I wonder if the "no booms over land" rule will always remain in force. When I was a child, the planes from Whiteman AFB broke that rule quite often. It was interesting to hear the boom over the phone when speaking with a school friend who lived say eight miles away, and then immediately hear the whole house shaking when the plane got to my end of the circuit. It would have been annoying at night, I suppose, but during the day it was not a hardship. These military planes made no particular effort to climb to high altitude before breaking the barrier, either. While the area I'm talking about is rural, it's much more heavily populated than are e.g. the Great Plains.

So, I think that high-altitude sparse-population daytime routes could be developed that would admit supersonic flight over much of North America.

The no commercial sonic booms legislation might go away if it were an American company asking for it. I have no doubt that the Concorde being foreign owned helped speed that legislation through Congress.

Of course being a little no-name company won't help matters much here, but I expect that actual production of this would involve a partnership (or probably buyout) with one of the big name companies that have a lot of congressmen on their payroll.

There has also been a lot of research into minimizing Sonic Booms since the 70s. Military jets typically don't care, but passenger jets could definitely benefit.

If they can get supersonic passenger planes flying over the ocean again, they won't be an obscure company anymore.

You may not have minded your entire house shaking, but most would probably quickly grow to resent such unnecessary disruption.

It's a good way to kick everyone in a large region out of their zone. If this was a constant occurrence, work may quickly cease, or become greatly diminished.

Sure, but these were 1980s-era fighter/trainer jets flying at probably 1000 ft., and it only shook the whole house when they flew pretty close. Other times one might only hear the boom when outside. I think a passenger craft of recent design of recent materials, flying at 40k ft. could do much better, even before routing to avoid populated areas. I don't think anyone, even those who live on ranches in the Dakotas, really has a right not to hear a noise during the daytime.

I don't think people have the right to pollute noise everywhere.

And I do wish humans where mindful about the noise pollution the dump where 'nobody lives'. The noise emitted by shipping vessels is having a harming effect on sea life.

I could have sworn the Concorde was still glass-breaking loud at 40,000. Reardless, NASA is working on getting rid of the sonic boom http://www.sciencealert.com/nasa-is-building-a-jet-that-brea...

I used to live under the Concorde flight path near Heathrow. Twice a day there'd be this crackling rumble and all the windows would shake; and this was flying subsonic.

Concorde was really, really loud --- a lot of that was due to being a really old plane with old engines (aircraft have gotten way quieter since the 1970s), but even back then it was considered loud:

http://news.bbc.co.uk/2/hi/uk_news/3581192.stm

It was exempt from the usual noise regulations and on takeoff it'd set of car alarms in the airport carparks.

I still miss it, despite the noise. I'd hear the noise and look up, and there'd be this beautiful delta-wing shape slipping through the clouds...

It's really hard to quiet down Turbojets. Turbofans are much easier, but they don't work well at supersonic speeds.

I lived under the Concorde flight path near Dulles. I couldn't hear it, but we'd go out side to watch it fly over every now and then.

Modern aircraft are so dull! Efficient, safe, cheap, reliable even, relatively comfortable, but so boring. Even the A380 is a boring, and that's an office block with wings. How can something so incredible be so deadly dull?

...yeah, yeah, I know, being dull is an accomplishment in itself, and the duller aircraft are the better they are, and the one thing that every passenger pilot in the world wants is a thoroughly uninteresting flight. But, dammit, they're still so dull.

I miss Concorde.

A380 passes overhead here every day on final, it is uncanny how it just seems to hang there on account of it being so large that relative to its speed it takes a while to move it's own length. Sure it's still going quite fast but it doesn't seem that it does and this sets of some 'it's going to fall' alarm at the back of my mind. Weirdest feeling.

Maybe? I don't think the Concorde ever flew over the Ozarks, or indeed any location in which I found myself while they were still flying.

Boom's Kenrick Waithe worked on that same project when he was at Gulfstream and when he was at NASA.

At least one real-world test was conducted about how people acclimate to sonic booms[1] with an eye towards seeing how people would take SST airliners. It didn't go very well. In general, it seems that enough people do think it a hardship to kick up a fuss that will keep SSTs from being a reality over the US for awhile.

[1] - https://en.wikipedia.org/wiki/Oklahoma_City_sonic_boom_tests

You're right, it has been awhile since the mid-60s. If we were talking about flying F-104s and B-58s, that would be very relevant information. As I understand it, Boom are developing a new aircraft. They're probably aware of that test and indeed lots of other information about supersonic flight.

