The Bloomberg article doesn't seem to touch on what specifically is going on with the Trent 1000 (but my understanding was that protective coatings weren't holding up to air pollution). In any case, General Electric is having problems specifically with the air-cooled blades that Bloomberg's pinning Rolls' troubles on. Keeping the blades solid at those temperatures is almost wizardry. Fascinating stuff.
A Thai Airways lost an engine (GE90) on one of their 777s recently due to problems with the air cooling. As a result eight GE90 engines are now subject to an additional inspection. Here's a video touching on the GE problem by a tech who works on GE turbines for a living:
Son of a friend works for Rolls and gave me the same story on protective coatings. They tried to trim costs too far on the final stage of the blade hardening process. The BBG article has an Emirates exec demanding fit for purpose aircraft. But, IMHO, relentless downward pressure on costs from us (the passengers) and the airlines is pushing all the manufacturers to cut to the bone. And then beyond the bone. Someone once asked John Glenn what he was thinking when he sat on top of a rocket ready to launch. His reply: "every component built by the lowest bidder!". As ever, you get what you pay for...
Pollution causing jet engine issues is scary. The countries and engineers building the engines don't encounter extreme pollution and the places experiencing the worst pollution aren't major hubs for aircraft development. It's an "out of sight/out of mind" type of issue during a record period of air travel growth all around the world
I hope ICAO can begin studying the affects of pollution on aircraft more heavily because compressing air with an AQI over 1,000 (like India has experienced recently) could have very unknown consequences elsewhere in the engine after the blades, (unless it just pushes all the pollution particulates back into the cabin, which is another issue that needs to be solved)
Airborne particulates are absolutely not “out of sight/out of mind” for engineers designing commercial jet engines. That’s an absurd statement. It’s one of the top considerations for those engineers.
There's a lot of hope out there for ceramic matrix composites. Not only can some materials handle much higher temperatures (which translates to higher pressure ratios and higher efficiencies), but they do it at lower weights and higher strengths, with high resistance to oxidative degradation in the presence of contaminants.
No, turbine inlet temperatures are physically possible to get higher.
Mitsubishi has been developing a turbine for 1700C inlet temperature, and it seems they are getting close.
Second, it is possible to reduce compression losses in 3 spool designs.
Fan designs are getting better, and more efficient. Gearboxes for mid-sized engines are planned, and it's possible we'll see them in GE90 class engines eventually.
Lastly, it's entirely possible to slap a recuperator, intercooler, and reheater on the engine if things will get too desperate.
"Mitsubishi has been developing a turbine for 1700C inlet temperature, and it seems they are getting close."
And how long does the blade stay together? What happens to the blades if a foreign object is ingested? These blades are being made to run at T that make them very ductile, the centrifugal forces literally bend the blades.
Mitsubishi isn't the only one trying to increase the T.
"Second, it is possible to reduce compression losses in 3 spool designs." And increase the losses due to mechanical coupling and decrease reliability.
"Lastly, it's entirely possible to slap a recuperator, intercooler, and reheater on the engine if things will get too desperate. " At what weight and aerodynamic cost?
Its not my intention to contradict you, but to highlight that it's not obvious that any of these things will ever commercially.
Current airliners appear to burn half the fuel per passenger mile as did early '70s airliners. This reflects both propulsion and aerodynamic improvements.
On top of this slightly increasing passengers, their luggage, and a few extra seats has fairly minimal impact on aircraft weight. The aircraft’s maximum fuel/range is impacted, but that’s rarely an issue.
Yes, but parasite drag is indirectly affected by weight. A lot of the parasite drag comes from the wings and engines, and they scale up with weight, as long as you want to keep the same takeoff/landing distances.
This is a comparison of the impact of seating arrangements for otherwise identical aircraft. The maximum takeoff weight stays the same, the difference is how much fuel they can add before they hit it.
Which is why ultra long haul flights tend to have more leg room. This can be as much as 5 inches for the same airlines.
Fair enough, but my point was that for a given set of capabilities (landing speed/distance, range), if you want to add more payload, you need more wing. The additional payload costs you drag from induced drag, but it also costs you parasite drag from the bigger wing you need to generate that lift at landing speed.
You even see this with some stretched versions of airliners, they enlarge the wings or make changes to the high lift devices.
It improves the payload fraction of total mass. That is generally better. But you might have to factor the expected total mass into the design. If you want to transport the payload mass of a 747 in lead bars, the smallest plane that can fit the volume will certainly not work. But a plane designed for that lead load would be far more efficient than a 747 (or modern equivalent) that is flying almost empty by volume.
This is partly due to the application of computer controls and partly due to the application of things like direct fuel injection, turbocharging, etc. that were previously available only on racing or aircraft engines.
For example, the Cosworth DFV normally aspirated Formula 1 engine with 182 cubic inches was making over 520 horsepower (2.9 / cubic inch) by the end of its career in 1983.
Combustion engine development was oddly stunted though. We have known the basic formula for power for a very long time (forced induction + high compression + high octane fuel). Superchargers are ancient, turbos aren't new either, although I guess fuel injection had to wait for computers to be reliable and cost effective. Even then I don't fully understand why it took 30 years for automakers to figure out how to produce high power engines that met emissions standards.
It didn't take long to know how to do it. It took a long time to make cost effective parts that were reliable in doing it for the service life of a car. the bearings in a modern vw turbocharger are incredible. Imagine getting 100K Miles out of a turbocharger which can regularly spool to 200K RPMs. those bearings need to be made to incredible tolerances, which were not previously cost effective.
People generally overestimate the difficulty of designing a product and underestimate the difficulty of designing the equipment, processes, and systems needed to mass produce the product economically.
musk tweeeted a few years ago that "it isn't about the car, it's about the factory". he then proceeded to fail and redesign production due to overautomation, but the point stands and perhaps was stated in bold at that moment.
I think of it as a rule of five. Takes five times as much effort to design the production process as it does to design the product. And five times that to put it into production.
The number five is fungible depending on volume and similarity to existing products. It's why a hobbyist in his garage can design a product but can't commercialize it.
Is that true? There are a number of interesting corollaries if so, notably that China should get a lot more respect for extremely cheap mass-production of products, the U.S's position as "designer of products that are built elsewhere" is quite precarious, that software and other IP (where mass production is basically free) are basically the perfect businesses, and that services that can be provided without mass-producing a product will grow in importance.
I could buy all 5 of those statements, but it's interesting that the combined effect of them would be to push people out of making things and into manipulating brains (which itself is a statement I could believe).
It is true, and some Chinese production lines are truly feats of engineering. However, it's a little tricky to determine whether this is really Chinese values and engineering or the values and engineering they have imported from other countries. There's a lot of production lines in China that produce nonfunctional goods.
In the microelectronic and mechanical areas the strength of the Chinese market seems to be very, very lax IP law. While most of the interesting parts don't make it over to the western market, they have very featureful, accessible, and novel components that are made by cobbling together (potentially stolen or at least unlicensed) IP.
Historically US manufacturing used to be the best cost/performance optimized and this is what helped win WWII.
It's my impression that Germany and Japan are leaders in producing the capital equipment needed to set up manufacturing, although the US is fairly capable in some areas. I think that China imports a lot of equipment from them and then integrates it into factory systems.
You 5 statements are probably right with some qualification. For example, software mass production is basically free (actually just low cost) for apps distributed via the app stores. However, if you are selling software as a service at scale, setting up a cloud service with five 9s availability is complex and expensive.
Turbos often use fluid bearings, and if treated well can last indefinitely. I have an old Jap sports car in the shed with over 400k km on the original turbo.
