Ultrathin Sandwiches Help UAVs Lose Weight

The heavier a bit of flying tech is, the harder it has to work to fly. This creates a number of problems, including power drain, range and diminished payload. If weight goes down, on the other hand, everything gets easier. This is true for planes and helicopters, and even more so for UAVs.

Researchers at HRL Laboratories are chasing this lowered weight dream with a newly developed self-propagating photopolymer waveguide process that it us using to create ultra-thin sandwich structures that could provide a platform for micro-UAVs.

“Sandwich structures improve the performance of weight-sensitive vehicles like airplanes and helicopters because they’re lighter than solid materials,” said Dr. Christopher Roper, senior research staff engineer, HRL, and co-author of “Enabling Ultra-Lightweight Structures: Microsandwich Structures with Microlattice Cores,” published in APL Materials. HRL is a corporate research-and-development laboratory owned by The Boeing Company and General Motors.

Traditional methods of making sandwich structures do not scale down to the thickness and densities need for micro-drones, Roper said. To get

around the limitations of traditional methods, the team created this new fabrication process that leads to super low densities. This means that they can make structures at thicknesses similar to a US quarter, from 0.04 g/cm² down to 0.005 g/cm², but up to 99.6 percent lighter. The resulting “microlattice” material can then act as both the adhesive and core of the structure.

“These low densities are impossible with traditional sandwich structure fabrication techniques because the weight of adhesive would be greater than the weight of the facesheet and core it was holding together,” said Roper. “Micro-drones could facilitate scientific research or enable infrastructure inspections.”

Let there be lighter.