This whole "engineering vs physics" question reminds me of the misunderstandings people have of modern radio technology. Yes, in the 1920s they had to divide the spectrum into exclusive-use bands so that any particular use could transmit and receive clearly, but that was a limitation of engineering, not of physics. In the 2010s that is not a limitation we face, in general. Likewise, I expect that with modern materials and engineering software, progress can be made on the sonic boom issue.

I do generally agree with you, but I'm not really talking about engineering or physics, I'm talking about social acceptance.

If - via engineering, physics, magic or whatever - sonic booms can be minimized to the point of being indistinguishable from general background noise (or even only as intrusive as current subsonic airliners), I could be convinced that an SST project has a bright future. Until then, I don't think that they will - your first post mentioned that "the whole house shaking" didn't really seem to be hardship when it happened during the day; I'm merely commenting that there are some studies that indicate society as a whole isn't so accepting.

I used to live near an army training area. There were regular artillery exercises, and the bigger shells would literally shake the walls of the house. The smaller shells just made things fall off shelves.

I think any design that literally goes "boom" over land, even a little, isn't going to work. It's too much of an open legal target.

The design really does need to be damn near silent, or at least closer to a mild and unobjectionable "whomp", to have any hope of commercial success.

I think I've only heard one in my life. It was on surfside beach TX where I lived at the time. I was on a dock and heard a really low thunder sound. I can't say that it was "loud" like it would hurt your ears, but it really rattled everything around me (including my insides). And with that the neighbor's dogs came running over to me with their tails between their legs, and off in the distance I could here a jet really cuttin' through some wind.

I've known test pilots who have flown supersonic routes over continental USA at high altitude and had zero complaints. The boom intensity depends on weather conditions. Other times they did get complaints because the boom sounded like gunshots and got reported to the police.

Cruising above 60000 ft the boom from a larger aircraft might be noticed but not be objectionably loud.

I doubt the cost would be low enough to support demand.

Transonic (approximately Mach 0.80 - 1.2) flight uses significantly more fuel than subsonic flight does. Business jets like the Gulfstream G550 burn more fuel at M0.9 than regional Boeing 717(MD-95) at M0.75 with 4 times more passengers.

The F-22 Raptor can supercruise at M1.6, with half the range compared to cruise at M0.85 similar to other fighters.

If Boom can optimize an aircraft for supersonic transport it would still be expensive to operate. For comparison, no US operator has all business class scheduled flights from LA-NY, and British Airways flies their all business class NY-London flights in an VIP A320 series jet that cruises at M0.7 which is slower than most airliners on the route.

The Boeing 747 has one of the lowest cost/passenger mile (CPM) of any aircraft, and cruises at Mach 0.85. Different aircraft have been optimized for different speeds, and while it is true that a supersonic aircraft will likely have a higher fuel cost than a comparable subsonic aircraft, the difference may not be as large as we currently think.

There has never been a supersonic passenger aircraft built with modern turbofan engines.

The 747 efficiency drops off sharply above M0.85 cruise. I remember reading that the VC-25 (747-200 based) 100% thrust cruise speed is around M0.96 with considerable range penalty. The 747-400 has newer engines but pretty close 100% cruise speed. This is above the approved Mmo for the 747 and not authorized operationally.

Test pilots have reported that a Gulfstream G550 airframe can handle supersonic flight, and the BR710 turbofan engines can handle it. The limit is the engine intake design.

With an optimized intake, its entirely possible the fuel consumption at M2.2 would be comparable to ~M0.98

>There has never been a supersonic passenger aircraft built with modern turbofan engines.

that is one of the major issues here. Modern turbofans on large passenger planes like 787, 380, etc... are that efficient in major part because of high by-pass ratio. Which is not really an option for 2Mach+ speed.

As somebody mentioned, more comfortable 0.85Mach flight would be preferable in many situations to uncomfortable and very expensive 2Mach. If i were starting something like this i'd go straight for suborbital SFO to Singapore in under couple hours. Technology-level wise not that different, money is no issue in that segment (Branson's $200K is not that far from super-premium-business class for your priceless CEO) and there is always large money-no-issue fallback customer - military.

That's why the ticket is $5K. Even if your fuel estimates are correct, they will burn 4-5 times more fuel, but they will charge 10 times per ticket compared to economy. I just checked, and you can get $532 roundtrip NYC<->LON.

But a given airplane can carry a lot less people in a business-grade seat than in an economy seat. Also, NYC <-> LON for $500 is the price of only very few seats in a plane.

Yes- due to the time change, heading east from coast to coast is practically a day away as well.

Yeah, flying West to East, more speed wouldn't be a great help. I lose 2 hours getting there, 3 hours in time zones, an hour upon arrival. So red-eyes are the way to go. But if the reverse could be improved, that'd be a big help. I could fly West in the morning, get there the same time as I left, do a days business, and take the red-eye home. All in a day.