Sonic What?

by Susan Wiggins

Sonic booms, that’s what! I found some research that my mother Marion Deaver collected in the late ‘50’s concerning the consternation brought about by the sonic booms that accompanied supersonic flights originating from Edwards AFB and Plant 42 in Palmdale.

From the time of the first sonic boom when Chuck Yeager broke the sound barrier by flying faster than the speed of sound, to the present, sonic booms have been heard over Kern County and other parts of the nation. Referred to as “the sound of progress” by the Air Force, many residents of East Kern did not share that sentiment back then.

My mother said they “rattled her teeth.” She complained that the booms were responsible for some small cracks in her sheetrock walls, and caused an occasional picture to fall off the wall. Once she explained to me what the noise was, I thought they were kind of cool, especially when we were at school and some new kid would practically wet his/her pants when the sound came from overhead, followed by the sound of a jet.

When I was little we lived in the post WWII era of the Cold War. We practiced getting under our desks in case of nuclear attack. (Like that would work!) We were told that Edwards AFB was a prime target and that it was only 25 miles away from Mojave. I found the sonic booms to be reassuring that someone else was flying up there to protect us.

During that time my mother wrote an article that said a sonic boom was defined as “a resounding noise carried to our ears at the speed of sound.” The question was posed as to whether people would get used to the noise, as we have gotten used to the sound of railroad trains careening through our city. The Air Force thought if it was explained that people would accept the sounds, as “progress.”

The answer pretty much was a resounding “no.”

To understand the principles of a sonic boom, one must understand the definition of the speed of sound and Mach numbers. On a standard day at sea level, the speed of sound travels in the air at 1,118 feet per second, or 760 mph. When a plane travels faster than the speed of sound it develops shock waves. As the jet approaches the speed of sound the waves cannot travel as fast as the airplane, so they “hitch a ride” on the fuselage. Since they aren’t along to move the air a shock wave is created. When the shock wave hits the ground it creates a noise identified as a sonic boom.

Public meetings were held and it was agreed that the jet corridor would be moved to limit the possibility of shock waves enveloping the communities near Edwards. The center line of the corridor was then 50 miles south of Bakersfield. Test flights were conducted at 30,000 feet, and low altitude flights, which make the biggest sonic booms, were conducted over isolated areas in the vicinity of Edwards. Booms were heard, but teeth were not rattled.

Interestingly, the Air Force and NASA last year conducted tests and asked residents of Edwards to listen for sonic booms and give feedback as to their intensity. Sensors on the ground also gathered data.
The Waveforms and Sonic boom Perception and Response, or WSPR (get it?) gathered the data and its participants hope to develop technology so that planes can break the sound barrier and not “disturb the peace.” But of course, “much more research is needed” before the sounds go away completed.

Through the years most of us have grown accustomed to the sounds, including the twin boom from the Space Shuttle that told us all it was safely in our atmosphere and would land soon at Edwards AFB.
After all these booms are indeed the “sound of progress.”