The potential of SST?

[Riain]

I'm flying to London on Tuesday; an 8 hour leg to Singapore followed by a 13.5 hour leg to London, and in the past have flown Melbourne-LA 4 times - 15.5 hours once with a direct connection to NY. Naturally I'm dreading this ordeal and it got me pining for Supersonic Transport.

What is the best case scenario for SSTs if things fell their way?

• US SST spec for mach 2.2-2.5 rather than 2.7-3
• US selecting the slower but less complex Lockheed L2000
• The sonic boom issue being handled very differently, allowing an over CONUS air route or two.
• SSTs entering service in 1972 prior to the Oil crisis
• Other things

For context; by the time the Boeing 2707 SST was cancelled in May 1971 there were 115 unfilled orders by 25 airlines, while Concorde had 74 orders from 16 customers.

 

[Michel Van]

There were allot of problems with US - SST
Too ambitious going for Mach 3.5, what needed allot expensive R&D and would given very expensive to build and Maintain SST for PAN AM & co.
Boeing went for komplex variable-geometry wings, the biggest in World had they build that bird.

Lockheed L-2000 would have be good choice at speed of mach 2.2 and longer range
Cheaper to build because no need for expensive Titan in fuselage and Winds edges

But SST ran into Serious problems in 1970s
First Mass transportation with Boeing 747 (and Lockheed try with C-5 as L-500 airliner but ran into serious problems with C-5 and corruption cases)
Issue of Sonic boom of SST over country and environmental problem. forcing the Airline to put SST in intercontinental flights.
The Oil Price shock that forced the Airliners to rethink there strategy, to buy expensive SST and run a small Fleet of them, under current situation was out of question.
Here the Boeing 747 was solution to some of the Airlines, cheaper with more paying passenger = higher profits

For the Concorde it had two major disadvantage, number of Passengers 80-120 and it's Range of 3690 miles
had the Concorde a range about 4079 miles it could have reach more destination what made that SST more attractive for Airlines like PAN AM
they had plan for a Concorde 'B' model that would fulfill the range and economic Olympus 610+25% jet engines.
but they canceled it together with Concorde production in 1976.

Again Airliner make profit by number Passengers in a Plane, here a expensive to maintain SST with 120 passengers make not much profit.
here had the L2000 (mach 2.2) with 273 passengers more attractive for airlines

 

[Simon]

They had plan for a Concorde 'B' model that would fulfill the range and economic Olympus 610+25% jet engines, but they canceled it together with Concorde production in 1976.

Looking at the proposed specifications for the Concorde Model 'B' they don't on the face of things look like massive changes. Since it was unlikely that any more aircraft would be produced do people think that they might have been able to retrofit them to the already built ones? The major task would seem to be the changes to the wings, so the question becomes could the changes be made without times and costs being so high as to make it not worth while.

Concorde would still be a dead end but if it had been more successful then it might have kept the idea of supersonic transports as a vaguely credible idea in the future.

 

[sts-200]

I'm flying to London on Tuesday; an 8 hour leg to Singapore followed by a 13.5 hour leg to London, and in the past have flown Melbourne-LA 4 times - 15.5 hours once with a direct connection to NY. Naturally I'm dreading this ordeal and it got me pining for Supersonic Transport.

What is the best case scenario for SSTs if things fell their way?

• US SST spec for mach 2.2-2.5 rather than 2.7-3
• US selecting the slower but less complex Lockheed L2000
• The sonic boom issue being handled very differently, allowing an over CONUS air route or two.
• SSTs entering service in 1972 prior to the Oil crisis
• Other things

For context; by the time the Boeing 2707 SST was cancelled in May 1971 there were 115 unfilled orders by 25 airlines, while Concorde had 74 orders from 16 customers.

Have a good trip, and I empathise; but at least it isn't three legs, which it would likely be on an SST.

If the US went for Mach 2-2.2, I suspect they might have done better.
Concorde's designers picked 2.05 for both engineering and commercial reasons. It was the fastest that could be done using the best available Aluminium alloys, without the need for Titanium and without a unacceptably short airframe life. Going to 2.7 barely reduced trip times once you allowed for takeoff and landing, and wasn't worth the huge complexity and cost.
Supersonic corridors in the US were never going to fly (sorry, couldn't resist); it would always be losing someone's vote.

