[HN Gopher] Swiss' Entire Boeing 777 Fleet Now Has Shark Skin Te...
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Swiss' Entire Boeing 777 Fleet Now Has Shark Skin Technology
Author : belter
Score : 76 points
Date : 2024-05-18 20:08 UTC (2 hours ago)
(HTM) web link (simpleflying.com)
(TXT) w3m dump (simpleflying.com)
| massenpunkt wrote:
| Some more technical information:
| https://cleantechhub.lufthansagroup.com/en/focus-areas/aircr...
| kryptoncalm wrote:
| 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."
| bamboozled wrote:
| 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.
| Raidion wrote:
| The plane can carry 45,000 gallons of fuel. 2.1 bucks a
| gallon. So probably 500 bucks of savings a flight since
| most flights arent full capacity. 130k flights in '23. So
| ez 65 million in savings a year.
|
| Worth doing for the environment even if it's cost neutral
| probably.
| r00fus wrote:
| There's a cost/benefit ratio chart in that link from GP
| comment.
|
| The ROI appears to be 2 years. Considering the application
| is relatively easy, this looks like a good deal for
| airlines.
| dredmorbius wrote:
| 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.
|
| <https://swiss.newsmarket.com/english/press-releases/swiss-
| ad...>
| jt2190 wrote:
| Swiss Magazine post "AeroSHARK: inspired by shark skin"
| https://www.swiss.com/magazine/en/inside-swiss/sustainabilit...
| pcurve wrote:
| 2200 ton saved for 12 planes is about 1.5milliom usd
|
| Each 777 can carry about 150 ton of fuel.
|
| So they got about 15 fill ups free
| carlosjobim wrote:
| That sounds like at least a percent or two in savings per year,
| which is not too shabby.
| nimish wrote:
| BASF quotes 1-1.5%, which is pretty damn good for a one-time,
| low-cost application.
|
| I guess Swiss is Lufthansa's test before rolling it out to
| the rest of the group's brands.
| philjohn wrote:
| Yep - the more detailed page on the Lufthansa site states a
| 777 sees a 1% reduction in aerodynamic drag (it's a bit less
| for a 747 at 0.8%)
| yatz wrote:
| 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.
| Cthulhu_ wrote:
| 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.
| Gravityloss wrote:
| 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.
| toss1 wrote:
| >>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.
| Delmololo wrote:
| 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?
| adgjlsfhk1 wrote:
| 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.
| simonjgreen wrote:
| The 787 and the A350 are both a delight to fly long haul
| s1artibartfast wrote:
| I still prefer A380 when I can get one. The extra space is
| amazing.
| gruez wrote:
| Isn't that determined by seat pitch, which in turn is
| arbitrarily configurable by the airline? What does the
| model have to do with it?
| skissane wrote:
| Given how huge the A380 is, it is more likely to fly less
| than completely full, which increases the odds that
| you'll have vacant seat(s) next to you in economy class.
| dredmorbius wrote:
| 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.
| ChrisMarshallNY wrote:
| 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).
| adgjlsfhk1 wrote:
| > because of the carbon-fiber construction
|
| yes
|
| > so metal oxidation isn't an issue
|
| no. It's not rust, but that higher pressure air can hold
| more water at the same relative humidity. The higher
| pressure air is achievable because carbon fiber has higher
| tensile strength per weight.
| WalterBright wrote:
| 62,000 flight hours
| dredmorbius wrote:
| Flight hours or flight _cycles_?
|
| 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.
| WalterBright wrote:
| Hours. I remember the incident with an Aloha Airlines 737
| where fatigue damage caused the failure of part of the
| structure. Those airplanes were only used for very short
| hops, hence a high ratio of cycles/hours. While they were
| within the 62,000 hour limit, the cycles were very high and
| were not anticipated in the fatigue calculations.
|
| The criteria might have changed since that incident.
|
| Maintenance schedules are based on hours. Pilot experience
| is also logged as hours.
| mattmaroon wrote:
| It's actually both, specifically because of that
| incident. (Pretty much any time a commercial jetliner
| crashes, a rule changes, and it's been that way for
| decades.) There's an hour number and a cycle number for
| many maintenances, and whichever comes first triggers the
| maintenance. Hulls, however are rated for a max number of
| cycles due to fatigue caused by the
| pressurization/depressurization and that's the part of
| the plane that cannot be replaced. So the plane usually
| gets junked or shipped to a developing world airline due
| to cycles.
| sitharus wrote:
| 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
| bamboozled wrote:
| Because of what ?
| t0mas88 wrote:
| Higher air pressure (lower cabin altitude) and higher
| humidity. Both make passengers feel better.
| mattmaroon wrote:
| 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.
| t0mas88 wrote:
| 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.
| philjohn wrote:
| Lufthansa are also rolling it out across their entire freight
| fleet.
| t0mas88 wrote:
| Which is also only 11 wide body aircraft :-)
| alchemist1e9 wrote:
| I guess Lufthansa is now a fairly small airline then? Years
| ago it was a big one. Of course I can remember flying Pan
| Am so doesn't mean much.
| ilrwbwrkhv wrote:
| I'm not flying on Boeing. I make sure I fly only on Airbus.
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