Tech updates of interest
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Tech updates of interest
Just a couple of interesting articles (RE: the A340-500/-600 landing gear test rig and MTU's HPC12 experimental six-stage compressor)
Latest gear from Airbus
Despite rapid and effective advances in computer simulation software, the necessity of physically testing systems as a final proof of design efficacy remains, which is why the largest Airbus landing gear test system yet constructed has just come on stream. It will complete more than 6000 cycles before the end of this year for the forthcoming longest-range and largest-capacity Airbuses built so far, the A340-500 and -600. Apart from the physical distance between the main and nose landing gears, the test rig is described as being a full-scale copy of the actual aircraft landing gear system, complete with wheels, tires, and associated hydraulics and control hardware. The rig is at the facilities of Airbus UK at Filton, England. Airbus UK is responsible for the design and build of Airbus aircraft wings and for the specification and integration of the landing gear system into the aircraft. Design and supply of the landing system equipment is the responsibility of 14 different international suppliers.
The aircraft use an all-new center landing gear supplied by Messier-Dowty and, for the first time, brake-by-wire for both the primary and back-up braking systems, supplied by Messier-Bugatti, is incorporated. Although the system is based on the landing gear design of the current A340, the much higher maximum takeoff weight of the new aircraft (up from 275 tonnes to 365 tonnes) demanded some major changes.
There are three particular elements of note. First, the center landing gear has been completely redesigned to a four-wheel bogie, with all wheels braked. Second, the higher weight of the aircraft has seen tire suppliers Michelin and Goodyear develop what are described as the highest load-rated tires for any civil aircraft. According to Airbus, each tire is capable of carrying a weight greater than that of a 30-tonne juggernaut while travelling at the speed of a Formula One car. Third, Airbus said that the greater aircraft weight loading has also led to the development of its largest ever carbon brakes. These are supplied by AlliedSignal and BFGoodrich. Each brake can absorb up to 115 MJ—equivalent to simultaneously stopping 320 one-tonne cars from 60 mph—requiring the brake discs to withstand temperatures approaching 1500°F.
Test work on the rig, which cost some $12 million to build and equip, will continue throughout 2001, and well over 6000 cycles are scheduled. Intensive efforts have been made to create a full-scale copy of the actual aircraft's landing system. This includes the length of the pipework used to construct the test rig duplicating that of the actual landing gear system on the aircraft. The A340-500/-600 are slated to enter service next year.
On another note, low-weight aluminum compressed air pipework is being used for jigs for the construction of wings for the A340-500/-600 and for the A330/A340. Produced by SimplAir, the pipework forms a framework for each of the jigs, creating workstations. Air tools can be connected "at any point" in the SimplAir pipework, said the manufacturer. Each framework comprises mainly 80-mm pipework, with the air passing up the jigs through column risers and branching out at each level in pipework sections measuring 4-12 m long. Its light weight allows the SimplAir pipework to be suspended from, or fixed to, any existing ceiling or wall surface via hanging or wall-mounting brackets, but provides no extra support to the structure. The jigs are three-story structures, and air tools are used at every level during wing construction.
http://www.sae.org/aeromag/techupdat...h4.htm#feature
Six-stage compressor program
Munich-based MTU Aero Engines is progressing development of its HPC12 experimental compressor. It is a six-stage transonic high-pressure compressor with a pressure rise capability of 11:1 and is designed as a fully functional engine component. The company reports that in a two-week trial simulating harsh conditions in a service environment, the compressor delivered "outstanding results." The two-week test included pressure ratio, airflow efficiency, surge margin, and other performance elements. MTU said that it used 3-D aerodynamic design techniques to achieve optimal compressor efficiency and robustness "even at high stage pressure ratios." It added that 3-D design "appreciably lowers" manufacturing and maintenance costs over comparable current compressors: "These costs are crucial criteria, especially in medium- to long-haul service."
The HPC12 program includes the development of highly heat-resistant materials for the final two compressor stages. On the basic HPC 12 work, MTU is cooperating with the DLR (German Aerospace Center) and with academic institutions.
Next month, MTU is scheduled to ship the first production EJ200 engines to be installed in the special Eurofighter IPA (Instrumented Production Aircraft). By 2005, a total of 363 engines are scheduled for delivery to power Eurofighters. Production engines were tested at Rolls-Royce (UK), FiatAvio (Italy), ITP (Spain), and by MTU itself.