If they had made it into service more widely, there would have been boom and bust cycles due to fuel prices, even worse than regular airlines experienced.
There would also be huge noise challenges once the Stage 2 regs came in (IIRC it was 1985), meaning a whole new generation of planes and engines would be needed for production to continue beyond that point. As airports start to restrict noise, we'd have seen existing SSTs go out of service through the '90s.
Concorde B (theoretically) could meet Stage 1, but that required a new engine, which wasn't trivial and was regarded as a good way of spending more money to get only some of it back.

 

[sts-200]

Looking at the proposed specifications for the Concorde Model 'B' they don't on the face of things look like massive changes. Since it was unlikely that any more aircraft would be produced do people think that they might have been able to retrofit them to the already built ones? The major task would seem to be the changes to the wings, so the question becomes could the changes be made without times and costs being so high as to make it not worth while.
....

No.
It needed a new engine (that's over a hundred million, even in the '70s), and making changes to the loading of the existing wings would have altered their shape during supercruise (meaning you need a new wing).

 

[riggerrob]

How often were Concordes chartered as transport for the filthy rich?

 

[hammo1j]

There's a fair few firms aiming executive class SST s for 2025 ish. These are very much within the envelope of Concord but using better tech.

One really fascinating development proposed in general airliners is eliminating windows from airliners and facing the seats backwards to travel. This would result in tremendous savings or space increase and improve safety.

I would nt mind that but most people do...

 

[Riain]

The issue as I see it is that with only 14 Concordes from 1976 SST never reached critical mass to overcome many of it's problems. For example there is no push to change the overflight laws in the US with only 14 aircraft available only to the rich, however with some 115 US designed SSTs in service the push to ameliorate this would likely gain momentum. Similarly the cost of the maintenance of some 14 unique/orphan aircraft is astronomical, but if the 76 Concorde orders of 1971 had been filled this would drive the costs down and also make it worthwhile to conduct upgrades like removing the flight engineer down the track. Similarly larger production runs would mean that the likes of the Concorde B would be built, which means a much larger range of routes available.

Perhaps the biggest mistake of the SST debacle was the US specifying Mach 3 and 4000nm range, although the 250 pax is a move with enormous potential. I think a better idea would have been for the US to trade of speed for range and spec mach 2.2+ but 5000nm range, separating itself from Concorde by size and range rather than IOTL attempting to do so by speed. JFK agreed in 1961 to subsidise 75%, and Congress funded it up to 1971 so with different choices US airlines might have gotten a similar sweetheart deal that Air France and British Airways got by the government writing off the development costs.

I think the over CONUS sonic boom issue would be ameliorated if the 115 US SSTs ordered in 1971 had entered service, perhaps by flying over the Great Lakes, avoiding overflying cities and allowing supersonic speed over the sparsely populated west.

As for the general potential, on the assumption that 76 Concordes get built (16 A and 60 B) and 115 Lockheed L2000s (like Concorde later ones have longer range), I think if they get built they will get used for a while particularly as their niche is found and greater numbers drive demand up and cost overheads down.

 

[DougM]

I don’t think even with 100+ jets that the sonic boom issue can be made to go away.
Imagine if you house happens to sit under that line. Of you horses.

And I also don’t understand why facing seats backwards would give you any more room then facing them forward. And the windows are not effecting space but may effect structure especially in a supersonic aircraft with the heat issues.

 

[Riain]

I don’t think even with 100+ jets that the sonic boom issue can be made to go away.
Imagine if you house happens to sit under that line. Of you horses.

No it isn't going away, however that doesn't mean it can't be managed to an extent in order to reduce its impact. Some 80% of US people live in cities, so SST routes don't fly supersonic over cities for starters which takes care of 80% of the problem. The Great lakes, the eastern and western seaboards and gulf coast can over overwater routes between certain large US cities which takes care of another small part of the problem. Another part of the problem can be addressed by using the sparsely populated centre-west part of the country to provide supersonic airspace, again avoiding overflying cities. IOTL the Concorde managed to undertake some workarounds like this, at one stage flying to central America supersonic from NY to Florida, subsonic across Florida then supersonic again over the Gulf. Later the route was changed to avoid Florida and fly supersonic over water the entire way.

Its also important to bear in mind that the CONUS market isn't the only game in town, a handy one to have for sure but not likely to cripple non US SST operators.

