14 hours ago, FBW737 said:

Looks like the Concorde designers got everything right since this new offering nearly 60 years later looks pretty much the same as a Concorde.

Mind you, it'd nearly as good looking as Concorde!

That should have read 'not nearly as good looking as Concorde!'

1 hour ago, Bob Scott said:

What I really meant to say is the advertising sounds like a game of eco-Buzzword Bingo.

 

Didn't to me to be honest, all relevant terms. Matter of opinion I suppose. 

 

1 hour ago, Bob Scott said:

The most relevant economy and carbon footprint comparisons aren't made with the Concorde, they're made against the various subsonic options coming available in the same epoch. 

 

You do realise they say they are using carbon neutral fuel. So yes, we can compare carbon footprints with subsonic jets, and its a lot lower, potentially zero in comparison to a subsonic jet using conventional fuel. But of course we are aren't supposed to be talking about climate change on the forum, and debating carbon footprints heads us in that direction. Economically yes, higher speed flight will involve a higher fuel burn than a subsonic jet but I'm sure the company in question has done an analysis and determined that they are likely to have the customers and be profitable. I don't think they will have just guessed and dived in. I would imagine they have employed some pretty talented people to determine such things. More talented in this field than us perhaps. 

 

1 hour ago, Bob Scott said:

It's pretty hard to accept that saving a couple hours of flight time on a leg by burning over 40% more fuel is oh so eco-friendly, net carbon-zero wonderful.

 

It is "oh so eco-friendly" in terms of carbon footprint, unless they are lying or fail to achieve their aim in this respect. What would concern me is whether they, or their supplier, could manufacture the required quantity of SAF for regular flights.

 

1 hour ago, Bob Scott said:

I wish they'd just dispense with the dishonest and thickly laid-on hyperbole

 

Lets accuse them of that after the fact, not before they've had a chance to achieve what they say they are trying to achieve. Scepticism is fine, but we should avoid cynicism.

United Airline have made a conditional offer for 15 aircraft apparently. So it seems United Airline see this as a potentially viable prospect.

 

Edited April 23, 20224 yr by martin-w

3 minutes ago, Christopher Low said:

I would assume that there are solutions in development with respect to the supersonic shockwave problem. Not being able to fly faster than Mach 0.95 over land would hardly be a great advert for a next generation supersonic airliner.

 

There are Chris. NASA and others are working on sonic boom mitigation as we speak. Boom haven't gone that route though it seems.

8 minutes ago, Christopher Low said:

I would assume that there are solutions in development with respect to the supersonic shockwave problem. Not being able to fly faster than Mach 0.95 over land would hardly be a great advert for a next generation supersonic airliner.

Well if they did that it would be the first time something that exceeded the sound barrier didn’t create a shockwave audible from the ground.

Even at 9 miles up the sonic boom from Concorde was extremely loud. Maybe if you build something small enough the sonic boom would be quieter. But Boom looks pretty large. Maybe they have people who can “do the math”! 😉

3 minutes ago, Ray Proudfoot said:

Well if they did that it would be the first time something that exceeded the sound barrier didn’t create a shockwave audible from the ground.

 

They are working on it Ray.

NASA's low-boom flight demonstration. 

https://www.nasa.gov/X59

 

Quote

 

NASA's aeronautical innovators are leading a government-industry team to collect data that could make supersonic flight over land possible, dramatically reducing travel time in the United States or anywhere in the world.

The Low-Boom Flight Demonstration mission has two goals: 1) design and build NASA's X-59 Quiet Supersonic Technology, or QueSST, research aircraft with technology that reduces the loudness of a sonic boom to a gentle thump to people on the ground; and 2) fly the X-59 QueSST over select U.S. communities to gather data on human responses to the sound generated during supersonic flight and deliver that data set to U.S. and international regulators.

 

 

NASA’s First Test to Lower the Sound of Sonic Booms Was Successful

https://interestingengineering.com/nasas-first-test-to-lower-the-sound-of-sonic-booms-was-successful

44 minutes ago, martin-w said:

There are Chris. NASA and others are working on sonic boom mitigation as we speak. Boom haven't gone that route though it seems.

Then how on earth do they expect to fly at supersonic speed over populated areas?

Martin, I posted same time as you. Will reply later.

@martin-w, a test with a smaller model was “successful” whatever that means. The acid test is with a full-size version.

Interesting that no stats were published.

