Making material gains

Aerospace designers will cunningly employ the term ‘unobtainium’ to refer to exotic or costly materials - or even when researching the development of a material that is perfect for their needs in every respect - except that it doesn’t actually exist!

Unobtainium can also be applied to those materials that are capable of withstanding the extreme temperatures required in the latest aero engines. Often, designers will daydream of designing an aircraft which requires components with the strength or resilience beyond that of available materials.

Titanium was once seen unchallenged as the industry’s lightweighting metal of choice, but whilst its unique, high strength-to-weight ratio properties and corrosion and temperature resistance ensured it has consolidated its standing as a firm favourite, non-metallic materials like carbon fibre-reinforced plastics are gradually eroding the metallic dominance within aerostructure manufacturing demands.

Meanwhile, exacting safety-critical demands mean we’ll always be faced with arduous and often torturous material certification requirements. Imagine a giant version of the Scales of Justice, where on one side you have the finished aircraft, and on the other a huge pile of documentation. The upshot being that the aircraft won’t fly until the documentation is the same weight as the aircraft!

For whatever story that might play out, designers live in hope that somehow base metal can eventually be turned into gold. They continue to look for that sweet spot; they’re still eager to tap into the mother lode hidden at the end of the runway.

Mike Richardson, editor