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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

#71

Post by Scramblejams »

trhway wrote: post #6

i'm in no way qualified to give any praise/criticism, it just caught my attention (from the linked post on their cockpit/fuselage bonding https://blog.boomsupersonic.com/20-hour-bonding-event-speeds... ) "It’s the following morning and bonding appears to be successful, but it’s essential to confirm that the bond lines are shaped correctly or “filleted.” A member of the engineering team, who is certified in the proces…

One issue with Ti: Tooling costs, particularly for manufacturing skins. Tooling for shaping metallic skins to the required dimensions is fantastically expensive, which can be prohibitive for prototypes. Carbon fiber can be shaped much more inexpensively.

BTW, "scaling for production" in aerospace doesn't mean a tremendous amount of units, most of the time. Lotsa carbon aircraft running around have been built in a manner not too differently from this one. So those labor costs tend to work out okay.

For a while I did repair design and analysis for engine nacelles made out of carbon fiber. These were new parts, right off the production line, with various flaws that commonly happen when you make an airplane out of cloth and glue. I was amazed by how much manual labor can go into declaring a particular part flight-ready, and the financials still penciled out, apparently. We must have been well into the six figures on one particular nacelle in post-fabrication engineering analysis work, just to show that the flaws had been repaired adequately for entry into service.

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

#72

Post by phire »

jamestimmins wrote: post #58
loeg wrote: post #40

Earlier quoted context omitted.

The company's goal is overland supersonic flight. Profitably, ideally. To make that even a legal possibility means demonstrating they can be somewhat quieter than prior supersonic aircraft. This aircraft is a proof-of-concept.

Is it specifically to demonstrate that they can make a quiet aircraft then? I think I'm curious specifically whether this is more about internal R&D and building systems, or if it's meant to demonstrate they have the capability to to create a performant supersonic aircraft, which they can take to potential investors.

This demonstrator is a 1/3 scale model of their final design.

It allows them to prove their exact final design will be quiet, along with verifing the rest of the aerodynamics.

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

#73

Post by Scramblejams »

starpilot wrote: post #21
trhway wrote: post #6

i'm in no way qualified to give any praise/criticism, it just caught my attention (from the linked post on their cockpit/fuselage bonding https://blog.boomsupersonic.com/20-hour-bonding-event-speeds... ) "It’s the following morning and bonding appears to be successful, but it’s essential to confirm that the bond lines are shaped correctly or “filleted.” A member of the engineering team, who is certified in the proces…

Carbon is much lighter than titanium for similar strength. Found a cool table for this, sort by "specific strength": https://en.wikipedia.org/wiki/Specific_strength#Examples Originally, the F-22 was going to be built mainly of carbon fiber, this was changed to titanium to reduce cost. This was in the 1980s... CF is MUCH cheaper today and almost commodity material used extensively in civilian aircraft.

And it would probably interest OP to know that it's not just basic strength-versus-mass where carbon shines. With metallics, you have that strength in every direction. But most parts only need to be strong in a limited number of directions. With carbon, you can tailor the part to provide strength only in the directions needed, which means you're using less material. More weight savings on top of what you already gained* by switching to carbon in the first place.

[*] It ain't all sunshine and roses. Sometimes it just doesn't work out. Substantial strength reductions due to heat and moisture absorption are real. Other factors exist that'll ruin your weight savings too. A former boss of mine designed a carbon nacelle inlet lip for a popular airliner, but it was a short haul aircraft, which means lots of trips, which means lots of abuse from careless ground handlers. After accounting for that, it weighed as much as his reference aluminum design. The nacelle went into production with aluminum inlet lips.

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

#74

Post by hindsightbias »

bacondude3 wrote: post #45
AWildC182 wrote: post #37

Earlier quoted context omitted.

Building a plane in my garage. You'd be surprised how minimal yet how strong a lot of these structures are. The vast majority of the material I use is thinner than a credit card.

