The US Defense Advanced Research Projects Agency (DARPA) is considering funding research into so-called micro air vehicles - aircraft with wingspans which measure just 150mm - which scientists believe could be used for tasks such as surveillance and detection of toxic chemicals on the battlefield.
The aim is to keep the unit cost of the tiny aircraft down to around $1,000, allowing them to be flown in hazardous environments on an expendable basis.
Several organisations working on the technology, including DARPA and the Defense Airborne Reconnaissance Office, met in February for a two-day conference at the Georgia Institute of Technology in Atlanta.
"When you approach technical people with this idea, their first response is that you cannot build an aircraft this small and make it useful," says Dr Sam Blankenship, who chaired the conference, and is co-ordinator of the Georgia Institute's "MicroFlyer" programme. "But many people, including us, think you can," he adds.
Development work is focusing on revolutionary flight controls, propulsion systems and avionics which will be required to keep the weight of the aircraft and its payload below 50g. Flight-control concepts under evaluation include electrically actuated, piezoelectric structures, while several institutions are working on micro-jet engines, pulsejets and ducted fans.
Engineers also hope that advances in micro-electronics technology will enable them to develop guidance and navigation systems, and video transmitters, suitable for micro air vehicles.
"We're not really sure what will turn out to be the most difficult challenge," says Blankenship. "Once funding is available, we think it might take three years to build a flying prototype."
Source: Flight International
