NASA is going to assemble a quiet supersonic aircraft: X-59 QueSST

[mfb]

TL;DR Summary

The final approval to build the X-59 QueSST has been given. It will be reviewed in late 2020 for a flight in 2021.

Press release

The Concorde could only fly supersonic while over the open ocean - the sonic boom was too loud. NASA is looking for aircraft designs that are much quieter. While the X-59 itself isn't very practical for passenger transport it might have some direct military applications and help design passenger-friendly aircraft in the future.

What do you think - is there still a market for civilian supersonic aircraft? They are faster, but they are more expensive and offer less comfort than subsonic aircraft.

 

[anorlunda]

I think the technology is very cool.

But I also think that as a commercial passenger plane that it would be a new form of conspicuous consumption in an era where we are supposed to feel guilty about the climate. It would be trashed in the media and on the Internet.

Isn't air travel already being publicly shamed in Europe?

 

[MikeeMiracle]

Definately there is a market, since when is faster travel not desirable. I am sure if it was economical to have Concord run to modern standards that it would stil be running. The Russian version is still running.

 

[mfb]

The Russian version is still running.

If you mean the Tupolev Tu-144: That was retired long ago.

Time in the air can be used for work today and more meetings are done remotely. Getting from A to B faster is still interesting but the travel time became useful work time.

 

[MikeeMiracle]

Travel time becoming useful work time is only valid if your work is done on a computer / remotely, and even then you may need internet access to do it remotely. The beauty of Concord was that you could fly across the atlantic for a meeting and be back the same day. If your an engieneer needing physical access to equipment then you are looking at less travel time = less downtime = less total cost (accounting for the faster method of transport costs similar to the alternative methods of transport vs the cost of the engineer's time.)

This is true of all travel not just planes. Being able to move quickly makes us more productive overall. In the UK we are going through this debate right now with regard to the proposed HS2 (High Speed 2) railway project. The UK is totally London centric but if you can get from London to an office in another location in 2 hours rathar then 5 hours you are more likely to open an office there and "spread the knowledge/wealth" as such.

Faster transport infrastructure will always get used and taken advantage of in my opinion.

 

[berkeman]

It seems like one of the initial applications for this technology would be in an SST version of the Executive LearJets. They already look pretty similar...

https://www.nasa.gov/press-release/...-research-aircraft-cleared-for-final-assembly

https://www.claylacy.com/wp-content/uploads/2019/02/Learjet-70-847-Ext.jpg

 

[anorlunda]

Leer Executive Jets

Pun intended?

 

[berkeman]

Pun intended?

Whoops! Fixed, thanks.

 

[PAllen]

Summary:: The final approval to build the X-59 QueSST has been given. It will be reviewed in late 2020 for a flight in 2021.

Press release

The Concorde could only fly supersonic while over the open ocean - the sonic boom was too loud. NASA is looking for aircraft designs that are much quieter. While the X-59 itself isn't very practical for passenger transport it might have some direct military applications and help design passenger-friendly aircraft in the future.

What do you think - is there still a market for civilian supersonic aircraft? They are faster, but they are more expensive and offer less comfort than subsonic aircraft.

These days, how can you offer less comfort than current aircraft (at least for standard coach/economy class)? About all they could do to be worse would be standing room with no rest rooms.

 

[mfb]

@MikeeMiracle: Not many engineers are needed that urgently in different places, and even they will have some work on a computer. Internet access is not fast on planes but certainly available.

These days, how can you offer less comfort that current aircraft (at least for standard coach/economy class)?

Potential customers for supersonic jets won't fly coach today.
For the price of a Concorde coach ticket you could get two nice first class tickets on a subsonic aircraft. For the price of a supersonic Learjet equivalent you can probably get a much larger subsonic private aircraft.

 

[Vanadium 50]

What do you think - is there still a market for civilian supersonic aircraft?

I don't think so. JFK-LHR (the old BA Concorde flight) is 3451 miles. It's blocked at 6h 45m , with about 6h in flight. I have never walked off a plane onto the curb at Heathrow in less than an hour, and everyone recommends arriving 2h before an international flight. So we have just under 10h with 6h in flight. Doubling the speed of the flight only shaves 30% off of the time.

