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American Airlines agrees to purchase Boom Supersonic Overture aircraft

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Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#441

Post by panick21_ »

nautilius wrote: post #312
ucha wrote: post #298

To everyone saying this will not work because it's more expensive... jets were more expensive than turboprops. And even though the former use more fuel, we prefer them. The costs of flying an airplane isn't proportional to its fuel usage. The faster an aircraft is, the more flights it can perform per day. The carbon emissions impact of flying a gas-guzzling supersonic aircraft aren't evident either. Of course, more g…

> The costs of flying an airplane isn't proportional to its fuel usage. The faster an aircraft is, the more flights it can perform per day. It is indeed not proportional, but not in the way you are thinking. Drag (and ~fuel consumption) scales with velocity squared, so a plane flying twice at fast (and neglecting any time at the airport, which would make the argument even worse) would use four times as much fuel. I.e…

> a plane flying twice at fast would use four times as much fuel

Not that this only applies if they fly at the same altitude. If you fly higher you can avoid that. That of course causes other problems but it is a relevant factor.

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#442

Post by chasil »

HPsquared wrote: post #317
solardev wrote: post #168

Earlier quoted context omitted.

What makes the newer engines so much quieter?

They have larger fan blades, for one. That means they move a large volume of air relatively slowly, instead of a small volume of air moving quickly. Consider the difference between a large shop fan, and a small high pressure compressed air nozzle commonly used in workshops for cleaning, with both sized to give the same "reaction force" (i.e. the same thrust). The high-pressure nozzle makes much more noise.

The metallurgy of the fan blades has also vastly improved.

Monocrystaline fan blades have very different material properties from the polycrystaline blades that (I am guessing) were used on Concorde.

https://www.americanscientist.org/article/each-blade-a-singl...

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#443

Post by leecarraher »

is the contract public? i would like to see what contingency is in place if Boom fails to deliver. Or more to the point, is this more PR to make AA appear to be forward looking, and bolster Boom's reputation with a deal that will never come to fruition. It's a win-win for investors

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#444

Post by chroma »

zymhan wrote: post #163
flerchin wrote: post #9

Not a lot to go on here. Boom projects first flight in 2026 for the Overture. They seem to be fairly close to first flight with their XB-1, but it has not flown yet. I congratulate them on getting funding, but all the hard parts are ahead. https://en.wikipedia.org/wiki/Boom_XB-1

They still don't have an engine that allows them to fly supersonic...

Boom's original bet was that they could use better aerodynamics and materials to get supersonic speeds using existing engines. This saves a ton of time and money since you don't need to get the engines certified. The prototype uses three non-afterburning GE J85 engines[1], which produce 2,950 lbs of thrust each. It should have a top speed of mach 2.2.

The main issue is that their production aircraft will need more powerful engines, and modern civilian airliner engines have large fans, high bypass ratios, and high compression ratios, all of which make them difficult to adapt to supersonic flight. It looks like their plan is to collaborate with Rolls-Royce to build a suitable engine using an existing engine core. I hope they can pull it off.

1. https://en.wikipedia.org/wiki/General_Electric_J85

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#445

Post by dfadsadsf »

theYipster wrote: post #345
FredPret wrote: post #266

Earlier quoted context omitted.

It always makes a lot of sense - time saved is time saved. Flying east fast after a day of meetings means you get in bed on time.

No it doesn't. You are forgetting timezones. The above poster is correct - supersonics are suboptimal for eastbound, especially when you consider they can only be used at speed over the ocean. A super sonic flight that leaves JFK at 6PM arrives at 2AM in LHR after 3 hours of flying plus a 5 hour time zone change. It's much more optimal to take a lie flat seat on a traditional aircraft, get a decent nights sleep on th…

As somebody who flew quite a few lie-flat business flights on JFK->LON - you absolutely do not get good night sleep. Flight time is 7:30 and you can realistically go to sleep 30 minutes after take off (when they start serving food and other passengers are still noisy - good luck falling asleep quickly) and you are generally woken up about 1-1.5 hour before landing (Why? I have no idea but they turn on the lights, serve breakfast and do announcements about weather in London about that time before landing). So you get at most 5.5h of mediocre quality sleep which is better than nothing but not enough to function 100%.

3 hour flight will change a lot of things for JFK-LON business trips as they open up opportunities to loose only 1 full day during business trip instead of loosing two full days. I generally stay on NYC time with meetings in the afternoon LON time if trip is less than 5 days so short flight is game changer.

