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Aviation History
2003
2003 - 0025.PDF
TECHNOLOGY COMBUSTORS MICHAEL PHELAN / LONDON Swirling thruster to shrink ramjets Technology promises to reduce size of missiles and offer high-performance combustion for hypersonic projects Boeing is developing compact, high-performance combustors that it hopes will greatly reduce the size of ramjet-powered missiles and aid hypersonic projects and third-party engine developers. The compact swirl-augmented thruster (CoSAT), developed by Boeing Rocketdyne and Simma Technologies, promises high-perfor mance combustion in weight- and volume-limited propulsion systems. The device, consisting of a sys tem of guide vanes, swirls the air entering an engine's combustor. Boeing Rocketdyne Joint Strike Fighter (JSF) lift thrust augmenta tion (LTA) project engineer, Bob Pederson, says "the swirl pattern induces a recirculation zone in the combustor, eliminating the need for flame holders". This promotes a stable flame, increases fuel mixing and turbu lence levels, and enhances flame propagation. Pederson claims com bustion efficiency is 90-99%. The system was originally devel oped to provide additional lift thrust for Boeing's Short Take-Off and Vertical Landing (STOVL) X-32 JSF bid that lost to the rival Lockheed Martin X-35 (see dia gram). Two LTAs provided 3,6001b (16kN) additional thrust during vertical lift operations, burning bleed air from the main engine's turbine with additional fuel, and delivered a fuel specific impulse of about 2,400s. Boeing says the technology's reli able performance across wide throt tle limits means engineers can easily scale the design for other applica tions, such as gas turbine engines, ramjets, and turbo-ramjet and rocket-ramjet combined cycle engines. Pederson says: "We're try ing to get the technology known: we're working with the hypersonics team in the Phantom Works and briefing the US Air Force, Navy, NASA and DARPA [Defense Advanc ed Research Projects Agency]." X-32B VERTICAL LIFT AND CONTROL THRUSTERS Lift thrust augmenters use turbine bleed air to generate increased thrust , FLIGHT .. ..... ....• ... The performance of ramjet-pow ered missiles depends on their size and weight, Pederson says. "A typi cal long-range, rocket-ramjet pow ered, Mach 4 to M6 missile has a combustor length-to-diameter [1/d] ratio of five." The length is driven by an ineffi cient conventional flame stabilisa tion and combustion propagation step-down mechanical flame holder, and the boost propellant packaging needed to accelerate the missile to ramjet takeover speed. "Using CoSAT technology, an 1/d ratio of 1.6 is possible, and we'd like to achieve less than one," Pederson says. The booster fuel would then be packaged separately and ejected as the ramjet takes over at M2 or M3. In a turbo-ramjet combined cycle engine, turbojet compressor air could be burned by the ramjet using CoSAT technology to quicken the boost phase, as well as in the ramjet-powered phase at higher speeds. AIRPORT SAFETY Air France in security tests Air France has tested a Sagem- developed fingerprinting security technique at Paris Charles de Gaulle Airport. The week-long test was conducted on flights to Tel Aviv, and aimed to ensure all passengers who checked bag gage also boarded the aircraft. The biometric technology compares fingerprints taken at the check-in desk with those taken at the boarding gate. Air France says the system "represents a real opportunity to improve the check-in and board ing processes for passengers while maintaining irreproachable safety standards". The experiment was con ducted on volunteer passengers and the airline is analysing the results. A similar system for air port employees is being tested at Paris Orly Airport. MAINTENANCE On board fault checks promise health boost Boeing aims to revolutionise pre ventative line maintenance with the commercial launch of its Airplane Health Management (AHM) system in 12 months' time. Boeing AHM programme man ager Robert Manelski says the real time onboard fault notification sys tem could be in service early 2004, if mid-year beta-testing with partici pating customers is successful. The system datalinks fault mes sages from an aircraft's central main tenance computer (CMC) to Boeing ground stations, which are passed instantaneously to the operators base. Manelski says AHM will be used for "fault-forwarding, provid ing advance warning of failures ...and aiding fault prioritisation for non-airworthiness-related faults". He adds: "We've been recording fault indications on in-service 747- 400s and 777s and we've mined the data for significant samples. Our confidence in the patterns is very high, as we are using real-life data instead of trying to model the oper ating environment." When first deployed, the bene fits of the AHM system will be eco nomic rather than safety-related. The extra information should allow airlines to make a more informed decision as to when to perform preventative line-mainte nance work with minimum sched ule impact or financial penalties. While AHM would be the vehicle for more wide-ranging prognosis in the future, Manelski says the tech nology for such applications "is not yet mature". SEE FEATURE P26 BAE/DDC-I SYSTEM BAE Systems has teamed with DDC-I to create a development environment for safety-critical software. Combining BAE's CsLEOS Arinc 653-compliant real-time operating system with DDC-I's SCORE multi-language development environment, SCORE-653 will support both Ada and C languages and generate application software for PowerPCs. F-16 SOFTWARE Lockheed Martin has selected Green Hills Software's Integrity real-time operating system for the F-16 Block 60's colour dis play processor. The "ultra-reliable" operating system provides software partitioning, memory protection and real-time response with guaranteed resource availability, Lockheed Martin says. www.fliqhtinternational.com FLIGHT INTERNATIONAL 14-20 JANUARY 2003 23
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