller-tips reaching the speed of sound, mainstay for powering military combat aircraft, other engines the aircraft speed had to remain in the vicinity of 500 mph. It were also being improved upon for use on various other types was realised that if aircraft performance was ever to increase, of aerial platforms. Mach 3 fighters and their engines may have a way would have to be found to improve the design of the pis- lost some relevance after the arrival of space-based and near ton engine—or, alternatively, a wholly new type of power plant space platforms, but there are other fields where technological would have to be developed. The latter proved to be an easier advancements offer capabilities to match emerging requireoption with the advent of the gas turbine engine, commonly ments. While advanced models of turbojets are being used for called a ‘jet’ engine, which, as the events unfolded, ushered jet fighters, turboshafts are being further honed to power the in a revolution in aviation almost as vital as the first heavier- new breed of helicopters. Similarly, while advanced technolothan-air flight by the Wright Brothers. gies are being used in the field of turboprop engines, predomiIssue 5 • 2009
SP’S AVIATION
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