Why dont we have battery powered air planes, when we have battery powered cars?

We do battery electric planes. Here is a sampling:

-- http://www.gizmag.com/go/5901/

-- http://www.gizmag.com/demoichelle-electric-paris-a...

-- http://www.alternative-energy-news.info/world-spee...

-- http://www.gizmag.com/eads-green-cri-test-flight-s...

-- http://www.gizmag.com/aircraft-achieving-electric-...

-- http://electric-vehicles-cars-bikes.blogspot.com/2...

-- and even electric helicopters: http://www.gizmag.com/sikorsky-project-firefly/159...

If you have been following solar and electric flight you would notice that several milestones have been broken this year. These include a UAV that was flown for two weeks without stopping, day and night, without fuel. It used lithium sulfur batteries and solar panels. http://electric-vehicles-cars-bikes.blogspot.com/2... And then there was the 24 hour maned flight of the Solar Impulse which also uses batteries and solar panels. http://www.gizmag.com/sunseeker-solar-powered-airc...

EDIT: ALL 6 the above initial cites are for BATTERY POWERED PLANES not solar planes. They have been being worked on for several years and are not so uncommon at least in concept and prototypes.

In large part because you need energy from the engine to turn the prop. A jet engine develops thrust from the combustion reaction.

An electric motor of sufficient power generation for a plane the size of Cessna 172 or 182 would weigh more than the engine it uses. They are still a small aircraft, so their lift capacity is limited to about 4 adults as the total payload with a full fuel load is only 800 pounds. Fuel capacity to get just a tad over 500 miles, or about 900 KM. The problem is that is under static conditions, over 3 hours at 75% of full power. In terms of weight, the fuel load should be about a 500 pound fuel load. The rate of battery consumption in a car gives you under the same circumstances- about 1 hour drive time (60 mile range) And that is just with 1000 pounds of batteries producing energy for the rough equivalent in gas terms of a 75 HP engine. So you would have no reserve- and maybe 20 minutes of practical flight time.

See for yourself: http://www.cessna.com/single-engine/skyhawk.html

The 172 and 182 are the same class for size, that number happened to be horsepower of the engine spinning the propeller. The Skyhawk is just the newer designation.

http://www.cessna.com/news/fast-facts.html is the page where you can jump to the single engine planes, select skyhawk (because their frames pages do not allow you to extract the url for the page itself) You can get an interior view of the aircraft- it's cozy.

Where are you going to put the batteries? A small 650Ahr forkift battery is about 30 inches by 24 by 12 inches. It weighs a mere 650 pounds.

How can you ensure a 45 minute reserve?

How do you deal with the matter of "self discharge" something batteries do to a greater or lesser extent?

What type of motor? who makes it? Does it have secondary brushes if a brush type?

The weight of that motor versus the gas engine is going to make an aircraft you cannot get off the ground with solar film applied to the wings- it just is not going to happen. It will be an expensive brick with tiny hershey bar wings plunging to earth. The gas engine is much lighter in compairison when all is factored in.

In a single engine aircraft- as good as their dead stick glide rates are- power=altitude. There is not enough energy density in the solar cells to keep an aircraft the size of a small Cessna or Piper or Diamond up in the air. A UAV is a very small lightweight aircraft with no room for people or much cargo. So they can have large wing surfaces, they do not need to meet FAA safety requirements either. A UAV is nothing more than a large winged model aircraft. Sophisticated- yes, they also do not weigh more than a few hundred pounds.

As an ultralight, if you are a tiny person- you might stand a chance of getting off the deck if your headwind is sufficient, but your air/flight time will be limited if you don't have bright sun light, Few thermals or updrafts to take advantage of. Ultralights made from hang gliders are you best chance, but you will be very limited due to the weight considerations.

As for a commercialy produced aircraft- If I were to buy one, I would want one I could afford with the most range and comfort for the money.

As for the charging of the batteries- the current methods work just fine, no need to change them. You might do well to visit Oshkosh Wisconsin next year for the Experimental Aviation Association Fly in. Take a look at what is out there. Talk with the people- Your market would be so small as to not even be profitible.

An airplane requires such an enormous amount of energy, it is not possible with current technology to run one (beyond remote controlled models) on electricity. A plane would not be able to absorb sunlight quickly enough from the sun, and it wouldn't be able to be powered by wind because.... this is kind of hard to put into words, but.... you can not utilize energy you are fighting against. Any wind power harnessed by a plane (or car, or anything else moving) would be greatly overpowered by the wind resistance.

Hopefully though, in the future, we will be able to make batteries light enough and solar panels efficient enough to power a plane. It would be nice to be able to fly to Maui without the guilt of having burned 20 gallons of Jet-A per passenger.

Yes it will matter that its heavier. Fossil fuels make such a great fuel because they are packed with an incredible amount of energy for its weight. Heavy batteries cannot simply store enough power to produce electric planes.

(This is ignoring the experimental Solar Impulse, which does not carry passengers or any cargo payload.)

To fly a plane you need a lot of energy that cannot (so far) be taken from alternative power sources like the sun and the wind. Cars that work with batteries are not as big as an airplane is and do not carry so many people.

In the future they will probably exist, because technology evolves continuously.

It's a matter of power/ weight ratio. Solar powered planes are flying but the payload is insignificant.

It would be a lot heavier. Weight is a bad thing on a plane. Also electric cars suck because of our limited current technology. Planes would be worse.

because you need to have an enormous battery that is very powerful because an airplane is a lot more complicated than a car. making the kind of battery it needs would be extremely expensive so it's not cost effective becaue if they did you would pay more for a ticket just like you pay more for a battery operated car

You want to be 30,000 feet on a battery powered plane . It uses more energy on

take off . You would not make it out of city .

Weight.

A battery that stores enough energy for the flight, is very heavy.

The plane can not fly as high, as fast or as far.

For that reason, the Airline makes more money fueling with jet fuel, which is the ONE true reason.