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Boom XB-1 First Supersonic Flight [video]

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Re: Boom XB-1 First Supersonic Flight [video]

#31

Post by hnuser123456 »

kindatrue wrote: post #9
dylan604 wrote: post #6

I know nothing about Boom. Why is this impressive? We've achieved supersonic for passengers before. Are we meant to be interested just because someone is taking up the mantle again, or is there some new design that makes it impressive?

Previously Boom's CEO said this: “That’s not travel, that’s like a thing you might hope to do once in a lifetime,” says Scholl, before adding, “Versus where we want to get, which is anywhere in the world in four hours for 100 bucks.”[1] Anywhere in the world in four hours for $100 USD really caught people's imagination and attention. I'm puzzled by how they will achieve this. [1] https://www.cnn.com/travel/article/bo…

Huh. The longest flights are around 10,000 miles. They usually cost over $1000. Fuel apparently accounts for about 25% of ticket price on long haul, so $250 in fuel normally. To do that in 4 hours is to travel 2,500 mph. Naively, traveling twice the speed requires 8x the power, so going over 4x the usual 550mph should mean over 64x more fuel burn, or $16,000 in fuel alone. Maybe a bit less since drag doesn't grow quite as quickly above transonic, call it $10,000. But if a ticket's only $100, I guess they've figured out how to get gas for 0.25% of typical prices.

Re: Boom XB-1 First Supersonic Flight [video]

#32

Post by EA-3167 »

dylan604 wrote: post #6

I know nothing about Boom. Why is this impressive? We've achieved supersonic for passengers before. Are we meant to be interested just because someone is taking up the mantle again, or is there some new design that makes it impressive?

There are some interesting technological developments around fuel efficiency and minimizing the "sonic boom" that's felt on the ground. Neither of those killed Concorde though, because the entire idea of Concorde turned out to be incredibly faulty. MOST people weren't in such a hurry to get from point A to point B that they'd pay 5x-10x a normal business/first class ticket to cut a trip down by 50% or so. The intended 100+ units to be built and sold turned out to be a fantasy, airlines weren't interested.

Now consider what's changed: Back when Concorde was new, airline security was perfunctory and brief, so the time spent in the airport was a fraction of total travel time. Today that represents potentially 2+ hours of your travel time that can't be omitted. For much of Concorde's life the modern internet wasn't a thing, or at least mature; every business traveler didn't have the ability to have a conference call IN MID FLIGHT. Today that's routine.

So what's the hurry exactly? Sure some people might have a need or desire, but the planned jet holds 64 people who are going to have to pay through the nose to make it profitable for an airline. Who are these people who wouldn't rather take a sleeping pill or futz around on their laptop instead?

tl;dr Supersonic civil aviation is an ECONOMIC problem, not a technological one, and the economics haven't changed.

Re: Boom XB-1 First Supersonic Flight [video]

#33

Post by rbanffy »

hangonhn wrote: post #22
ortusdux wrote: post #19

Earlier quoted context omitted.

The Concorde relied on an afterburner to achieve supersonic flight, so it burned a ton of fuel. It also could not go supersonic over land because its sonic booms were too loud. This mean that flights could only go over the ocean, and they were expensive due to fuel costs. Boom's goal is to reduce the sound of their sonic booms 30x and eliminate the need of afterburners.

No. I don't think that's correct. The Concorde used its afterburners during take off and to get through the transonic region, where the drag is very heavy. Once you've gone past that the drag drops. At that point the Concorde can turn off the after burners. Source: https://www.heritageconcorde.com/concorde-engine-re-heats

Legend says the Tu-144 used afterburners the whole time while supersonic, but, then, it seems five units have engines without afterburners (RD-36-51's replacing the Kuznetsov NK-144 used in most of the fleet).

I wonder what was the noise level in those late models.

Re: Boom XB-1 First Supersonic Flight [video]

#34

Post by ics »

For those wanting to jump to where it goes supersonic, it happens a little after minute 11 on the flight time. The camera shots are clearer during subsonic flight, then it gets fairly blurry. The takeoff and climb were interesting to see; also before it goes supersonic the shots from the air are remarkably clear.

Re: Boom XB-1 First Supersonic Flight [video]

#35

Post by rbanffy »

talldayo wrote: post #20
bangaroo wrote: post #12

Earlier quoted context omitted.

i don't disagree with any of that, i'm extremely skeptical that they will ever scale this up however: there is, now. this is a civil aircraft flying supersonic, which is still some sort of interesting fact.

"Civil" supersonic aircraft is a designation, that's it. Like the other comment said - you can fly supersonic military jets with a civilian designation as long as the jet is deemed airworthy. The real question is whether this will ever scale up to be a passenger aircraft. There are still a huge number of unsolved problems, many of which plagued the Concorde in the best of years. I don't think a scaled demonstrator is…

This is the first supersonic aircraft in a long time that started as a civilian one and was never intended for military applications. Loses points for the military engines though.