I want to hear more about building a plane in one's garage. Are you using a kit? How hard is it? Cost? How will you transport it to an airport once it's finished? It sounds like it would be a great project. Thanks.

Kits have become progressively simpler to build. The example like the RV below would conservatively take over 1500 hours. A newer Vans RV-12, much less. A Rans S-21, possibly 600 hours. Looking at their wing build:

https://www.youtube.com/watch?v=iPJgm7qP3FY

dramatically simpler than an RV-8. My -8A flying cost was about $75K a decade ago, it would probably take at least $90K today. An S-21 would probably be more.

Some kits come with a folding wing option, so they can be trailered.

The primary decider in the difficulty/time factor is community and your Technical Counseler [1] (usually a multi-kit builder and FAA approved). If you’re able to build near a very active community (Livermore has a lot of RVs), these people will show up at your house/hangar and get/keep you going. Amazing people who can teach you a lot.

1. https://www.eaa.org/eaa/aircraft-building/volunteer-assistan...

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

#75

Post by earthtourist »

I like the idea of supersonic passenger jets existing again. I'm not sure I really see the point though.

Would you rather fly in business class comfort for 8 hours or with less comfort for 4 hours? Almost doesn't seem worth the expense and risk of going supersonic.

I would be so much more excited about an airplane that was large enough that economy class seating was as comfortable as business class seating is today. That would be much more revolutionary.

I would also get excited about an airplane that was vastly safer than the already-quite-safe airplanes we have.

An airplane with a fail-safe fuselage that can disconnect from the rest of the plane, parachute to the ground and land (or float) safely. This could potentially eliminate fire danger by jettisoning everything flammable (gas filled wings, engines, cockpit, and whatever else).

The fact that flying is uncomfortable and still-too-scary to millions of people are the biggest opportunities for innovation that I see.

Flying at 500+ MPH is already quite fast given the size of the planet.

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

#77

Post by cornellwright »

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?

I've seen many of Boeing's wing assembly lines and there are a lot of similarities here, except that this is clearly not set up for mass production. (Which makes sense for a demonstrator.)

Also from the startup ground robot prototypes I've seen (and made) this looks much neater and more planned out than what's normal.

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

#78

Post by mrcartmenez »

everyone wrote: post #69
yazaddaruvala wrote: post #9

The blog post is hyper focused on the wings and didn't make a lot of sense without context. This link[1] was extremely useful to better understand what Boom is doing and how far along they are. [1] https://boomsupersonic.com/xb-1/build

omg that website is freakin' terrible!

Like they tried to rip off the old Mac-Pro site but fluffed it slightly

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

#79

Post by xiphias2 »

everyone wrote: post #69
yazaddaruvala wrote: post #9

The blog post is hyper focused on the wings and didn't make a lot of sense without context. This link[1] was extremely useful to better understand what Boom is doing and how far along they are. [1] https://boomsupersonic.com/xb-1/build

omg that website is freakin' terrible!

Wikipedia is here to the rescue:

https://en.wikipedia.org/wiki/Boom_XB-1_Baby_Boom

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

#80

Post by tlb »

hadlock wrote: post #24
mauvehaus wrote: post #17

This is probably a dumb question, but if the wings are now closed forever, how does one do maintenance or inspection of the mechanical flight control systems composed of cables and pulleys? Is the expectation that the XB-1 is going to be used in flight for far less than the design life of those mechanical systems?

Yeah as I was reading this, all I could think about was how there was no serviceability or reproducibility, the focus was on just building it, probably within a weight budget. There doesn't seem to be any long term breakthroughs or industry advancement here as all applications are specific to this model. By sealing the wings forever you are sort of guaranteeing steady business for the fabricator's check book as new o…

Keep in mind this is a 1/3 scale demonstrator, not intended for mass production.

https://blog.boomsupersonic.com/what-is-a-demonstrator-aircr...

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