The FireDrone can withstand a much higher temperature than a standard quadcopter, and could therefore be a major asset for firefighters.
Few jobs are as dangerous as that of professional firefighters who must deal with large fires. Between unexpected explosions that can char anything in a fraction of a second, structures and trees that collapse without warning or the permanent risk of asphyxiation, they have to face a multitude of vicious traps. Despite the evolution of technology and techniques, these highly unpredictable environments put their composure and ability to improvise to the test.
Over the last decade, however, firefighters have received very significant help with the democratization of drones. These little contraptions are a big help when deciding the best approach to enter a disaster area.
Thanks to the reconnaissance work of these flying scouts, they can notably avoid the most exposed areas. Devices that carry thermal cameras can also help firefighters identify the source of the fire or the most threatening flame fronts. This makes it possible to manage the situation quickly, and above all by taking a minimum of risk.
But this valuable logistical support also has its limits. In areas where combustion is in full swing, the temperature can exceed 1000°C. However, consumer drones do not have the slightest chance of surviving such a furnace. Even the copper wires of the on-board electronics begin to melt above 1083°C. So they have to be content to do their best from a respectable distance. This deprives firefighters of information that could enable them to optimize their strategy before venturing into the realm of truth, at the very heart of the blaze.
A heat resistant drone
To fill this gap, researchers have rolled up their sleeves. Two teams from the Swiss Federal Laboratory for Materials Testing and Research (Empa) and Imperial College London are developing a heat-resistant drone. Its objective is to analyze the source of the danger closely in the case of an urban fire or a forest fire.
The Empa press release explains that David Häusermann, the instigator of this work, began by working with firefighters to determine the characteristics of such a drone. With this information in hand, he turned to a second Empa laboratory. This is where another team designed the armor that will soon allow a machine soberly called FireDrone to help firefighters.
To achieve this, the group led by Shanyu Zhao and Wim Malfait was inspired by certain animals such as penguins or arctic foxes. These species have several tissues (fat, fur, etc.) that allow them to withstand extreme temperatures.
A mini airgel-based flying fortress
But, mimicking these thermoregulatory layers is not enough. As always in the case of drones, it is also necessary to find a light and relatively resistant material at the structural level. To overcome these obstacles, the researchers bet on one of the rare ultralight thermal insulators: an airgel studded with tiny nanometric pores.
In this case, they opted for a polyimide-based airgel. It is a material from the family of plastics which is used in particular by NASA for the insulation of space suits. They then added silica, which is used in the composition of fire-retardant suits for firefighters. Finally, they reinforced the structure with fiberglass, which is less heat resistant but significantly stronger than the airgel itself.
From this composite material, the researchers designed armor that protects the battery, motors and on-board electronics. To finish, they integrated a cooling system, then covered the arms and the propellers with a reflective aluminum layer.
Conclusive tests and real concrete potential
Despite its imposing size (it measures approximately 50 cm in height), the maneuverability of the machine remains excellent according to the engineers. They were therefore able to carry out high temperature tests by flying it through a class C fire, that is to say a gas fire.
The armor of the machine has shown itself to be relatively efficient during these exercises. ” Even after several flights, the FireDrone’s electronics, thermal camera and CO2 sensors are remained intact, and remain ready for the next tests », explains Häusermann.
Note that even if the temperature was relatively close to that of a real fire, it was not a real test in real conditions. Indeed, this “clean” gas fire does not produced no soot. However, these blackish residues which appear during an incomplete combustion could also constitute a threat for the drone. It will therefore be necessary to organize new tests to check how the FireDrone behaves in such an environment.
Despite this shortcoming, the approach seems to have convinced observers. In any case, this is the opinion of Stefan Keller, an expert consulted by Empa during this experiment. ” If a drone can perform an initial reconnaissance of the situation, we will not need to send firefighters immediately to the danger zone. For us, this progress is extremely interesting “, he believes.
Finally, the researchers suggest that their drone could also be used in diametrically opposed conditions, such as polar regions and glaciers. Empa engineers are currently discussing with potential industrial partners to explore this approach. Taken together, these projects will accelerate the development of a new generation of drones capable of operating in very difficult conditions.
The text of the study is available here.