Timeline for Is there a limit to the possible altitude for electric jets?
Current License: CC BY-SA 3.0
11 events
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| Feb 11, 2018 at 23:54 | comment | added | Peter Kämpf | @enderland: McDonnel-Douglas demonstrated re-useable rockets a quarter of a century ago. However, the cosy duopoly for rockets in the US saw no need to advance to an orbital version. By hiring the best engineers from both, SpaceX had no problem to actually build the real thing. With Tesla, Musk happened to buy a company which was serious about doing EVs right, with lots of battery capacity (what their competition avoided). In both, Musk showed good engineering judgement. He does not with aircraft, however. | |
| Feb 11, 2018 at 20:21 | comment | added | enderland | It's worth recognizing that many of the things that SpaceX and Tesla are doing were also decreed to be impossible or very unlikely several decades ago. That's no guarantee he will succeed at this endeavor, but worth pointing out. | |
| Feb 11, 2018 at 19:24 | comment | added | Peter Kämpf | @user15864: In subsonic flight it is indeed as you say (apart from density-related effects like less damping, and temperature-related effects like more friction drag and more heat engine efficiency), but when you come close to the speed of sound a new kind of drag emerges which will spoil the picture. | |
| Feb 11, 2018 at 19:06 | comment | added | user15864 | I guess what I have trouble wrapping my head around is the following: let's say in a Cessna 150 I cruise at 100 knots IAS at sea level (ISA). Then the TAS would be also 100 knots. But when I climb, and IAS stays at 100 knots, the TAS would more and more increase because the air is less dense and so the plane can fly faster through the air until it meets the same resistance than at SL. So the plane still "thinks" it is flying 100 knots even though it is faster already. Why wouldnt it be the same for a supersonic aircraft like the Concorde? Is it different due to some kind of supersonic effects? | |
| Feb 11, 2018 at 19:04 | vote | accept | user15864 | ||
| Feb 11, 2018 at 18:00 | comment | added | Ville Niemi | Yeah, but all the articles were specific about VTOL. I don't think its possible unless the intended range is short. Which would make supersonic performance irrelevant. | |
| Feb 11, 2018 at 17:42 | comment | added | Peter Kämpf | @VilleNiemi: Electric VTOL is even more challenging - the only remotely realistic concept I know of is from Volocopter, and there are quite a few out there. | |
| Feb 11, 2018 at 13:05 | comment | added | Ville Niemi | I looked it up a bit and the available info seems very vague. The main idea seems to be that it is VTOL. I am guessing that even when supersonic it gets lift mainly by vectored thrust. And that it is more of a "potentially supersonic due to high engine power and low drag" than "actually has the range for supersonic to make sense". I guess "supersonic" is mostly because it sounds cool? It seems rather incidental to the main concept anyway. | |
| Feb 11, 2018 at 12:15 | history | edited | Peter Kämpf | CC BY-SA 3.0 |
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| Feb 11, 2018 at 11:41 | history | edited | Peter Kämpf | CC BY-SA 3.0 |
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| Feb 11, 2018 at 11:33 | history | answered | Peter Kämpf | CC BY-SA 3.0 |