What flies like a helicopter and drops chemical-laden ping pong balls? Firefighting drones, of course! Drones are the latest tools for battling grass fires in the Great Plains and western states.
Firefighting drones actually combat blazes by starting new ones. Fighting fire with fire isn’t a new tactic. Forestry managers sometimes start a “controlled burn.” They ignite brush and small trees under carefully controlled conditions. The burn consumes all flammable material from an area, removing fuel that a wildfire might rage across. When the wildfire hits the bare spot, it weakens or even dies out.
The firefighting drones drop small orbs (not actual ping pong balls!) filled with a chemical mixture. During flight, the aircraft pierces the ball with a needle. Then the plane injects another chemical before releasing the ball. The mixture ignites one to two minutes later.
Drones drop the balls in a preset pattern. The pattern controls how the fire spreads. Local and federal officials hope the drone firefighting technology could help clear overgrown vegetation in rugged, hard-to-reach terrain.
Helicopters already use the balls to start controlled burns. But drones are cheaper and more portable. The drones cost between $6,000 and $8,000 each.
"You could afford one of these on the back of your fire truck, whereas you probably can't afford to have a full-sized helicopter parked at your fire station," says Carrick Detweiler, a drone researcher.
Scientists hope drones may eventually be used to set controlled fires in hard-to-reach places. Universities in Colorado, Pennsylvania, and Switzerland are exploring similar technology.
This spring a team from the University of Nebraska–Lincoln flew an unmanned aircraft over the grassland at the Homestead National Monument of America. The drone rose from the prairie and hummed toward the horizon through a smoky haze. Minutes later, it began releasing balls. A series of small fires quickly grew and merged into one. The drone firefighter worked.
Researchers must still solve some problems. In early tests the balls exploded. One caught fire before being released. Wind is also a limiting factor. Lightweight drones cannot be used in the high winds that sometimes stoke wildfires.
Sebastian Elbaum, a computer science and engineering professor, sees plenty of use for drones in firefighting. "Imagine [firefighters] having this in their backpack, pulling it out and telling it, 'Hey, go scout out there. Check whether it's hot. Check whether it's safe.'”
