Interurbans of the skies! Makes sense, I like it.
Firelock76At any rate, the main attraction of air travel is its speed in getting from Point A to Point B. There's nothing very fast about these electric aircraft, although they are amazing.
I think you are completely missing the point about what the Israeli aircraft, or indeed any similar ‘green’ autonomous aircraft, is best at doing. Part of it is like a cross between the GM mid-Fifties arguments for ‘bustitution’ of interurban-style routes and the old rationale for flying cars, with a little dollop of “where we’re going we don’t need ... roads” thrown in for fun. It’s the ability to great-circle span a fairly wide number of regional facilities, which still often have ready access to other modes of transport, that is significant here.
And yes, these things might be slow even by Mooney standards, let alone small turbofans. (Zunum appears to be intending to use large ducted fans, and 340kt cruise [edit, it’s mph; misread it, but still] is not particularly slow.) If you compare even the slow ones with the ‘best‘ HrSR proposals, they no longer look slow, do they? and that’s before all the EIS, NIMBY, funding, and yes, absence of perceived benefit for ‘nonusers’ that the ‘same’ capacity that would have to be provided or built out as regional rail would demand...
I'd give all-electric powered commercial passenger carrying aircraft as much credence as those rumors or enthusiastic reports of a resurgence of lighter-than-air (AKA Zeppelin or blimp-type) aircraft, at least at this time.
Who knows what the future may bring, however?
At any rate, the main attraction of air travel is it's speed in getting from Point A to Point B. There's nothing very fast about these electric aircraft, although they are amazing.
In case you had not noticed, this is not about airliners, unless you consider small commuter aircraft ‘airliners’ because they have paying passengers in them — I do not.
Likewise no one is arguing fuel energy density, least of all me. (BTW I think you have misread specific energy for energy density in your Wikipedia table for Jet A, but ~33 still makes the point well enough). There is a more important criterion for ‘battery’ structures that come closer to liquid-hydrocarbon energy density: they release closer-to-hydrocarbon-combustion energy release levels; ask Samsung even this early in the battery-packaging game).
If I were actually building a commercial automous-regional aircraft it would have a combustion engine ... but it might just as likely have electric drive with short-term battery power (cf. Tesla in ludicrous mode if you need to know why) as be turbofan/shaft powered, and there is money to be had for ‘zero’ or low-emission designs that is absent for, say, the next Embraer or Moller. Call the combustion engine a ‘range extender’ if you prefer, as Zunum does.
Last I looked, single-engine general aviation and even ‘sport’ helicopters didn’t run battery-only. So, in part for the same reasoning you seem so eager to give, I think it makes sense to have at least emergency-recharge capacity on a nominal all-electric design. I had no real hesitation when flying sailplanes out of Blairstown to head down towards Virginia, but (1) it was better in a motorglider; (2) I was prepared for long hikes and expensive recovery at almost any time; (3) it would be ridiculous to take passengers without assurance I could reach safe landing on glide alone. The situation is little different (except for achievable glide ratio, which I suspect is in fact worse for the Israeli aircraft) for a pure electric design.
1) consider energy density of jet fuel, 42.8, vs lithium metal batteries, 1.8
2) Would you fly an Airliner without a Pilot?
OvermodI’d still want a combustion-engine backup in the airframe somewhere.
single engine powered planes and helicopters don't have backups.
greg - Philadelphia & Reading / Reading
I think the discussion is important enough to be on a ‘passenger railroading’ forum — although yes, far more relevant to ‘clientele’ on an aviation forum — because the technology Dave was describing, taken together with the FAA expanded system of regional airports, represents an alternative to much of the regional rail as well as, pro and con, a system feeding modes of LD transportation.
As a different and slightly ‘arch’ viewpoint: why have expensively-provided trains in states that don’t want to pay for them when you have an effective feeder system to trains people want to ride?
I suspect many people will be just as disinclined to ride these electric-airplane things long distances as they would the very similar Hyperloop cars. And if it becomes possible to get from home to an Amtrak stop in relative minutes instead of hours, perhaps even with civilized amounts of luggage (as opposed to what sank JFK Jr ) the difference between regional electric air and cattle-class security-ridden gas-turbine commercial aviation might prove ‘enough’ for a great many people to use the former while avoiding the whole airline-terminal mayhem that is, now, no longer a necessary or even preferred destination for autonomous small flights...
Of course, you’d have to improve no few things about the present Amdreck experience, dining-car and other food-service optimization being just one tiny but initial topic. But I think it may be fun to consider just what kinds of trains, regional or longer-distance, might be facilitated by quick and relatively delay-free access.
I have also been wondering if the technology has a future for re-crewing freight ... but that IS not a topic for a thread in this forum...
