I haven't thought that air travel can be made significantly better but I think 5 years ago or so I flew the dream liner for the first time and it was so much quieter and so much better because of it.
Anyone knows how long a airplane has to fly to be written of?
Roughly 25 years. The other thing that you probably didn't notice directly but made you feel better is the better pressurization. Newer planes tend to keep higher pressures (since carbon fiber is ridiculously strong), which helps prevent some of the general discomfort of flying.
NB, for any budding bathynauts: carbon fibre is strong under tension, which is precisely the use-case for higher-than-ambient-pressure vessels such as air- and space-craft.
It's far less comparatively strong under compression, which seems to have been the principle failure mode of the now-permanently-submerged Titan.
The failure modes of explosive vs. implosive failure are also relevant. High-pressure implosions tend to collapse the entire hull, whilst so far as I understand, explosive failure, particularly at the relatively low pressure differentials of air and space flight, tend to be localised, and the fibre-reinforced nature of composite materials should reduce damage to the neighbourhood of the initial failure point in many cases. Implosive failure needn't actually penetrate the hull so much as crease it, a mode which CF handles poorly respective to the application.
I never got the chance to fly in a Dreamliner, but I have been told that its air is also more humid than standard jets (because of the carbon-fiber construction, I think, so metal oxidation isn’t an issue).
I assume you mean written off, and the answer is it's generally not about how long, it's about how many "cycles". Plane maintenance is usually required on a schedule based on how many flight hours or cycles, and it's usually the cycles they hit first. A cycle is a pressurization and de-pressurization of the cabin. This is what eventually kills a jetliner, the hull will fracture from the stress. The engines are designed to rebuilt/replaced periodically. The hull cannot be reasonably repaired once damaged.
Airliners are required to do different checks at different stages, and the big one costs millions of dollars and requires them to basically disassemble and rebuild the plane. They even may have to remove the paint to check the hull for issues. Industrialized nations generally will only do this a couple times before the cost is more than the jet is worth (I think this is generally around 20,000 cycles, depending on the plane) then they sell them to a third world airline who doesn't have as strict a regulatory scheme. Even then, they generally live on for quite awhile, our regulatory scheme is designed to get as close to zero risk as possible, not to be economical, and it's hard to argue with the results. This is one of many reasons why there are an order of magnitude more crashes in the developing world, though even still safety is high relative to almost anything other than first world commercial airlines.
"The recently imposed smoking ban on many commercial flights has had one distinctly unhealthy side effect -- it snuffed out the most popular method mechanics used to spot cracks in aircraft fuselages.
... mechanics could count on tell-tale build-up of nicotine around cracks as air escaped from the passenger cabin when the plane pressurized after lift-off."
> haven't thought that air travel can be made significantly better
I wonder if it could be made significantly worse. Leg room has been reduced overtime as far as I can tell. I’m 198cm, and it’s actually hell. I probably need to just pay more and go nearer the front, however this would only solve the legroom problem. The seats are too low and aren’t even close to supporting someone tall. I’m in NZ so everything is far away, and 18+ hour flights are actually awful.
I recently flew on an A320neo and then an A320ceo a few days later, both in similar cabin positions and the difference was incredible. On the neo I could easily talk to the cabin crew without raising my voice, the ceo felt like I was having to shout.
I’m flying on an A380 in a few days, that will be interesting experience after only flying long haul on 777s in the past few years
When it comes cases of travel feeling worse, I find it's always worth making sure you adjust the cost for inflation.
Sure, we'd expect certain engineering things to get cheaper over time, but you can also see why some luxury touches got phased--or rather priced--out. :p
I suspect that pressure hull and wing spars experience the greatest loading and fatigue, and may be differentially influenced by overall flight time and takeoff/landing cycles.
Most relevant part: “By applying a total of 950 square meters of AeroSHARK riblet film to the fuselage and engine nacelle surfaces of a Boeing 777, fuel savings of approximately 1.1 percent can be achieved.”
Seems hardly worth it ? 1.1%? What about the cost of application and maintenance ? I’m guessing it’s plastic too, which will pollute the environment somehow.
That provides more information (and visuals) on the technology itself.
I've spent a few minutes looking for imagery of the film itself, sufficient to show details. There's surprisingly little, and I suspect the manufacturer doesn't want visual details of the skin itself available.
There's a schematic in the link below, which also shows the contrast of the AEROShark film to actual shark skin. The film is more grooves than scales, for those curious.
>>AeroSHARK replicates this hydrodynamic property on aircraft. It is a "special film" made up of "tiny 50-micrometre riblets that reduce aerodynamic drag during flight."
While it's at this point obviously tested and proven to work, I wonder about the size of that texture in relation to the texture on actual shark-skin, and whether they are working at similar Reynolds numbers.
