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Boom supersonic jet readies for rollout

airlineratings.com

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Re: Boom supersonic jet readies for rollout

#91

Post by maccam94 »

bobthepanda wrote: post #67
ghaff wrote: post #44

Earlier quoted context omitted.

Once you start having refueling stops, you're losing a lot of the benefits to supersonic flight. Many of the inefficiencies are in the subsonic range and now you're going to be in queues for takeoff.

The airports where one might refuel don't necessarily have to be big congested megahubs. Boom's a small plane, I wonder what the runway requirements are?

The Boom plans to land at 185 knots/213MPH, comparable to a 737-800. They probably need a fraction of the distance to stop though, since the plane has about 1/3 of the seating capacity.

Re: Boom supersonic jet readies for rollout

#92

Post by maccam94 »

dhosek wrote: post #28
hinkley wrote: post #16

Earlier quoted context omitted.

They may also find SpaceX eating their lunch, if the rumors of ballistic flights have any substance to them at all. And the EPA doesn't curb-stomp them.

Ballistic flights make no sense at all. Consider how finicky rocket launches are about weather. So you need to go to the spaceport for your launch, hope that you don't get scrubbed by the weather and save a few hours? Hard to see how that makes any sort of business sense.

Some of the wind sensitivity comes from the hulls being long and narrow. SpaceX's Starship design will be much wider and thus more robust compared to their Falcon 9 rocket.

Re: Boom supersonic jet readies for rollout

#93

Post by bobthepanda »

smachiz wrote: post #78
bobthepanda wrote: post #74

Earlier quoted context omitted.

To address the "empty Concorde" problem, Boom is explicitly targeting a 50-seat business class layout with similar seat cost per mile. Filling 50 comfortable seats is an order of magnitude easier than filling 100 uncomfortable ones.

Umm... ask every 'business class only' airline that has come (and gone...) about that.

Building an entire airline around it is stupid.

Building certain premium flights around it, not necessarily; Singapore Airlines operates a 67-seat business class on a plane from Newark to Singapore that only has business and premium economy. BA operates a 32-seat business-only flight from London City to New York via Shannon. And these are just the subsonic flights.

JAL is one of the bigger investors in this project, so it's not as if there's no interest at all.

Re: Boom supersonic jet readies for rollout

#94

Post by avmich »

orbital-decay wrote: post #17
avmich wrote: post #5

>the development of the first privately built supersonic airliner and the second ever after Concorde Sad that in a rather specialized article author isn't familiar with such basic facts.

"Privately built", so it's technically accurate, even if there's still an elephant in the room. Similar to that amusing SpaceX marketing speak with the Falcon Heavy being "the most powerful orbital rocket since Saturn V", which was also technically true because both Energia flights were payload-assisted. (they changed that line since then)

The sadness comes from that it's quite misleading. Saturn-V couldn't bring to orbit the satellite of some 100 tons - the mass of Space Shuttle orbiter, which Space Shuttlle launch system obviously could. Saturn-V could either send to LEO the Skylab - less than 80 tons - or bring to orbit an Apollo stack, from which a lot of mass was the 3rd stage of Saturn-V with carefully unspent fuel, intended to provide translunar injection; that stack, yes, was way more than 120 tons. So is Saturn-V less powerful to LEO than Space Shuttle? We usually don't do this hairsplitting and leave the crown with the Mighty Saturn. Here we can also see a technically accurate reading, but the problem remains - the author omits an important member of supersonic commercial flights fame - the one with some 55 passenger flights, which is more even than half of Falcon-9 flights and e.g. way more that Spruce Goose flights.

I do think that HN readers generally know - and ought to know - better.

Re: Boom supersonic jet readies for rollout

#95

Post by Balgair »

ars wrote: post #45
nimbius wrote: post #41

Real question: have we solved the radiation problem yet? The concord's solution was to sample exposure with a cockpit Geiger counter and descend to 40kft if things got too hot.

Some discussion on this topic: http://health.phys.iit.edu/extended_archive/0407/msg00074.ht...

Where in the heck did you dig that up? What a jewel of a site!

Re: Boom supersonic jet readies for rollout

#97

Post by credit_guy »

galacticaactual wrote: post #23

As a (pre-Covid) extreme frequent flyer, supersonic and other rapid point to point initiatives are thoroughly unenticing. Part of the reason I loved long flights was the ability to put away the laptop and zone out to a book or movie with some wine before landing, dealing with immigration, hotels, Ubers, and days of frenetic, high stress meetings afterward. The prospect of trying to optimize how fast we can jump from…

> zone out to a book or movie

I can do that when I'm home. But at home I can also stand up, go for a walk, or go to the restroom without having to wait in line, or go to sleep, etc. In a long flight I can do none of these. I can instead suffer from dry air, I have a hard time sleeping in something that is a bad approximation of a bed, etc, etc. Oh, and don't ask me if my kids enjoy 10-hour flights (of which they have experienced a few, unfortunately). Sometimes it's so stressful for them that their immune system is ravaged, so we spend time with doctors instead of enjoying vacation.

The shorter the flight, the better for me. If I can afford it. But before it's cheap it first has to exist.

Re: Boom supersonic jet readies for rollout

#98

Post by na85 »

abeppu wrote: post #33

Can anyone here comment on the kinds of things you can and can't learn accurately from a scaled prototype? I'd guess that for something that flies, changing the surface area/volume ratio makes a big difference.

In aerodynamics we have several "similarity" quantities such as the Reynolds Number which is a dimensionless coefficient that characterizes (in a nutshell) the ratio of inertial to viscous forces in a flow.

Much research has gone into the applicability of scale models to real world conditions and the validity of a model is contingent on maintaining similarity coefficients. So for example you want your model to be flying at the same Reynolds Number as your full size aircraft will. If you can achieve those conditions then you can expect good predictive results from your model.

In general you can learn a great deal about your aircraft from a model including handling and stability characteristics but you're limited by the tunnel and the test apparatus. Post stall behavior comes to mind as something I would imagine to be very difficult to investigate with a scale model in a tunnel.

Re: Boom supersonic jet readies for rollout

#100

Post by Robotbeat »

ClumsyPilot wrote: post #86
Moto7451 wrote: post #80

Earlier quoted context omitted.

> Seems to me that everything is nonlinear in the domain of aircraft, particularly when concerned with "efficiency". The same physics applies to fast trains and other modes of transit. Fast electric trains have the advantage of not having to lug their fuel along with them at speed. > consider that energy is a function of both power and time applied; if you double the speed to fly from say London to NY, would you cut…

Fast electric trains are also, well, electric already. Powering planes in a sustainable marrer is not a solved problem.

So I think that’s not really true. Even existing battery chemistry could do 1000km per stop (although it still needs certification for aircraft) and at comparable speed as HSR. That’s much longer than the California HSR project that was canceled, plus you just need a recharge (or swap) to continue on your way. With further efficiency improvements and battery chemistries in development right now like Li-S, we could potentially do 4000km flights (enough to reach Hawaii... and anywhere else using multiple hops, as Boom is planning). And shorter flights at higher than HSR speeds.

HSR has its own unsolved problems. Like not being able to work over deep ocean... and insane infrastructure costs.

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