I believe they are thinking that one is a solved problem (Jet Engine) and the other is a novel problem (Airframe with reduced supersonic noise). There has been some work done on the sonic boom problem, but not nearly as much as the jet engine problem.
They will probably just iterate from an existing engine design rather than trying to re-invent one. Just because no one is manufacturing them doesn't mean the designs are not there to be used.
Jet engine is a "solved" problem for like 4 Western companies (GE, Pratt-Whitney, Rolls-Royce, Safran) plus some Russian and Chinese state-owned enterprises that mostly do military work. These organizations guard their secret sauces vigorously. Designing a cutting edge jet engine from scratch (i.e. with competitive fuel efficiency) is NOT a trivial task.
>> Jet engine is a "solved" problem for like 4 Western companies (GE, Pratt-Whitney, Rolls-Royce, Safran) plus some Russian and Chinese state-owned enterprises that mostly do military work.
There's actually quite a few companies that make small turbojets especially for military purposes and up to a certain point, you can even DIY your own from spare parts (there are some Youtubers that have done that). That's the first tier and includes companies like Williams, usually producing <5,000 lbf engines.
Then you have companies like Garrett/Honeywell that can make engines that output tens of thousands lbf like the TFE731 for mid-range jets and fighter jets. These can power big jets but not very fuel efficiently; that's the second tier.
The next tier up is the high bypass turbofans producing tens of thousands lbf used for commercial aviation and afterburner engines for last gen fighter aircraft are a completely different story. The GP is right there are only a few players in the game. Due to scaling laws, at this point it becomes less about the design and more about the metallurgy and material science. Magic like single crystal alloys are critical here and are very closely guarded secrets because the knowledge unlocks everything from ICBMs to gaseous centrifuges to nuclear reactors.
Ha jet engine that can be certified maintained and is efficient is barely solved by GE. That’s it nobody else can make a modern commercial aircraft engine that isn’t a total money pit.
They are at least a generation behind GE and the company is on life support so I don’t see them closing the gap. Pratt now Collin’s has engines too but their commercial engines are 3-4 generations behind.
Although I think it's not going to be as easy as picking one up at the corner store, I do not think supersonic flight (which occurs every day on thousands of airframes) will compare to the level of complexity of landing a human being on an irradiated airless rock 238,900 miles above the earth's surface and returning them safely.
Edit: There are private groups that own supersonic aircraft and maintain them. EG:
They can get a hold of existing models and diagrams to produce their own copies since the patents have long since passed and been declassified for decades.
One of the key features of Overture is its planned use of e-fuels.
I think this is almost crucial. Airlines are not going to line up to buy non-renewable, fuel-guzzling, net CO2-gushing supersonic jets for use over the next couple decades.
Isn't it completely irrelevant for their development how the fuel is produced? My understanding is that E-fuels are exactly the same as "normal" fuels. They are just produced in a carbon neutral way. You can fly a 50 year old Concord on e-fuels.
Airlines are almost certain to face significant carbon regulation or carbon taxes in the next couple of decades. In turn, lots of engines will be effectively banned.
Of course, this is nothing new: noise abatement effectively banned a whole lot of engines, too.
I don't think it requires giving up on "affordable global flight". It might be a bit more expensive -- getting aircraft to be tens of decibels quieter cost something, too.
Externalities -- whether they're noise imposed on a community or climate impacts -- aren't generally addressed by the market on its own.
Indeed, we have a new regulatory regime coming into play for airplane emissions slowly-- with first effects in 2028.
I mean, it's already happening all over the world. It's not just Germany.
The UK already taxes carbon in aviation fuel. It's about to implement a carbon pricing mechanism for jet fuel obtained in jurisdictions without it.
The EU is implementing carbon taxes, and a mandate for Sustainable Aviation Fuel. In 25 years, it will be illegal across the EU27 to use aviation fuel that is not at least 70% Sustainable Aviation Fuel.
China has the world's largest emissions trading program. Civil aviation will be included next year.
Australia has a carbon tax, and will soon have mandates on civil aviation emissions.
Brazil does not yet have a carbon tax, but in the past year there has been legislation proposed, and it looks likely to be coming sometime soon.
The US EPA just announced regulations that will not force, but will certainly make it cost prohibitive to sell lots of gasoline cars ten years from now. Civil aviation is a likely next target.
The sun's variation in intensity over the solar cycle has a typical 0.2C difference... and even then, 5 years later you get the 0.2C "back".
If you're saying "another Maunder Minimum":
- There is no consensus that is going to happen; or even a majority view that it will.
- It sure doesn't look like the Maunder minimum caused significant cooling overall (perhaps at most 0.4C, so not much more than a normal solar cycle). Yes, Europe's temperatures swung more than this.
>The sun's variation in intensity over the solar cycle has a typical 0.2C difference... and even then, 5 years later you get the 0.2C "back".
On what are you basing this statement? The climate models I've looked into were wrong about the effect of clouds and ignore types of energy from the sun.
>- There is no consensus that is going to happen; or even a majority view that it will.
If I am walking towards someone in a rocking chair, they may be moving towards me or away from me at any point, but overall I will get closer. Similarly, if solar cycle causes a variation of .2C back and forth, it doesn’t eliminate a non-oscillating trend.
When weighing what is likely to happen, fringe beliefs don’t matter much. I would not bet on a Maunder minimum to save us, because A) it is not a big enough effect even if it happens, and B) it is probably not going to happen.
You've edited your comment-- I'm glad you've reconsidered including the below which violate the site guidelines:
> Oh please, spare me the polemics.
> Do you stand to benefit financially, directly or indirectly, from climate change?
But: I think most of us stand to lose significantly from climate change.
They announced they're building their own because the regular engine OEMs showed little interest. Even if required modifications to historic or military turbojets are minor, there's a lot of expense in certifying them for use for a new type of passenger aircraft, and modern economical turbofans were not designed for supersonic flight...
(Almost?) exclusively on military planes which have different return on investment needs than commercial aircraft that need to be efficient first and foremost (ask Convair and BAC/Sud Aviation how many airlines valued speed over efficiency).
If China is anything to go by, immensely more so, and you are not significantly helped even if you had all the documents and industry secrets required to design and build a modern engine!
The complexity of designing an engine is comparable to that of designing an airframe.