[Shreyans_Jain]

Question: Is the sonic boom something momentary that happens when the aircraft breaks the sound barrier? Or is it something that happens continuously for as long as the plane remains supersonic?

[ToThePoint]

Originally Posted by Shreyans_Jain

Question: Is the sonic boom something momentary that happens when the aircraft breaks the sound barrier? Or is it something that happens continuously for as long as the plane remains supersonic?

Wikipedia: A sonic boom doesn't occur the moment an object crosses the sound barrier and neither is it heard in all directions emanating from the supersonic object. Rather the boom is a continuous effect that occurs while the object is travelling at supersonic speeds.

[dheer4]

I desperately want this to succeed being an aviation buff!, but the economics make no sense.

The plane supposedly seats 65-80 depending on the configuration and takes 3Hours and 30 Minutes to go to London. For example, an Airbus A350 carries around 300-410 and can seat upto 450. I really feel that select few would pay for the extra added cost to fly from such routes.

A typical LHR to JFK would cost around 500$ and upwards. A full flight would bring in around 160,000$ and upwards(Approximately) to the airline usually for the route before expenses.

for the Boom to make sense, the airlines should sell a seat close to the 2,000$ mark to at least match the A350, making a seat's price almost on par with Business class prices.

Adding to this, the aircraft has not even gone into production, so if we include inflation and the rise of aviation fuel, It might hit close to 3,000$ or more by the time it launches at the end of this decade.

This might make sense for those travelling for Business or for those who fly really frequently.

[Jeroen]

Originally Posted by dheer4

for the Boom to make sense, the airlines should sell a seat close to the 2,000$ mark to at least match the A350, making a seat's price almost on par with Business class prices.
.

We will have to see how they position this plane. The Concorde was positioned way above normal business and even first class price points. It varied over the years, but a Concorde ticket would easily cost five times the regular business ticket price.

You did get a true VIP treatment for that price. Concorde passengers did not mix with the regular plebs at airports. They had their own checking/security/immigration and luggage fasciliteert. All to give the passenger a unique experience away from the hustle and bustle of being a regular passenger.

There is an interesting anecdote about how BA decided on the ticket pricing. Very early they figured out that virtually none of their passengers booked their own flights in Concorde. They had personal assistants doing such mundane tasks of course. They interviewed the passenger on what they felt was the ticket cost. The answers they got were consistently 2-3 more expensive than they actually had paid! So BA decided to charge them the higher cost.

It was not just the higher fuel price that did Concorde in. It was a combination of various factors. One being the increasing maintenance price of these, by then, age airframes. Concorde was state of the art technology when it was introduced. Many new technologies and systems, materials. After a while that begins to show in preventive maintenance.

I think this new supersonic plane is likely to be able to more efficient in many ways. It won’t have afterburners. (Note: the Concorde only used afterburners during take off, climb and acceleration, during mach 2 cruise it did not use after burners)

There is so much more knowledge about building these high performing planes. Also, the design methods are so much better. Let’s face it, Concorde was still designed mostly by slide rule! An incredible feat, but it shows ultimately.

I don’t have the expertise to really judge how feasible this initiative is. I hope it does make it through. The fact that two carriers have signed up and are committing considerable amounts of money and time no doubt of some of their top people, means they are serious about it.

I had the pleasure of flying Concorde only once. A short demo flight around Gatwick. We did not go supersonic.
But almost, even more importantly, I actually flew the actual Concorde simulator in 2016:

https://www.team-bhp.com/forum/comme...simulator.html (Experience: British Airways Concorde Simulator)

Jeroen

[SmartCat]

Originally Posted by ads11

Another key speedbump for Boom is reliant on NASA's QueSST (Quiet Super Sonic Transport) demonstrator finally cracking the key to minimising the sonic boom as much as possible (and make no mistake, that's a big if).

Originally Posted by thehighwayman

Even when the plane materializes, they still cannot overcome one of biggest problem of supersonic planes - the sonic boom.

Originally Posted by V.Narayan

In my opinion completely impractical in terms of sonic booms over land routes,

Gents, Boom will be flying at high subsonic speeds over land and supersonic speeds over oceans. From Boom website:



Next obvious question would be - why didn't Concorde do the same? That's because Corcorde engines were highly inefficient at subsonic speeds. So it looks like Boom just solved the subsonic fuel efficiency problem.

