Electric Airplanes

[NeilBlanchard]

Here's one electric airplane:


(click on image for link)

Here's another:


(click on image for link, including video)

[Old Tele man]

...I can just see it now--a stewardess frantically running up & down the isle asking passengers if anyone has any spare BATTERIES whenever their airliner has to go into a "holding pattern" around a busy airport!

[dcb]

what is the effect on weight and range and power?

Oh, wait, it is a tiny fraction of liquid fueled, like so many electric cars that go 40 miles. I bet it costs a fortune too. They can have it put out the same power for a tiny fraction of the range or some other combination of a fraction of liquid fuel capabilities.

There's lithium, right next to ZERO on energy/mass and energy/volume...

[jamesqf]

Originally Posted by Old Tele man

...I can just see it now--a stewardess frantically running up & down the isle asking passengers if anyone has any spare BATTERIES whenever their airliner has to go into a "holding pattern" around a busy airport!

Somehow I doubt that :-) Even if electric airliners someday become practical - well, does the cabin crew run around asking passengers if they happen to have any jet A on them when a flight goes into a holding pattern nowadays?

Even now, there are places where electric airplanes could work, starting with (as mentioned on that other thread) self-launching sailplanes. Then there are possibilities in the Light Sport class, where you may never travel long distances. When you figure that 100LL avgas is now $7.09/gal at my FBO (plus a quart of not-cheap aviation oil every 10 hours or so), and that a major overhaul of an aircraft engine was IIRC about $12K over a decade ago (about $16K now, from a quick search), electric power for sport flying begins to look kind of attractive.

Then too, as with the Tesla, there are people to whom the impact, environmental & otherwise, of burning oil is more important than money.

[Odin]

Originally Posted by dcb

There's lithium, right next to ZERO on energy/mass and energy/volume...

I'm pretty sure that chart is taking the energy of a lithium ion battery its self, not one fully charged with electricity.

[robchalmers]

My Li-Po race cels are lighter than my Li-Fe's and you've got to remember with electric there would be little differential between take-off and landing weight and you could dump all the fuel pressurisation/cooling sytem just think of the turn around time if it was a cell exchange at each air port rather than a charge!

[skyl4rk]

electric power has taken over in the remote control airplane hobby

[dcb]

Originally Posted by Odin

I'm pretty sure that chart is taking the energy of a lithium ion battery its self, not one fully charged with electricity.

Not sure why you think that. Can you offer any supporting evidence?

per: Lithium-ion battery - Wikipedia, the free encyclopedia
Volumetric energy density: 250 to 620 W·h/l (900 to 1900 J/cm³)[2]
1000 cm³ = 1L
~2MJ/L energy density for lithium batteries, which is about what was plotted, compared to ~37MJ/L for diesel.

Originally Posted by robchalmers

...with electric there would be little differential between take-off and landing weight..

That is another disadvantage of electric plains, the batteries still weigh a ton when they are depleted, whereas your fuel tanks do not. Dead weight on a plane translates into inefficiencies, you have to create more lift, which doesn't come for free.

Originally Posted by robchalmers

...just think of the turn around time if it was a cell exchange at each air port rather than a charge!

Great, just make sure the airports are spaced 10 miles apart so you can make it to the next one

Originally Posted by skyl4rk

electric power has taken over in the remote control airplane hobby

Indeed, such toys, that have no need for payload that run for maybe 10 minutes (well I usually catch a thermal or two also), do not need to be uber efficient. There are still a lot of fuelies left when the pilot is serious about performance.

As an aside, excellent performance can be had with NO motor too (and extra weights are usually needed), though around here I just bungee launch:

http://www.youtube.com/watch?v=Oix6sHKzOLU

[dcb]

What I find funny about that video is the RC jet guys are lucky to push 360mph

http://www.youtube.com/watch?v=dTHWBSluUjU

. Maybe you get 200mph with an electric RC, and the no-motor plane serves them both up for raw top speed (and endurance and efficiency and cost) under the right conditions

[Ryland]

Originally Posted by dcb

Great, just make sure the airports are spaced 10 miles apart so you can make it to the next one

At least at my local air port most people with small private planes don't take them on long trips and that plane has a 140 mile range, so you are good for a trip to a cabin or taking someone on an air tour of the area and the best part is, if you have your own air strip... straight section of road or field, you don't need to get fuel deliveries there any more, you just need a 220v outlet.

It also sounds like these planes cost about the same as the gasoline counterparts but are much simpler so when you get your annual inspection done you get your electric motor checked and maybe bearings replaced compared to a gas engine plane that gets it's engine tore down and rebuilt.