[Gravityloss]

Are jet engines really that fussy with the fuel? Traditional gasoline Otto engines need high octane fuel because the fuel is injected before compression, so the gasoline should not spontaneously combust even at high compression rates.

Diesels are less strict since the fuel is only injected when it needs to immediately combust. But there are still knocking issues from combustion dynamics. Rudolf Diesel's first engine ran on peanut oil. Ships run on very heavy sulphur rich fuel oil. The range is wide.

But jets? It's a flow process, not back and forth. Historically they were very attractive partly because they were not at all fussy about the fuel they use... If gasoline was cheap, from first principles one could assume that jets would run just fine with it, with only few modifications.

[BoxOfRain]

Wasn't there a turbine-powered car at one point that would run on just about anything and was very reliable but got canned because of the high production cost?

[alephnil]

There was the Rover Jet-1 from 1946. It is exibited (or at least was) at London science museum.

https://collection.sciencemuseumgroup.org.uk/objects/co25218...

"When JET 1 was launched, the gas turbine ‘jet’ engine was seen as a symbol of modernity and of British technical prowess. Many viewed it as the power source of the future, but test driving showed that its poor fuel consumption and slowness to respond to the throttle made it unsuitable for road transport."

Gas turbines are efficient when they are allowed to run at optimal speed, which is close to the maximal power. Cars starts and stop all the time which is not optimal. In addition, acceleration is poor, which most car owners would find unacceptable. For uses where they can run for a long time on optimal speed, like in power plants, they are a good fit, otherwise not so much.

[Gravityloss]

Yes. In the past turbines were very inefficient. Much higher compression ratio and thus efficiency nowadays. But piston engines have also improved. One problem with jets is that they don't scale down so well because of clearance issues.

Also they might need a secondary system to take energy from the hot exhaust gases. GE has proposed supercritical CO2 cycles for that. Could get total efficiency close to diesel, maintenance windows might be more frequent though.

This thread tells how you can run some jet engines on gasoline, though some pumps need to take that into account since it doesn't lubricate as well as kerosene. https://www.airliners.net/forum/viewtopic.php?t=751755