Washington, D.C., is covered by some of the most restricted airspace in the world, but that doesn't prevent dozens of government agencies, the military, police, hospitals and other operators from flying helicopters over the U.S. capital. On any given morning, D.C.-area residents running, biking or walking their dogs along the Potomac River are treated to (or tormented by, depending on one's point of view) to helicopters flying the route into and out of the city.On the 10th episode of Rotor Radio, Andrew Logan, founder of the Twitter handle @HelicoptersofDC, joins us to discuss all that chopper traffic and the data-gathering game he's developed to keep track of it all. He's now got more than 8,600 rotorcraft-rapt followers. Dozens of D.C.-area residents, many of them stuck gazing out of their home windows for months on end, regularly participate in "copterspotting." They spot Air Force UH-1s, Department of Energy Bell 412s, Presidential VH-3Ds and other models. Using their phones, they snap photos or take video, then upload to Twitter using the hashtag #copterspotter and the helicopter emoji, then tag a geographical location. It's a game, citizen journalism and a crowd-sourced data gathering effort all in one. Logan has plans to plug the data into an algorithm that could eventually ID helicopter models automatically, but for now it's all good fun.