18 minutes ago, martin-w said:

You do realise they say they are using carbon neutral fuel. So yes, we can compare carbon footprints with subsonic jets, and its a lot lower. But of course we are aren't supposed to be talking about climate change on the forum, and debating carbon footprints heads us in that direction. Economically yes, higher speed flight will involve a higher fuel burn than a subsonic jet but I'm sure the company in question has done an analysis and determined that they are likely to have the customers and be profitable. I don't think they will have just guessed and dived in. I would imagine they have employed some pretty talented people to determine such things. More talented in this field than us perhaps.

They claim the airplane will be "net zero carbon", but the "Sustainable Aviation Fuel" they say it will run on is biofuel--you know, like when we divert corn and other grains from human consumption to make fuel, as we do now to make the ethanol mixed with gasoline at most US gas pumps.  And, again, subsonic aircraft will also be able to burn the same fuel, and a lot less of it on a per pax-mile basis.  From a conservation perspective, how much you burn can be just as important as what you burn in a world with an exponentially exploding population to feed and shelter.  I want to see how the assumptions built into operating whole fleets of jets with "100% SAF" impact the global food supply, for example, and what the actual input costs in terms of water usage and other forms of energy inputs would be.  Many pie-in-the-sky alternative fuel analyses fail to take the full range of input costs and other second/third-order consequences into account, or assume technologies we don't have and may never have right into existence.

I'm not against the idea of supersonic airliners, but neither am I expecting that the lessons we learned from Concorde no longer apply.  As Ray pointed out up-thread, many of the same constraints that hindered the Concorde do still apply.  Supersonic jets still make shock waves that, on the low end, are an aesthetic nuisance and unpopular addition to the copious sound pollution already all around us, and on the high end, they disrupt livestock and wild animals and can even break stuff.  Putting up with that across continents so a relative few wealthy folks can trim a few hours off their flight schedules isn't likely to be any more popular an idea than it was in the 60s and 70s.  The 4250 NM range of the Boom jet is pretty anemic compared to a B777/B787/A330/A350 and leaves most Asia-North American city pairs out of reach, same as with the Concorde, etc etc.  But maybe it'll work...if they can overcome those challenges, more power to them.  If overcoming them means trying to lobby governments into shoving the consequences down our throats as opposed to mitigating them, well, that's a different story.

I remain, however, highly sceptical of a glossy advertising brochure so heavily laced with eco-buzzwords that it looks like the Greenpeace PR dept wrote it.  When I see that sort of overt pandering, alarms start ringing and the BS flag starts running up the flagpole.

A few supersonic "thuds" per day (assuming that this new technology works) would not annoy me in the slightest. Certainly not as much as hundreds of cars, trucks and buses do on any high street in the country on a daily basis.

3 hours ago, FBW737 said:

That should have read 'not nearly as good looking as Concorde!'

I get that you are proud of the Concorde, and you should be. 

However, there is no comparison to Boom's aircraft because the Concorde's development and operation was heavily subsidized by the British and French govts., otherwise it would never have operated for as many years as it did,

Dave

1 hour ago, dave2013 said:

I get that you are proud of the Concorde, and you should be. 

However, there is no comparison to Boom's aircraft because the Concorde's development and operation was heavily subsidized by the British and French govts., otherwise it would never have operated for as many years as it did,

Dave

WHAT?

why would I be proud of the Concorde? I had nothing to do with.

I was merely pointing out based in the CGI rendition of it that it is visually almost identical to the Concorde.

but it doesn't have the majestic quality of the Concorde aesthetic. IMO

 

13 hours ago, Bob Scott said:

And, again, subsonic aircraft will also be able to burn the same fuel, and a lot less of it on a per pax-mile basis.  From a conservation perspective, how much you burn can be just as important as what you burn in a world with an exponentially exploding population to feed and shelter.

 

Well yes, but it was your reference to carbon emissions I was referring to, not general conservation. Boom claim carbon emissions will be low or net zero, they haven't claimed this will be a super economical aircraft with the fuel consumption of a subsonic passenger airliner. 

I was also referring to your comment that "The very real physics of supersonic flight are gonna slap 'em silly, me thinks." Again, they will have been smart enough to consider such things.

 

 

Quote

I want to see how the assumptions built into operating whole fleets of jets with "100% SAF" impact the global food supply, for example, and what the actual input costs in terms of water usage and other forms of energy inputs would be.

 

I agree, although SAF can be made from food waste, that may be what they plan. And as I previously mentioned, whether the quantity of SAF would be available for regular flights of many such aircraft, currently there's very little aviation SAF around ands what is around is expensive. 

 

Quote

Supersonic jets still make shock waves that, on the low end, are an aesthetic nuisance and unpopular addition to the copious sound pollution already all around us, and on the high end, they disrupt livestock and wild animals and can even break stuff. 