That headline sounds big, but "entire fleet" in this case is only 12 planes. And those 12 are about half of Swiss' wide-body fleet.
That makes it a tiny airline in comparison to others. For example Lufthansa group (which Swiss is a part of) has 98 wide-body aircraft. Competing Air France group has 165. The US is similar, Delta has 164. The Middle East is on another scale, Emirates has 249...
Still a nice innovation, but as a headline "Lufthansa group tests shark skin on 12 Boeing 777s" would be more realistic.
It might even compound. Ie if because of the sharkskin you have to take less fuel onboard, then the plane will be lighter and you will consume even less fuel.
On long distance flights a significant portion of total plane weight is fuel.
Add the opportunity cost of grounding the plane for about a month to apply the coat, plus the cost of the coating. It can easily outweigh the savings or push the ROI to over many years.
LOL 1 month and minimal costs, for years of reduced fuel costs, someone did the calc above and its ~35m in savings a year seems worth it to me given they list the ROI of the film at 2 years.
Yeah but planes fly a lot over the span of 25 years or so; granted, they need to be repainted every once in a while. It does add up, is all I'm saying.
Readit News
Anyone knows how long a airplane has to fly to be written of?
It's far less comparatively strong under compression, which seems to have been the principle failure mode of the now-permanently-submerged Titan.
The failure modes of explosive vs. implosive failure are also relevant. High-pressure implosions tend to collapse the entire hull, whilst so far as I understand, explosive failure, particularly at the relatively low pressure differentials of air and space flight, tend to be localised, and the fibre-reinforced nature of composite materials should reduce damage to the neighbourhood of the initial failure point in many cases. Implosive failure needn't actually penetrate the hull so much as crease it, a mode which CF handles poorly respective to the application.
Airliners are required to do different checks at different stages, and the big one costs millions of dollars and requires them to basically disassemble and rebuild the plane. They even may have to remove the paint to check the hull for issues. Industrialized nations generally will only do this a couple times before the cost is more than the jet is worth (I think this is generally around 20,000 cycles, depending on the plane) then they sell them to a third world airline who doesn't have as strict a regulatory scheme. Even then, they generally live on for quite awhile, our regulatory scheme is designed to get as close to zero risk as possible, not to be economical, and it's hard to argue with the results. This is one of many reasons why there are an order of magnitude more crashes in the developing world, though even still safety is high relative to almost anything other than first world commercial airlines.
... mechanics could count on tell-tale build-up of nicotine around cracks as air escaped from the passenger cabin when the plane pressurized after lift-off."
https://www.upi.com/Archives/1988/05/27/The-recently-imposed...
I wonder if it could be made significantly worse. Leg room has been reduced overtime as far as I can tell. I’m 198cm, and it’s actually hell. I probably need to just pay more and go nearer the front, however this would only solve the legroom problem. The seats are too low and aren’t even close to supporting someone tall. I’m in NZ so everything is far away, and 18+ hour flights are actually awful.
I’m flying on an A380 in a few days, that will be interesting experience after only flying long haul on 777s in the past few years
Sure, we'd expect certain engineering things to get cheaper over time, but you can also see why some luxury touches got phased--or rather priced--out. :p
I suspect that pressure hull and wing spars experience the greatest loading and fatigue, and may be differentially influenced by overall flight time and takeoff/landing cycles.
I've spent a few minutes looking for imagery of the film itself, sufficient to show details. There's surprisingly little, and I suspect the manufacturer doesn't want visual details of the skin itself available.
There's a schematic in the link below, which also shows the contrast of the AEROShark film to actual shark skin. The film is more grooves than scales, for those curious.
<https://swiss.newsmarket.com/english/press-releases/swiss-ad...>
While it's at this point obviously tested and proven to work, I wonder about the size of that texture in relation to the texture on actual shark-skin, and whether they are working at similar Reynolds numbers.
That makes it a tiny airline in comparison to others. For example Lufthansa group (which Swiss is a part of) has 98 wide-body aircraft. Competing Air France group has 165. The US is similar, Delta has 164. The Middle East is on another scale, Emirates has 249...
Still a nice innovation, but as a headline "Lufthansa group tests shark skin on 12 Boeing 777s" would be more realistic.
https://de.m.wikipedia.org/wiki/Lufthansa_Group
Each 777 can carry about 150 ton of fuel.
So they got about 15 fill ups free
No, It says a week in the article.
“Each aircraft takes about a week to have its AeroSHARK film applied, which requires high-precision workmanship from our personnel.”
I guess Swiss is Lufthansa's test before rolling it out to the rest of the group's brands.
https://www.youtube.com/watch?v=VUiGhyHC-1A