Material technologies

An SCT has only a small payload fraction; therefore it becomes very weight sensitive. To make a Concorde-like SCT viable, the necessary reduction of structure weight (compared to available technology, e g A340) will be about

30% for a Mach 1.6 SCT 40% for a Mach 2.0 SCT 50% for a Mach 2.4 SCT.

Even when considering for the high unit price of an SCT. this seems to be very risky’ But still some improvements in other technologies, especially configuration selection, may reduce the weight improvement requirements given above

New Materials:

For Mach numbers below 1.8. highest temperatures occur in sunshine on ihc ground. For Mach numbers above 1.8. cruise temperature becomes important, especially in respect to life time Below Mach 2.0. emphasis for the airframe is still more on light weight than on temperature Some materials envisaged arc carbon fibers (CFRP), metal matrix compos­ites (MMC) for highly loaded parts and ceramics.

For supersonic engines creep resistant high temperature matenals are required (peak tem­perature at cruise).

Manufacture:

New methods are required to manufacture very light weight structures and elements. For new materials, methods must be developed to fabricate parts and to join them to assem­blies.

Concepts for inspection, repair and crashworthiness are required.

All these have to be qualified early.

Structure design:

Materials and manufacturing principles must be integrated in the design process. For higher Mach numbers, the design must consider for thermal dilatation and stress.

Optimization methods will reduce weight and integrate structure design with other disci­pline’s needs.

Aeroelastics:

Provide data early in the design process, to direct the interdisciplinary design to an opti­mum solution which considers for aeroelastic deformation and which will have a safe flutter margin.

Integrate stiffness (and thermal» design with aerodynamic design (aeroelastic/ aerother- moclastic tailoring)

Certification:

New materials and manufacturing methods must he certified, before being considered in design.

For Mach numbers above 1.8, thermal fatigue properties must be demonstrated for the materials, for structural concepts, and for the aircraft itself

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