Seems they are skimping on 3-D printers from AliExpress. :-)

If you give professional chef an elaborate dish and the recipe for it, will they be able to make exactly the same thing?

Probably not, in isolation.

But can the original chef that wrote the recipe produce the same thing several million or billion times a year?

We can't even replicate the F1 engine, or make new nukes anymore, and we have the recipe book and the chefs.

We can’t make F1s because the supply chains that made the materials and the parts no longer exist. We could try to approximate one with new materials and techniques, but it would not be an F1 - it’d be a design derived from it.

That’s the thing with the chefs - you can’t make a mammoth dish because there are no more mammoth to cook.

Yes they do, the supply chains still exist, we still use many of those alloys, etc. We still make rocket engines. In the F1's case we were just going too fast and didn't write things down.

In the nuclear weapons case we deliberately dismantled it.

> In the nuclear weapons case we deliberately dismantled it.

I'd say that is actually a good thing. Nukes are meant not to be used. They are a deterrent, so it's important they exist, that they are functional, and that you are willing to use them to hit hard against an aggressor. MAD kept us alive until now.

Chinese fighter jet engines are supposedly already better than the best Russian jet engines they've been given, though. General perception is that the WS-10 is generally better than the AL-31FN, hence why they started replacing AL-31s with WS-10s, both in domestic and export aircraft. The WS-15, if it does get even close to it's design goals, would be significantly better than any Russian engine.

They seem to be struggling a lot with airliner engines, yes, but they've only recently even considered making them. Even then, the WS-20 has entered service, and if it matches claimed specifications, it's as good as anything Russia has either.

The recent leaked picture showing a J-20 with dual WS-15 puts their development on par with F-119/F-135. Lets see how quickly they can ramp up production. It seems they have fixed their supply chain issues.

It seems easier to make an engine that gives very high power at the expense of efficiency than an extremely efficient engine with reasonable power which is what airliners want.

In the Pacific, efficiency is the main goal for fighter jet engines. The goal of the WS-15 is to have F-35 level efficiency while being able to go relatively far in the supersonic regime and outrange every US plane.

And of course the engines for strategic lift planes are based around efficiency first.

I could believe the J-20 could match the F-35, and apparently the Air Force could believe it too because there’s also the F-22. And strategic lift planes use normal jet engines not supersonic ones so they face the same issue as Chinese airliners do.

The F-22's engine are not as good as the F-35 engine. It gets around that by simply being a larger plane and having a second engine.

Both modern fighter jets and airliners use turbofan engines, the difference is the bypass ratio (hence the size of the bypass blades). For both low and high bypass, Chinese engines are supposedly better than Russian engines. They aren't better than Western engines but they're not that far apart. As far as airliners, the airliner engine is a different design from the WS-20 because of different requirements. It started development far later than the WS-20 and it has been flight tested after only 5 years, which isn't bad at all.

They recently got the WS-20 and WS-15 which puts them very close to US engines.