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#446

Post by samstave »

jseutter wrote: post #203
samstave wrote: post #107

Earlier quoted context omitted.

r/noStupidQuestions ; Can these be 'stacked' - Can you have a turboFan in line with a turboProp such that the output of the wash of the Fan feeds into the Prop, but with a portion of the wash spinning to thrust on the outer ring of output.=, via a design in the cowlings which is hyper directed thrust vents (think the grid of straws used to funnel water into a cohesive column, which can be directed) Imagine a small di…

As far as has ever been discovered - no, this won't work. You can think of a fan as just a prop enclosed in a housing (jet engine). A prop loses effectiveness at the speed of sound because the air passing the prop gets a high pressure shock wave that effectively makes the prop not prop-shaped, so it can't move air. Picture it as using a hammer on glass instead of pushing on glass with your hand, one works way better…

>a high pressure shock wave that effectively makes the prop not prop-shaped, so it can't move air.

Leading micro eddys can solve this.

If the induction is a straight stream, it will fail - you need to direct micro eddys

If you do this with mechanical means (deflection cowlings) you will hit a limit.

The ideal design is in the funneling of eddys as they traverse in a super spiral between the front eddy and as it spirals to the thrust vector.

however, pre-ionizaton, and then magnetic ion direction can swirl the eddy to the desired output. However, AIR is not the thrust component at this time, its ionized energy which is being "thrust" (thrust is typically thought of as a 'push' - but this is actually a 'pull'

Identify a spot, pull yourself to it. As opp

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#447

Post by Retric »

0000011111 wrote: post #397
jandrese wrote: post #380

Earlier quoted context omitted.

Fuel prices were absolutely an issue for Concorde. BA struggled immensely with the Arab oil embargo and the per-seat cost for the Concorde shot up into the stratosphere and ticket sales collapsed.

We can easily model this in a sheet. Like this one: https://docs.google.com/spreadsheets/d/1JhvGd6iVWNweMM-PYk3z... At todays Jet 1 A US fuel price of $3.07 per gallon it would cost $108k to fill the Concord. Which holds 120 passengers. That comes out to a cost of $900 per person passenger on a full fight. If the cost of fuel were double like a few months ago then that cost would be $1,800 per flight. Compared to a B…

Meanwhile a one way ticket cost US$975 in 1977 or inflation adjusted about 4,700$ today. Which increased faster than inflation so by mid 90’s your talking around 6,000$ which is something like 12,000$ today.

Thus fuel while expensive wasn’t a deal killer over most of it’s history as long as they could keep most seats filled.

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#448

Post by berkut »

Retric wrote: post #378
jandrese wrote: post #368

Earlier quoted context omitted.

And they still have not solved the problem that ultimately sunk the Concorde. Fuel costs made it unprofitable to operate whenever the price of oil went up. The small niche of customers willing to pay a significant premium in order to save some travel hours is not big enough to sustain an entire industry of specialized mechanics, parts suppliers, pilots, etc... Basically you need a critical mass of people riding these…

They seem to have dramatically reduced fuel consumption, but fuel wasn't the issue for the concord the limited number of viable routes where. Going from the Concrods 3550nm range to 4250nm should help with that as it opens up several new routes and longer routes see a more significant drop in travel times.

From what I've read, the Concordes had preferential landing treatment on westbound flights into JFK and Dulles, due to their shortage of fuel, and the controllers would often allow them to land before other planes that had been queuing for a while. (They used a separate controller radio frequency apparently for the initial request, and then switched to using the main frequency).

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#449

Post by ant6n »

JCM9 wrote: post #11

Strong FOMO settling in. Premium transatlantic routes routes like NYC-LHR are super important to the bottom line of the big legacy carriers. If one airline has supersonic and others don’t that could be a huge blow to the others. Of course things didn’t work out that way with Concorde, which was not commercially successful and more of a spectacle than something founded in business fundamentals. But if Boom can make su…

> Optimized for speed, safety and sustainability

I hope any airline that gets these gets punished by all the other customers for the environmental irresponsibility of pushing this gass gussling technology.

Wow, you can blow through your whole annual carbon budget in only 4 hours!!

Re: American Airlines agrees to purchase Boom Supersonic Overture aircraft

#450

Post by _ph_ »

_gu8l wrote: post #216
awb wrote: post #183

Earlier quoted context omitted.

> over water All the imagined routes are over large bodies of water. Is it key to the functionality or intent of the aircraft in some way? Why not NYC to LAX in 3 hours?

A bunch of replies say that wouldn’t be allowed, but I heard sonic booms regularly while living near an Air Force Base in California. It didn’t seem to affect the hundreds of thousands of residents nearby. Is there an actual reason why we can’t have one every day at 10am or on some other regular schedule?

I remember growing up during the cold war in western Germany which was formally under the control of the allied forces. So they were allowed to go supersonic with the military jet aircraft and frequetly did so, even in rather populated areas (by German standards - in general, Germany is much denser populated than the US). It was a bit annoying but definitely survivable (here I still am).

I think it was a mistake for the US to ban supersonic flight outright and especially at all altitudes. I can't imagine a sonic boom being a huge problem, if you are 10 miles up or higher.

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