When a brand new aircraft takes to the sky for the very first time, just about every aspect of the aircrafts' performance has been predicted to a tee. Computer modelling and flight simulators allows the test pilot to experience how the aircraft will perform long before wheels ever leave a runway.
But things were not always this way. Take the 1940's for example. There was no computer aided design (CAD) back in those days. So pilots took aircraft into the air for the first time with crossed fingers and a lucky charm in the pocket. And one look at the video below will tell you why. In this landing, anyone sitting at the front of the aircraft would have tested their nerves as oscillations because just prior to touchdown. But spare a thought for anyone at the rear of the aircraft. Air-sick bags anyone?
The Douglas XB-19 was a prototype aircraft designed to test flight characteristics for giant bombers. It was the largest bomber built for the US at that time. Weighing 82 tons it was that heavy the wheels broke through the runway on at least one occasion.
Only one of these aircraft were ever built. It was replaced by an even larger aircraft, the Convair B-36 peacemaker.