Hannover, 18. September 2007. - The engine weight has strong impact on fuel consumption and emission, every pound of weight reduction per engine will safe about 1.6 pounds of fuel or five pounds of CO₂. For better propulsive efficiency new engines need larger fans and need to run hotter and spin faster. To meet these contrary targets the larger fan diameters and higher mechanical loading has to be more than compensated by super light weight designs to achieve the customer expectations. Enabling technologies are more integrated designs, advanced materials and further design optimisation.

Examples for more integrated designs are titanium blisks instead of conventional bladed compressor stages, inertia welded rotor drums, and even nickel based blisks for compressors. In the future the blisk technology will even migrate into the hot part of the engines, e.g. for dual alloy turbine blisks. The advances made already are enabled by innovative manufacturing technologies.

Materials used in modern jet engines are dominated by titanium and nickel based super alloys, both difficult to machine. For even lighter engines in the future the content of PMC will be growing. More advanced materials like nano-reinforced titanium and aluminum, fiber reinforced metal and ceramic parts as well as smart materials will be applied in the next generation of military engine and within the next decades also in commercial engine products. Substantial efforts will be necessary to develop stable and economic production and quality assurance processes in parallel.

The higher mechanical and thermal loading means also that design margins have to be further reduced without giving up anything on the safety and reliability of aero engines. The design optimization  will be based on an overall probabilistic approach but also use opportunities to further utilize the potential of the material. Apart from advanced coating and cooling technologies and surface treatments the manufacturing processes will be key to these technologies. Giving up design margins means challenging the production also. Tolerances must be kept within a narrower band, process control and NDI need to be further improved to avoid and detect even smaller flaws in the parts than today without loosing economical efficiency in production.

Simultaneous progress on design, materials and production processes is required to deliver future super light engines for the benefit of the passengers expenses and our global environment.

For more information please contact:

Dr. Erich Steinhardt
MTU Aero Engines GmbH
Technologie und Vorauslegung
Dachauer Straße 665
80995 München
Tel. +49 89 1489 2483
erich.steinhardt@muc.mtu.de