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Airbus E-Fan Electric Aircraft Makes First Flight
An anonymous reader writes "The aviation industry has taken a tentative step toward electric power with the successful maiden flight of the Airbus E-Fan. The manufacturer known for the massive A380 jetliner began testing this small experimental aircraft last week, with the ultimate aim of lowering the huge carbon dioxide emissions from commercial flights. The E-FAN is powered by 120 lithium-polymer batteries, and can fly at speeds up to 136mph. Measuring just 19 feet from nose to tail, the compact aircraft show that Airbus probably isn't ready for commercial zero emissions flight just yet, but it does highlight the potential benefits."
Jet fuel has at least 50 times the energy density of lithium batteries, so even accounting for the low efficiency of jet engines, that hour looks about right.
The aft main wheel includes an electric motor with 6kW power, which provides taxiing and acceleration up to 60km/h during the take-off
This may give the "plane on a treadmill" problem a bit more traction.
Knowledge Brings Fear
YES zero-emissions! The vehicle emits no carbon dioxide.
Which is why battery-powered planes are stupid. But not necessarily electric propulsion. If you can actually fly an electric engine, you can get experience and improve on it, so that if and when you come up with a better way of providing electrical power (electrochemical fuel cells, fission reactor, Mr. Fusion, very long tether, microwave death ray), you will be able to mate it to a mature technology. I say kudos!
Jet fuel has at least 50 times the energy density of lithium batteries
But it is also converted to thrust at only about 30% efficiency, while the lithium batteries are over 90%. So that gives a ratio of about 15:1, not 50:1. Of course, that is still pretty bad.
If it was so practical, why did they wholly cut funding. Seems like they had a long way to go to make the nuclear design feasible to where the crew was safe.
And how many civilians would fly with a nuclear reactor?
Replacing the nuclear reactor with batteries means A LOT of batteries. So I'm not sure how you can claim the whole idea is feasible just from a working nuclear design.
According to a Discovery Channel documentary:
1) There were two kinds of engine: Indirect Air Cycle that never got off the drawing board and Direct Air Cycle, that was actually built and tested but it emitted radioactive pollution and even back in the 50s and 60s people started to have second thoughts about a hundred or more things like this making regular operational flights spewing radioactive material over the countryside. http://en.wikipedia.org/wiki/A...
2) What happens when one crashes? (see pollution concerns raised in point 1).
3) Shielding proved to be a problem. The aircraft power plant was only partially shielded because of weight constraints. The crew sat in "radiation shadows". and the power plant radiated in all other directions.
5) Combat aircraft have been known to have very high peace time attrition rates, a case in point being the F-104 at 30%. (see pollution concerns raised in point 1).
4) The thing would have been a logistical and maintenance nightmare.
5) ICBMs became a more capable and practically unstoppable delivery options. ICBMs were also likely to be a much safer weapons package during handling and in day to day peacetime operation.
6) Nuclear submarines became a viable option. Here weight was no issue so reactors could have full shielding and safety mechanisms. Subs were also way stealthier than any bomber so their combat survivability rating was higher and they carried a bigger war-load.
Only to idiots, are orders laws.
-- Henning von Tresckow