London, June 7 (IANS) Light fuel cells are likely to power tiny, unmanned choppers that will look for people trapped in debris or examine contaminated terrain. Since large numbers of fuel cells are required to deliver enough power, manufacturers tend to stack them, making the chopper heavy.

But this problem has been overcome by researchers from Technical University of Berlin’s Fraunhofer Institute for Reliability and Microintegration IZM.

They have developed a fuel cell that weighs only 30 grams with an output of 12 watts, or the equivalent of a high density of 400 watts per kg, achieved in much larger systems.

The fuel cell is light enough to power a 20-cm helicopter. It is being developed as an EU project, and will be used in future for missions such as locating victims trapped in fallen buildings, monitoring traffic or investigating places contaminated by chemical accidents.

How did researchers manage to reduce the weight of the fuel cells so dramatically? “We use very thin, planar fuel cells,” explains IZM team leader Robert Hahn. “We have replaced the metal plates by lightweight plastic spacers.”

The researchers have no need for an additional pump to provide an adequate air supply: The wind generated by the helicopter’s rotor blades goes directly into the air vents.