First Boeing 787, in the flesh

[Ma Deuce]

Of course, this all pales in comparison to the one comfort improvement everyone would like to have but will likely never see -> more leg room!

Unless you're willing and able to pay for business or first class. If I were going on a 12+ hour flight, I might consider that worth it (provided I can get seats on a flight within the timeframe I want), but otherwise? Nah.

[Howedar]

The low humidity of the typical pressurized passenger plane dries out the mucus membranes of the mouth and throat, making you more vulnerable to infection. The necessity of recirculating the cabin air means whatever germs people bring aboard not only stay aboard, but they are shared amongst everyone riding along. (In recent years HEPA filters and other devices have been added to on-board systems where possible, which helps somewhat).

This is an oft-cited issue, but it's also almost entirely fictitious. A 737's ECS system runs at a speed great enough to completely change the air in a four-bedroom house in, if I recall correctly, about four minutes. Airplane ECS systems move a lot of air. And they have to - if they didn't, the people inside would cook. Get hundreds of people in a little tube and you end up with a pretty powerful heater. The best source of cool air is, of course, outside.

[Broomstick]

Yeah, but a 4-bedroom house doesn't have 100-200 people sitting in it, now does it?

Yeah, the ECS moves a lot of air - because if it didn't, the people inside would pass out and die from lack of oxygen. At cruise the air outside is too thin to sustain life. But it isn't just a matter of moving air, it's also what's in the ductwork, the fact that the air is at minimal humidity, and so on. No, the air isn't a toxic soup but it isn't the freshest stuff, either. There is considerable room for improvement and I, for one, welcome anything to improve the interior environment in passenger aircraft. Better filters and increased humidity are both positives.

[Howedar]

Broomstick, speaking as someone who literally has worked in the airliner ECS industry... the amount of air recirculation is negligible compared to any other enclosed space with multiple people in it.

[Broomstick]

OK, did you read the part where I pointed out that it's not just the air exchange rate? What sort of shit gets caught in/is growing in the ductwork?

And, unless you have gale-force interior air circulation in the cabin, you still have a shitload of people crammed together, breathing and sneezing and coughing on each other.

Maybe you do know more about this than I do, but there sure is a perception that breathing airplane cabin air can pose at least a slightly elevated risk

[Lisa]

I'm curious why it has to be painted, I had two bicycles made from carbon fiber and neither of them required paint over the epoxy, you could see right through to the weave...

[aerius]

I'm curious why it has to be painted, I had two bicycles made from carbon fiber and neither of them required paint over the epoxy, you could see right through to the weave...

Chances are it is painted, almost every carbon frame I know of is covered with some kind of clearcoat to protect against UV rays. There are some time-trial or other superlight frames which don't have the clearcoat, but those aren't exactly made for everyday use.

[Ma Deuce]

I'm curious why it has to be painted, I had two bicycles made from carbon fiber and neither of them required paint over the epoxy, you could see right through to the weave...

Sure they didn't have a UV-inhibiting clearcoat? Additionally, I would doubt that the epoxy used on the 787 is the same chemical formula as the one used on your bike.

Besides, aircraft epoxy bonds would be subjected to FAR greater stress than those on a bicycle, so it would be more important they retain 100% of their strength, where an epoxy bond on a bike might be able to lose a fair fraction of it's peak strength with no consequence. Then you factor in that a commercial aircraft is exposed to sunlight almost it's entire life, usually at altitudes where UV exposure would be more intense than at ground level, over an expected service life of 30 years.

[aerius]

Besides, aircraft epoxy bonds would be subjected to FAR greater stress than those on a bicycle, so it would be more important they retain 100% of their strength, where an epoxy bond on a bike might be able to lose a fair fraction of it's peak strength with no consequence. Then you factor in that a commercial aircraft is exposed to sunlight almost it's entire life, usually at altitudes where UV exposure would be more intense than at ground level, over an expected service life of 30 years.

Heh, you haven't seen me mountain bike, a carbon frame would last 2-3 years at most under my hell abuse.