[V.Narayan]

Originally Posted by SmartCat

Gents, Boom will be flying at high subsonic speeds over land and supersonic speeds over oceans. From Boom website:

Attachment 2348755

Next obvious question would be - why didn't Concorde do the same? That's because Corcorde engines were highly inefficient at subsonic speeds. So it looks like Boom just solved the subsonic fuel efficiency problem.

Thank you SmartCat.

All,

That is exactly what the Concorde did too. Infact once it had reached its supersonic cruise speed the Concorde would switch off the afterburners and super cruise on {almost} full dry thrust. The new engines without doubt will be more efficient but if you have flights that are 40% over land and 60% over the sea your biggest advantage is lost. So it might still make sense for a London to NYC but less so for a London to Chicago and even less for a Berlin to Chicago. Anyway I am not a fan of these supersonic ozone depleting toys for boys especially when time from entering the airport to exiting it at the other end is counted which is what the travel really is for the passenger.

Another data point from the real world of operating an aircraft as opposed to the sexy world of supersonic flights:

Maintenance man hours per flight hour

For a typical civilian jet airliner = 12 to 17 hours

For the English Electric Lightining fighter which I rate as the most poorly designed supersonic jet fighter ever from a major country. It was so bad on availability and maintainability that its ground crews nicknamed it the "Frightening" = 36 hours

Concorde = 57 hours

Operating an aircraft is like an iceberg. The flight is the 10% the passengers see. 90% is the prep, maintenance, turning around, training, safety checks you don't see.

[satish.gawai]

While this is exciting we should not forget the concord story. while the technology has grown all these years, there are many questions that need to be answered like,

-If it flies at 60K feet (at supersonic speed), will it not disturb the environment over there? -what could be the long-term effect of this?
-Very disturbing sound to the nearby residents when concord used to fly. Even glass breakage on some buildings was observed in some cases (as per the concord case study). how it is taken care of.
- like concord, will it be positioned for the rich/superrich only considering only 80 passengers will fly and the operating cost?
- It is interesting to see its business model.

[satish.gawai]

Question: Is the sonic boom something momentary that happens when the aircraft breaks the sound barrier? Or is it something that happens continuously for as long as the plane remains supersonic?

As far as I know, the sonic boom will be a continuous phenomenon once the object breaks the sound barrier and remains supersonic. Correct me if I a wrong.

[SR-71]

Wondering what sort of wake turbelance these birds will create flying @ Mach 1.x and its impact on vertical seperation. Yes I understand most commercial flights have a service ceiling of 40K feet and these new supersonic birds claim to fly as high as 60K feet. But if they become mainstream there might be multiple of them zipping around in addition to military jets which probably use similar service cielings...

I watched this viode of a business jet which was flying a 1000 feet below an Emirates A380 and almost crashed after getting caught in the 380s wake turbulance.

https://www.youtube.com/watch?v=O8a_lvC33Do

[Jeroen]

There have been many books written about Concorde. Many of you will be familiar with the Haynes owner workshop manuals on many cars. I have quite a few of them. They also did one on the Concorde.



I find it one of the most interesting books about Concorde. Lots of images and drawings explaining how the Concorde came about and how it was flown, operated and maintained. The original agreement between France and the UK to develop, design and build Concorde (or SST as it was referred to) was signed in 1962! That is 60 years ago. Interestingly, no escape clauses were included. By 1969 it made its maiden flight, with first Mach 2 flight in 1970. Concorde received full commercial certification by the French and UK authorities end of 1975.

In those years leading up to commercial readiness several carriers did sign up to procure Concorde. For various reasons most dropped out and only Air France and British Airways did. The financial details and how much the respective governments subsidised remains a much debated topic. But in general it is believed the government ultimately payed for a lot!!

Concorde was not only restricted to subsonic speeds across land due to its sonic boom. With maximum fuel on board, they needed to burn a certain amount first in order to trim rearward. Till such moment they had to remain subsonic.

Concorde is one of the very few, if not only commercial jet air liner, that did not suffer from corrosion. All aircraft suffer from corrosion as water/condensation finds its way in small cracks. However, it was found that as Concorde warms up during supersonic flight any water would vaporise!

Anyway, this book is full of these kinds of details and many anecdotes, crew stories etc. Will we ever see such a book on this new Supersonic airliner?

