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How many countries make their own jet engines? US, UK, France ... anyone else?

Russia, China, India, both South and North Korea, Iran, Turkey, Israel, and Czech Republic all manufacture jet engines domestically.

The German part of Rolls Royce - that's where the new B-52 engines are coming from for example.

Russia and China

I was intrigued by an above comment about miniature jet engines - Iran last year announced a jet-powered Shahed drone variant, which uses an engine that has an interesting backstory:

There are many variants of [the French Microturbo TRI 60] engine and it is used in many missiles and UAVs, as listed below. Aside from the known uses listed below, it is widely speculated that Iran illegally purchased many TRI 60 engines from Microturbo to assemble C-802 cruise missiles purchased from China. It is unclear which variant was purchased. Iran also reverse-engineered this engine as the Toloue-4 turbojet engine. Toloue-4 is used in several Iranian military equipment including Iran's copy of C-802, the Noor missile.

It's fascinating how many engineering artifacts turn out to have been invented just once. This is the same engine used in Storm Shadow / SCALP EG, so both sides in the Ukraine war are firing variants of a 1970s miniature French jet engine at each other.

https://en.wikipedia.org/wiki/TEM_Toloue-4

https://en.wikipedia.org/wiki/Microturbo_TRI_60



> I never thought this would be possible in my lifetime.

I used to work in Computer Vision and Image Processing. These days I utter this sentence on an almost daily basis. :-D


> Why not, for example, a wavelet transform.

That is a great idea for a paper. Work on it, write it up and please be sure to put my name down as a co-author ;-)


Or for that matter, a transform that's learned from the data :) A neural net for the transform itself!

That would be super cool if it works! I’ve also wondered the same thing about activation functions. Why not let the algorithm learn the activation function?

This idea exists (the broad field is called neural architecture search), although you have to parameterize it somehow to allow gradient descent to happen.

Here are examples:

https://arxiv.org/abs/2009.04759

https://arxiv.org/abs/1906.09529


Mostly because of computational efficiency irrc, the non linearity doesn’t seem to have much impact, so picking one that’s fast is a more efficient use of limited computational resources.

I wonder how much of the HN readership was not even born then....?

Probably a decent number. I first heard of HN around 2010 when I was in university.

I assume that plenty of university students find their way to HN still. And that many of them will have been born around the mid-2000’s.

I only barely make the cut myself to having been born a few years before 1993.


One of the nice things about HN is the wide age range of the participants. I have read interesting and thoughtful comments from people who said they were high school students all the way through to people a decade or more older than me (I'm sixty-seven).

Can confirm. Recent graduate who found HN during my second year at university.

That's good! Do your friends know about / use HN?

(Sorry for conscripting you as a guinea pig but it's hard to get this kind of info!)


Person born in 2000 here. My friends and colleagues at university generally don't know about HN.

Have told a few people about it but the only person I really converted into also becoming a regular reader is my dad. It's good because now whenever we see each other we have a lot of topics and stuff to discuss that we both read about here.


HN is officially a dad site now.

OTOH, I first read the article when it ran in 1993.

Have you seen the egg prices lately...? ;-)

I am curious how much they are in your country? In Poland one egg costs about $0.30

About $0.60 currently in the USA, which is quadruple what they were at this time last year. Supposedly this is mostly because many egg suppliers had to cull their flocks due to the current H5N1 bird flu. But there is also concern that egg prices have been rising in general in the long term due to industry consolidation and monopolization.

https://www.nytimes.com/2025/02/25/business/egg-prices-bird-...


> About $0.60 currently in the USA,

... IF you can find them in a store. Our local Trader Joe's (a grocery store) in SF has been out of eggs for a while.


No shortage in Seattle. About $8/dozen which is about double normal.

About USD 1.50 per dozen here in South Africa.

I would not consider Trader Joe's to be a grocery store.

One dozen is about CAD 3.00 just north of the US border. So I guess about $0.20 USD each.

anyway, the new political administration is bound to solve the problem with costly eggs any minute now, and the soaring egg prices were without a doubt caused by the previous administration :-)

USD$0.30 to $0.40 per egg in Fiji.

Why so expensive in Fiji? I mean it's not that expensive, but more than I'd expect from Fiji, where I can imagine chickens and pigs are running around everywhere between the straw huts and palm trees.

Our producers don't have the economies of scale that yours do. Also, our chickens refuse to stay in their cages and lay eggs, preferring to spend all their time lying around on hammocks under coconut trees sipping pina coladas.

In 2008, the California High-Speed Rail Authority estimated the initiative would cost $33 billion and begin service by 2020, and voters approved $9 billion of bonds for the project. . . Meanwhile, the current cost estimate ranges from $89 billion to $128 billion, according to the authority.

and have they built anything yet?

Yes- for political reasons, they chose to build a small segment in the middle of the central valley. It will connect Merced to Bakersfield. They started building it, but didn't finish (it's on hold due to budget constraints). I think they've built a few bridges, prepped the ground, but not really started laying track yet.

Maybe they should also buy a hyperloop :D

For political reasons, but that's the least expensive and least technically risky portion. The portion back into LA and the portion back into SF are going to make the prices they're paying for this easy section pale in comparison.

They're hoping the sunk cost fallacy will get them the money they will need on the hard parts.


It will take another 150 years to finish.

@dang has a neuralink implant directly feeding HN to his brain...

If you're having to take a loan to pay for basic stuff for your family, that means you're either spending too much or earning too little.

The government's debt is not the same type of thing as household debt. Can you elaborate on how you think they are the same? Do you believe there are not other factors besides just credits being less than debits?

So people shouldn't take out a mortgage on a house? Shelter is pretty basic.

"basic stuff" != "mortgage".

I mean things like food, clothing and utilities.


To quote Goodhart's Law: When a measure becomes a target, it ceases to be a good measure.

Or, as in the case of LLMs and benchmarks: When a benchmark becomes a target, it ceases to be a good benchmark.


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