Meanwhile, MTU is continuing its development of a new family of geared turbofan engines in partnership with Pratt and Whitney and FiatAvio via the Advanced Technology Fan Integrator (ATFI) program. The powerplants would be for large business jets and regional jets, and the target is to offer enhanced economics together with lower noise (30db(A) less than Stage 3 requirements) and emissions levels. The program has the additional aim of reducing manufacturing costs by some 30% compared to current ungeared turbofan engines together with lower life-cycle costs. Power output is likely to be at two levels: 10,000 lb for 50-60-seat aircraft and 18,000 lb for 100-seat airplanes.
According to the company publication MTU Report, the partnership is working in anticipation of requirements for an ATFI powerplant. Martin Wiedra, Senior Manager, New Products at MTU stated, "We want to use the demonstrator program to mature the technology to a point where we can promptly convert it into a new product when the time and market have come for it."
MTU sees business jets being introduced that have wider fuselages able to provide added comfort and believes this development will lead to the need for advanced, economical engines using geared-fan technology. Future upgrades of current business jets might also offer opportunities.
The company explains the concept of the geared fan as interposing a reduction gear between the fan and low-pressure turbine, "which in today's engines are on a common shaft and necessarily rotate at the same speed," but can then each run at its own optimum speed, which for the fan is lower than for the turbine. "What the ATFI demonstrator is to prove is that an engine with a high-speed, low-pressure turbine transmitting its power to the fan through a gearbox will distinctly improve consumption, noise levels, and, above all, costs," said MTU.
MTU's particular role in the program is development of the high-speed, low-pressure turbine. The company has noted expertise in this area and is confident that it can reduce the number of turbine stages and therefore cut weight and manufacturing costs. Experience gained within the Engine 3E technology program (previously described by Aerospace Engineering, it is German industry/government-funded) is benefiting from the work.
To cope with the unparalleled high powers and temperatures, MTU is developing new blade materials and airfoils as well as new rotor concepts and brush seals for the high-speed low-pressure turbine. The company said that the low-pressure turbine's development and production content in the overall program is about 25%. According to MTU, that stake might grow appreciably if the company manufactures the high-pressure turbine as well, an option that is currently being discussed.
http://www.sae.org/aeromag/techupdate/04-2001/tech2.htm
Latest gear from Airbus
Despite rapid and effective advances in computer simulation software, the necessity of physically testing systems as a final proof of design efficacy remains, which is why the largest Airbus landing gear test system yet constructed has just come on stream. It will complete more than 6000 cycles before the end of this year for the forthcoming longest-range and largest-capacity Airbuses built so far, the A340-500 and -600. Apart from the physical distance between the main and nose landing gears, the test rig is described as being a full-scale copy of the actual aircraft landing gear system, complete with wheels, tires, and associated hydraulics and control hardware. The rig is at the facilities of Airbus UK at Filton, England. Airbus UK is responsible for the design and build of Airbus aircraft wings and for the specification and integration of the landing gear system into the aircraft. Design and supply of the landing system equipment is the responsibility of 14 different international suppliers.
The aircraft use an all-new center landing gear supplied by Messier-Dowty and, for the first time, brake-by-wire for both the primary and back-up braking systems, supplied by Messier-Bugatti, is incorporated. Although the system is based on the landing gear design of the current A340, the much higher maximum takeoff weight of the new aircraft (up from 275 tonnes to 365 tonnes) demanded some major changes.
There are three particular elements of note. First, the center landing gear has been completely redesigned to a four-wheel bogie, with all wheels braked. Second, the higher weight of the aircraft has seen tire suppliers Michelin and Goodyear develop what are described as the highest load-rated tires for any civil aircraft. According to Airbus, each tire is capable of carrying a weight greater than that of a 30-tonne juggernaut while travelling at the speed of a Formula One car. Third, Airbus said that the greater aircraft weight loading has also led to the development of its largest ever carbon brakes. These are supplied by AlliedSignal and BFGoodrich. Each brake can absorb up to 115 MJ—equivalent to simultaneously stopping 320 one-tonne cars from 60 mph—requiring the brake discs to withstand temperatures approaching 1500°F.
Test work on the rig, which cost some $12 million to build and equip, will continue throughout 2001, and well over 6000 cycles are scheduled. Intensive efforts have been made to create a full-scale copy of the actual aircraft's landing system. This includes the length of the pipework used to construct the test rig duplicating that of the actual landing gear system on the aircraft. The A340-500/-600 are slated to enter service next year.
