Still increases air resistance. It gets hit by air, and that pushes it back into the fuselage.

Larger aircraft commonly have a ram air turbine (RAT) or Air Driven Generator (ADG) to provide some electrical power and hydraulics in certain emergency situations.

On CRJs, it’s right up the front: https://www.youtube.com/watch?v=MxgPrpjByTE

Still delivers a percent or two penalty to fuel burn, and the tiny little generator doesn’t even come remotely close to making up for that.

The issue with aviation hydrogen is… well, lots.

• Fuel cells are heavy and direct combustion is inefficient and tougher than burning kerosene.

• Aircraft typically use the wing structural members as the fuel tank walls. Both cryogenic and pressurised options make that a non-starter.

• Lower density means much bigger tanks.

• Self-vapourising fuel is a major crash issue.

• Round trip efficiency for H2 is still terrible.

Plants may not be particularly efficient per km^2 but arable land isn’t actually that hugely scarce.

Reducing aviation is really the only thing that’s actually going to work.

Biofuels/ethanol/SAF are much the same; often derived from corn.

In many cases, the oil/gas/electricity used for harvesting, processing, cracking etc. is actually comparable to or exceeds the carbon released by simply drilling for and burning the oil in the first place.

What I mean is that the bulk of current copper wiring goes towards distribution and consumption, not generation.

Yes, but big batteries everywhere is going to effect that if there’s copper in lithium batteries, and apparently there is.

This isn’t a big thing. This is a constant thing in every system. It’s the push and pull between efficiency and resiliency. More storage capacity is less efficient when things are going well, but is more resilient and adaptable when they’re not.

Excess storage capacity, sure.

But inflating the base battery capacity to cover people having showers at 5pm because it’s easier than storage water heaters and time/remote controls is stupid. You can reduce the base need for batteries by reducing the need for electricity in the first place and reducing the use of vehicles that need to carry batteries in place of e.g. overhead catenary.

You’re wrong in terms of long distance power lines being mostly copper, but this does seem a lot like fossil fuel propaganda.

Motors, generators, and transformers can be built using aluminium; they’re just a bit bulkier and less efficient. Very common practice.

It looks like CCA might be making its way back into house wiring in the near future, with much lower risks than the 70s aluminium scare.

The big thing is that batteries really should be a last resort, behind demand response (using power when it is available, rather than storing it for later), long distance transmission, and public transport instead of private vehicles.

That’s incorrect. Aluminium is about 30% worse by volume than copper, meaning you need to go up a size. What stopped it being used for houses was that the terminations weren’t good enough, because aluminium has different thermal expansion and corrosion properties, plus they were using much worse alloys. That’s now mostly fixed and if you’re in the US, there’s a very good chance that your service main is aluminium, and there’s talk of allowing copper-clad aluminium (CCA) for subcircuit wiring.

Per mass, aluminium is a better conductor, which is why it’s almost exclusively used overhead and in pretty significant volumes underground. The power grids were built on ACSR.

We have 5S.

The tool cabinets are in useful places but the keys for them are all back at the maintenance office.

They threw out the spare bolts because it was easier than organising them.

Sounds like they need to move to either ZIF connectors or 48V power; this kind of power over high pin counts isn’t really practical.

There’s a reason electrical codes don’t usually let you use parallel conductors below about 4AWG/60A per conductor.

Google has removed the video through an automated process without talking to the owner of the channel or verifying who owns the video in the first place.

Honestly sounds like Hanlon’s Razor on Google’s part. No collusion necessary, just can’t be bothered to maintain/staff an actual effective system.

Are you talking about China or the US there?

That’s not bad pricing wise. There’s very very little prosumer gear that’s multi gigabit and it’s all much higher price, or it’s just a PC with several NICs.

If and when we move to hyperfibre this is going to be pretty high up on the list.

I’m not sure that lossy compression on vectors is strictly impossible.

You can do things like store less colour information and simplify splines so that curves are less complex.

Lots of places also have variable limit signs that get updated based on traffic, accidents etc.

Here in NZ those seem to all be marked on the speed limit maps as 100km/h even if in some places the signs never go above 80.

Ngauranga Gorge is one such location and I believe has the country’s highest grossing speed camera.

Everything burns up regardless of size. Big things might not finish burning by the time they hit the ground.

You need either enough thrust to slow you to ~mach 2, or a heat shield to do the same by aerobraking.

It’s called aerobraking for a reason: you’re using friction to turn kinetic energy into heat to slow down, but that heat goes into the air and your heat shield instead of brake pads and rotors.

603 for maglevs, 574.8 for steel rail, set in France in 2007 by a hotted up, modified TGV.

China holds the record for a stock train at 487, set in 2010.

(all per Wikipedia)

It looks like the article might be implying that they will be the fastest trains operating in revenue service when they enter service, but that surely needs to be demonstrated with a production train in revenue service.

Depends on the size of the plane. For bigger jets, yes, but for smaller planes the width of runway you need to do a u-turn is about the same as the width you need to safely land of a gust pushes the plane a bit sideways.

Usually you do a 180 rather than reversing blind.

There’s a good chunk of the world where you don’t ever have to water lawn, except when initially seeding it.

Regular trains don’t run underground. Lots of opencast mines exist .

Basically all mines have an above ground terminal where whatever you mined is unloaded from your underground trains, lifts, haul trucks or whatever else onto storage piles, then loaded onto the actual long distance trains.

If the mine entry is up a mountain, then the trip down from that point will be a net energy producer regardless of anything else.

I wouldn’t be surprised if there are electrified railway lines doing the same. Regenerate large amounts of energy into the grid while descending loaded; consume a relatively small amount of energy to haul the empty train back uphill.