>Even then I don't fully understand why it took 30 years for automakers to figure out how to produce high power engines that met emissions standards.
They could probably have done it before, but this stuff is expensive. The current make/model of the first car I bought in the 90s costs double what it did then if you buy it new. I don't think the demand for efficiency really came in until oil prices started shooting up and the government imposed stricter CAFE standards.
Fuel injection has been done forever without electronics even (purely mechanical), and with electronics but without computers decades before the first microprocessor came around.
The increase in performance goes hand-in-hand with emissions standards because - to some approximation - a more fuel efficient engine is more powerful for the same displacement than one that isn't. CFD is what really drove the last 25 years of improvements in this field, better models of what actually happens in a combustion chamber have helped tremendously in extracting the last bit of performance from the engines. The F1 engines are amazing in this respect, their longevity is terrible but their performance is nothing short of incredible in terms of thermal efficiency (> 50%; long thought to be impossible).
> more fuel efficient engine is more powerful for the same displacement than one that isn't
Not necessarily true, but for kinda stupid reasons. Carburetors often run cooler at the intake than fuel injection, resulting in more peak power despite worse economy. I am aware that this is not actually relevant here, I just think it's interesting.
My main point is that in that in the early 70s Chevy's small blocks could make damn near 400 horsepower. Fast forwards and it isn't until that late 80s that you see a consumer car with north of 250 (grand national), and that was a pretty extreme outlier. Move to the early 2000s and we finally get modern Chevy LS motors which are once again making north of 400hp from the factory. These are still single cam, 2 valve per cylinder V8s though.
In 1971, Car & Driver claims a Corvette with 425 hp did 0-60 in 5.3 seconds[1]. 1/4 mile was maybe 13.8 s. A 2008 Corvette with supposedly similar power did 0-60 in 4.1 seconds and 1/4 mile in 12.5.[2]
Yeah, there's some difference in weight, and modern transmissions, tires, and suspension are better and so on, but there is usually such a big difference that I think most of it is that horses used to be smaller.
I've seen several cases where a famous old sports car, likely running at 75% of the power when new, manages to beat the 0-60, 1/4 mile, and lap times of old. Just because tire technology has come that far in the last several decades.
But also keep in mind that significant engineering has gone into the best engines of today to broaden the torque and HP curves. It's not unusual to have 90+% of torque from 1800 rpm to 6500 rpm. That alone could significantly help performance numbers. After all it's the area under the torque/hp curve that matters, not the peak.
Imagine judging a runner by their peak speed, instead of the time to get across the finish line.
"the mammoth 500 cu. in. (8,194 cc) engine in the Cadillac Eldorado fell from 400 gross horsepower (298 kW) in 1970 to only 235 net horsepower (175 kW) for 1971. The real decline wasn’t quite as steep as it looked; the 1971 engine did have a lower compression ratio to prepare for the adoption of unleaded gasoline, but the 1971 gross rating was still 365 hp (272 kW), so the actual loss was about 10%, not more than 40%"
Car ICEs have to be dirt cheap. Jet engines are expensive enough to include expensive goodies.
For example, an Mercedes claims its F1 engine achieves 50% thermal efficiency. That's insane, and maybe double what a car engine achieves. It also costs $1million(???)/unit.
Not sure I agree with that one. Turbos are hardly new, the benefits of higher compression ratios are new, and generally the design goals of the engine is the biggest part of a change.
It used to be that engines were robust. You could turn them off whenever, you could change the oil rarely, and without significant abuse or poor luck they would easily hit 200k miles. MPG wouldn't precipitously drop if you had something on the roof, a trailer, or were speeding. Just look at any manufacturers v6 3 liter for an example.
Today's motors are mostly 2 liter 4 cylinder turbos. They are pretty heat sensitive, have CPUs to manage their cooling, and are pretty hard on oil. Even with good maintenance they have a surprisingly high failure rate within the first 100k miles, but often outside of warranty. Look at the decreasing CPO warranties from Subaru, Audi, Lexus, BMW, etc for evidence. These high strung 4 cylinder turbos are efficient within a narrow range, but can often produce surprisingly poor efficiency when towing, putting anything on the roof, or even just speeding.
The biggest technological improvement I've seen in cars in the last decade is the transmission. Today's automatics and DCTs are mechanical marvels that exceed the performance and efficiency of manual transmissions. They also largely obviate the problem with the 2 liter turbos that have much narrower power/torque curves than the larger displacement engines of yesterday.
>After close to a century of development, one would think it would be near its technical limits.
Why would one think that? It seems kind of arbitrary. Guns have been developed and iterated on for half a millennia and there are still technological advancements coming out regularly.
Gunpowder-based gun technology has kinda plateued too. We pretty much hit the practical limits of size during WWII with Schwerer Gustav and battleship cannons, and the fastest firing guns still use the basic design of Richard Gatling from 1861. Most recent innovations have been in the work of pointing the gun in the right direction moreso than the gun itself.
Then again, I guess caseless could be the next big innovation if they figure out the heat problem...
Caseless ammunition, or telescoping ammunition (or both at the same time.) Either could conceivably increase how much ammunition soldiers can carry, but I'm not holding my breath for either.
The status quo seems firmly in "good enough" territory and I'm pretty sure some of the other supposed benefits of caseless will fail to manifest. In particular, advocates of caseless ammunition have on occasion claimed that guns would be simplified by not having to eject brass, but I don't think that's true since said guns would still need a reasonable way to eject chambered but unfired ammunition (even if it was open-bolt.)
The Winchester '94 rifle has been in production for 125 years now, and is still available for the 30-30 brass case, centerfire, smokeless powder cartridge.
There was a rapid evolution of rifles from the flintlock, black-powder, muzzle-loader to the repeating, brass cartridge, smokeless powder rifle. Since then, rifles, machine guns and pistols have evolved through successive refinements.
Not really in firearm design since the 1950s/60s or so. There are small improvements, but the basic operating mechanisms everyone's using haven't changed since then. (Compared to the previous 60-70 years which saw the introduction of smokeless powder, box magazines, self-loading, automatic fire, etc.).
(Optics are seeing this kind of development though).
A friend in the industry explained to me recently that part of the problem is requirements creep while the engines are being designed. I am definitely _not_ a mechanical engineer - so take what I say with a grain of salt - but I did think there were some interesting parallels to software development.
New engines are normally designed alongside a particular aircraft. The aircraft manufacturer optimistically estimates how much thrust will be required. Over years of development, the predicted weight of the aircraft increases and the aerodynamics get slightly worse. To compensate, the engine manufacturer needs to find a way to squeeze more thrust out of the engine - but without changing its size or overall architecture.
This can be resolved by adding extra complexity in the form of extra compressors or stages. Alternatively, you can try to run the engine at higher temperatures and pressures. While it's still possible to certify the engine and run it safely, you will probably experience many more maintenance issues than if the engine was running inside its original design parameters.
When an aircraft is released engine development doesn't stop. These things are always undergoing revisions, performance upgrades, ADs, and even just performance upgrades / downgrades / operating procedure changes based on data from in field running.
I doubt an engine would undergo the addition of a stage as that's pretty major but there's no reason a mfc couldn't charge you a mil for better compressor blades and give you a thrust rating upgrade for your patronage.
Edit: I'll keep talking as more info is coming to my head. Jet engines have fadec computers that get to decide what your maximum power level is. This maximum is programmed into the engine as a thrust rating.
Let's say you engine has 8 possible power levels to configure, when you test the engine when new or after maintenance, you will look up a chart based on parameters that your test cell has logged, ie thrust vs EGT (exhaust temp) is a big one, so too is vibration at the different bands. This chart will tell you what to program the ECU with (forgot the actual acronym, its analogous to an ECU on a car).
