A graduate of West Point, Schalk joined the new branch of the U.S. military, the “Air Force”. He graduated first in his class from the Air Force Experimental Test Pilot School at Edwards Air Force Base in California, where he worked under Chuck Yeager and flight-tested fighters.
Later, as a test pilot for Lockheed’s famous “Skunk Works”, Schalk helped design the cockpit of the A-12 Blackbird, the prototype for the SR-71 high-altitude reconnaissance plane. On April 26, 1962, over Nevada, he was the first to take the A-12 on a flight. He got it up to over 90,000 feet and reached a top speed of 2,287 mph — top secret information at the time. He died in Virginia on August 16 from leukemia and pneumonia. He was 76.