 

[kernals12]

In 1964, the US Air Force started flying F-104s at supersonic speeds over Oklahoma city to see how much of a problem sonic booms would be. In 6 months, there were nearly 10,000 claims of damage from the sonic booms, mostly broken glass and cracked plaster. 147 windows broke on downtown skyscrapers.

There's no way such damage could be tolerated. Even if the government hadn't banned supersonic flight over land, the cost of litigation would prevent most airlines from doing it.

 

[Riain]

In 1964, the US Air Force started flying F-104s at supersonic speeds over Oklahoma city to see how much of a problem sonic booms would be. In 6 months, there were nearly 10,000 claims of damage from the sonic booms, mostly broken glass and cracked plaster. 147 windows broke on downtown skyscrapers.

There's no way such damage could be tolerated. Even if the government hadn't banned supersonic flight over land, the cost of litigation would prevent most airlines from doing it.

Yes, I'm aware of that, and they did other things with the XB70 and B58 Hustlers, however it's important to note that these planes flew supersonic over a major city.

There are officially two types of urban areas: “urbanized areas” of 50,000 or more people and “urban clusters” of between 2,500 and 50,000 people. For the 2010 count, the Census Bureau has defined 486 urbanized areas, accounting for 71.2 percent of the U.S. population. The 3,087 urban clusters account for 9.5 percent of the U.S. population.

Though these smaller urban clusters account for a relatively small portion of the total population, they make up the vast majority of the roughly 3,500 "urban" areas in the U.S. But is a town of 2,500 people really what we think of as "urban"?

According to the Census Bureau, a place is "urban" if it's a big, modest or even very small collection of people living near each other. That includes Houston, with its 4.9 million people, and Bellevue, Iowa, with its 2,543. https://www.citylab.com/equity/2012/03/us-urban-population-what-does-urban-really-mean/1589/

As the map above shows there are huge parts of the US, particularly in the west, where there are huge gaps between cities of over 50,000 and even big areas where they can't even muster a town of 2,500 people. I don't think it is beyond the reals of possibility to map out some routes in parts of CONUS that the sonic boom wouldn't bother too many people.

Also for perspective people in cities the world over have to deal with disruptive noise from trains, trucks and aircraft. Why is this particular noise, heard in low population areas, particularly bad?

 

[KokkenKunten]

How often were Concordes chartered as transport for the filthy rich?

Not once. BA's fleet were, however, regularly utilised on charters for 'ordinary people' to enjoy a couple of hours over the Med & experience supersonic flight. They were ludicrously popular, incredibly profitable & created more goodwill for the airline (and particularly, the aircraft itself) than seems plausible today.

 

[kernals12]

Yes, I'm aware of that, and they did other things with the XB70 and B58 Hustlers, however it's important to note that these planes flew supersonic over a major city.

View attachment 484873
Also for perspective people in cities the world over have to deal with disruptive noise from trains, trucks and aircraft. Why is this particular noise, heard in low population areas, particularly bad?

It's not just a noise, it's a destructive pressure wave.
Also note how a flight from Atlanta to Boston will take you over the very highly populated Northeast corridor.

 

[Riain]

It's not just a noise, it's a destructive pressure wave.
Also note how a flight from Atlanta to Boston will take you over the very highly populated Northeast corridor.

Yes, and that has to be minimised. It is dependant on the size of the aircraft, its altitude and speed so a big mach 3 plane at low (for SST) level will do more damage than one flying at high level at mach 2.2.

IOTL the Concorde managed to undertake some workarounds like this, at one stage flying to central America supersonic from NY to Florida, subsonic across Florida then supersonic again over the Gulf.

The SST would not be supersonic over the NEC, and it will be doing the longer distances. Secondly routes will incorporate overwater legs as much as practical, perhaps even the Great Lakes and certainly coastal routes when available. Thirdly the US population density is not uniform, there are large parts of the country where it might well be possible to fly at certain speeds and altitudes without causing damage. Fourthly, CONUS is not the world, plenty of other countries don't care about sonic booms in the US and will buy SSTs for their own reasons.

 

[DougM]

How exactly are you going to use the Great Lakes to route anywhere of interest?
Lake Michigan is only about 120 miles wide and points basically north. Lake Erie is only about 55 miles wide and lake Superior is to far north to be useful.

And yes you may be able to avoid 80% of the population but the population you do fly over is not going to be happy.

