Scientists create edible drone built of rice cakes and gelatin that can save lives

The IEEE/RSJ International Conference on Intelligent Robots and Systems in Kyoto last week saw an ingenious creation presented by researchers from the Swiss Federal Institute of Technology Lausanne. Their paper described a drone made from rice cakes.

Mind you, this was no light matter. Titled 'Towards Edible Drones for Rescue Missions: Design and Flight of Nutritional Wings,' by Bokeon Kwak, Jun Shintake, Lu Zhang, and Dario Floreano from EPFL, the paper detailed a drone that could "boost its payload of food from 30 percent to 50 percent of its mass", according to a release.

Still, was it really necessary, one might ask. The drone could be a game changer for those who are unable to access food. Food-delivery drones may not be able to do an efficient job as while they have enough battery range for usage within cities, they might not last on long-distance journeys or in remote locations.

The drone in question, however, will not only be able to reach the person but also provide sustenance right away, ensuring less waste. Whenever a drone is asked to transport anything, the bulk of what is moved is the drone. Most of them carry about 30 percent of their mass as payload, which comes in the form of 'useless' things like wings.

Puffed rice bears resemblance to polypropylene foam, regularly used in drones

The researchers used compressed puffed rice to design the wing of the partially edible drone. Now, compressed puffed rice, which is strong and light, is very similar to expanded polypropylene (EPP) foam, commonly used as wing material in drones. Rice is also "affordable, accessible, easy to laser cut", all while having a "respectable" calorie density.

"Achieving sufficient mechanical properties while maintaining low weight (with food materials) was the foremost design criteria in designing the edible wing. We can expand the design criteria to contain higher calories by using fat-based material—for example, edible wax; fat has higher calories per gram than proteins and carbohydrates," Kwak told IEEE Spectrum in an interview.

So, how is the drone created?

The first step is to laser cut the round rice cakes into hexagons so that they can stick easier, to fabricate the wing. Gelatin acts as the glue, and after it dries, the wing is packaged in plastic and shaped to ensure that it doesn't fall apart in wet or humid environments.

You can't eat the entire drone

Interestingly, the size of the wing depends on nutrition requirements over flight. A wingspan of about 275 inches (700 centimeters) will suffice to deliver 300 kcal, the equivalent of one breakfast serving.

The entire drone isn't edible; the structure and tail surfaces are made of carbon fiber and foam. These drones can fly, and achieve speeds of about 10 meters per second.

Next, the researchers will be working on structural components like wing control surfaces, which will be "made of edible material by 3D food printing or molding. Other things that will be considered are an edible/water-resistant coating on the surface of the edible wing, and degradation testing of the edible wing upon a time (and water exposure)," said Kwak.