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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

#21

Post by starpilot »

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.

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

#23

Post by ocdtrekkie »

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?

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

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

#24

Post by hadlock »

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

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

#25

Post by mauvehaus »

starpilot wrote: post #20
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?

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.

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

#26

Post by [deleted] »

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?

[deleted]

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

#28

Post by jandrese »

nickff wrote: post #18
Justin_K wrote: post #12

Earlier quoted context omitted.

Yea, not very scientific. Seems like ultrasonic tests would be good here. I think they do something similar to check welds on ships.

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.

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

#29

Post by inamberclad »

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?

Removable inspection panels are standard.
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