 

Well yes, but as I mentioned before, I don't think the qualified people that have analysed the feasibility of this concept have gone ahead without considering such things and whether the concept is still viable. They obviously feel it is viable. United Airlines seem to think its viable too. As for "breaking stuff" that would only be an issue at very low altitude, and you can be sure they wont be traveling supersonic at 500 feet. 😁

 

13 hours ago, Bob Scott said:

I remain, however, highly sceptical of a glossy advertising brochure so heavily laced with eco-buzzwords that it looks like the Greenpeace PR dept wrote it.  When I see that sort of overt pandering, alarms start ringing and the BS flag starts running up the flagpole.

 

Where exactly did yous see this? I've not seen anything like that. Just the proper terms used for what they are trying to achieve. I doubt United Airliners and others would be jumping onboard if they thought the company were propagating BS. 

Don't get me wrong, in my opinion its a pointless exercise, in that we are getting along fine as we are, and we don't need a supersonic concept like this. However, I do think you are edging toward cynicism rather than scepticism and under estimating the companies ability to consider the negatives you have highlighted. 

Edited April 24, 20224 yr by martin-w

13 hours ago, Christopher Low said:

A few supersonic "thuds" per day (assuming that this new technology works) would not annoy me in the slightest. Certainly not as much as hundreds of cars, trucks and buses do on any high street in the country on a daily basis.

 

Yep, the shockwaves would be generated at high altitude too. So not particularly troublesome on the ground. 

There is a common misconception with sonic booms though, in that many think it occurs once when the aircraft breaks the sound barrier. Not true, the boom is a continuous effect that occurs throughout the supersonic flight, sweeping across the countryside. .

Edited April 24, 20224 yr by martin-w

14 hours ago, Ray Proudfoot said:

@martin-w, a test with a smaller model was “successful” whatever that means. The acid test is with a full-size version.

Interesting that no stats were published.

 

What they are trying to achieve is a gentle thud instead of a boom. The X59 is due to carry out community flight testing in 2023 - 2025. this will be over US cities to evaluate the community responses for regulators. this could then enable commercial supersonic travel over land.

 

Quote

 

The Low-Boom X-plane will be 94 ft (29 m) long with a 29.5 ft (9.0 m) wingspan for a maximum takeoff weight of 32,300 lb (14,700 kg). Propelled by a General Electric F414 engine, it should reach a maximum speed of Mach 1.5 or 990 mph (1,590 km/h), and cruise at Mach 1.42 or 940 mph (1,510 km/h) at 55,000 ft (16,800 m).^[18] The cockpit, ejection seat and canopy come from a Northrop T-38 and the landing gear from an F-16 Fighting Falcon.^[6] Its engine will provide 22,000 lbf (98 kN) of thrust.^[19]

The ground noise is expected to be around 60 dB(A), about 1/1000 as loud as current supersonic aircraft. This is achieved by using a long, narrow airframe and canards to keep the shock waves from coalescing.^[5] It should create a 75 Perceived Level decibel (PLdB) thump on ground, as loud as closing a car door, compared with 105-110 PLdB for the Concorde.^[6] The central engine has a top-mounted intake for low boom, but inlet flow distortion due to vortices is a concern.^[12]

The flush cockpit means that the long and pointed nose-cone will obstruct all forward vision. The X-59 will use an enhanced flight vision system (EVS), consisting of a forward 4K camera with a 33° by 19° angle of view, which will compensate for the lack of forward visibility.^[6][20] United Technologies subsidiary Collins Aerospace was selected to supply its Pro Line Fusion Cockpit avionics, displaying the boom on the ground, and EVS with long-wave infrared sensors.^[21] The Collins EVS-3600 multispectral imaging system, beneath the nose, is used for landing, while the NASA external vision system (XVS), in front of the cockpit, is giving a forward view.^[12]

 

 

https://en.wikipedia.org/wiki/Lockheed_Martin_X-59_QueSST

@martin-w, so its cruise speed is now just Mach 1.4. That’s 400mph slower than Concorde. 😳 940mph versus 1320-1350mph. Concorde was 44% faster.

That’s just 60% faster than a 787. They would have to be careful with ticket prices. It looks like a half-way house between current subsonic aircraft and Concorde. Rather than son of Concorde it might be better named Concorde-lite.

The lack of forward visibility could be its biggest issue. I remember in the early days of Concorde’s design the cockpit forward windows were very small and the US FAA said it wouldn’t be approved unless they were enlarged.

Might this be the Achilles’ Heel of Boom? What happens should there be a full electrical failure?

Concorde employed ramps to slow the air into the engines once supersonic. I see no equivalent for Boom. But that’s necessary to avoid engine flameout. They still have major hurdles to overcome before this is viable.