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Comment by ifwinterco | Hacker News Reader

If you want to sell commercial jets to anyone who isn’t Chinese, 20Y old engines aren’t good enough because modern engines are slightly more fuel efficient.

The difference isn’t huge (I think it’s 10-20% or something), but when fuel is your main cost that’s enough to make older engines undesirable

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The GEnx which powers the 787 is a 20 year-old engine design. There are thousands of jets flying around with 40+ year-old engine designs, especially in operations like charter and cargo where the aircraft spends more time on the ground than in the air. At the right price a 20 year-old design would be quite viable. Which indicates China is much more than a decade behind.

I mean, the "right price" for a 15 year old 787 (with a fresh new set of life limited parts and maintenance checks) is around a third of the cost of a new one and they're now starting to be parted out for their components (newer 787s have updated GEnx engines with better fuel economy, which is a big part of their higher value). And Boeing reckoned they needed to sell 1100 units to break even on the programme, which is a lot aircraft to sell if your design is only competitive with 15 year old aircraft airlines are trying to get rid of. People are already starting to breaking up old 787s for scrap because there are more buyers for spares than old 787s...

China may or may not be much more than a decade behind in their engine technology, but there's no commercial case for designing a new aircraft with engine variants so outdated they wipe >$100m off the sticker price of the aircraft....

What from I understand the issue is mainly service frequency rather than fuel efficiency.

Also, the domestic commercial jet market is still sizable, so excluding the domestic market from analyses is kinda weird.

Finally, lots of countries are spooked by arbitrary US sanctions and want to diversify.

Yes I think eventually they will catch up because the Chinese domestic market is big enough to give them a market while they iterate.

With petrol/diesel engines they just gave up and went straight to electric, but there's no viable alternative to jet engines for planes, so they'll put in the work (plus the military incentive running in parallel)

> no viable alternative to jet engines for planes

No, but regional aviation can be well served by electrification - a jet engine needs to run at a speed it pushed enough air through itself to propel the plane forward, but a turbine feeding a generator that powers a couple electric motors can run at a far more forgiving regime.

As pointed out elsewhere, all it might take is a paradigm shift to unseat the current incumbents.

>With petrol/diesel engines they just gave up and went straight to electric

This isn't really true. Chinese ICE vehicles are also sold worldwide, and Geely has some genuine ICE engineering achievements:

https://www.autoblog.com/news/geely-just-built-one-of-the-mo...

> The difference isn’t huge (I think it’s 10-20% or something)

A 10-20% reduction in fuel burn is actually considered pretty huge...

Indeed, a 10%-20% difference is so much that airliners would sell their grandmother (if they had one) for a leap like that. A 2% improvement is considered significant and is a massive economic incentive, even more so these days for long-haul flights which are now in some cases 50% longer due to conflicts, and at times extreme price hikes for jet fuel.

(This applies a bit less to military engines though, where performance is a more important factor. Fuel efficiency is still important though)

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