On another note, low-weight aluminum compressed air pipework is being used for jigs for the construction of wings for the A340-500/-600 and for the A330/A340. Produced by SimplAir, the pipework forms a framework for each of the jigs, creating workstations. Air tools can be connected "at any point" in the SimplAir pipework, said the manufacturer. Each framework comprises mainly 80-mm pipework, with the air passing up the jigs through column risers and branching out at each level in pipework sections measuring 4-12 m long. Its light weight allows the SimplAir pipework to be suspended from, or fixed to, any existing ceiling or wall surface via hanging or wall-mounting brackets, but provides no extra support to the structure. The jigs are three-story structures, and air tools are used at every level during wing construction.
http://www.sae.org/aeromag/techupdat...h4.htm#feature
Six-stage compressor program
Munich-based MTU Aero Engines is progressing development of its HPC12 experimental compressor. It is a six-stage transonic high-pressure compressor with a pressure rise capability of 11:1 and is designed as a fully functional engine component. The company reports that in a two-week trial simulating harsh conditions in a service environment, the compressor delivered "outstanding results." The two-week test included pressure ratio, airflow efficiency, surge margin, and other performance elements. MTU said that it used 3-D aerodynamic design techniques to achieve optimal compressor efficiency and robustness "even at high stage pressure ratios." It added that 3-D design "appreciably lowers" manufacturing and maintenance costs over comparable current compressors: "These costs are crucial criteria, especially in medium- to long-haul service."
The HPC12 program includes the development of highly heat-resistant materials for the final two compressor stages. On the basic HPC 12 work, MTU is cooperating with the DLR (German Aerospace Center) and with academic institutions.
Next month, MTU is scheduled to ship the first production EJ200 engines to be installed in the special Eurofighter IPA (Instrumented Production Aircraft). By 2005, a total of 363 engines are scheduled for delivery to power Eurofighters. Production engines were tested at Rolls-Royce (UK), FiatAvio (Italy), ITP (Spain), and by MTU itself.
Meanwhile, MTU is continuing its development of a new family of geared turbofan engines in partnership with Pratt and Whitney and FiatAvio via the Advanced Technology Fan Integrator (ATFI) program. The powerplants would be for large business jets and regional jets, and the target is to offer enhanced economics together with lower noise (30db(A) less than Stage 3 requirements) and emissions levels. The program has the additional aim of reducing manufacturing costs by some 30% compared to current ungeared turbofan engines together with lower life-cycle costs. Power output is likely to be at two levels: 10,000 lb for 50-60-seat aircraft and 18,000 lb for 100-seat airplanes.
According to the company publication MTU Report, the partnership is working in anticipation of requirements for an ATFI powerplant. Martin Wiedra, Senior Manager, New Products at MTU stated, "We want to use the demonstrator program to mature the technology to a point where we can promptly convert it into a new product when the time and market have come for it."
MTU sees business jets being introduced that have wider fuselages able to provide added comfort and believes this development will lead to the need for advanced, economical engines using geared-fan technology. Future upgrades of current business jets might also offer opportunities.
The company explains the concept of the geared fan as interposing a reduction gear between the fan and low-pressure turbine, "which in today's engines are on a common shaft and necessarily rotate at the same speed," but can then each run at its own optimum speed, which for the fan is lower than for the turbine. "What the ATFI demonstrator is to prove is that an engine with a high-speed, low-pressure turbine transmitting its power to the fan through a gearbox will distinctly improve consumption, noise levels, and, above all, costs," said MTU.
MTU's particular role in the program is development of the high-speed, low-pressure turbine. The company has noted expertise in this area and is confident that it can reduce the number of turbine stages and therefore cut weight and manufacturing costs. Experience gained within the Engine 3E technology program (previously described by Aerospace Engineering, it is German industry/government-funded) is benefiting from the work.
To cope with the unparalleled high powers and temperatures, MTU is developing new blade materials and airfoils as well as new rotor concepts and brush seals for the high-speed low-pressure turbine. The company said that the low-pressure turbine's development and production content in the overall program is about 25%. According to MTU, that stake might grow appreciably if the company manufactures the high-pressure turbine as well, an option that is currently being discussed.
http://www.sae.org/aeromag/techupdate/04-2001/tech2.htm
