We'd walk around the house and see if they broke any windows this time. I visited Edwards AFB once and wondered to myself if any of the windows were glass or were they all Lexan?
We were doing supersonic drops of MK 84 (2000 lb) Air Inflatable Retards (AIR) from an F-111D and an F-111F at 200' AGL on Eglin AFB's ranges near Ft Walton Beach, FL. You have to be careful with supersonic low level flight because you can get atmospheric ducting, which will carry the sonic boom miles downrange. We carefully checked with the Eglin weather shop each morning to make sure there was no problem for our test drops. Sonic boom loudness is proportional to the mass of the vehicle, and the F-111s weighed ~70,000 lbs during the drops. The drops were made at 700 KCAS, about mach 1.2 at sea level. One day, the weather guy fouled up and, upon our return, the airbase group commander was waiting for us. Turns out we had busted about $50,000 worth of windows in a small town several miles away that was lined up with our bomb release ground track. Luckily we had all the documentation that we had done what we were supposed to do, and the weather man ended up taking the blame. We did end up buying some beers in the club, though. Blew over a sailboat flying subsonic overwater one day, but that is another story. Taz Terry Phillips
I've never heard a sonic boom. I'd give anything to see a jet fly low right by at mach 1+, assuming I didn't receive any permanent hearing damage.
Nice reminds me of a time I was testing a Jet-Ski at Elephant Butte Lake in NM when I got buzzed by German Tornado. Had to check my wet suit after that one
The only booms I've heard in the last 30 years were at a couple of the October open-houses at Edwards. Typically they would open the show with one and repeat it just after the lunch break. Generally Chuck Yeager would be in the airplane, either as pilot or passenger, and the last time the airplane was an F-15D flying very high over the base, probably 30,000 feet or more. They just can't get that sonic-boom thing out of their system at that place!
Rob, Jim- High altitude sonic booms are fairly mild and cause very little damage, just generate noise complaints. Most bases in the olden days of the 70s and 80s had supersonic corridors where Functional Check Flights (FCFs) could be performed on aircraft after they came out of major maintenance. The one we had in NM ran from Socorro south to just above the Mexican border. We took the aircraft up to mach 1.65-1.80 to ensure the bleeds opened in that mach range. It usually consisted of watching the bleed instruments carefully and reciting "Come, on bleeds, please open." When one engine's bleeds did not open, there would be a violent compressor stall that felt like someone had hit the side of the fuselage with a sledge hammer and sounded even louder. Flames would come past the cockpit, which you would swear could not happen at mach 1.80 or so, and the aircraft would yaw pretty violently from the assymetric thrust. Shut that engine down while bringing the other one to Mil power and then descend until you could try an airstart. Deceleration was so violent during a compressor stall or when you brought both engines back to Mil from Max AB at mach 2+ on a successful run, you would be thrown forward into your harness from the deceleration. Made many single engine landings caused by unsuccessful FCFs. Also went the fastest I have ever gone, mach 2.55 (~1500 KTAS) in an F-111D FCF at 49,500'. Had to have a pressure suit to go over 50,000'. Your blood boiled if the aircraft had cabin pressure failure above 50,000' without a pressure suit. On that particular day, we maxed out the mach meter and actually went a little beyond the last mark. Upon pulling the engines to Mil, both left and right Engine Oil Hot lights came on, because the afterburners were used to cool the oil. Checklist calls for shutting down the engine when that happens, but with both lit, we decided that was probably a bad idea. Luckily no Airbus software to help us out like Sully's Airbus. On that flight we also got the Total Temp warning light. That means if you do not slow down within 300 seconds, the airframe will begin melting and structural failure will occur. Fun flight and the F-111F was much faster than the F-111D, with 2x25K engines vs the F-111D's 2x20K engines. We even had an F-111F that would supercruise, but that is another story. Taz Terry Phillips
I think the last one I heard was at Edwards for the 40th anniversary of Yeagers breaking the sound barrier. He flew by in an F4 at 1.5 or something. He was pretty high. First time in many years. I had forgotten how loud it can be. It was at that moment I wondered about all the windows in that place.
Chas- No, the blood would actually start boiling like a tea kettle because the partial pressure was so low at 50,000'. The bubbles then go where they are not wanted (heart, brain) and you die. Water boils at 212 degs F at sea level and about 201 degs F here at my house at 6000', where atmospheric pressure is less. By the time you reach 50,000', the water vapour pressure is the same as atmospheric pressure, and boiling begins spontaneously. Taz Terry Phillips
