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Jet engines are conceptually simple and very low maintenance but still very expensive. Difficult materials and high precision. And use a massive amount of fuel.

• jillesvangurp 8y ago
  It's pretty clear what the economics are. Electrical engines are relatively uncomplicated, small, light, and extremely reliable. Also, they tend to last quite long. E.g. in many electrical cars, engine failures or battery replacements tend to be relatively rare and are typically not needed until after hundreds of thousands of miles on the road and usually not because they failed but simply because of degraded performance. With electrical planes you'd expect similar benefits. Maybe a regular quick inspection of the few moving parts for wear and tear, make sure battery performance is fine and that any sensor read outs don't hint at any problems with cooling, performance, etc. Of course you still need to inspect the rest of the plane as usual. However, the engine tends to be one of the more expensive parts normally. Jets are indeed reliable but they do need to be inspected regularly to ensure they stay that way. If e.g. there's some hairline cracks or corrosion, the engine might still work but be about to fail in some spectacular way. Inspections for that are expensive and a regular thing. Same with piston engines. Typically engines are certified for a fixed number of hours before they need their overhaul. I expect similar inspections and overhauls to be needed for electrical engines for the same reasons. But they should be much cheaper to do and the engines could likely be certified for much longer because there is less that can go wrong with them. So, less frequent inspections and overhauls, and cheaper inspections are a good thing. Also replacing parts / engines is likely to be a lot simpler if there are any problems. Other factors are that unused engines tend to need more attention when you take them back into use. E.g. oil can solidify, fuel lines can clog up, etc. Most planes need to be flow regularly in order to avoid extra maintenance cost. To make sure things are functioning, you also have elaborate warmup and runup procedures before take off. A jet or piston engine is not usable until a few minutes after startup when everything is nicely warmed up and properly lubricated. Then you need to typically still go through elaborate runup procedures. Electrical engines are a lot less needy. Also they don't need to warm up, you just flip a switch and they are ready to go. And that's aside from the fuel cost of course, which is a big deal as well.
  • Gravityloss 8y ago
    But if you look at the whole plane, the electric one will be about double the weight. What about the landing gear? Brakes? Control surfaces? All double size. The battery will likely be a somewhat complex system with active cooling and monitoring and will need maintenance. They are aiming for higher than car level energy to weight ratios. If they use a battery with air as a component, that's also again somewhat more complicated. There's probably a trade off point in flight hours per year, above which the electric plane is more affordable. Depends on finances, too since likely it's more expensive to acquire.
• asdfadsfgfdda 8y ago
  In the light turboprop market, jet engines are surprisingly primitive. The most common engine family (PT6A) was created in the 1970s. Today, the engines cost half a million dollars new because the production volumes are tiny and the liability costs are huge. I don't see a reason why electric airplanes will avoid either cost issue.