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XB-1's wings are officially closed out

blog.boomsupersonic.com

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Re: XB-1's wings are officially closed out

#91

Post by NickNameNick »

jandrese wrote: post #28
nickff wrote: post #18

Earlier quoted context omitted.

Ultrasound inspection is very common for multi-layer composite construction. There are large machines which transmit the ultrasound through a water jet, for use in mapping the characteristics of curved surfaces. This water jet ultrasound non-destructive testing (NDT) is used in aerospace for carbon laminates. That said, 'tapping' is an acoustic inspection technique, and can get good results. I am not sure why they se…

They're probably having the guy hit it with a mallet and listen for voids because they're a Mickey Mouse operation by aerospace standards. Plus this is a model so if something does go catastrophically wrong it at least won't kill anybody, probably.

It's a demonstrator, not a model - It has space for 2 test pilots.

Re: XB-1's wings are officially closed out

#93

Post by mrfusion »

mauvehaus wrote: post #88
0xff00ffee wrote: post #35

Man I'd be sweating like a pig if I was direct-applying epoxy to a prototype so close to done. I'm used to code where trial and error is de rigueur, I forget sometimes you only get one chance.

The biggest change in switching from software to woodworking is that when you cock things up in woodworking, you can't git reset your problems away. The closer I get to done, the more careful I get. Scrapping a part at the beginning sucks, but it's mostly a material cost at that point. As you close in on done, the time dominates the cost, and you get real careful when you have a lot of that in.

You switched? I’d love to hear more. How why?

Re: XB-1's wings are officially closed out

#94

Post by selectodude »

kleton wrote: post #76

Why are human test pilots still used in $current_year?

Pilots have a better chance of saving the plane if something goes wrong, software is less good at dealing with edge cases than an experienced test pilot and in order to figure out what the edge cases are in order to programmatically deal with them, you need a human to find out what they even are and figure out how to fix them.

Re: XB-1's wings are officially closed out

#95

Post by kevin_thibedeau »

barkingcat wrote: post #61
jupp0r wrote: post #43

From their web page: “Faster travel brings the world’s people, cultures, and experiences within reach. Life happens in person, and at Boom we see breaking the time barrier as a moral imperative. XB-1 is the first step in bringing supersonic travel back to the world.” -- Blake Scholl, Founder and CEO The life happens in person part currently sounds like a relic from the past. I hope Boom makes it through the travel re…

A possible new tagline: Spreading Covid beyond the speed of sound.

They are primed to capture the market of wealthy preppers in need of a way to bug out to their island sanctuaries.

Re: XB-1's wings are officially closed out

#96

Post by starpilot »

iandanforth wrote: post #56

The level of care and organization in this photo feels equivalent to what I would expect for a ground robot prototype out of a startup. Can any aerospace engineer comment on what they see? Does their setup inspire confidence?

It looks normal. Our shop (assembly line building full aircraft from material stock, 2 football fields long) was like that except most of the workers were filipino or hispanic, wearing street clothes. When they filmed a TV commercial there, they brought in actors wearing red jumpsuits to scurry around as technicians. Because like you, that is what the public expects.

Re: XB-1's wings are officially closed out

#97

Post by pdoege »

mauvehaus wrote: post #89
pdoege wrote: post #84

I'm surprised by the assembly tolerances. .05-.1" The F-35 is assembled to .003" The usage of control cables and pulleys is odd. I would have expected hydraulic/electric actuation in a Mach 2+ aircraft.

The F-35 is also low-observable. I'm a total lay-person on this one, but I'm betting that the tolerances for achieving flight (even at Mach 2.2) are a lot looser than the tolerances for being invisible.

Yeah, the F-35 is actually milled down during/after assembly for low observables. However, the Mig-21 can hit the same speeds as the XB-1 and it has panel gaps visible from several meters.

I did some reading and the XB-1 does use hydraulics. From VEP and other companies.

It looks like they will be using titanium leading edges to handle the heat loads.

They are using a J85-GE-15. I don't think that will allow them to reach M2.2. Closer to M1.7 or so? Depends on the inlets I think. (I was wrong on the engines. They are using 3x engines, not the 2x afterburning that I was expecting. So the speed looks reasonable)

Re: XB-1's wings are officially closed out

#98

Post by robotresearcher »

friendlybus wrote: post #62
babesh wrote: post #53

Earlier quoted context omitted.

They are targeting $5K for round trip tickets between NY and London. It is really just making it faster for the rich to travel for fun or work. Supposedly it is inherently 3X as expensive as subsonic planes from a cost per seat mile point of view. It is basically a cheaper replacement for the Concorde. Also it seems that their biggest difficulty is coming up with suitable engines. The engines that they need don't exi…

If supersonic travel were ever to be the norm it has to start at the high end first like Tesla did.

Concorde's first flight was 1969 and ran commercially until 2003. High end demoed.

Re: XB-1's wings are officially closed out

#99

Post by robotresearcher »

flyinglizard wrote: post #87
tinco wrote: post #66

Earlier quoted context omitted.

They are though. Tesla is a horrible example, electric cars have better fuel economy, so should have a lower TCO for daily users in the long run. Which has always explicitly been Tesla's goal in the long run. This plane, while awesome, is not a Tesla, it's never going to be as cheap as a commercial flight, and it's certainly not going to make the world a better place.

Fuel cost is far from being the dominating factor in TCO; that would be depreciation. I just ran Edmunds TCO calculator on an Audi A6: 5 year TCO of $70k, with depreciation over 5 years being $35k and fuel only contributing $9k. Electric cars are nowhere near an affordable means of transportation right now (that would be a Hyundai Accent), so GP point stands true.

How does the A6 compare with Model 3?

Re: XB-1's wings are officially closed out

#100

Post by unchocked »

nickik wrote: post #59
babesh wrote: post #53

Earlier quoted context omitted.

They are targeting $5K for round trip tickets between NY and London. It is really just making it faster for the rich to travel for fun or work. Supposedly it is inherently 3X as expensive as subsonic planes from a cost per seat mile point of view. It is basically a cheaper replacement for the Concorde. Also it seems that their biggest difficulty is coming up with suitable engines. The engines that they need don't exi…

I hate points like this. Pretty much all technology starts out for rich people. I mean if you don't have supersonic flight at all its technology will not improve either, neither will the economics of scale. Air travel itself is already only for the rich, and travel in general is mostly for the rich, if you want to look at it from the poorest in the world. Elon made this point the best with Tesla, and in 10-20 years t…

Well that's analogical reasoning at work. Physics would remind you that drag is proportional to velocity squared, so going say 3x faster would encounter 9x more resistance over 1/3rd the time for an energy requirement 3x more than the slow boat.

That's back of the envelope, but it's in the ballpark. Going faster costs more.

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