[SeanB]

Salt is an issue as you get salt spray even far inland, especially in winter from road deicing, so you really want to wash it off regularly.  Deicing has a detergent and a gelling agent in it, to both have it adhere as a film, and to stay in a thin film for long enough for the ionic salts in it to depress the melting point of the ice far enough so it melts. That stuff is corrosive, so you really want it to only stay on for a while before it melts the ice and falls off, and then is scrubbed off in flight. Most in flight deice is done using either electric heat or hot air bled off the engines, or via rubber boots that swell to break the ice off. Spraying the deice fluid at high pressure both ensures loose ice will be popped off, and also you want to get the fluid under the ice, and use pressure to move it off. A trickle will not do, you need to have enough pressure to cause the skin to vibrate, breaking the bond between ice and metal. That is why deicing has to be careful around probes and static ports, so as to not fill them with the corrosive liquid.

Aluminium will, for almost every alloy, have a thin layer of oxide on it, to be shiny the oxide just has to be thin, so the important part of it is to not grow the oxide, so you want to keep it clean, and a thin organic wax coat, or a thin polymer clear coat, will do this easily, though salt will cause issues by either dissolving the oxide, or growing it thicker.

[alancalverd]

Many thanks! Old wisdom among fliers:

After 100 hours, you know everything
After 1000 hours you realise you don't know everything
After 10,000 hours you know you will never know everything

[Petrochemicals]

No need to keep polishing, just have to do a weekly wash to keep salt accumulation from building up.

Aluminium, particularly the soft ductile stuff I would imagine pressure hulls are made from for reasons of stress fracture inhibition would generally need a fair ammount of maintenance to remain as low friction as possible. Perhaps a Teflon paint job would be best, or maybe dimples like a golf ball.

[paul cotter]

Not by any means an expert but I believe natural aluminium is not used in aircraft. I think It may be duralumin or similar alloy, considerably stronger than natural aluminium.

[Bored chemist]

"Pure" aluminium is used for foil, electrical cables and pretty much nothing else because it's too soft.
I think it's fair to say that the aircraft industry has put some thought into this.
Sometimes, they do their thinking a bit late...
https://en.wikipedia.org/wiki/BOAC_Flight_781#Initial_findings_and_reaction
And sometimes they forget to think about things that they should already know.
https://www.ft.com/content/ab798d0c-ed7f-4df7-9689-d7405e7ee365
someone did come up with this
https://en.wikipedia.org/wiki/Alclad
the best of both worlds.

[Petrochemicals]

Not by any means an expert but I believe natural aluminium is not used in aircraft. I think It may be duralumin or similar alloy, considerably stronger than natural aluminium.

I would imagine what ever they use in the pressure hull it has qualities in it to avoid stress fracture as seen in the boac comet crashes, I shouldn't think it is the same structural aluminium seen in other parts of the aircraft.

[evan_au]

I shouldn't think it is the same structural aluminium seen in other parts of the aircraft.

As I understand it, part of the solution was to make the windows more rounded in shape. Stress tends to build up at corners of a window.

Of course, it would be much safer and cheaper to have passenger aircraft with no windows at all - just give everyone a screen with selectable views from the pilot's seat, the tail, first class (left and right), straight down, etc. I once travelled in an A380 that had about 5 selectable views, as well as the more traditional satellite view...

[alancalverd]

The military also have the sense to face passengers backwards. Much safer when landing on a rough strip,and quicker to exit whether by parachute or jeep.

A Navy wife of my acquaintaince once managed to get a courtesy flight for herself and children to meet her husband on a foreign posting. They went in a mostly-empty RAF Hercules with a very friendly loadmaster. On returning to school one produced the obligatory "what we did on holiday" essay: "We flew backwards to America and played football on the plane". Was sent home with a note about "overactive imagination".

[paul cotter]

Interesting. I once saw a picture of a Vickers vc10 with the seats backwards. I was wondering is this normal ?. must have been a troop carrier.

[SeanB]

Normally done to pack in a lot more sardines, as now you can share leg space between the 2 rows, and thus leave room for more cargo as well. On the Hercules you also had the rather interesting toilet, which was just basically a tube to the outside, where the pressurisation removed liquid faster than you could produce it. However on those I flew on we only had seating sideways, edge of cabin and central row, allowing the space to be used for cargo. My seat of choice was right by the wing root, behind the thin red line on the wall (turbine blade comes through here, as shown by a few Antonov crashes recently), so you were at the most stable point on the plane, and could do odd things in turbulence, like have a bottle of cooldrink with the bottle going wild, but the level of liquid staying still relative to the bottle side. Yes i did have a few of the clear plastic baggies with, just for the queasy souls near me, though the guys on the cargo at the rear were literally flying in the back.

[alancalverd]

On the Hercules you also had the rather interesting toilet, which was just basically a tube to the outside, where the pressurisation removed liquid faster than you could produce it.

Also a feature of some gliders (10,000 ft with no engine heating). Known as the "Irish/English/Polish/French/German microphone" before the days of political correctness. Venturi tube instead of cabin pressure - yet another example of Bernouilli in action.

[Peter11]

Well they use to use conductive coating a black paint on the  aircraft to spread the lightning charge across a large area with composites they use a metal mesh embeded in the composite that does the same thing.With out a conductive coat a lightning strike would put a hole in the aircraft.They also use to use a techneque called flame spray which put a thin metal coat that also spread the lightning charge. Most are composites today so wire mesh is the current tech to offset damage.I inspected many of them for a major manufacturer I should know.

[teto10]

it can't always be easy to do so, especially large, less nimble aircraft. I don't know.