OBT: The technological developments of passenger airplanes and buses are of relevence to passenger railroading because they provide competition.
OK?
You might want to move this discussion to the Aviation Week or Flight Global websites.
JPS1I have a picture of some pilots sitting around an Army Air Corps field in 1917 ... they might want to know what is a movie?
Are you kidding? To give just one example: Charlie Chaplin's career was already compellingly established by that year. D.W.Griffith had already made 'Birth of a Nation' and 'Intolerance'. I believe Edison was using the term 'moving pictures' as early as 1896, and 'movie' is probably just a clipped formation from that, known to be a common term before (probably well before) 1913. "Flicker", like "flivver", is slang.
Now, were you to tell them that color, high definition, and sound would be required, except as an intentional trope, in those movies, you might get more of a reaction. You could probably have shown silent movies, even with gramophone accompaniment or even dialogue as was possible then, in the earliest DELAG Zeppelin flights.
What is to say that airplanes will not be powered differently?
The development of the 'electric airplane' follows almost directly from the improvements in 'drone' technologies combined with the higher energy density and radically falling unit cost per kwh of various lithium-ion technologies that are suitable for an 'aircraft' duty cycle. This includes the ability to use voltage-to-voltage conversion cheaply to keep motor torque high right to the end of battery discharge capacity, if that is needed. (The safety consideration of high-energy-censity batteries is not a 'showstopper' for me; just as in the early years of aviation, when gasoline proved a cantankerous and often dangerous fuel, electric storage with similar energy density will often prove dangerous when shorted or released.)
In my opinion, it makes little more sense to build a pure electric airplane than a pure electric car -- we might ask Norm or someone else with knowledge of practical FBO whether extending something like the Tesla 'supercharger' network to regional airport facilities would be practical -- especially when it continues to be relatively easy to produce very-long-loiter performance with some forms of combustion engine. The distinctive problem with aircraft is that you have no great assurance of 'coming to a safe stop' when your power is depleted, even with "BRS GHA", and there is little substitute for the ease with which a little extra liquid fuel can be transferred or topped off compared with the arrangements to suckle the Electricity Fairy. I would note that, as with the general provision of a steering wheel in automobiles, the use of 'alternative fuels' to relatively stable liquid fuels like gasoline or cetane has not produced a particularly pervasive alternative over the past century or so, and I include CNG, LPG, and carrier fuels in general in that.
Now, it's much easier in principle and practice to design 'safe' autonomous aircraft than autonomous roadgoing vehicles, so it's more interesting to speculate that we might get to at least some flying cars (at last!!), perhaps more quickly than full autonomous automobiles. It appears to me that the Israeli proposal recognizes some of this. Whether it will pass legal and political challenges, especially in North American markets, is another story entirely.
JPS1 54light15 No pilot? No conventional engine? Runs on batteries? What could possibly go wrong? Also, they might want to know what is a movie? No one knows what the future will bring. But it is likely to be much different from today.
54light15 No pilot? No conventional engine? Runs on batteries? What could possibly go wrong?
No pilot? No conventional engine? Runs on batteries? What could possibly go wrong?
Also, they might want to know what is a movie?
No one knows what the future will bring. But it is likely to be much different from today.
They might have known them as flickers.
Remember Dick Tracy comics ? Wrist radios with antenna wires up the sleeve ? Pure fantasy from old ancestor's beliefs. Now way past that concept with wrist I pods. Future even 10 years up is impossible to conceive.
Analog TV 7 years ago with all the snow will never get better. Now HD TV.
I have a picture of some pilots sitting around an Army Air Corps field in 1917. It subsequently became Love Field, which among other things is the home of Southwest Airlines.
Had someone told them that by 1990 or thereabouts people would be able to fly from LAX to Melbourne, Australia, in a little over 14 hours, at an altitude of more than 30,000 feet, and have dinner while watching a movie, they probably would have thought the person belonged in an asylum. Also, they might want to know what is a movie?
No one knows what the future will bring. But it is likely to be much different from today. Most land and sea vehicles probably will be powered differently. What is to say that airplanes will not be powered differently?
Rio Grande Valley, CFI,CFII
54light15What could possibly go wrong?
You mean "go wrong ... go wrong ... go worng ... "
blue streak 1What about that electric airplane that ran just on solar?
This one?
What about that electric airplane that ran just on solar ?
Yeah ok....you first. I'll take the train, thank you.
Yes, it’s serious and yes, it’s practical, although until safe energy density in these batteries gets higher I’d still want a combustion-engine backup in the airframe somewhere. There has been active discussion of electric and hybrid aircraft almost since the extended regional air feeder system was first proposed. Norm et al. will know more about present development or opportunities in the United States.
Am unsure about taking this seriously:
Steve Sattler <sattler31@gmail.com>
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