Editor’s Note: The North American Rockwell OV-10 Bronco was developed back in the 1960s specifically for counter-insurgency (COIN) operations, and another one of its primary missions was flying Forward Air Control-Airborne (FAC-A). The airplane can carry up to three tons of external munitions and is able to stay on station for over three hours. A pair of Broncos have been brought out of retirement for Operation Inherent Resolve as part of an experiment.

War was just an experiment for two of the U.S. military’s oldest and most unusual warplanes. A pair of OV-10 Broncos—small, Vietnam War-vintage, propeller-driven attack planes—recently spent three months flying top cover for ground troops battling [Daesh] militants in the Middle East.

The Broncos’ deployment is one of the latest examples of a remarkable phenomenon. The United States—and, to a lesser extent, Russia—has seized the opportunity afforded it by the aerial free-for-all over Iraq and Syria and other war zones to conduct live combat trials with new and upgraded warplanes, testing the aircraft in potentially deadly conditions before committing to expensive manufacturing programs.

That’s right. America’s aerial bombing campaigns are also laboratories for the military and the arms industry. After all, how better to pinpoint an experimental warplane’s strengths and weaknesses than to send it into an actual war?