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Boom XB-1 First Supersonic Flight [video]

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

#291

Post by hugs »

cryptonector wrote: post #286
scythe wrote: post #275

Earlier quoted context omitted.

Noticeable is certainly a way of putting it. https://en.wikipedia.org/wiki/Oklahoma_City_sonic_boom_tests >However, in the first 14 weeks, 147 windows in the city's two tallest buildings, the First National Bank and Liberty National Bank, were broken. If a sonic boom is "noticeable", that's one thing. But the problem is that even from cruising altitude they're shockingly loud. If the sonic boom is merely bearable, th…

GP was asking about this flight's sonic boom. That's the whole point of Boom: to make supersonic airplanes with small sonic booms.

First confirmation I've found so far on this exact question: "XB-1 is supersonic! (No boom audible here, as expected)" - Jon Ostrower https://bsky.app/profile/jonostrower.com/post/3lgsvea6zbs2x

Raises more questions though, because there were two other chase planes. Did the other planes stay below the sound barrier at all times?

Edit to add: Was no audible boom expected because of the planes themselves or because of where the people were watching from?

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

#292

Post by ortusdux »

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

"The Concorde relied on an afterburner to achieve supersonic flight..."

"The Concorde used its afterburners ... to get through the transonic region..."

Am I missing something, or is there no difference between these sentences?

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

#294

Post by stouset »

aeturnum wrote: post #281
Retric wrote: post #269

Earlier quoted context omitted.

It’s hard to argue a startup succeed until profits > investment.

This is only true from the point of capital - if a startup changes the world in a way you like it can be a success to you. Profitability brings a certain approval and sustainability, but don't confuse that with your goals in what you are working on.

In what way do you think building a new but still-uneconomic supersonic plane is going to change the world for the better?

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

#295

Post by stouset »

pembrook wrote: post #228
itsoktocry wrote: post #214

Earlier quoted context omitted.

This is a long way from a supersonic passenger flight, isn't it?

Endless pessimism, even in the face of evidence to the contrary is a hallmark of HN. Thank you for continuing the tradition. May you never hold out hope for anything positive in the future.

I don't think you fully appreciate the number of obstacles in the way of new entrants building commerically-operable airplanes. Flying a supersonic prototype is amazing. But it is a depressingly-small amount of the overall work necessary to simply start taking passengers, much less make something economical, and even less to make something succeed.

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

#296

Post by Sohcahtoa82 »

chgs wrote: post #256
EA-3167 wrote: post #32

Earlier quoted context omitted.

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 intende…

Last time I flew from Heathrow it was 45 minutes from car to take off, and that was with a 20 minute door close. It doesn’t take 2 hours to go through security , certainly not in the first class section in any case.

I fly a couple times a year from Portland, OR.

The line at security is typically 0-20 minutes. Add in walking time, and I'm getting from car to gate in 10-30 minutes.

But I still feel like I need to get to the airport at least 90 minutes, if not 2 hours early, just in case I end up flying on a day where 1 of the 2 security checkpoints is entirely closed and every traveler is now forced to go through a single checkpoint and it's going to take over an hour.

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

#297

Post by notahacker »

reaperducer wrote: post #209
alex_duf wrote: post #120

Earlier quoted context omitted.

I assume the question was about the questionable economics of running a super-sonic airplane profitably. The Concorde was notorious for bleeding money. Maybe the premium aspect will be enough, given that we have a bigger and bigger chasm between rich and poor, or maybe the economics of running it won't compete against sub-sonic, lower fuel consumption planes.

The Concorde was notorious for bleeding money. I see this stated all the time on HN, yet there's a whole section at the top of this very comments thread where people are talking about how very profitable the Concorde was. One person quoted the line "There were times, in fact, when the seven aircraft in the fleet would contribute around 40 per cent of BA’s entire profits."

The key point is that the seven aircraft (two of which they paid £1 for!) spent very few hours per week in the air, because whilst it was profitable on one transatlantic route at very high prices, it would have lost money on just about any other route or with more frequent operation. And to have a profitable airframe programme you need your customers to be able to operate more than a couple of routes.

(the 40% figure is more an indication of BA's sometimes thin margins than massive unfulfilled potential)

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

#300

Post by nine_k »

stouset wrote: post #294
aeturnum wrote: post #281

Earlier quoted context omitted.

This is only true from the point of capital - if a startup changes the world in a way you like it can be a success to you. Profitability brings a certain approval and sustainability, but don't confuse that with your goals in what you are working on.

In what way do you think building a new but still-uneconomic supersonic plane is going to change the world for the better?

Uber and Lyft are largely still unprofitable, but they definitely have changed the landscape, as many would argue, to the better.
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