From 1955 to 1973, Americans filed over 40,000 complaints against the Air Force because the endless sonic booms. Since 1973, no commercial flights can meet or exceed supersonic speeds over the continental US. Even the military has to meet very specific criteria to exceed the sound barrier. Many of us born during and after those years have never heard a sonic boom. For us, it would be remarkable. For our parents and grandparents, these booms had become a nuisance.
Because of its strategic location, Illinois, eastern Wisconsin, northern and central Indiana, and Michigan found themselves frequently plagued by this “man-made thunder” from 1960 to 1969. In fact, these states had earned the semi-official nickname “The Sonic Boom Corridors.” (one of which is pictured above).
Jets tear the sound barrier at 767 mph at sea level, a feat first achieved by Chuck Yeager in 1947. The only prop plane to even approach the sound barrier was a British Spitfire that hit Mach .92 (606 mph) in 1944; in that case, air compressibility shattered the Spitfire’s propeller and warped its wings mid-flight. Somehow, the pilot miraculously glided the Spitfire to ground and walked away.
After Yeager’s record-setting flight in the X-1, the Air Force produced faster and faster jets, but it was the adoption and incorporation of the supersonic B-58 Hustler in the early 1960s (replacing the old and lumbering B-47 Stratojet) that really exposed the Midwest to the sonic boom.If you lived near Chicago and heard sonic booms in the 1960s, these B-58s Hustlers were the most likely culprits.
How much energy is in a sonic boom?
A hard and fast answer for this question is difficult, because the force and speed changes depending on the jet in questions, altitude, and even humidity. If you went insane and were a few feet from a jet’s “shock front”, some funky things would happen to you…none of them good.
Without choking on aerodynamics, let’s stick with simple decibels. A sonic boom’s shock front (the cone of opaque air in photographs) produces roughly 200 decibels of sound. That is very, very loud. This is equivalent to standing near the Saturn V rocket as it launched (204db), being within a few miles of Krakatoa as it erupted/exploded in 1883 (202db), swimming within a few yards of a sperm whale when it flexes its deadly echolocating skills (174db), or being near the detonation of Tsar Bomba, the largest nuclear explosion in history (224db). Your eardrums would tear like wet tissue, your lungs would flatten from the overpressure, your bones might…You get the picture.
It’s important to remember that those breaking the sound barrier were thousands of feet (tens of thousands even) in the air, so those living in the Sonic Boom Corridor, aka the Cold War Corridor, mostly dealt with it as a nuisance.
The Cold War Corridor
Before the flood of ICBMs shelved the bomber’s role in the Cold War, the speed of bombers’ first strike theoretically determined the “winner” of a full-scale nuclear exchange (in reality, NO ONE CAN WIN).
Bomber groups located inside the United States, near the East Coast or the Midwest, followed a flight path over Lake Michigan and the Great Lakes, exiting the US through Canada and then to Greenland. During drills or alerts, the groups would return to the United States. If war broke out, then it was on to the Soviet Union (see Dr. Strangelove). Luckily that final step never happened.
In the Midwest, these routes brought the bombers directly over Indiana, Illinois, Michigan and Wisconsin. Bomber wings of the subsonic B-47 or the B-52s didn’t disturb Americans as much. Those were just a distant drone in the sky. Although loud and lumbering, these lumbering jets flew so high and slow that were only a little louder than commercial jets.
The B-58 Hustler: America’s Big, Fast Bomber
Then came the Hustler. In 1962, it looked like something from the not-too-distant future. The Hustler had a tailless delta-wing design: a triangle-shaped body configuration ideal for high-speed flight. It had no bomb bays, but could carry up to five nuclear bombs beneath its wings. State-of-the-art engineering and the use of aluminum honeycomb paneling kept the weight of its body at a minimum (just over 13% of its total weight), allowing for four beastly General Electric J79-GE-1 turbojet engines.
Most impressively, the massive B-58 (as long as a blue whale) was capable of sustaining Mach 2, just over 1500 mph. The B-58 wasn’t easy to fly, but this endeared it to pilots even more. Only the best of the best flew the Hustler, and in a naturally competitive profession like piloting military jets, bragging rights were currency.
This new bomber came with a hefty price tag and even heftier operational costs. The entire Hustler program cost about $3 billion, or about $21 billion today. The Strategic Air Command only bought 116 Hustlers, distributing them in two bombing groups: the 43rd Bombardment Group (out of Carswell and later, Little Rock, Arkansas) and the 305th Bombardment Wing (at the Bunker Hill Air Force Base in central Indiana, now called the Grissom Air Reserve Base).
What Ended the Sonic Boom Era?
The Air Force wasn’t in business to anger taxpayers, and they made a few token concessions. In most flight drills, command told the Midwestern Hustler creews to wait until they hit the empty space above the Great Lakes before opening up the afterburners. Above the lakes, only the fish would be startled.
But there’s a concept in military flight called creepback.
Discovered in World War II, creepback is a tendency for pilots to over-anticipate targets and drop bombs too early. In this case, it meant open the throttle too early. Suddenly, these B-58 Hustlers were breaking the sound barrier not over the cold waters of Lake Michigan, but over the densely-packed cities surrounding it. Complaints kept pouring in. The deluge of complaints didn’t do much to curtail supersonic flight.
For every letter denouncing the shattered sound barrier, there was another that celebrated the sonic spectacle. In those terrifying years of the Cold War, when wide-scale conflict seemed likely instead of possible, the bombers were a reminder of the American military standing sentinel, much like the 250 Nike missile bases ringing American defense zones. And proponents also noted (and this IS true) that no civilian has ever actually been hurt by a sonic boom.
No, sonic booms ended for two practical reasons: money and missiles. From its introduction to its retirement, Convair built 116 B-58 Hustlers. Of those 116, 26 were destroyed in accidents, taking 36 crew members with them. That’s 22% of the bombers destroyed and a 10% crew fatality. That is roughly equal to Omaha Beach on D-day.
The B-58’s dominance in the air was short-lived. As a response to the bomber’s speed and altitude capabilities, the Soviets dramatically improved their surface-to-air missile systems (SAM), mass producing almost 5,000 of the advanced S-75 launchers across Soviet-controlled territory. These killer SAMs could fly higher and faster than the B-58.
Our military’s strategic response to the S-75 required bombers that flew low and fast. The Hustler could fly low and it could fly fast, but not at the same time. Ultimately, the Hustler’s cost sealed its fate. The military could have SIX wings of B-52s for the same price as TWO wings of B-58s.
The end of the B-58 Hustler came in January 1970, when the remaining bombers were put away into storage and eventually scrapped. The sonic booms that had filled the Midwest skies went with them. Today, only 8 Hustlers remain. All are museum pieces and none are capable of flight. They are a sleek and shiny reminder of mankind’s amazing engineering feats and, in the case of thermonuclear war, mankind’s most absurd folly.
Want to Know More?
Read about the 1964 “broken arrow” incident involving a slick runway, a B-58, 14,000 gallons of jet fuel, and five nuclear weapons in our article “The Broken Arrow at Bunker Hill.“
Natural sonic booms? Learn how the squeaks, squelches, and snaps of the sperm whale are actually one of deadliest tools in nature. Smithsonian Magazine‘s Eric Wagner explains this phenomenon in “The Sperm Whale’s Deadly Call.”
Marvel at the short but spectacular history of the B-58 Hustler in Dale Smith’s article “Speed Freak” for Air & Space Magazine.