So to your point, when you get more performance out of an engine, you can set these levels higher, so you wouldn't expect more degradation from you engine for a higher power level as the manual will tell you what power level the engine can be set to which will keep everything within its maintenance limits. (Sorry if that's not super clear)
Edit 2: Funny implementation detail of setting a thrust rating, it's literally a jumper based system similar to old motherboards, except you manually wire a blanking plug to bridge the connections.
A blanking plug is an electrical connector that has a cap on it with a little bit of space to run wires from one pin back to another.
If this happens "normally", that means the engine manufacturer can predict they will be asked for X% more thrust with the same size/arch/features - so they can plan for this in advance.
I can't read the linked article, but in general, any technology constantly tries to push the limits. Jet engines are a very mature technology, so there are less improvements by just improving the general design. The next step is optimizing each part, e.g. by selecting new materials to make the parts from. This usually means a large performance leap - new materials can mean a way better performance - but also a time where there are struggles to make a new material working reliably. With time and experience, reliability grows and progress slows down till the next large step, which might reduce the reliability somewhat.
On top of those things, I heard stories that GE for example laid off a large amount of their experienced engineers. This certainly increases the risks with new designs.
Only tangentially related, but when I was at VT there was a lot of interesting research going on to move engine testing to the ground. There's engine/aircraft compatibility issues around blended wing body aircraft. You can read more about it at the link below.
note that there isn't that much efficiency left on the table: the best turbine is about 62% thermal-efficient[1] (note - not an aircraft engine). compare that to the theoretical carnot cycle at approximately jet operating temperatures - it's about 80%. these things are approaching dark magic territory at ~75% theoretical thermodynamic maximum.
Raise the temperature, slap on recuperation, reheat, and intercooling, add bottoming cycle and you will certainly get to 70%+ with modern materials and sufficiently large turbines
By my calculation the carnot efficiency for the jet operating temperature is about 85.5%: 1-T_cold/T_hot, where T_cold ~ 230K (it's quite cold at high altitudes) and T_hot ~ 1588K (or 2400 F, which is the hottest temperature in the Leap engine produced by GE, which powers the 737-Max [1]). This is only possible though because of GE's usage of the ceramic matrix composites (CMC) which allows for 150-200K hotter temperatures than classical alloys.
Now the current CMC method employed by GE uses silicon carbide, which has a melting temperature of about 3000K. If one day they could switch to hafnium carbide, with a melting temperature of more than 4100K, the carnot efficiency could reach more than 89%.
Sure, but I think cows producing methane is probably more harmful and more immediately easy to fix (i.e. I'd rather go on holiday than eat meat). The Earth can probably support air travel if we can get rid of most other sources of greenhouse gases.
There may be solutions to that in the form of feed additives to reduce methane emissions.[1] But as that source notes "methane from animal agriculture is just 5 percent of the total greenhouse gases produced in the United States -- much, much more comes from the energy and transportation sectors", so I'm a skeptical to the suggestion that it is more harmful and easier to fix.
This is an excellent diagram that breaks everything down [1].
It actually shows you are probably right, meat vs air production, meat is 2.5% and air is at 3.3% of greenhouse gases.
Livestock emit methane (although there are potential solutions for that), and they also can help development of topsoil, and sequester a lot of carbon, when they're grazing and not force fed corn and grain in a feedlot.
Also note that North America used to have as many as 60 million Bison, versus about 95 million cattle today. And cattle emit about as much or less methane than bison do, per animal.
neither solve the issues air travel does. the amount of rail needed to funnel the same amount of traffic one of the larger airports generate would be phenomenal let alone where could you even put it down? then of course comes the small problem of how many miles cross ocean which puts rail right out of the equation.
Seriously, look at an airport. get the number of flights and where they come from and their frequency, now imagine trying to build a sufficient number of rail lines to do the same.
air travel saves time that no rail line could except in short hop scenarios where extra time to process through an airport might tip a balance. let alone you can have nearly an number of planes in flight between two points
you're comparing status quo (super cheap flights, arguably borderline too cheap to be economically sustainable even without factoring in carbon and water vapor externalities) with something that doesn't even exist and then proclaim it's out of the equation. change prices and the equation may surprise you.
> the amount of rail needed to funnel the same amount of traffic one of the larger airports generate would be phenomenal let alone where could you even put it down?
A fully loaded ICE 4 high speed train can pack 830 people, an A380 615.
> get the number of flights and where they come from and their frequency, now imagine trying to build a sufficient number of rail lines to do the same.
The answer is multimodal transport and connections. With airplanes, transit takes time and effort - with trains, next to zero. Take, for example, a traveller from New York (USA) to Gaimersheim (DE, Bavaria): airplane connects New York to Munich. Then you travel with the S-Bahn regional train to Munich Central train station, take an ICE high-speed train to Ingolstadt, and switch to the regional train which takes you to Gaimersheim.
Air traffic is a luxury that's not really warranted or necessary. It has a huge environmental cost. I never said rail is faster and better, it's just necessary to prevent climate change that will kill billions of people.
If in the future some modes of transportation are banned, everybody will feel sorry to not have enough railroad and nuclear energy.
Chiming in from Hamburg, Germany with its main station at 550.000 pax per day in 2018. About crossing the oceans: What about floating submerged pipes, maybe going to artificial island hubs in international waters with blackjack and hookers? Has the hype left the loop? Where is your VISION?
Efficiency, when talking about mature markets, is rarely about emissions, it is about cost. We could have zero net emissions today by using pure hydrogen or biofuels in existing turbofans with little modification.
It does, however, matter quite a bit for emerging technologies which may be aimed at lowering emissions. Higher efficiency, for example, can overcome a lot of drawbacks that come with new technologies, like power to weight ratios. Electric cars, for example, have nowhere near the amount of energy storage that gas fueled cars do, but they are now getting similar ranges because they convert it to kinetic energy much more efficiently.
> Unlike carmakers, the airlines lack viable technological alternatives. Biofuels have potential but fully electric large commercial aircraft are probably decades away.
Huh? Sure they have alternatives: Fuel cells, or non-polluting combustible pairs of compounds, e.g. Hydrogen + Oxygen (or even Hydrogen + Air?) . Also, I'm no physicist, but I'm pretty sure it's more efficient to convert to kinetic energy (almost) directly rather than through electricity - meaning that electric engines don't make much sense.
Correct me if I'm wrong!
Also, even with current technology - passenger aircraft engine turbines are quite far from their maximum potential efficiency; see @baq's comment.
small nitpick, but hydrogen + oxygen combustion isn't really non-polluting unless you can do it in a vacuum. at high temperatures, the fuel also reacts with nitrogen in the atmosphere, creating NOx.
"I'm pretty sure it's more efficient to convert to kinetic energy (almost) directly rather than through electricity - meaning that electric engines don't make much sense."
An electric motor is >90% efficient. Sure you're added an extra stage converting to electricity, but so what?
Electric drives are so efficient, diesel ICE locomotives have had electric drives (in lieu of transmissions) since the 1950s. That is, they have massive diesel engines that generate electricity instead of moving the train directly.
No. Electric is the best way to convert renewable energy to useful flight energy.
Anyway, it bothers me one people refer to the constraint being "large aircraft" when the real difficulty on electric flight is range, not how big the aircraft is. Electric flight scales up just fine. It's the range issue that's hardest. Currently can do 1000km, maybe up to 2000km with lithium ion and lithium sulfur chemistries with optimized structure and aerodynamics. Could scale up to larger sizes if desired.
