Back to blog

Supersonic jets may be about to make a comeback

See blog

Readers' comments

Reader comments are listed below. Comments are currently closed and new comments are no longer being accepted.



An aeroplane that will shave 2.5 hours off the typical flight between New York and London is nice, but surely optimising the journey to the airport, cutting the hassle of going through passport control and waiting for luggage can achieve nearly that.

To put it differently, the prospect customers of supersonic jets will mainly use the service to satisfy their ego and sense of self importance, mostly another story to brag about to friends, not for a measly improvement in the ETA, given all the restrictions and technical issues the article raised.


A supersonic jet that has to land to refuel defeats the purpose of the jet. Why not in flight refueling? The military has been doing it for decades. Their supersonic jets don't seem to have a problem with it. There are enough ex-tanker pilots and boom operators around who can show you how its done.


If the jet flights faster than the earth's rotation, the traveler would actually go back in time (when fly westward, of course).


Jet planes replaced propeller powered planes for three reasons:
1 - Halving trip times (the least important reason)
2 - Enabling flying at higher altitudes (dramatically reducing weather-related accidents caused by local storms) &
3 - Using cheap kerosene rather than expensive avgas
So passengers would reach quicker, have less chance of getting killed and (most importantly) at a cheaper price.
I don't see SSTs becoming popular with current or developing technologies. The (yet undiscovered) engines on this type of plane should be powered by a (yet undiscovered) fuel.
And when that plane is built in the (distant) future, it will easily handle noise restrictions by flying at extremely high altitudes... noise regulations are not the real roadblock; the problem is the ticket price.

Michael Dunne in reply to CaptainRon

What do you mean? Thought the average cost of a round trip ticket with the Concorde back then was in the range of $10,000 to $12,000?
And the article claimed the routes "would have cost $20,000 on Concorde in today’s dollars. "

Gordon L

A turbofan powering a supersonic aircraft: Can they actually do that? Can a fan actually handling an inflow of airtravelling at supersonic speeds?

View Pointer

In the 1960s and 70s the stationed Western forces of America, Great Britain, France and Canada were free to fly their military jets at any speed across West Germany. They frequently exceeded the speed of sound, creating sonic booms in their tails. As children we relished watching pairs of jets approach, waiting for the sonic booms to follow after the aircraft had well passed us, frequently in low level flight. We felt anticipation and excitement similar to fireworks going off on New Year’s Eve. Sonic booms can become just another fact of life, much like firetruck sirens in the distance. Perhaps in time speed restrictions in North America will be experimented with and loosened as citizens gradually realize that sonic booms are at most a momentary inconvenience.

Yes, 2023 is coming around a bit fast - just five years away. So agreed, the article seems to convey a bit of an optimistic view.
For success with supersonic transport, range and speed would need to be upped, by a good bit, to service an AsiaPac/Pacific Rim market. As for the 1960s, speeds of mach 2.5 to Mach 3 were not really achieve with civil transport (the B-70 achieved it, same with SR-71). And probably for good reason - as in really hard to achieve, for the price of a first class ticket, let alone business class.
As for the moon landings, that was dissipation of political will from success. The US threw away a lot of assets/know how that could have been built upon from that moon race (see Skylab as an example, but also ditching other projects like the NERVA engine). Scaling down investments in the late 1960s on into the 1970s led to a miss opportunity in my view (space stations, space manufacturing, more extended stays on the moon, flyby of Mars/Venus, larger probes getting sent out into the solar system, lift capability for a variety of needs - including Reagan's Star Wars vision in the 1980s, etc.).

Michael Dunne in reply to TS2912

What do you mean by "undiscovered" when referencing engines?
Commercializing (making certain technologies practical/feasible) concepts presents some big challenges, but you have had ideas about ramjets (and hybrids/variants) around for some time, accompanied by some experimentation/implementation.


Reaction Engines' Sabre engine (hybrid air breathing rocket) could allow travel at mach 5. It can also fly at sub sonic speed over landmasses.Once you get up to speeds of Mach 5 routes over the north and south poles as well as Oceans become practical.


Being unable to fly within the U.S. is a bit of a drawback for a business jet, and regulators in other countries may not be that much keener. Who wants to convince voters (or even non-voters) to put up with sonic booms so a handful of executives can shave a few minutes off their trip? Quieter booms might help, but the fact that NASA and Lockheed are "experimenting" along those lines gives little hope that breakthroughs will be incorporated into jets that will "enter service in 2023".
A Mach 1.4 plane also promises a pretty small decrease in travel time, especially after accounting for lower-speed stretches and mucking about at airports. Mach 2.2 is more interesting, but would still be restricted to mid-range transoceanic routes. Really, it seems like Concorde's old routes might still be the only economical ones (which suggests a passenger service, not a business jet). For all the noisy marketing efforts of the startups, it also sounds like investments have been small (it's the aerospace industry; they probably got $10M by checking under the couch cushions).
Like landing on the moon, supersonic passenger flight aims to repeat something accomplished in the 1960s. Both are things we stopped doing for a reason. Maybe we'll see supersonic passenger travel again someday, but it probably won't be soon.

