Fast food: Edible drone could provide life-saving nutrition

Once in a while, an engineering project comes along that is so outside the conventional boundaries, so dazzlingly different and daringly eccentric, that you cannot help but stop and marvel.

The edible drone is one such creation. Developed by a team at the Swiss Federal Institute of Technology in Lausanne (EPFL), the device is designed to deliver life-saving nutrition to people in emergency situations, such as stranded climbers. 

In some ways, the idea is simple – drone payloads are limited to 10-30% of overall mass owing to the energy requirements of flight, putting a strict weight restriction on deliveries. Instead of carrying food in an inert cargo box, why not put it to use by building parts of the drone with edible materials, increasing the food-drone mass ratio to 50% and delivering more calories, with a longer range? 

Spend a few minutes discussing the edible drone, however, and you might think of some truly strange questions.

Fast food

First up, what food is the drone made of? Those hoping for a takeaway classic such as pizza might be disappointed: “We used rice cookies, which can be found from any grocery store, and we glued each cookie with edible gelatine material,” says researcher Bokeon Kwak. The cookies, known as rice cakes in the UK, were used as the main material in the wings thanks to an appealing combination of mechanical properties and nutritional value. 

“The density of the rice cookie is almost comparable to a widely used engineering material,” says Kwak. Those foam materials are “typically super-lightweight” while sturdy enough for flight, he added.  

The rice cakes were laser cut into hexagonal tiles to maximise their surface area while minimising their perimeter, keeping additional mass from the edible adhesive as low as possible. 

With a wingspan of almost 70cm, the flight-capable prototype can provide 300 calories. The gelatine means the drone is not vegetarian. 

So, how does it taste? No one has eaten the wings of a completed drone so far because the university lab is not food grade and uses some nasty chemicals, but they will essentially taste like plain, unflavoured rice cakes. The researchers are working with food material scientists, however, and could add flavours in future. 

The team also hopes to make the drone a more well-balanced meal by adding other carbohydrates, proteins and fats to the edible structures. An additional 80g payload could deliver water or vitamins. 

Higher biodegradability than conventional materials is an added bonus, meaning the drone will leave much less waste if left behind in the environment. 

Edible electronics

The next steps include improving the drone’s flight and making more of the craft edible, as only the wings are so far. “With a drone there are certain limitations when it comes to the electronics,” says Markéta Pankhurst, project manager for the RoboFood project at EPFL – but even some of those could be replaced in future. 

Edible electronics, such as batteries, are being developed elsewhere in RoboFood, a collaboration with Bristol University in the UK, Wageningen University in the Netherlands, and the Italian Institute for Technology in Milan. Other projects include an edible gripper, edible soft robotics and electronic skins. 

Kwak hopes to have an entirely edible robotic prototype in three to four years. A commercial version of the edible drone would likely take a few more years. Maybe by then the wings might have a bit more flavour – sweet chilli, perhaps?