Airbus E-Fan Electric Aircraft Makes First Flight 160
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."
Flight time 1 hour (Score:4, Informative)
For this version of the plane.
http://en.wikipedia.org/wiki/A... [wikipedia.org]
Re:Flight time 1 hour (Score:5, Informative)
Jet fuel has at least 50 times the energy density of lithium batteries [wikipedia.org], so even accounting for the low efficiency of jet engines, that hour looks about right.
Re:how do you charge the batteries? (Score:2, Informative)
Using electric vehicles (planes, trains or automobiles) is not just about shifting the CO2 emission point.
It allows use of energy sources that would not otherwise be viable for transportation (liquid hydrocarbons have a significant premium over other forms such as gas or solids). In addition land based power facilities have significantly higher efficiencies (open cycle gas turbines are lucky to get 40% efficiency, stick a waste heat recovery boiler on the back end and it is up to 60% efficiency).
The other alternative fuel for air transport I can see would be LNG (liquified natural gas), at that point we need several generations of improvement in scramjet technologies (air breathing rockets anyone?).
Re:NOT zero-emissions! (Score:4, Informative)
It is getting old, and it proves your intelligence that you keep repeating it.
It keeps getting repeated because people keep misusing the term "zero emission". When you use an absolute term such as "zero emission" it is either true or false. In this case "zero emission" is false. All electricity from the grid, which is where these aircraft will probably be charged from, has some component of fossil fuel based generation. Therefore by using grid power the aircraft is causing emission; just on another location.
How much pollution went into making that gallon of fuel?
No one claimed fossil fuels were zero emission.
What the poster is trying to get at is to use a more accurate term such as "low emission" which is a true statement.
Re:NOT zero-emissions! (Score:2, Informative)
The fossil fuel based generation plants that send energy to the grid and charge the plane do emit carbon dioxide. Therefore by charging the aircraft carbon dioxide is emitted. Therefore using the plane causes carbon dioxide to be emitted. The plane is not "zero emission" but "lower emission" in another place.
Re:Flight time 1 hour (Score:5, Informative)
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 [wikipedia.org], 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.
Re:How is that practical? (Score:5, Informative)
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... [wikipedia.org]
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.
Re:Flight time 1 hour (Score:4, Informative)
Not to mention that the aircraft doesn't have to carry consumed fuel, while it has to carry consumed batteries. And in some cases, aircrafts take off with near empty fuel tanks but with overweight loads and refuel once airborne.