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The Race to Build the First Sustainable Supersonic Jet

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Re: The Race to Build the First Sustainable Supersonic Jet

#31

Post by mrfusion »

jpeanuts wrote: post #24

In my opinion it is disingenuous to call any supersonic aircraft sustainable. Independently of any clever aerodynamic design to moderate the drag coefficient, aerodynamic drag always increases like the velocity squared. Doubling the speed will mean applying 4x the force for 1/2 the time, so all propulsive efficiencies being equal, you will expend twice the fuel to go the same distance - at an absolute minimum. In rea…

You’re not factoring in the ability of supersonic planes to fly at higher altitudes lowering air resistance.

Also these planes could entice the rich to forgo flying on private jets. I’m sure 50 folks on a supersonic jet is still more efficient than 50 gulf streams.

Re: The Race to Build the First Sustainable Supersonic Jet

#32

Post by grizzles »

I flown many long haul flights. The first time I heard Musk propose using rockets for international travel I thought it was insane. I still do. But if they are accident free for the next 10 years; would I then? Probably - if they could manage to keep my trip under ~3Gs.

Re: The Race to Build the First Sustainable Supersonic Jet

#33

Post by KoftaBob »

jpeanuts wrote: post #24

In my opinion it is disingenuous to call any supersonic aircraft sustainable. Independently of any clever aerodynamic design to moderate the drag coefficient, aerodynamic drag always increases like the velocity squared. Doubling the speed will mean applying 4x the force for 1/2 the time, so all propulsive efficiencies being equal, you will expend twice the fuel to go the same distance - at an absolute minimum. In rea…

Air transportation only makes up 10% of emissions caused by the transportation industry, and that industry as a whole makes up 26% of total global emissions. In other words, air transportation makes up 2.6% of global emissions, which is not even remotely close to being a "major contributor to CO2 emissions".

As for your last sentence, if we can find ways to travel the world faster, why the hell not? Once we start having this attitude of "good enough", we stagnate as a society.

The biggest sources of pollution are passenger cars, energy production, and agriculture. Rather than stagnate our aviation technology in order to tackle something that makes up 2.6% of pollution, let's make those other industries green.

Re: The Race to Build the First Sustainable Supersonic Jet

#34

Post by namirez »

mrfusion wrote: post #31
jpeanuts wrote: post #24

In my opinion it is disingenuous to call any supersonic aircraft sustainable. Independently of any clever aerodynamic design to moderate the drag coefficient, aerodynamic drag always increases like the velocity squared. Doubling the speed will mean applying 4x the force for 1/2 the time, so all propulsive efficiencies being equal, you will expend twice the fuel to go the same distance - at an absolute minimum. In rea…

You’re not factoring in the ability of supersonic planes to fly at higher altitudes lowering air resistance. Also these planes could entice the rich to forgo flying on private jets. I’m sure 50 folks on a supersonic jet is still more efficient than 50 gulf streams.

This is a common misconception. Flying at higher altitudes doesn't mean just lower air resistance; it means lower lift as well. As a result you have to fly faster for compensating lower air density. If you do the math, you realize the overall effect would be higher energy consumption.

Re: The Race to Build the First Sustainable Supersonic Jet

#35

Post by GordonS »

ryanlol wrote: post #21
vilhelm_s wrote: post #8

Earlier quoted context omitted.

This will be a private jet, and they are pretty expensive. Apparently flying in a Bombardier Learjet costs something like $7000/hour [1], while a first-class ticket is more like $1000/hour. [1] https://www.aircharterserviceusa.com/about-us/news-features/...

> while a first-class ticket is more like $1000/hour. I usually pay like 160eur/hour for top tier F products like the Emirates A380. I just paid a little over 4000 euros for a 32h round trip with that particular offering. I don’t chase after deals, I just tend to depart from a city without many F pax. Of course, YMMV.

This doesn't seem possible - I have never seen first tickets that cheap from anywhere to anywhere. Can you provide a few example routes?

Re: The Race to Build the First Sustainable Supersonic Jet

#36

Post by FDSGSG »

GordonS wrote: post #35
ryanlol wrote: post #21

Earlier quoted context omitted.