Still impressively cool.

Re: Boom XB-1 First Supersonic Flight [video]

#36

Post by dylan604 »

bangaroo wrote: post #12
dmitrygr wrote: post #10

Earlier quoted context omitted.

> there hasn't been supersonic civil aviation There still isn’t, and this is not a very interesting stepping stone. We already knew that we could fly a plane quickly. This company has no engines for their allegedly full scale plane. The last manufacturer dropped them a few years ago, and there has been no movement in that direction. This demonstrates the easiest part of what they’re trying to do, not the hardest. Thi…

i don't disagree with any of that, i'm extremely skeptical that they will ever scale this up however: there is, now. this is a civil aircraft flying supersonic, which is still some sort of interesting fact.

Do none of the private jets like G6s or whatever fly supersonic?

Re: Boom XB-1 First Supersonic Flight [video]

#37

Post by WillPostForFood »

dmitrygr wrote: post #10
bangaroo wrote: post #8

Earlier quoted context omitted.

there hasn't been supersonic civil aviation, as far as i am aware, since the concorde was grounded. there are no active commercial aircraft capable of going supersonic. this is significant because it's the first civil aircraft to reach that milestone since the ending of the concorde program.

> there hasn't been supersonic civil aviation There still isn’t, and this is not a very interesting stepping stone. We already knew that we could fly a plane quickly. This company has no engines for their allegedly full scale plane. The last manufacturer dropped them a few years ago, and there has been no movement in that direction. This demonstrates the easiest part of what they’re trying to do, not the hardest. Thi…

The equivalent of a hand drawn ui mockup for a future “AGI workstation” would be a hand drawn mockup of a supersonic plane, not a functional supersonic plane.

Re: Boom XB-1 First Supersonic Flight [video]

#38

Post by Ajedi32 »

hnuser123456 wrote: post #31
kindatrue wrote: post #9

Earlier quoted context omitted.

Previously Boom's CEO said this: “That’s not travel, that’s like a thing you might hope to do once in a lifetime,” says Scholl, before adding, “Versus where we want to get, which is anywhere in the world in four hours for 100 bucks.”[1] Anywhere in the world in four hours for $100 USD really caught people's imagination and attention. I'm puzzled by how they will achieve this. [1] https://www.cnn.com/travel/article/bo…

Huh. The longest flights are around 10,000 miles. They usually cost over $1000. Fuel apparently accounts for about 25% of ticket price on long haul, so $250 in fuel normally. To do that in 4 hours is to travel 2,500 mph. Naively, traveling twice the speed requires 8x the power, so going over 4x the usual 550mph should mean over 64x more fuel burn, or $16,000 in fuel alone. Maybe a bit less since drag doesn't grow qui…

Once you get out of the atmosphere, drag (and fuel consumption) is ~0. So theoretically possible, but I'm not sure if that's what he was talking about. Certainly Overture won't be capable of that.

Re: Boom XB-1 First Supersonic Flight [video]

#39

Post by anothertroll456 »

hangonhn wrote: post #22
ortusdux wrote: post #19

Earlier quoted context omitted.

The Concorde relied on an afterburner to achieve supersonic flight, so it burned a ton of fuel. It also could not go supersonic over land because its sonic booms were too loud. This mean that flights could only go over the ocean, and they were expensive due to fuel costs. Boom's goal is to reduce the sound of their sonic booms 30x and eliminate the need of afterburners.

No. I don't think that's correct. The Concorde used its afterburners during take off and to get through the transonic region, where the drag is very heavy. Once you've gone past that the drag drops. At that point the Concorde can turn off the after burners. Source: https://www.heritageconcorde.com/concorde-engine-re-heats

[flagged]

Re: Boom XB-1 First Supersonic Flight [video]

#40

Post by hnuser123456 »

Ajedi32 wrote: post #38
hnuser123456 wrote: post #31

Earlier quoted context omitted.

Huh. The longest flights are around 10,000 miles. They usually cost over $1000. Fuel apparently accounts for about 25% of ticket price on long haul, so $250 in fuel normally. To do that in 4 hours is to travel 2,500 mph. Naively, traveling twice the speed requires 8x the power, so going over 4x the usual 550mph should mean over 64x more fuel burn, or $16,000 in fuel alone. Maybe a bit less since drag doesn't grow qui…

Once you get out of the atmosphere, drag (and fuel consumption) is ~0. So theoretically possible, but I'm not sure if that's what he was talking about. Certainly Overture won't be capable of that.

Fair, I hadn't considered the intercontinental ballistic passenger missile approach.
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