So, this have been bugging me for a while - what when we actually come to limits of the new technological and scientific advances that got us through the 20th century? I doubt that anyone here doesn't see a comparison to Moore's law. Supersonic passenger flight isn't happening, Musk's spaceship (or at least, it's use for passenger travel) is a huge gamble...
What if, among all the possible visions of the future, 2119 will have roughly the same tech as 2019? I don't doubt that there will be cosmetic differences, I'm talking more about about the fundamental stuff: energy efficiency, FLOPs, bandwidths, etc, being in the same order of magnitude. What if 2219 and 2319 still says the same, and the hockey stick of growth turns into another plateu?
TBH, this future frigthens me even more than nuclear war or climate change. For both these old horrors, we at least know the theoretical solutions; but if we simply run out of new things to discover that make a difference for us as a species, what then?
> if we simply run out of new things to discover that make a difference for us as a species, what then?
Nothing left to do but live a good life and to try to make sure everyone is fed, happy, and treats the earth and everything else in it as well as they can.
Biotech is still in its infancy and mastering DNA would open up a new frontier where humans can edit the genetic code to what makes a human. Assuming it isn't universally banned.
The only truly depressing future to me is if interstellar travel really is as hard as it seems to us now. There kind of needs to be a physics/propulsion discovery on the order of magnitude of electricity or the journey can only be feasibly made by the immortal AI robot race that replaces us.
Interstellar travel IS hard, but the current laws of physics allow it to be done. Crewed interstellar travel can be done on timescales of ~50 years to the nearest star system using ~10Terawatt of solar power in space to power efficient beamed macron propulsion with the benefit being that most of the investment is in the macron beamer and power supply which stays in the solar system and can be reused like once every few months, sending a stream of ~100 ton spacecraft on magsails to Alpha Centauri (using the magsails to brake against the interstellar medium near the destination). Two way trips are not feasible in a human lifespan as it currently is, but one-way settlement of nearest stars is, with a stream of supplies and settlers arriving every few months.
To really make this feasible, improvements in hibernation tech could help. Induced torpor over a week or two already works and could be used repeatedly so that psychological time in transit is only a few years (and the reduction in metabolism from torpor may also extend calendar life of the crew, but that is not yet proven). Even modest life extension (i.e. increasing healthspan from ~mid-60s to mid-80s or longer) would significantly increase the viability of human settlement of Alpha Centauri, and we're just getting to grips with the biochemical tools needed to fight aging, so who knows over a few centuries what will be possible. I think increase in human healthspan and lifespan is more likely than a dramatic practical but fundamental physics breakthrough cutting down the time.
There's a lot of exploit to do in computing, I mean, we've sat on top of hardware improvement and just slurped it up... We can do loads more with what we've got in the locker now, and what's happening isn't the end of hardware improvement is just the end of rapid exponentials.
Supersonic passenger flight is happening. Boom Supersonic is building their (crewed) subscale supersonic demonstrator right now. They hope to pick up where Concorde left off (but much more efficient and slightly faster and more granular, enabling more routes).
NASA is building a low-boom civil supersonic demonstrator (also crewed) that will demonstrate sonic-boom-lowering techniques to enable passenger supersonic flight over the continental US.
There's lots of room to improve these things still. And I'm excited still about lithium battery tech. It's the internal combustion engine of our century and its consequences are perhaps even more far-reaching. The theoretical useful energy of the most advanced versions of this, the lithium-air battery, are on par with that of hydrocarbon fuels, so by the middle of the century it's likely we'll have completely clean civil supersonic transport with low acoustic emissions as well.
I think we still have a very long ways to go to advance technology. Vacuum tunnel maglev trains allow higher efficiency than even conventional rail but without an ultimate speed limit. They could operate at hypersonic speeds in 100 or 200 years from now, with the energy recouped regeneratively at the end. That makes efficiency orders of magnitude better than today's passenger air travel with speed increased by an order of magnitude.
I think ultimately in the further future, if you want something exciting it'll be:
Further urbanization of everything, so humanity concentrates in opulent metropolises well-connected by ultra-efficient transport. Food production increasingly goes to single celled organisms, freeing up space for rewilding of the Earth and healing of the ravages of industrialization while individual well-being is far greater. Human economic expansion in space is technically unbounded. The solar system allows access to many, many orders of magnitude greater energy supplies without an impact on the Earth's ecosystems. Things that can tolerate latency, like high performance computing will leave the planet to access unlimited energy in space (Moore's Law coming to a slow end will actually enhance this transition as you can afford to amortize the hardware over long enough periods of time for this to make sense).
Musk's spaceship is just a taste of what's possible. Improvements in efficiency in even chemical rockets (by reducing structural weight, fine-tuning Isp over the mission cycle, using hydrolox near stoichiometric to enhance performance) can reduce cost of space travel to about what long-haul passenger travel currently is.
I think things will continue to improve. And these are only the foreseeable things. The actual future will contain many unforeseeable discoveries.
None of this is guaranteed, but it can be ours if we so decide to make it thus.
> TBH, this future frigthens me even more than nuclear war or climate change. For both these old horrors, we at least know the theoretical solutions; but if we simply run out of new things to discover that make a difference for us as a species, what then?
This is very, very unlikely. Take a look at all open questions in physics, and you'll see that our understanding of the universe has severe gaps. Usually, whenever such a gap is filled, there's a technological boom. For instance, Einstein got us some: not only relativity (allowing for things like GPS), but also the photoelectric effect, allowing for (eventually) solar panels. Greater understanding of semiconductors (in no small part due to the above) brought us transistors, cheap lasers, which were refined (and still are) by quantum physics. We are dabbling into quantum computers now.
Mind you, both lasers and radio waves were considered curiosities with no practical applications.
Fusion research is still ongoing. Progress is slow, but steady. Once we have mastered, we'll have access to cheap and plentiful power, which will open up applications previously not even considered before. If it is possible to shrink the technology to less then building sized, then you'll also see vehicles (ships or spacecraft).
Bio technology is still in its infancy. I cannot predict what the results will be, it's far too early.
Some of the rapid progress from the last century might have been an anomaly. But we are not even close to running out of things to learn.
The mid 70’s was golden era of supersonic research. Supersonic engines are just regular jet engines with a Turbofan. Add in wings swept further back in a Delta pattern like the Concorde and you have...supersonic aircraft that comfortably can do Mach 1.5-Mach 2.0.
Today, I think there is just 1 functioning wind tunnel in the US that can do supersonic research, so sad. If you live in the Bay Area you pass it, just look at Moffet Field on your way north of San Jose.
The Japanese and Australians, due to their remote location in part, have done most of the significant research of any last few years.
Why did SuperSonics not go anywhere with essentially every major civilian project being mothballed?
1. Materials Science: we simply don’t have reliable data for how long XYZ Metal lasts at extreme temperatures of supersonic flight. If you read Michael Crichton’s Airframe from 1996 (great novel), they mention that aircraft are designed with a lifespan of a human. 80 years. It’s insane how long these things fly. The heat is so extreme, the Concorde would fully extend 1 foot (it was made in part of titanium) during flight. Many crashes have occurred, such as Alaska Airlines Flight 261 in 1999 from Mexico to California, because the maintenance time frames of these parts is still not fully understood. And that’s for subsonics!
2. Noise: No way around it. The decision to build aircraft close to cities was essentially finalized in preparation for World War II. You can dampen significantly, but it is painfully loud. Landing outside the city with fast train back is best solution.
