The Bell X-1 was designed around the shape of a .50 caliber BMG bullet, since that was a shape that was known to fly faster than the speed of sound.
During WWII pilots experienced ‘compressability’, which occured near the speed of sound and caused the controls to ‘lock up’. The original X-1 had a conventional stabilizer/elevator configuration. As Chuck Yeager approached the speed of sound the elevator became ineffective because the shock wave was ‘blanking it out’. He regained control after reducing speed, but the flight could have ended in disaster. The programme could have been ended as well, if the X-1 could not be controlled. Fortunately Bell had built a trim mechanism into the stabilizer so that Yeager could control pitch by using the trim toggle switch.
George Welch may have ‘broken the sound barrier’ while diving an XF-86 Sabre two weeks before Yeager’s flight in the X-1, but that achievement is unofficial. Yeager is credited with ‘breaking the sound barrier’ in level flight.
Anyway, I don’t think there was any doubt that an angine could be made to propel an aircraft past the speed of sound; but there was concern that an aircraft might not be able to be controlled at that speed.
I was sitting in my parent’s house enjoying a Christmas (or Thanksgiving) vacation several years ago in SouthWest Georgia when this sonic boom rattled our house pretty good. I’m thinking to myself, what the hell would be flying over this area at supersonic speeds. I found out the next day that it was a Space Shuttle landing at Canaveral 300 miles away.
A supersonic Vulcan would produce two booms, one at the point it breaks the sound barrier and one at the point it leaves a crater.
More on topic… Most supersonic planes indeed produce more than one boom, usually one originating in the nose and another in the tail extreme; IIRC the Concorde made two booms separated by 0.4 seconds (very vague memory, could be a different number); the thing is that since that sound travels on a conical path with it´s vertex on the point of origin, and both cones have different geometries, they intersect at two points in space producing under certain conditions a super-boom much more destructive than the usual thing.
All cites for this are buried on my aviation literature, I guess I could look up for it tomorrow.
While I have not heard many sonic booms I have heard a few and those I did hear were from very high flying planes (space shuttle once too). I thought it was pretty cool but can see how several per day could get annoying but break windows? Didn’t seem near powerful enough for that.
I would think the SST, if allowed overland routes, would slow to subsonic while still very high so breaking windows would not be an issue (annoying people is another matter).
About 10 years ago there was a big hub-bub over sonic booms heard over the Southern Caliornia area that came at seemingly regular schedules, usually on a Thursday. I heard these booms myself several times over the course of a few months, and yes, it was always on a Thursday. The local news interviewed a USGS seismologist who used the network of seismographs to plot a track and speed of the craft creating these booms: it was crossing over the SoCal coast coming from the southwest towards northern Nevada (location of the Tonopah AFB, testing site for previous “black” projects like the F-117) and was travelling an many multiples of Mach. Many folks have attributed these observations to the existence of the Aurora spyplane, a replacement for the SR-71. Or space aliens… :rolleyes:
I’ve read articles complaining that sonic booms can cause miscarriages and ( over time ) damage to the heart. Don’t know if it’s true, but it is given as a reason to dislike them.
One aspect i haven’t seen touched on – a sonic boom is proportional to the energy involved. The energy, in turn, increases dramatically as the plane increases in size (I’m tempted to say it’s proportional to the square of the cross section of the aircraft, but I’m going from hazy memory, so take that with a grain of salt).
What that means is that the sonic boom from a commercial airliner is substantially louder than that from a jet fighter.
Most of us who have heard sonic booms have heard the tamer fighter-jet versions, although I’m sure that in occasional cases a B1 Lancer or the like might have gone supersonic near a populated area.
I live near Dulles airport, where the Concorde landed for a decade or so. By all accounts it was never supersonic over land, so long before it reached my neighborhood it was no longer generating a sonic boom.
It was still the loudest thing I’ve ever heard in my life.
I have no idea why…maybe the engines were just big honking monsters, or maybe there was some kind of leftover shockwave traveling with the plane. But there was never any doubt when the Concorde came in. Other planes could be heard only pretty much overhead as they came down for a landing – even the much bigger 747s. The Concorde could be heard from anywhere in the region – even well out of sight – a deep, rumbling tunder that grew and grew for what seemed like several minutes. It sounded like the eastern half of the county was sliding off the edge of the world, we used to say.
If that was the level of sound permitted, it’s no wonder no one let it go supersonic over land. What a noise that would have been!
Why should the desire of a few self-important rich people to save, what, maybe 20 minutes off the end of their flight be allowed to discommode and annoy everyone else for hundreds of square miles?
The Concorde engine technology was fro the 1960s. Engine quitening became a big issue in the seventies and most modern airliners have modern engines that are quiet. Concorde was stuck with ancient technology.
Any new SST would most likely have much quieter engines.
The flight time difference was much more remarkable than 20 minutes. The Concorde could do Washington to Paris in 3.5 hours. “Normal” jets today make the trip in about 7.5 hours or more than twice the time.
Is that worth having your teeth rattled regularly? Maybe not but I still wish I had gotten to fly on it. Would’ve been cool to see the sun move backwards!
As mentioned the Concorde was shockingly loud just on takeoff/landing due to its rather old tech engines. Modern commercial jets are far quiter than jets of 30 years ago and of course the Concorde even beat out those jets for decible levels. When compared against modern jets the Concorde really stuck out noise wise even when subsonic.
I used to live on a military base in Germany (CFB Lahr) and once in a while (I’d say a few times a year) we’d hear a sonic boom. I guess this was for some sort of testing or studies or something, because every time I remember hearing it and seeing a plane in the sky, it always looked like the jet that made the boom was accompanied by one with a giant radar thingy on it’s back. I was young, so my memory could be cloudy.
Anyways, I know of at least one broken window, although it was already somewhat weakened by the hole in it from a baseball game! Nothing quite like getting a math test interrupted by a sonic boom - for some reason, the teachers always allowed us to run to the window to see if there was anything to see. Good break from long division
Just to return to the fear factor part of the question, I’m curious as to what the exhibits said such to give it such prominence. As a kid in the 50s, I was inured to the sonic booms that would regularly hit the SF Bay Area, and didn’t sense that the adults around had any more concern than irritation with the surprise, and speculation about the effect on sheetrock, etc. For the most part, the booms were just a reality in the Cold War environment, but not “feared.”
By the early 60s regulations about planes going supersonic over populated areas lessened the appearance of booms in my neck of the woods, so when they did happen, it did cause momentary fright occasionally–but only because some folks were always waiting for the first Soviet bombs to drop. In one high school class in 1963 we had a whopper of a sonic boom bow in the classroom windows. A girl sitting next to me went completely white, and I comforted her by saying, “Nah, if it had been The Big One, we would have seen the blinding light first” (Knowledge courtesy of a decade of “duck and cover” films, etc.).
I seem to remember that concorde ran with four afterburning turbojets, whereas nowadays all civil jets run turbofans, mainly for fuel-efficiency reasons. I have been in Osterley under the Heathrow flightpath when Concorde went over and it was staggeringly loud. Imagine having two F15s coming over your house wingtip-to-wingtip on a daily basis for a good idea of how local residents experienced Concorde. What it would have been like if they lit the reheaters at low altitude I can’t even imagine. :eek:
I took Sailboat’s 20 minute comment to be referring to the time saved if the concord was allowed to go supersonic over the land portion of the atlantic flight.
I saw and heard that at the Farnborough Air Show in 1966- An RAF Vulcan with an underslung Concorde Engine as an Engine Testbed. It flew along the runway at about 100ft and as it drew level with the grandstands, lit the afterburner and went up at about a 45 degree angle.
