I can help (multiple spine issues).

I was big, now im just a little big, but can do the same weight for the longest. Now that it's been a few years of compression I am noticing fatigue doing 'common' things like holding arms and shoulders up too long - yet can still do the heavy weight. So - it's complicated! My first spine doc visit schedule this week. But more or less the size goes real fast, and the strength far slower.

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>Think of where batteries have gone in the last 20 years. Where will they be in 30 years from now?

Is this actually a reliable trend though? We're talking about charge density (energy per unit mass) specifically. Lithium battery tech was invented in the 70's and developed significant charge density refinements up through the 90's. (This is based on a bit of research and my historical recollection; I was unable to find a reliable chart of lithium battery tech charge density over time.) And although there have certainly been further improvements over the last 20 years, my understanding is that they have been incremental improvements and with diminishing returns. Although we may still be able to squeeze out a few small improvements, lithium battery storage tech has already been developed to store close to its maximum theoretical charge density.

Additionally, lithium battery tech is close to the best theoretical electrochemical scenario, so there isn't some new chemical battery tech "waiting in the wings".

At this point, further significant advances in battery charge density will likely require a fundamental breakthrough; and these are uncommon and unpredictable.

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This content makes my current state of endurance even more disgraceful

"Hear" needs to be defined. It's not just the physical mechanism.

Provided your hearing is perfect, you are still bottlenecked in the brain. The reason being is your brain sorts out what you're focused on and excludes everything else to the best of it's ability. This is what allows you to concentrate on something in a noisy office, etc. But there is a limit.

The limit is in your conciousness. You only have no much of it and it doesn't divide very well. Each sound would require it's own attention and humans just aren't wired that way. In theory, you could train yourself to some degree but it's still an uphill battle.

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>Will leaded avgas for small piston planes still be the only common option?

Leaded avgas will certainly be banned by that point, if not sooner. Older engines designed for leaded gas depend on the lead and other additives (like zinc in the oil) for wear protection but those can be managed by adding a bottle of additives to the gas for planes that still need leaded gas.

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It helps with aliasing and time stretching, but idk much more than that. I personally don't go over 48k because the benefits aren't worth the disk space.

I would say the comparison with resolution for audio is how high in pitch we can hear, how low, to what degree of precision we can tell how loud something is, like if you raise the volume of a sound in increments what's the smallest increment you could perceive. For audio this basically comes down to bitrate and samplerate, and we maxed those out a long time ago.

In so far as number of sounds, it's just after a while it becomes a mess.

Like, imagine waves in a pool. If you have one wave, you can see it easily. You could mix a number of waves and still be able to tell which is which. But after a while, the water would just be a mess of noise.

When you listen to a record, every element sounds distinct, and clear, because the engineers mixing the music made sure if did that. Even just a few elements can really start clouding over things and making them intelligible.

Just like if you have one person talking that's easy, 2 people taking you could go back and forth and you know they are distinct voices. After a certain number of voices, it becomes noise. If you have enough noise, you won't notice an extra voice being added.

Right, but this still misses the point. There's a risk of dying in a car crash when you drive and there's a risk of dying in a bicycle accident if you decide to ride your bike instead, but you're only ever taking on one of those risks at any given time. One risk completly REPLACES the other, depending on the decision you make.

Covid however, is an ADDED risk in addition to every other decision you make daily. Sorry if I wasn't being clear.

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Think of the dangers that tons of fuel pose in aircraft!

We figured that out, we'll figure out battery safety too

Something to remember is that general aviation planes don't typically use modern complicated engine designs. Complicated engine designs are one more way for something to go wrong and planes often fly in very different conditions than cars. Moreover, 40 year old planes are flying 40 year old engines, or at least the designs are that old if the engine has been replaced. It's not legal to just swap a new engine type into an old plane.

GA planes also have tight weight tolerances. They just aren't designed to carry a lot of extra weight and so an engine with lots of extra stuff could easily use up a lot of useful capacity, especially on a four seat plane which is really "two seats and luggage" or "four seats and no luggage".

One of the common questions people have is why planes don't use automobile engines since they are commonly mass produced. The issue becomes that you need a transmission and the extra weight of the transmission makes it difficult to convince anyone to even try getting it certified. I only know of one attempt at it.

Using the Cessna 172 as an example since it's so common, the Continental O-300 engine used for many years is a 6 cyl 300 CI 145 HP engine producing about 230 ft-lbs of torque at 2200 RPM. Note: plane engines can't rotate fast because the tips of the propeller would break the sound barrier and the shockwaves would cause issues (and by issues I mean death and destruction). How many 5 liter/300 CI 6 cyl engines do you know of in cars and how many produce much more torque than HP?

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Thanks for the detailed answer. I appreciate the real-world example which clears up some misconceptions.

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Back to living under the flight path, as I do very near a small regional airport with maybe 20 flights a day. The jets do leave a greasy soot on my trees, and we don't get a lot of rain (except this year) so it builds up over time. Fortunately I live on the landing side, so quieter and presumably cleaner.

I don't have much hope the soot will go away. The jets over my house are A320's and 737's, plus a few puddle-jumpers. I can't see them being electrified, and future bio-fuel is probably just as sooty.

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