The Air Car Nears Completion

torok writes "According to an article on Gizmag, Tata, India's largest automotive manufacturer, has developed a car that runs on compressed air. It costs less than $3 USD to fill a tank on which it can run for 200 to 300km. The car will cost about USD $7,300 and has a top speed of 68mph. About once every 50,000 km you have to change the oil (1 liter of vegetable oil). Initial plans are to produce 3,000 cars per year."

Comments

Re:I'm impressed

[hey!]

While I agree in principle, I'd be interested in the assumptions you used to reach that conclusion (e.g. how much energy it takes to move the machine a km).

The amount of energy needed to move a person that far is not that much. An average cyclist can produce something like 3watts/kg. A 75kg cyclist produces something like 225 watts; assuming he can travel at about 20km/h, we can put a lower bound on the energy needed to move a typical person 200km at 2250 watt hours.

Let's assume we have an engine that is as efficient as the rider (for setting the lower bound) and weighs as much as the rider. Lets suppose that we need twice the energy to move engine and rider the 200km. So we need 4500KWh.

Assuming that electricity costs $0.10/KWh, then such a machine would consume forty five cents to move a person 200km.

To put it in perspective then, the claim is that this car can move a person from place to place using only fourteen times the energy a reasonably fit cyclist would use.

And yet they do explode

[JayBat]

Scuba tanks *do* explode, generally while being filled, caused by a combination of fatigue, corrosion, and manufacturing defects. You don't want to be around when it happens. Google for scuba tank explosion.

-Jay-