3. Fuel costs and burn. Supersonic research got underway right as Earth Day started. Lots of supersonic tech relies on afterburners, terrible mileage. It was bad timing.
4. 2003 Concorde crash where a tire was hit on the runway, and the entire aircraft exploded. This should have not happened for a tire collision. SuperSonics are fragile because of all the design tradeoffs one has to make (currently).
They do as much computer modeling as they can (partially because wind tunnel testing is insanely expensive), but you still need to do some wind tunnel testing to make sure your models were valid.
> 2. Noise: No way around it. The decision to build aircraft close to cities was essentially finalized in preparation for World War II. You can dampen significantly, but it is painfully loud. Landing outside the city with fast train back is best solution.
What are we talking about here, building aircraft or operating them? Factory noise or takeoff/landing/sonic boom noise?
Previous commenter had it right. Supersonic aircraft have terrible lift/drag. This means that they will always burn much more fuel. Since the extra speed is really only useful for long flights, a supersonic aircraft has to carry a higher fraction of its weight in fuel, further reducing efficiency.
This makes supersonic airliners infeasible for the really long routes that they would truly help with. The Concorde only shaved 3.5 hours off the NY-London time, and cost about 8x as much to operate.
The extremely high costs then mean that you have to sell what are essentially coach seats at greater than business class prices. There aren't many people willing to pay business class prices, so you can't run the planes very often, and you can only run them between very large, rich cities.
Since the whole point of supersonic is speed, you can't effectively sell connecting flights, because if you fly, say, Boston-London through NYC, the direct flight from Boston subsonic will arrive at nearly the same time as the supersonic flight with a connection.
This leads to a very small passenger market. It also means that supersonic planes will operate on an infrequent schedule. Many people in a position to pay for a supersonic flight will prefer a subsonic flight that meets their schedule over a supersonic flight that doesn't.
With the advent of lie-flat beds, in-flight wifi and power, and higher cabin pressurization, being on an airplane an extra 3.5 hours isn't even so bad anymore, so the practical advantage isn't nearly as great.
All of these factors make supersonic a very small niche market. This means that few planes will be produced. High performance aircraft have high development costs, and those need to be amortized over the production run. Concorde was a complete financial disaster because they only produced 14 of them, for all of the reasons above. The only solution is to somehow make the airframe far more efficient.
> With the advent of lie-flat beds, in-flight wifi and power, and higher cabin pressurization, being on an airplane an extra 3.5 hours isn't even so bad anymore, so the practical advantage isn't nearly as great.
I think this is huge. From what I read, the cabin of the Concorde was very cramped. I would prefer business class on a 787 or A380 vs being cramped and arriving faster.
The size of the seats was a little bit worse than what airlines sell today as premium economy.
It's interesting to see what Boom is doing here relative to Concorde. They have a similar sized cabin, but they propose to configure it with fewer but larger seats.
They will have more efficient engines and a lighter airframe, but the lower efficiency at higher speeds means they can't match subsonic range, so they'll have to make a fuel stop on transpacific flights, which hurts comfort and will cost at least an hour per flight. Economically, transpacific routes may make more sense even with the fuel stop. Concorde probably could have done this too, but Air France and British Airways didn't serve these routes. All of the very long routes they might have used it on crossed Europe and Asia where they couldn't go supersonic.
"The Low-boom Flight Demonstration mission has two goals: 1) design and build a piloted, large-scale supersonic X-plane with technology that reduces the loudness of a sonic boom to that of a gentle thump; and 2) fly the X-plane over select U.S. communities to gather data on human responses to the low-boom flights and deliver that data set to U.S. and international regulators."
I wonder how much fuel and maintenance could be saved on airliners if airports had giant electro-magnetic catapults like naval carriers to accelerate and launch aircraft without consuming as much fuel at high power.
Very little. By one estimate jets burn about 10% of fuel to reach _cruising altitude_. [1] Unless the catapult got you up to altitude it would not help much. Catapults solve a different problem, namely taking off from a short runway.
> I wonder how much fuel and maintenance could be saved
Maintenance?
Catapults are notoriously finicky and expensive to operate. Also the additional stresses on the airframe couldn't possibly reduce maintenance. If anything (assuming they could withstand them), they would require more inspections.
Catapults only solve the problem of not having enough runway. And you'll notice that fighter jets taking off from carries will be on full thrust and full reheat.
The biggest issue for innovation in aircraft, is due to the sheer capital it requires to develop both jet engines and the aircraft, which results in companies developing these separately. For there to be more innovation in the space there needs to be closer alignment between aircraft manufacturers(Airbus, Boeing) and jet engine manufacturers (Rolls Royce, GE, P&W). There's talks of blended wing bodies etc, which would improve aerodynamic efficiency but I can't see anything like this happening given the way the industry is set up.
If we let companies race to the bottom leaving only a duopoly, then one of those companies mortally wounds themselves with flawed profit-margin-enhancing tech (787 MCAS, VW diesel, Galaxy battery fires, Deskstar HDDs) are we not at risk of entering a technological dark age?
Nah. The magic is not the company. It's the people in it.
When Nokia's retail division went up it a ball of flames, the engineers didn't just disappear and become janitors or something. They formed HMD, who is the one of the very few mobile phone makers seeing ear on year growth in shipments.
Raw human talent is the major driver of innovation. Companies are just one way they organise themselves. Open source is another. Different organisations suit different circumstances, but you always need the raw human talent.
I wonder if this means Boeing/Airbus/etc will have to move towards flying wings or other designs which might risk some degree of passenger comfort to achieve efficiency goals?
This is like the 737 Max problem all over again, the regulators need to step in and say that there's not enough margin in these designs to be reliable and safe. This would force the Airbuses and Boeings of this world to go back to four engines in their new designs, which they should have never abandoned in the first place.
As I've said for many years, cutting air travel prices to the bones is a very dangerous affair—as it results in substandard/shithouse quality engineering being installed in aircraft (cost-cutting results in designs that have insufficient safety/reliability margins).
Travelers need to get used to paying about 30% to 40% more per trip—and the regulators should be spruiking this message loud and clear from upon high until the plebs get the message!
(It's all pretty basic really—it's a no-free-lunch argument.)
It seems far from clear to me that increasing prices for air travel in pursuit of further increased safety would help overall when it is already incredibly safe. Higher prices may encourage air passengers to switch to less safe forms of transport (bus, car) leaving more people killed in transportation accidents overall.
Betteridge's law of headlines is an adage that states: "Any headline that ends in a question mark can be answered by the word no". It is named after Ian Betteridge, a British technology journalist who wrote about it in 2009, although the principle is much older.
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[ 816 ms ] story [ 1321 ms ] threadA Thai Airways lost an engine (GE90) on one of their 777s recently due to problems with the air cooling. As a result eight GE90 engines are now subject to an additional inspection. Here's a video touching on the GE problem by a tech who works on GE turbines for a living:
https://www.youtube.com/watch?v=0GxvEQZil2U
I hope ICAO can begin studying the affects of pollution on aircraft more heavily because compressing air with an AQI over 1,000 (like India has experienced recently) could have very unknown consequences elsewhere in the engine after the blades, (unless it just pushes all the pollution particulates back into the cabin, which is another issue that needs to be solved)
Mitsubishi has been developing a turbine for 1700C inlet temperature, and it seems they are getting close.
Second, it is possible to reduce compression losses in 3 spool designs.
Fan designs are getting better, and more efficient. Gearboxes for mid-sized engines are planned, and it's possible we'll see them in GE90 class engines eventually.
Lastly, it's entirely possible to slap a recuperator, intercooler, and reheater on the engine if things will get too desperate.