Michael Dunne

It is interesting to see talk of a supersonic renaissance transport, but there was once talk of a nuclear renaissance (with energy generation) that hasn't panned out.
I think the article touched on a good point - these craft will require range, to traverse the Pacific.
I think that is crucial because I believe it will be the Pacific rim that will provide the market(s) for innovation in transport. In contrast to the 1960s, around a good part of the Asia Pacific region there are a good number of countries with mature or emerging affluent and business classes as a result of years of healthy growth/economic development.
As a result there are a good number of customer segments that feel time is money, and could welcome time savings in travel, and/or folks who are status conscious and would be up for purchasing a first class or business class ticket for travel on supersonic aircraft.
And, $5,000 is not outrageous for business class. Its like $6,000 to $10,000 depending on time and the yield management algorithm(s) to travel business from say JFK to Dubai.
I think the boffins ought to go back to the old designs for ~Mach 3 speed, like the Lockheed L-2000, the Boeing 2707, etc.; and then see how an aircraft carrying 300 people comfortably across long distances (from San Francisco to Haneda, or LAX to Shanghai, etc.) could be accomplished with advances since 1960s (and feasible developments in the near future), including:
- Modeling/design
- Engines (including ramjet concepts)
- Electronics/computing/controls
- Advanced materials
If such a craft could be brought to market, for seats costing $5,000 or $6,000 apiece, I think a carrier could do pretty well (maybe also give generous opportunities for road warriors to cash in their miles, to build awareness/demand?)... especially one in Japan servicing long routes (of which there are a few).

Michael Dunne in reply to ashmash

"optimising the journey to the airport, cutting the hassle of going through passport control and waiting for luggage can achieve nearly that."
How? There seems to be a few constraints that make it difficult to shave 2 1/2 hours from "ground operations" (procedures).
The carriers are going to want people at the airport by a certain time, to ensure that checked bags make it to the plane, and that people have time to get through security.
Checked bags are probably going to take at least 18 to 20 minutes to be conveyed from the plane to the baggage claim carousel. If such a benchmark could be consistently fulfilled, that would probably save 10 to 20 minutes.
Not everyone lives near a rail line that provides a "somewhat direct" path to the airport, let alone a pretty dedicated express train (like the Heathrow Express). Now if a dedicated JFK express line was put in place, with a few limited stops (say in Brooklyn), then folks in Manhattan could save much time (maybe 30 or 40 minutes or so?)...
What would you suggest for improving passport control? JFK has kiosks now, but they don't seem to speed up things...

AGB17 in reply to daysaccountedfor

"Being unable to fly within the U.S. is a bit of a drawback for a business jet, and regulators in other countries may not be that much keener."
Indeed - and mention in the article of the specific US ban is highly misleading. Trans-US was effectively the only over-land route that BA and AF wanted to fly Concorde, so that's where the general noise ban was introduced. Other countries in mainland Europe and over in Asia - had specifically banned Concorde supersonic overflights, but the markets in that direction were never very feasible for Concorde anyway, because of necessary refuelling stops to, say, Japan, Korea and even down to Oz: for them, there was no point in crafting general anti-supersonic legislation for something that was not really going to happen anyway. Many Euro folks harp on about the US "killing Concorde" - but as you say, it very far from obvious that Europe itself, or any other land mass, would have accepted persistent sonic booms in the past, or will do so in the future. What doomed Concorde - that lovely, lovely thing - was that it was a costly, complex product that could effectively serve only one developed market: coastal western Europe to coastal NE America.

Michael Dunne in reply to Michael Dunne

Interesting press release from last fall:

Reaction Engines Inc., the U.S. subsidiary of Reaction Engines, today announced that it has received a contract from the U.S. Defense Advanced Research Projects Agency (DARPA) to conduct high-temperature airflow testing in the United States of a Reaction Engines precooler test article called HTX. The precooler heat exchanger is a key component of the company’s revolutionary SABRE air-breathing rocket engine and has the potential to enable other precooled propulsion systems. The primary HTX test objective is to validate precooler performance under the high-temperature airflow conditions expected during high-speed flights up to Mach 5.

“We have been greatly encouraged by the increasing interest in our technology’s potential and are thrilled to embark on our first U.S. government contract with DARPA for HTX,” said Dr. Adam Dissel, President of Reaction Engines Inc. “Full-temperature testing of the precooler will provide the most compelling near-term proof of the technology’s potential to accelerate the future for high-speed air-breathing systems.”

The HTX precooler test builds upon previous successful ground tests of the precooler technology conducted at ambient environmental conditions in the United Kingdom. These previous tests validated precooler design methodology, manufacturing techniques, and test operations plans.

To support HTX testing, Reaction Engines is constructing a new high-temperature airflow test facility, located in Colorado. Under the DARPA program, the company aims to establish the facility’s capability to provide airflows in excess of 1800°F (1000°C), analogous to air-breathing flight above Mach 5, and then conduct the testing of a Reaction Engines-supplied precooler starting in the spring of 2018.

Mark Thomas, Chief Executive Officer of Reaction Engines, commented, “The announcement of DARPA’s contract is fantastic news and provides us with the opportunity to demonstrate our innovative heat exchanger capability in the world’s largest aerospace market. This will accelerate our development efforts and strengthen key relationships.”

Reaction Engines has world-leading expertise in the design and manufacture of compact, lightweight heat exchangers capable of cooling airstreams from over 1800°F to -240°F (1,000°C to -150°C) in less than 1/20th of a second. Developed for the high-speed SABRE engines, the precooler heat exchangers prevent engine components from overheating at high flight speeds and thereby could enable new classes of vehicles and operational possibilities

Michael Dunne in reply to Big_bad_Vlad

That is a very intriguing project (and lineage/history, from the HOTOL program I believe). If they could move that along, get more backing; heck, even get treated more seriously, say along the lines of a crash program by governments (say a UK/Japan collaboration), that could lead to some very interesting engineering developments. Maybe not success complete/over-delivery outright/overnight, but at least movement towards a fundamental improvement/convincing advances in aviation sometime in the not so distant future.


Should range become a serious issue I would predict use of a simple solution with ample precedent: disposable drop tanks. The WWII variety were made of papier-mâché, eminently biodegradable in the ocean. Such added take-off weight might reduce the number of passengers, but many such flights will have just one super-rich individual plus a small entourage.