Jeroen

[quickdraw]

Originally Posted by V.Narayan

the sheer maintenance required by any supersonic aircraft in comparison to subsonic ones. The technology to design a supersonic passenger liner or business jet have existed for 50 years and there is a reason it has not been attempted after the Concorde

Are there no new innovations done by these guys in terms of aero & engines? I would assume them to be using something similar to the Pratt & Whitney J58 that were found in SR-71. My understanding is the material science and advancements in computers must have made it possible to have some significant improvements in this area. (Please excuse my limited understanding of jet engines)

Although I completely agree with all the points you have made in terms to the travel time by passenger, maintenance, viability of business etc. this is so exciting to me. On a primordial level I really wish to travel faster than sound at-least once in my life. But efficiently and without damaging the earth while doing it and I want to believe that current technology might make this possible.

[fhdowntheline]

While I think this news is exciting from a technology demonstration perspective, I believe there was a proposal by Boeing named "Sonic Cruiser" which aimed to extend the subsonic envelope by a few Mach decimal points (M-0.95) and yet remain viable commercially. That speed bump would save about 15% flying time . Some of that research, especially on composites, made its way into the Dreamliner (B787). Perhaps they could revisit this idea since it was made about 20 years ago.

[Jeroen]

Originally Posted by SR-71

Wondering what sort of wake turbelance these birds will create flying @ Mach 1.x and its impact on vertical seperation. Yes I understand most commercial flights have a service ceiling of 40K feet and these new supersonic birds claim to fly as high as 60K feet. But if they become mainstream there might be multiple of them zipping around in addition to military jets which probably use similar service cielings...

There are two main factors causing wake turbulence, jet wash and wingtip vortices. Jet wash is very turbulent but last a very short while. Wing tip vortices being the most relevant factor. As soon as a wing develops lift it will also create wingtip vortices. It is extremely relevant during landing and also take off.

An important factor contributing to wingtip vortices are the angle of attack. Pilots are taught to watch for wake turbulence, when you are low, slow and dirty. Which means you are flying slowly, close to the ground and are in landing configuration meaning you have flaps down.

Rule of thumb, the bigger, the heavier the aircraft is, the more wake turbulence it will generate. Separation of aircraft is determined by its category.





So this new aircraft will need to be categorised as well and will follow the appropriate separation rules. During take off, landing and cruise.

There are very few aircraft up at 60K feet altitude. This aircraft will never be mainstream. Although (some) military jets can reach these attitudes, very few do it. And if they do it is only for a very short time. They certainly dont cross oceans, simple not capable of that.

As a pilot of single engine planes, wake turbulence is something to be very much aware of. Just about any plane out there is larger than you. In order to avoid it, we need to adhere to separation rules as well. But even then, we take extra pre-caution. If you take off after a large plane, you won’t rotate until you are well past the point where the larger plane rotated. During landing you will ensure you flight path stays above that of the larger preceding aircraft and you touch down well beyond its touch down point.

Although wake turbulence is a well understood phenomenon, there is still more research ongoing to further optimise vertical and horizontal separation between air craft.

Jeroen

[AirbusCapt]

The near future is high-bypass turbo fan engines/better geared turbofan engines which work well at high subsonic speeds (.75 till .85 mach), give fantastic fuel economy and range with very little noise. The Airbus Neo and the Boeing Max are the begining of this development.
The immediate future is going to be narrow body long haul, the first in class being the Airbus A321 Neo XLR. This aircraft will possibly kill the current crop of widebody twin and quad jets by doing a Bangalore heathrow nonstop and consuming about a third of the fuel which a Boeing 777 now consumes. The widebody twins will possibly convert to freighter solely on their payload hauling abilities.
In this scenario of economical flying where does a supersonic jet fit it? It's almost impossible to build a cost efficient twin jet which supercruises at supersonic speeds without compromising on the range and or the payloads. A quad jet like a Concorde would be too carbon footprint heavy, not to mention highly fuel inefficient and a mantainance hog.
For the paying passenger fast business jets already exists which cross the pond in about 4 hours or so. To get that market to travel in a group of 60/70 would be almost impossible.
As a pilot I am excited at a return of the supersonic transport, but as a realist I feel this is more hot air than actual work on the ground

[TeddyBear]

Originally Posted by ajayc123

Just curious, would these planes require special runways? Or are our current runways in India ready to land these planes?

I remember seeing Concord landed in Chennai Airport back in 1990 ( Some Arab Sheiks charted trip elsewhere and it had a stopover in Chennai)

So existing runways are more than sufficient.