In the early fifties my mom had shadow boxes hanging on our living room wall that contained figurines and other bric-a-brac. Some days this stuff would spontaneously dance and vibrate off the wall. At the same time my body would feel a low vibration as I heard an almost inaudible throaty growl. Mom would grumble, "Darned B36 again! "
A B36 flying high in the stratosphere was the root of this household phenomenon. The Convair B36 bomber was a huge, strange-looking aircraft. It had six pusher propellers over 19 feet in diameter. Each turned through gearing at half the speed of the engine to prevent the blade tips from going supersonic. This created the unique sound and vibration that carried to the ground from an altitude of seven miles. I'll never forget that sound.
I never saw another plane like the B36. In addition to six backward-facing piston engines, it had four jet engines used mainly during take-off. It had retractable gun turrets for self-defense. These cumbersome planes seemed vulnerable to fighter defense, but a B36 could fly so high that it could evade jet fighters at 40,000 foot altitude by turning S-turns. The fighters' wings would stall if they tried to turn with the bomber. The plane existed to drop thermonuclear weapons or conventional bombs in warfare ... although it never dropped a bomb or fired a shot at an enemy. It took a crew of 15 to run one of those machines.
A flock of B36s lived at the 92nd Bomb Wing based 20 miles from my house. That was special to me, living in Spokane, where not much else seemed to happen in my life. Superior jet engine technology made the B36 obsolete. The replacement B52 could fly much faster and farther, but we had been there when Fairchild hosted the 92nd Bomb Wing and its B36s. Fairchild traded its last B36 for a B52 in our sophomore year of 1957.