And how long does the blade stay together? What happens to the blades if a foreign object is ingested? These blades are being made to run at T that make them very ductile, the centrifugal forces literally bend the blades.
Mitsubishi isn't the only one trying to increase the T.
"Second, it is possible to reduce compression losses in 3 spool designs." And increase the losses due to mechanical coupling and decrease reliability.
"Lastly, it's entirely possible to slap a recuperator, intercooler, and reheater on the engine if things will get too desperate. " At what weight and aerodynamic cost?
Its not my intention to contradict you, but to highlight that it's not obvious that any of these things will ever commercially.
Perspiration cooling, the blade itself will always stay around 1200C
> And increase the losses due to mechanical coupling and decrease reliability.
Three spool engines are already there, and flying
There is a lot of space to improve in
https://en.wikipedia.org/wiki/Jet_engine
After close to a century of development, one would think it would be near its technical limits.
Fuel efficiency trends for new commercial jet aircraft: 1960 to 2014
https://theicct.org/publications/fuel-efficiency-trends-new-...
https://theicct.org/sites/default/files/publications/ICCT_Ai...
Current airliners appear to burn half the fuel per passenger mile as did early '70s airliners. This reflects both propulsion and aerodynamic improvements.
Airbus A320 during Cruise: “The 7,900lbf of drag is composed of 4,700lbf of Parasitic drag or drag independent of lift and 3,200lbf of Induced drag or drag caused by lift.” https://leehamnews.com/2018/03/09/bjorns-corner-aircraft-dra...
On top of this slightly increasing passengers, their luggage, and a few extra seats has fairly minimal impact on aircraft weight. The aircraft’s maximum fuel/range is impacted, but that’s rarely an issue.
Which is why ultra long haul flights tend to have more leg room. This can be as much as 5 inches for the same airlines.
You even see this with some stretched versions of airliners, they enlarge the wings or make changes to the high lift devices.
Internal combustion engines in cars have been around longer and we’re still pushing record amounts of power and record amounts of efficiency.
For example, the Cosworth DFV normally aspirated Formula 1 engine with 182 cubic inches was making over 520 horsepower (2.9 / cubic inch) by the end of its career in 1983.
The number five is fungible depending on volume and similarity to existing products. It's why a hobbyist in his garage can design a product but can't commercialize it.
I could buy all 5 of those statements, but it's interesting that the combined effect of them would be to push people out of making things and into manipulating brains (which itself is a statement I could believe).
In the microelectronic and mechanical areas the strength of the Chinese market seems to be very, very lax IP law. While most of the interesting parts don't make it over to the western market, they have very featureful, accessible, and novel components that are made by cobbling together (potentially stolen or at least unlicensed) IP.
Historically US manufacturing used to be the best cost/performance optimized and this is what helped win WWII.
You 5 statements are probably right with some qualification. For example, software mass production is basically free (actually just low cost) for apps distributed via the app stores. However, if you are selling software as a service at scale, setting up a cloud service with five 9s availability is complex and expensive.
They could probably have done it before, but this stuff is expensive. The current make/model of the first car I bought in the 90s costs double what it did then if you buy it new. I don't think the demand for efficiency really came in until oil prices started shooting up and the government imposed stricter CAFE standards.
The increase in performance goes hand-in-hand with emissions standards because - to some approximation - a more fuel efficient engine is more powerful for the same displacement than one that isn't. CFD is what really drove the last 25 years of improvements in this field, better models of what actually happens in a combustion chamber have helped tremendously in extracting the last bit of performance from the engines. The F1 engines are amazing in this respect, their longevity is terrible but their performance is nothing short of incredible in terms of thermal efficiency (> 50%; long thought to be impossible).
https://autoweek.com/article/formula-one/mercedes-f1-engine-...
Not necessarily true, but for kinda stupid reasons. Carburetors often run cooler at the intake than fuel injection, resulting in more peak power despite worse economy. I am aware that this is not actually relevant here, I just think it's interesting.
My main point is that in that in the early 70s Chevy's small blocks could make damn near 400 horsepower. Fast forwards and it isn't until that late 80s that you see a consumer car with north of 250 (grand national), and that was a pretty extreme outlier. Move to the early 2000s and we finally get modern Chevy LS motors which are once again making north of 400hp from the factory. These are still single cam, 2 valve per cylinder V8s though.
WTF actually happened?
In 1971, Car & Driver claims a Corvette with 425 hp did 0-60 in 5.3 seconds[1]. 1/4 mile was maybe 13.8 s. A 2008 Corvette with supposedly similar power did 0-60 in 4.1 seconds and 1/4 mile in 12.5.[2]
Yeah, there's some difference in weight, and modern transmissions, tires, and suspension are better and so on, but there is usually such a big difference that I think most of it is that horses used to be smaller.
[1]https://www.caranddriver.com/features/g15379023/the-chevrole...
[2]https://www.motortrend.com/cars/chevrolet/corvette/2008/2008...
But also keep in mind that significant engineering has gone into the best engines of today to broaden the torque and HP curves. It's not unusual to have 90+% of torque from 1800 rpm to 6500 rpm. That alone could significantly help performance numbers. After all it's the area under the torque/hp curve that matters, not the peak.
Imagine judging a runner by their peak speed, instead of the time to get across the finish line.
https://ateupwithmotor.com/terms-technology-definitions/gros...
For example, an Mercedes claims its F1 engine achieves 50% thermal efficiency. That's insane, and maybe double what a car engine achieves. It also costs $1million(???)/unit.
It used to be that engines were robust. You could turn them off whenever, you could change the oil rarely, and without significant abuse or poor luck they would easily hit 200k miles. MPG wouldn't precipitously drop if you had something on the roof, a trailer, or were speeding. Just look at any manufacturers v6 3 liter for an example.
Today's motors are mostly 2 liter 4 cylinder turbos. They are pretty heat sensitive, have CPUs to manage their cooling, and are pretty hard on oil. Even with good maintenance they have a surprisingly high failure rate within the first 100k miles, but often outside of warranty. Look at the decreasing CPO warranties from Subaru, Audi, Lexus, BMW, etc for evidence. These high strung 4 cylinder turbos are efficient within a narrow range, but can often produce surprisingly poor efficiency when towing, putting anything on the roof, or even just speeding.
The biggest technological improvement I've seen in cars in the last decade is the transmission. Today's automatics and DCTs are mechanical marvels that exceed the performance and efficiency of manual transmissions. They also largely obviate the problem with the 2 liter turbos that have much narrower power/torque curves than the larger displacement engines of yesterday.
Why would one think that? It seems kind of arbitrary. Guns have been developed and iterated on for half a millennia and there are still technological advancements coming out regularly.
Then again, I guess caseless could be the next big innovation if they figure out the heat problem...
The status quo seems firmly in "good enough" territory and I'm pretty sure some of the other supposed benefits of caseless will fail to manifest. In particular, advocates of caseless ammunition have on occasion claimed that guns would be simplified by not having to eject brass, but I don't think that's true since said guns would still need a reasonable way to eject chambered but unfired ammunition (even if it was open-bolt.)
There was a rapid evolution of rifles from the flintlock, black-powder, muzzle-loader to the repeating, brass cartridge, smokeless powder rifle. Since then, rifles, machine guns and pistols have evolved through successive refinements.
(Optics are seeing this kind of development though).
New engines are normally designed alongside a particular aircraft. The aircraft manufacturer optimistically estimates how much thrust will be required. Over years of development, the predicted weight of the aircraft increases and the aerodynamics get slightly worse. To compensate, the engine manufacturer needs to find a way to squeeze more thrust out of the engine - but without changing its size or overall architecture.
