Military airforce bases have a frequent hum due to jets, helicopters, and drones. However, people who live near these bases or in their flight paths become used to the normal sounds.

Speed Of Sound

Jets and other military aircraft are required to fly under the speed of sound so that they will not set off sonic booms. However, for six months, the people of Oklahoma City had to endure the sound of 1,253 sonic booms.

Chuck Yeager's feat of breaking the sound barrier forever changed expectations for jets. Aircraft moved into the supersonic age, with military aircraft advancing to flying faster than the speed of sound.

This put pressure on commercial aircraft to do the same. But advancement in that direction had to take one thing into account, sonic booms over densely populated areas.

Of course, the effects had to be tested. With the support of the U.S. Air Force, the Federal Aviation Administration launched Operation Bongo II. The project would study how well structures and the public held up to the constant sound of sonic booms.

Operation Bongo II

They decided that the best location was Oklahoma City. The city's economy was heavily dependent on the neighboring Tinker Air Force Base and Mike Monroney Aeronautical Center, and the Chamber of Commerce was delighted to be chosen.

The study began on February 3, 1964. The first sonic boom was nice and early at 7 am. After that, seven more booms went off from the morning into the afternoon. The military used F-101 Voodoos, F-104 Starfighters, F-106 Delta Darts, and B-58 Hustlers.

The four months of flights had only 1 to 1.5 pound-force per square foot booms. However, at 14 weeks, the booms were bumped up to 1.5-2 psf, a more realistic range.

The operation was going very well, and the people in the city were not bothered by the constant sound. But, the buildings were not holding up as well. The first 14 weeks left 147 broken windows in Oklahoma's biggest buildings.

Eventually, civic groups went to the courts to stop the tests but were blocked by a district judge and local politicians. But, on May 13, a restraining order stopped the tests, however, temporarily. That is until the story made national headlines. The political pressure the program received brought the tests to a screeching halt on July 30 and ended America's foray into the SST race.