But yes, you pretty much nailed it with the life expectancy. A bicycle frame's only designed to last for 3-7 years, and if it fails it's only going to kill one person at most. Nobody expects a bike to last for more than 10 years unless it's a really high-end steel or titanium bike, and unless you've custom ordered a steel or Ti frame, you'll most likely be on your 2nd or 3rd bike by the time that 10 year mark comes around. Aluminum & carbon fibre bikes are frankly disposable commodities with a limited lifespan. It's not a coincidence that people who buy a bike that they're going to keep for 10-20 years always buy one with a steel or titanium frame.

[phongn]

The joys of carbon fibre - I want a CF tripod but they cost so much

[phred]

Carbon fiber is great stuff... as long as you're the consumer. The materials themselves are expensive, and it can be irritating as hell to work with.

nice plane though. is it just me, or are the engines really that huge?

[Vympel]

Meh. This aircraft lacks weaponry. It is therefore uninteresting to me.

[aerius]

The joys of carbon fibre - I want a CF tripod but they cost so much

Chances are it'll only get more expensive as Boeing and Airbus buy up all the carbon fibre on the market to build their planes.

[phongn]

The joys of carbon fibre - I want a CF tripod but they cost so much

Chances are it'll only get more expensive as Boeing and Airbus buy up all the carbon fibre on the market to build their planes.

There's a bunch of Chinese players moving into the market that have been pushing down prices but not quite to the extent I was hoping and some of them have ... questionable quality control.

[Lisa]

Quite possible the clear coat was uv inhibbiting, being that it was a CF bike in the early 90s i paid a pretty penny for it then kept it indoors other then when I was riding it, it got stolen though, but I kept the replacement in the house instead of the garage and sold it after 5 years for more then I paid for the original bike.... I have seen people break steel frames, my coworker snapped the seat tube by the bottom bracket on his bike (forget the brand, think it was a kona) while he was doing some "mild" mountain biking.

[Beowulf]

Just because it's steel doesn't mean it's quality. Low end bikes are probably steel too, simply because it's cheap. Doesn't mean the welding is worth a shit.

[Howedar]

OK, did you read the part where I pointed out that it's not just the air exchange rate? What sort of shit gets caught in/is growing in the ductwork?

And, unless you have gale-force interior air circulation in the cabin, you still have a shitload of people crammed together, breathing and sneezing and coughing on each other.

Maybe you do know more about this than I do, but there sure is a perception that breathing airplane cabin air can pose at least a slightly elevated risk

As I already said, that is not a correct perception. Full stop.

[Ma Deuce]

One other thing occurs to me: How would you repair structural damage to a 787, especially given it's one-piece fuselage sections? Would there be a way to "patch" the fuselage, or would the entire damaged section have to be replaced? I know Airbus is touting the A350XWB's composite panel-on-frame design as easier to repair, though regular airframe maintenance would almost certainly be higher.

[Broomstick]

OK, did you read the part where I pointed out that it's not just the air exchange rate? What sort of shit gets caught in/is growing in the ductwork?

And, unless you have gale-force interior air circulation in the cabin, you still have a shitload of people crammed together, breathing and sneezing and coughing on each other.

Maybe you do know more about this than I do, but there sure is a perception that breathing airplane cabin air can pose at least a slightly elevated risk

As I already said, that is not a correct perception. Full stop.

Can you offer something more substantial than "I said so"?

[Howedar]

I'm not sure what you want. I'm not going to write a book of theory. Actual air cycle machine performance characteristics are proprietary information, and at any rate I don't work at that company anymore so I couldn't get that information if I wanted to.

It was the subject of a half-hour lecture by the chief of engineering in the pneumatic controls department of the aerospace division of Honeywell, which does in fact build these systems for probably half of commercial aviation.

[MKSheppard]

Meh. This aircraft lacks weaponry. It is therefore uninteresting to me.

You'd be interested if it was Russian.

[MKSheppard]

It was the subject of a half-hour lecture by the chief of engineering in the pneumatic controls department of the aerospace division of Honeywell, which does in fact build these systems for probably half of commercial aviation.

That is teh awesome. Anything else that you remember from that lecture?