> while a first-class ticket is more like $1000/hour. I usually pay like 160eur/hour for top tier F products like the Emirates A380. I just paid a little over 4000 euros for a 32h round trip with that particular offering. I don’t chase after deals, I just tend to depart from a city without many F pax. Of course, YMMV.

This doesn't seem possible - I have never seen first tickets that cheap from anywhere to anywhere. Can you provide a few example routes?

Most Emirates long haul flights departing from AMS,BCN or MXP seem to be that cheap, I'm sure there are other cheap airports but I'm too lazy to look. This is probably the case with all the euro airports that don't charge super high fees and lack large quantities of F pax.

I'm seeing MXP-HKG at 4000eur for a round trip, MXP-BKK for 3800eur. There are probably even better deals available if departing from some third world countries.

I guess you're from the UK, I'm seeing BHX-HKG priced at around 151GBP/hr. Shockingly, LHR-HKG looks even cheaper at somewhere around 100GBP/hr.

Re: The Race to Build the First Sustainable Supersonic Jet

#37

Post by phunctional »

What about Boom Supersonic? They are partnering with Prometheus fuels that pulls carbon out of the air and turns it into fuel and also focusing on a commercial jet rather than private. There isn't even any mention of sustainability other than in the title of this article.

Re: The Race to Build the First Sustainable Supersonic Jet

#38

Post by lancesells »

mrfusion wrote: post #31
jpeanuts wrote: post #24

In my opinion it is disingenuous to call any supersonic aircraft sustainable. Independently of any clever aerodynamic design to moderate the drag coefficient, aerodynamic drag always increases like the velocity squared. Doubling the speed will mean applying 4x the force for 1/2 the time, so all propulsive efficiencies being equal, you will expend twice the fuel to go the same distance - at an absolute minimum. In rea…

You’re not factoring in the ability of supersonic planes to fly at higher altitudes lowering air resistance. Also these planes could entice the rich to forgo flying on private jets. I’m sure 50 folks on a supersonic jet is still more efficient than 50 gulf streams.

Flying private is as much about comfort as it is about time efficiency. Maybe the speed increases will make up for time spent on security lines, ticketing, boarding and departures but I suspect you'll start to see private supersonic jets for those that can afford them.

Re: The Race to Build the First Sustainable Supersonic Jet

#39

Post by taneq »

jpeanuts wrote: post #24

In my opinion it is disingenuous to call any supersonic aircraft sustainable. Independently of any clever aerodynamic design to moderate the drag coefficient, aerodynamic drag always increases like the velocity squared. Doubling the speed will mean applying 4x the force for 1/2 the time, so all propulsive efficiencies being equal, you will expend twice the fuel to go the same distance - at an absolute minimum. In rea…

"Sustainable" doesn't mean "optimized for minimal energy usage", it means "we can keep doing it without running out of anything."

If we can make jet fuel out of atmospheric CO2 using solar power without crippling the rest of our industry, it's 'sustainable' even if we just use that jet fuel for Nitro Circus antics.

Also, 'efficient' doesn't mean anything without saying what you're optimizing for. Slow, lightly loaded aircraft might be 'more efficient' in the sense that they use less jet fuel, but if your business involves a lot of air travel, it's going to be 'more efficient' in the sense of time and money to use a faster aircraft.

Re: The Race to Build the First Sustainable Supersonic Jet

#40

Post by perl4ever »

cletus wrote: post #30
melling wrote: post #26

Earlier quoted context omitted.

Nope, air transportation is not a major contributor to CO2. There are over 100,000 flights daily. They account for about 2.5% of CO2 emissions yearly. You know what is? Coal power plants that generate electricity. Maybe we should focus on electricity generation from coal. I’m a little surprised that more hasn’t been done. https://www.carbonbrief.org/mapped-worlds-coal-power-plants 13 years ago Google attempted their…

The real villain here is coal-powered planes! Ok, in all seriousness, the efficiency story for air travel is... complicated. So you claim planes account for 2.5% of CO2 emissions but air travel and transport is still a relative luxury enjoyed by a privileged few so that's not necessary accurate. I found this [1] that shows planes to be much worse than automobiles (per passenger per km) but again, it's complicated. Pe…

"It's the difference between able to go for the day or not"

Which points to how increases in capability and efficiency can stimulate demand, which could be a bad thing from an environmental perspective.

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