To cut the door-to-door time in half requires something as fast as the SR-71.

 

[Mark44]

So we have just under 10h with 6h in flight. Doubling the speed of the flight only shaves 30% off of the time.

To cut the door-to-door time in half requires something as fast as the SR-71.

Sounds like Amdahl's Law...

 

[Vanadium 50]

Gene Amdahl was a very smart man.

 

[anorlunda]

To cut the door-to-door time in half requires something as fast as the SR-71.

That's what makes me think that the market is not for airliners, but rather for supersonic private Lear Jets (Leer Jets, love the pun. ) Hence the political backlash. If only billionaires can afford these planes, there will be a lot of public opposition. Worse, if the popular notion is that NASA is doing research to benefit only billionaires, that too will cause backlash.

 

[berkeman]

Worse, if the popular notion is that NASA is doing research to benefit only billionaires

Well, they did mention "military applications" as well...

 

[jrmichler]

There are currently 2,153 billionaires in the world. Some of them have bought Boeing 747's as private jets. At least one of those 747's had a stable built in so that he could bring his horses along. There is also an Airbus A380 private jet out there. I suspect that a supersonic business jet would have a market.

I worked for a company located in Northern Wisconsin, USA. To travel by commercial air meant a two hour drive, two hour TSA time allowance, a short flight, another wait, at least one more flight, then a rental car. A normal business trip within the US was 12 to 15 hours each way, so at least three days total.

Travel by the company jet was different. Show up at the local airport (5 minute drive), sit around for 5 to 10 minutes, walk 50 feet to the airplane, sit down, and take off about 5 minutes later. Repeat on the way back, and the airplane left when we were ready. The same business trip was one day, and that day was typically 8 to 10 hours from start to finish. The refrigerator was stocked with soft drinks, and the under seat drawers had snacks (typically cans of mixed nuts). And leg room.

 

[member 656954]

Show up at the local airport (5 minute drive)

My uncle lives next to a regional airport and finds watching the planes a pleasant diversion some days, but apparently small / regional airports are generally in decline across the country. Still, that private jet seems like a nice way to travel, though if it traveled at twice the speed, would that have added considerably to your work time, @jrmichler?

 

[mfb]

I doubt Boeing 747 and Airbus A380 would have been developed if private planes of billionaires would have been the only market. Development of a supersonic Learjet equivalent will cost a lot, it must be popular enough to recover the development cost.

 

[jrmichler]

A couple of my business trips by air were short, about 150 air miles. Those trips were in a Beech Baron, which cruises about 200 MPH, so travel time was less than one hour. Driving time would have been about 4 hours. By car would have been one very very long day or two regular days.

The jet trips were in the Cessna Citation 650, and trip distances about 400 to 1000 air miles. All were out and back in one day. A supersonic jet would not have been noticeably faster, partly because of the 250 knot (288 MPH) speed limit below 10,000 feet. And the lower speed limits near airports.

The travel time improvement of a supersonic jet comes from 2000 mile and longer trips.

One manufacturer of business jets is Gulfstream: https://en.wikipedia.org/wiki/Gulfstream_Aerospace. They specialize in larger business jets, and currently employ 11,500 people. Boeing has their BBJ (Boeing Business Jet) division for those that want anyone of their models with a completely custom interior. Airbus has a similar division.

The size of the market, from https://en.wikipedia.org/wiki/Business_jet: In 2017, 676 business jets were shipped, led by Gulfstream with $6.56 billion for 120 aircraft, Bombardier with $5.2 billion for 140, Cessna with $2.87 billion (including propeller aircraft and 180 jets), Dassault with $2.42 billion for 49 and Embraer with $1.35 billion for 109.[11]. There may or may not be a sufficient market for a supersonic business jet to justify the development cost, but I am sure that several companies are doing serious market research on the subject.

 

[anorlunda]

I think it is an uphill battle.

From https://en.wikipedia.org/wiki/Supersonic_transport

The International Council on Clean Transportation (ICCT) estimates a SST would burn 5 to 7 times as much fuel per passenger.[36]

The referenced paper was from 2018.

