Heather Moore Niver 
Breaking the Sound Barrier [PDF ebook] 

For a long time, aviation experts and pilots thought aircraft couldn’t fly faster than the speed of sound. They believed there was a point where the plane and pilot would just explode! They called it the sound barrier. In 1947, Chuck Yeager proved that to be untrue, and in 2012, a skydiver broke the sound barrier without a plane to fly in! From the challenges of airplane technology to daredevil parachutists, the story of breaking the sound barrier is one that will have readers on the edge of their seat. Full-color images and detailed sidebars take history to new heights.