1. OIb/hr/lb, and a sea levelstatic thrust of 6000 pounds. The engine weighed about 1900poundsresultinginaTMIof 3.16. The advent of the Berlin Crisis and KoreanWar hastened the development of the afterburning turbojet J-47. More than 35000 J-47 engines were produced with andwithout afterburnerand powereda host of military aircraft, including 2000 8-47 bombers, each equippedwith six J-47's. J47 alsopoweredthefamous NorthAmerican F-86SabreJet, whichset aspeed recordof 670 mph. J-47was also the first jet engine certified inthe UnitedStatesfor commercial applicationin 1949.
2. In the 1950's, a number of technological breakthroughswere made. It is not possible to chronicle all the technical achievements of this period. The most notable breakthroughs are development of variable stators for the compressor which improved the starting problem and compressor stall margin, modulating afterburners, and air-cooled turbine blades boosted the maximum allowable turbine entry temperature and prolonged the life of the hotsections. These andother advances in the gas turbine technology led to the design of a number of successful afterburningturbojetswhichpoweredalmost allthe centuryseriessupersonicfightersand bombers. Among the well known engines are: Pratt & Whitney J-57, Bleed bypass turbojet J-58, and General Electric J-79. P & W J-57 was a landmark inthe turbojet history as itwasthefirstturbojetdesignedto adoptatwo-spoollayoutusedbymostof the current military and commercial turbofan engines. P & W J-57producedawet thrust of 14000 Ibf and weighed about 5000 Ibf yielding aTMIof 2.80.
3. General Electric J-79 afterburning turbojet proved to be one of the most successful propulsion systems. J-79, like P & W J-57, utilized a Twin Spool arrangement. This arrangement permitted increasedcompressorefficiencyand higher pressure ratio (c13)with 17 compressor stages. GE also introduced a single shaft version of J-79 equipped with variable stators. More than 17000 J-79 were reportedto have been built by The General Electric Company by the year 1987 and some 11000 engines were in active use. The J-79 is proclaimed to be designed with nolife-timeandcycliclimits! P&WJ-58bleed bypass turbojet (Figure 1) represents a marvel in the history of the gas turbine engine design. This engine is believed to be the most expensive and complicated design ever undertaken inthe gas turbine history. TwoJ-58spowerthe LockheedSR71 Mach+3 reconnaissanceaircraft. At low speed, the efflux from the engines provides the necessarythrust. At Mac 3, the engine core produces only 18% of the overall thrust,the restbeinggeneratedat suctionin the intake(54%)andfromthespecialejector nacelles(28%).TheJ-58bumsaspecialJP-7fuel supplied inflight by Boeing KC-1350 Tanker. AlthoughSR-71hasbeenretired,it is still being used by NASA for hypersonic research.