This can be resolved by adding extra complexity in the form of extra compressors or stages. Alternatively, you can try to run the engine at higher temperatures and pressures. While it's still possible to certify the engine and run it safely, you will probably experience many more maintenance issues than if the engine was running inside its original design parameters.
I doubt an engine would undergo the addition of a stage as that's pretty major but there's no reason a mfc couldn't charge you a mil for better compressor blades and give you a thrust rating upgrade for your patronage.
Edit: I'll keep talking as more info is coming to my head. Jet engines have fadec computers that get to decide what your maximum power level is. This maximum is programmed into the engine as a thrust rating. Let's say you engine has 8 possible power levels to configure, when you test the engine when new or after maintenance, you will look up a chart based on parameters that your test cell has logged, ie thrust vs EGT (exhaust temp) is a big one, so too is vibration at the different bands. This chart will tell you what to program the ECU with (forgot the actual acronym, its analogous to an ECU on a car). So to your point, when you get more performance out of an engine, you can set these levels higher, so you wouldn't expect more degradation from you engine for a higher power level as the manual will tell you what power level the engine can be set to which will keep everything within its maintenance limits. (Sorry if that's not super clear)
Edit 2: Funny implementation detail of setting a thrust rating, it's literally a jumper based system similar to old motherboards, except you manually wire a blanking plug to bridge the connections. A blanking plug is an electrical connector that has a cap on it with a little bit of space to run wires from one pin back to another.
Also the correct acronym is EEC.
On top of those things, I heard stories that GE for example laid off a large amount of their experienced engineers. This certainly increases the risks with new designs.
https://www.researchgate.net/publication/289985065_An_overvi...
[1] https://www.ge.com/power/about/insights/articles/2016/04/pow...
Now the current CMC method employed by GE uses silicon carbide, which has a melting temperature of about 3000K. If one day they could switch to hafnium carbide, with a melting temperature of more than 4100K, the carnot efficiency could reach more than 89%.
[1] https://www.ornl.gov/news/ceramic-matrix-composites-take-fli...
I don't think a more efficient jet engine will make air traffic environment-friendly anytime soon.
Sorry to hijack the conversation.
[1]: https://www.sciencedaily.com/releases/2019/06/190617164642.h...
[1] https://static.skepticalscience.com/pics/us-flowchart.jpg
Cow worries are just smoke to hide the real issue that is the fossil fuels, specially boats and planes.
What's easier to do telling people to stop eating steak, or getting governments to reduce their biggest "sponsors" earnings?
Also note that North America used to have as many as 60 million Bison, versus about 95 million cattle today. And cattle emit about as much or less methane than bison do, per animal.
https://daily.jstor.org/can-cows-help-mitigate-climate-chang...
Seriously, look at an airport. get the number of flights and where they come from and their frequency, now imagine trying to build a sufficient number of rail lines to do the same.
air travel saves time that no rail line could except in short hop scenarios where extra time to process through an airport might tip a balance. let alone you can have nearly an number of planes in flight between two points
The number of seats in a long distance train in India with about 24 coaches is about 1780 not including those without seats.
A fully loaded ICE 4 high speed train can pack 830 people, an A380 615.
> get the number of flights and where they come from and their frequency, now imagine trying to build a sufficient number of rail lines to do the same.
The answer is multimodal transport and connections. With airplanes, transit takes time and effort - with trains, next to zero. Take, for example, a traveller from New York (USA) to Gaimersheim (DE, Bavaria): airplane connects New York to Munich. Then you travel with the S-Bahn regional train to Munich Central train station, take an ICE high-speed train to Ingolstadt, and switch to the regional train which takes you to Gaimersheim.
If in the future some modes of transportation are banned, everybody will feel sorry to not have enough railroad and nuclear energy.
It does, however, matter quite a bit for emerging technologies which may be aimed at lowering emissions. Higher efficiency, for example, can overcome a lot of drawbacks that come with new technologies, like power to weight ratios. Electric cars, for example, have nowhere near the amount of energy storage that gas fueled cars do, but they are now getting similar ranges because they convert it to kinetic energy much more efficiently.
Huh? Sure they have alternatives: Fuel cells, or non-polluting combustible pairs of compounds, e.g. Hydrogen + Oxygen (or even Hydrogen + Air?) . Also, I'm no physicist, but I'm pretty sure it's more efficient to convert to kinetic energy (almost) directly rather than through electricity - meaning that electric engines don't make much sense.
Correct me if I'm wrong!
Also, even with current technology - passenger aircraft engine turbines are quite far from their maximum potential efficiency; see @baq's comment.
These produce electricity, so I don't see how they are an alternative.
> Hydrogen + Oxygen (or even Hydrogen + Air?)
Hydrogen is highly reactive, and not likely a safe fuel for commercial air travel.
An electric motor is >90% efficient. Sure you're added an extra stage converting to electricity, but so what?
Electric drives are so efficient, diesel ICE locomotives have had electric drives (in lieu of transmissions) since the 1950s. That is, they have massive diesel engines that generate electricity instead of moving the train directly.
Anyway, it bothers me one people refer to the constraint being "large aircraft" when the real difficulty on electric flight is range, not how big the aircraft is. Electric flight scales up just fine. It's the range issue that's hardest. Currently can do 1000km, maybe up to 2000km with lithium ion and lithium sulfur chemistries with optimized structure and aerodynamics. Could scale up to larger sizes if desired.
What if, among all the possible visions of the future, 2119 will have roughly the same tech as 2019? I don't doubt that there will be cosmetic differences, I'm talking more about about the fundamental stuff: energy efficiency, FLOPs, bandwidths, etc, being in the same order of magnitude. What if 2219 and 2319 still says the same, and the hockey stick of growth turns into another plateu?
TBH, this future frigthens me even more than nuclear war or climate change. For both these old horrors, we at least know the theoretical solutions; but if we simply run out of new things to discover that make a difference for us as a species, what then?
Nothing left to do but live a good life and to try to make sure everyone is fed, happy, and treats the earth and everything else in it as well as they can.
The only truly depressing future to me is if interstellar travel really is as hard as it seems to us now. There kind of needs to be a physics/propulsion discovery on the order of magnitude of electricity or the journey can only be feasibly made by the immortal AI robot race that replaces us.
To really make this feasible, improvements in hibernation tech could help. Induced torpor over a week or two already works and could be used repeatedly so that psychological time in transit is only a few years (and the reduction in metabolism from torpor may also extend calendar life of the crew, but that is not yet proven). Even modest life extension (i.e. increasing healthspan from ~mid-60s to mid-80s or longer) would significantly increase the viability of human settlement of Alpha Centauri, and we're just getting to grips with the biochemical tools needed to fight aging, so who knows over a few centuries what will be possible. I think increase in human healthspan and lifespan is more likely than a dramatic practical but fundamental physics breakthrough cutting down the time.
NASA is building a low-boom civil supersonic demonstrator (also crewed) that will demonstrate sonic-boom-lowering techniques to enable passenger supersonic flight over the continental US.
There's lots of room to improve these things still. And I'm excited still about lithium battery tech. It's the internal combustion engine of our century and its consequences are perhaps even more far-reaching. The theoretical useful energy of the most advanced versions of this, the lithium-air battery, are on par with that of hydrocarbon fuels, so by the middle of the century it's likely we'll have completely clean civil supersonic transport with low acoustic emissions as well.