Assuming a transcontinental flight you are flying over 2500 miles.
Assuming supersonic for 2000 of that.
Assuming a shock wave on the ground of a mile (seams extremely narrow). And let’s assume 1/4 of the distance is over uninhabited land. That leaves 1500 sq miles affected. Or 960,000 acres of affected land.
Assuming 100 per (a very high average as a house is usually on less then 1/2 an acre). Gives you 9600 houses that you have just made worthless.
Odds are you will see more habitable land with a wider ground effect. And a lot smaller plots of land . This number could easily triple.
And that is ignoring the annoyance factor. Those that are not being damaged just annoyed.
How far do you have to be away from a plane at 11 pm for you to not wake up the kids?
So you won’t ever get this approved from 11 until 6. Thus limiting usefulness.
You will need at least two east west routes and probably three. Add in at least two north south trunks and you are now talking about 4 times as many people being effected.
So we are looking at give or take 10,000 x 4 = 40,000. And you could be talking about 2 x as wide (20,000) and half as big (40,000) and that is for 3 routes and a shock wave of 2 miles and average of 50 acres per owner.
Now in a country of 300million that is not a lot but add in those that will be annoyed and you are starting to talk about real numbers.
And then we have other issues. Like any time anyone with a car living near the corridors gets a broken window they will be going after the airlines as you won’t be able to stop cars from crossing the corridors.
Next question what happens when the shockwaves meet? One plane going west one going east? Or for that matters does that even work or does the shockwave of two planes passing a few thousand feet apart cause problems? If so then you will see that 40,000 double again as you will need three corridors EACH WAY.
And let’s not forget the nature lovers. What is the effect of said shockwaves on wildlife? What about the hearing of the Owls for instance or the hibernation of bears? (Don’t laugh they go after the navy for its sonar effecting fish and dolphins and whales)

Sorry but unless you drastically change the US or discover some unknown way of eliminating the shockwaves you are not getting permission to fly these over land in the US. (And this is going to be a potential issue with the proposed supersonic billionaire toys)

 

[Riain]

@DougM of course it will fail if you set up assumptions that are meant to make it fail, and I already know exactly how to make it fail. How about trying to adjust those assumptions to make it succeed?

The reason I bring up the great lake is because it might allow an overwater segment for a Seattle-NY route by overflying lakes Huron-Superior for ~1000km after a ~500km subsonic sector. Once the route leaves Lake Superior in the west it is extremely sparsely populated, minimising the sonic boom impacts.

I also think it is extremely short sighted to focus only on the wholly internal CONUS as the be-all and end-all, especially once the longer-range B models come out. A flight might leave Texas, fly out over the Gulf supersonic, cross Florida subsonic and fly supersonic to London. Another flight might leave NY, fly supersonic over the Great Lakes and the middle of CONUS, slow to cross California and then supersonic to Hawaii. The speed restriction over densely population parts of CONUS are not a death knell in the right conditions.

 

[Mike D]

Not once. BA's fleet were, however, regularly utilised on charters for 'ordinary people' to enjoy a couple of hours over the Med & experience supersonic flight. They were ludicrously popular, incredibly profitable & created more goodwill for the airline (and particularly, the aircraft itself) than seems plausible today.

There used to be a charter flight from Heathrow to Liverpool for the Grand National, that can't have been cheap.

It used to pass over our back garden on the morning of the meet.

 

[KokkenKunten]

There used to be a charter flight from Heathrow to Liverpool for the Grand National, that can't have been cheap.

It used to pass over our back garden on the morning of the meet.

As with most things, I suppose it depends on your definition of 'cheap'. I don't have costs for the Grand National charters, but I can tell you that the first BA charter to Liverpool (there had been two Air France charters previously) on the 24th of September 1983 (BA9071C/9072C - flown by G-BOAF) was £196 including a supersonic run over the north sea. That's roughly equivalent to a fortnight's wages for a manual worker at 1983 prices.

 

[Dathi THorfinnsson]

It's all very well to say that much of the West is sparsely populated.
But over time, you're going to break windows in most of the ranch houses.
The booms will also spook cattle and other livestock. Not to mention wild animals.

And, I can't imagine how many avalanches will be caused, crossing mountains.

If you're going to pay for replacing and upgrading (100s of) thousands of windows, and accept a 5-10% reduction in beef production, then maybe.... But all that is going to make those flights a lot more expensive.

As for width of the boom. The shockwave is essentially a cone, so the width is surely at least that of the height above ground, so... About 10 miles.