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Comment by mauvehaus | Hacker News Reader

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?

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Aluminum aircraft go together more or less the same way. There will be some inspection panels but the interesting stuff is already exposed, there's very little reason to go inside the wings, particularly on a composite aircraft where corrosion isn't a problem. If you really need to see something, use a borescope.

What if a cable snaps or a pulley breaks?

You can see in the article that now no cables are in there during closing, they are in extra canals/tubes which can be accessed later on, be it for installing them in the first place or maintenance.

FWIW, the XB-1 is a "demonstrator". It's not necessarily intended to be a production design.

Removable inspection panels are standard.

They mention having a portable ultrasonic device for "seeing" inside the wing.

They probably use an electrified system with wiring and servos, levers and push rods. Prior to that we used hydraulics. These parts are probably accessible with removable panels.

If they had, they'd still have mechanical pivots and so forth that can wear, but the article specifically mentions pulleys and cables:

> The team also inspected flight control pulleys and cables, which are routed through the wings to the systems bay, as well as the aileron trays on the outboard portion of each wing. (Ailerons are the hinged part of each wing that control roll or maneuvers, and are controlled by the pilot via wire pulleys that run through the wings.)

I suppose that the cables have to run out of the wings and into the cockpit in order to be useful, and that you could put you adjustments for cable stretch, etc in a place you could get to them easily. Or add access panels, as you suggest.

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 ones will have to continue to be built for whenever there's damage (ground strike, etc).

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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