I think we still have a very long ways to go to advance technology. Vacuum tunnel maglev trains allow higher efficiency than even conventional rail but without an ultimate speed limit. They could operate at hypersonic speeds in 100 or 200 years from now, with the energy recouped regeneratively at the end. That makes efficiency orders of magnitude better than today's passenger air travel with speed increased by an order of magnitude.
I think ultimately in the further future, if you want something exciting it'll be: Further urbanization of everything, so humanity concentrates in opulent metropolises well-connected by ultra-efficient transport. Food production increasingly goes to single celled organisms, freeing up space for rewilding of the Earth and healing of the ravages of industrialization while individual well-being is far greater. Human economic expansion in space is technically unbounded. The solar system allows access to many, many orders of magnitude greater energy supplies without an impact on the Earth's ecosystems. Things that can tolerate latency, like high performance computing will leave the planet to access unlimited energy in space (Moore's Law coming to a slow end will actually enhance this transition as you can afford to amortize the hardware over long enough periods of time for this to make sense).
Musk's spaceship is just a taste of what's possible. Improvements in efficiency in even chemical rockets (by reducing structural weight, fine-tuning Isp over the mission cycle, using hydrolox near stoichiometric to enhance performance) can reduce cost of space travel to about what long-haul passenger travel currently is.
I think things will continue to improve. And these are only the foreseeable things. The actual future will contain many unforeseeable discoveries.
None of this is guaranteed, but it can be ours if we so decide to make it thus.
A vision of the future beyond the Earth in the timeframes you mention: https://vimeo.com/108650530
This is very, very unlikely. Take a look at all open questions in physics, and you'll see that our understanding of the universe has severe gaps. Usually, whenever such a gap is filled, there's a technological boom. For instance, Einstein got us some: not only relativity (allowing for things like GPS), but also the photoelectric effect, allowing for (eventually) solar panels. Greater understanding of semiconductors (in no small part due to the above) brought us transistors, cheap lasers, which were refined (and still are) by quantum physics. We are dabbling into quantum computers now.
Mind you, both lasers and radio waves were considered curiosities with no practical applications.
Fusion research is still ongoing. Progress is slow, but steady. Once we have mastered, we'll have access to cheap and plentiful power, which will open up applications previously not even considered before. If it is possible to shrink the technology to less then building sized, then you'll also see vehicles (ships or spacecraft).
Bio technology is still in its infancy. I cannot predict what the results will be, it's far too early.
Some of the rapid progress from the last century might have been an anomaly. But we are not even close to running out of things to learn.
The mid 70’s was golden era of supersonic research. Supersonic engines are just regular jet engines with a Turbofan. Add in wings swept further back in a Delta pattern like the Concorde and you have...supersonic aircraft that comfortably can do Mach 1.5-Mach 2.0.
Today, I think there is just 1 functioning wind tunnel in the US that can do supersonic research, so sad. If you live in the Bay Area you pass it, just look at Moffet Field on your way north of San Jose.
The Japanese and Australians, due to their remote location in part, have done most of the significant research of any last few years.
Why did SuperSonics not go anywhere with essentially every major civilian project being mothballed?
1. Materials Science: we simply don’t have reliable data for how long XYZ Metal lasts at extreme temperatures of supersonic flight. If you read Michael Crichton’s Airframe from 1996 (great novel), they mention that aircraft are designed with a lifespan of a human. 80 years. It’s insane how long these things fly. The heat is so extreme, the Concorde would fully extend 1 foot (it was made in part of titanium) during flight. Many crashes have occurred, such as Alaska Airlines Flight 261 in 1999 from Mexico to California, because the maintenance time frames of these parts is still not fully understood. And that’s for subsonics!
2. Noise: No way around it. The decision to build aircraft close to cities was essentially finalized in preparation for World War II. You can dampen significantly, but it is painfully loud. Landing outside the city with fast train back is best solution.
3. Fuel costs and burn. Supersonic research got underway right as Earth Day started. Lots of supersonic tech relies on afterburners, terrible mileage. It was bad timing.
4. 2003 Concorde crash where a tire was hit on the runway, and the entire aircraft exploded. This should have not happened for a tire collision. SuperSonics are fragile because of all the design tradeoffs one has to make (currently).
What are we talking about here, building aircraft or operating them? Factory noise or takeoff/landing/sonic boom noise?
This makes supersonic airliners infeasible for the really long routes that they would truly help with. The Concorde only shaved 3.5 hours off the NY-London time, and cost about 8x as much to operate.
The extremely high costs then mean that you have to sell what are essentially coach seats at greater than business class prices. There aren't many people willing to pay business class prices, so you can't run the planes very often, and you can only run them between very large, rich cities.
Since the whole point of supersonic is speed, you can't effectively sell connecting flights, because if you fly, say, Boston-London through NYC, the direct flight from Boston subsonic will arrive at nearly the same time as the supersonic flight with a connection.
This leads to a very small passenger market. It also means that supersonic planes will operate on an infrequent schedule. Many people in a position to pay for a supersonic flight will prefer a subsonic flight that meets their schedule over a supersonic flight that doesn't.
With the advent of lie-flat beds, in-flight wifi and power, and higher cabin pressurization, being on an airplane an extra 3.5 hours isn't even so bad anymore, so the practical advantage isn't nearly as great.
All of these factors make supersonic a very small niche market. This means that few planes will be produced. High performance aircraft have high development costs, and those need to be amortized over the production run. Concorde was a complete financial disaster because they only produced 14 of them, for all of the reasons above. The only solution is to somehow make the airframe far more efficient.
I think this is huge. From what I read, the cabin of the Concorde was very cramped. I would prefer business class on a 787 or A380 vs being cramped and arriving faster.
It's interesting to see what Boom is doing here relative to Concorde. They have a similar sized cabin, but they propose to configure it with fewer but larger seats.
They will have more efficient engines and a lighter airframe, but the lower efficiency at higher speeds means they can't match subsonic range, so they'll have to make a fuel stop on transpacific flights, which hurts comfort and will cost at least an hour per flight. Economically, transpacific routes may make more sense even with the fuel stop. Concorde probably could have done this too, but Air France and British Airways didn't serve these routes. All of the very long routes they might have used it on crossed Europe and Asia where they couldn't go supersonic.
"The Low-boom Flight Demonstration mission has two goals: 1) design and build a piloted, large-scale supersonic X-plane with technology that reduces the loudness of a sonic boom to that of a gentle thump; and 2) fly the X-plane over select U.S. communities to gather data on human responses to the low-boom flights and deliver that data set to U.S. and international regulators."
https://www.nasa.gov/X59
[1] https://www.quora.com/How-much-fuel-is-burned-during-take-of...
Maintenance?
Catapults are notoriously finicky and expensive to operate. Also the additional stresses on the airframe couldn't possibly reduce maintenance. If anything (assuming they could withstand them), they would require more inspections.
Catapults only solve the problem of not having enough runway. And you'll notice that fighter jets taking off from carries will be on full thrust and full reheat.
When Nokia's retail division went up it a ball of flames, the engineers didn't just disappear and become janitors or something. They formed HMD, who is the one of the very few mobile phone makers seeing ear on year growth in shipments.
Raw human talent is the major driver of innovation. Companies are just one way they organise themselves. Open source is another. Different organisations suit different circumstances, but you always need the raw human talent.
As I've said for many years, cutting air travel prices to the bones is a very dangerous affair—as it results in substandard/shithouse quality engineering being installed in aircraft (cost-cutting results in designs that have insufficient safety/reliability margins).
Travelers need to get used to paying about 30% to 40% more per trip—and the regulators should be spruiking this message loud and clear from upon high until the plebs get the message!
(It's all pretty basic really—it's a no-free-lunch argument.)