The weary reply, captured on video, was: “Battery.”
Small, potent lithium-ion power packs have transformed the world of radio-controlled model aircraft, much as they have allowed smartphones to get thinner, power tools to work longer and electric cars to go farther. But a pair of serious incidents this month involving rechargeable batteries in Boeing 787 Dreamliners have highlighted what model-airplane hobbyists long have known — lithium-ion technology comes with inherent dangers.
Considering the sheer numbers of lithium-ion batteries — more than 4 billion rechargeable cells were made last year, according to industry figures — fires are not common. After a battery-powered Chevy Volt ignited after a test crash in 2011, federal investigators said electric cars were no more vulnerable than gas-powered vehicles, more than 20 of which catch fire each hour in the United States.
Yet some risk persists, and the results can be startling. When a cellphone battery overheats — a rare event — it can eject itself with a loud “pop,” leaving singe marks behind. Lithium-ion battery packs can have prolonged fires as each cell, typically the size of a man’s finger, gradually ignites.
“It could be a smoke bomb. It could be a flamethrower,” said Gerard Back, a senior engineer with Hughes Associates, a fire-protection company in Baltimore that investigated the Volt incident. “I’ve seen them look like every type of firework you can imagine.”
Boeing and other manufacturers are keenly aware of this peril and have built in safety features designed to keep voltages within safe limits, prevent short circuits and confine damage when problems do occur. Lithium-ion batteries in laptop computers and other consumer devices are supposed to shut down rather than allow overheating that might cause a fire. In such ways danger is minimized, though not eliminated.
The technological trade-offs play out in especially stark relief within the sprawling world of radio-controlled airplane enthusiasts, who regard lithium-ion batteries with a mixture of fear and devotion even as they subject them to unusual stresses. The result is widespread acceptance that the same portable power source that allows for fast, long, graceful flights also occasionally causes these fragile toys to burst into flames — often, but not always, after crashes.
“They make life a lot better, a lot easier, but you have to manage the risk,” said Dave Brewster, 43, a professional pilot from Toronto who flies radio-controlled model airplanes as a hobby. “Everything in flight is mitigating risk.”
It was Brewster’s Reaper drone that crashed and caught fire on its maiden flight in August 2011, destroying a model that cost him several hundred dollars and hours of work. Like many who have suffered such mishaps, he uploaded video of it to YouTube for what amounts to an emerging genre of lithium-battery-related disaster films starring radio-controlled models — not just planes but cars and boats, too. (The flaming wreckage of a twin-engine model plane, posted in October 2009 and viewed more than 479,000 times, is accompanied by a soundtrack of bagpipes playing “Amazing Grace.”)