Topping the reasons why thermoplastics are gaining momentum are their processing capabilities, recyclability and short cycle times.

If you’ve ever gazed out of the airplane window while waiting to push back from the gate, you’ve probably seen large cargo containers – or unit load devices (ULDs), as they’re called in the industry – being placed onto the aircraft. For 30 years, ULDs were made from aluminum. But 12 years ago, CargoComposites introduced a new option. “We developed and patented a design using a thermoplastic fiberglass polypropylene composite,” says Tom Pherson, president and CEO of CargoComposites in Charleston, S.C.

The body of the ULDs are made from ½-inch thick panels comprising two fiberglass polypropylene skins that are continuously laminated onto a polypropylene honeycomb core. They are pressure formed to shape the edges, then machined, trimmed and drilled on a CNC machine. The containers feature a fabric door constructed of an ultra-high molecular weight polyethylene composite – the same material used in bullet-proof vests – with a special coating.

Thermoplastic ULDs are lightweight, durable and cost-effective, three important characteristics for the airlines that utilize them. Pherson says the average aluminum ULD weighs 180 pounds, while a thermoplastic ULD hits the scales at 127 pounds. That saves airlines more than $1,000 per container each year on fuel costs, he adds.

The TAPAS2 Torsion Box

The TAPAS2 consortium is developing a 39-foot thermoplastic torsion box for a tail structure for Airbus. Photo Credit: Copyright 2015 TenCate

“Airlines are waking up to the cost associated with ULDs,” says Pherson. “For years, aluminum was fine until they started looking at the economics behind the containers. Now they are more conscious about fuels costs and carbon dioxide emissions and looking for unique opportunities to save money.” Thermoplastic composites offer that savings: Pherson says his company’s ULDs provide “aerospace properties at industrial economics.”