 

[Vanadium 50]

If there is a market for a supersonic private jet for billionaires, why aren't they refurbishing the existing supersonic jets? There are 19 remaining Concordes and 16 Tupelov-144s somewhere.

 

[dlgoff]

It seems like one of the initial applications for this technology would be in an SST version of the Executive LearJets. They already look pretty similar...

https://www.nasa.gov/press-release/...-research-aircraft-cleared-for-final-assembly

View attachment 254250

What a cool looking airplane. I'm going to email this to my daughter and ask if she'd like to pilot it. She has flown this jet aircraft:

 

[mfb]

If there is a market for a supersonic private jet for billionaires, why aren't they refurbishing the existing supersonic jets? There are 19 remaining Concordes and 16 Tupelov-144s somewhere.

Too loud to fly supersonic over inhabited land, too big to land on most airports, and probably a nightmare to get that approved in a useful way.

 

[Dale]

I don’t think this is about the market as much as it is about the technology. A quiet sonic boom is cool technology. NASA isn’t aiming to sell a product.

Does anyone know if market considerations are a big part of its “Key Decision Points”?

 

[anorlunda]

I don’t think this is about the market as much as it is about the technology. A quiet sonic boom is cool technology. NASA isn’t aiming to sell a product.

Does anyone know if market considerations are a big part of its “Key Decision Points”?

This Strategic Implementation Plan sets forth the NASA Aeronautics Research Mission Directorate (ARMD) vision for aeronautical research aimed at the next 25 years and beyond. It encompasses a broad range of technologies to meet future needs of the aviation community, the nation, and the world for safe, efficient, flexible, and environmentally sustainable air transportation.

That doesn't mention marketable at all. One would hope that they would follow the lesson Thomas Edison learned after his first invention (an electric vote counter machine made for Congress) was accepted by the patent office but rejected by Congress.

“It was too fast and efficient for politicians of the day, and although it was unsuccessful, Edison learned a valuable lesson: one must truly consult the marketplace first before introducing a product,” --- Matt Andres.

I feel like a Luddite in this thread. My view is, "Hummer is to Tesla Model S as Supersonic is to conventional airliners." Although some owners might prefer the Hummer, the public hates it and loves the Tesla.

 

[Baluncore]

You need not fear. With only one engine it is a long way from becoming any sort of reliable executive jet.

The X-59 test bed may be quiet, but scaling up to a realistic SST will increase the length, width and number of engines, to make more noise and a bigger boom.

 

[mastermechanic]

A quick idea has come to my mind right now, what if the aircraft would use active sound cancellation just as is in the inside the aircraft? Reverse sound waves are emitted just in the instant of sonic boom. Nevertheless it's a good idea for sci-fi :)

 

[essenmein]

Didn't Putin float the idea of converting Tu 160 strategic bombers for private super sonic jets?

 

[mfb]

A quick idea has come to my mind right now, what if the aircraft would use active sound cancellation just as is in the inside the aircraft? Reverse sound waves are emitted just in the instant of sonic boom. Nevertheless it's a good idea for sci-fi :)

The main sound comes from the outermost tips in a continuous way (as seen from the spacecraft ). A speaker can't reproduce that continuity, and it can't be inside the shockwave either (as it would create its own shockwave then).

 

[trurle]

The main sound comes from the outermost tips in a continuous way (as seen from the spacecraft ). A speaker can't reproduce that continuity, and it can't be inside the shockwave either (as it would create its own shockwave then).

Well, realistically it would be something like slat bleeding air from additional compressor rather than speaker. The fuel efficiency would suffer though.

 

[chemisttree]

That's what makes me think that the market is not for airliners, but rather for supersonic private Lear Jets (Leer Jets, love the pun. ) Hence the political backlash. If only billionaires can afford these planes, there will be a lot of public opposition. Worse, if the popular notion is that NASA is doing research to benefit only billionaires, that too will cause backlash.

And since Lear jets have far fewer passengers there would need to be more of them. Ugh! All those sonic booms everywhere so some executive can go somewhere faster. IF they could make them quiet (not just quieter) and marketable (cheap) then sure but those are pretty significant “ifs.”
“If” they would develop transporter technology we wouldn’t need planes at all.