In the US, cars are most often used for hauling (unfortunately) just one person. Though these cars have come a long way in efficiency, only about 4% of the energy consumed is used for hauling the passenger, while the machine uses 96% of the energy for hauling itself; about 3,500 lbs of metal and plastic for moving a 150-lb person!
Hopefully, machines like the following wearable motorcycle will give us the comfort of climate-controlled enclosure at a two-wheeler fuel efficiency, in the near future. It appears pretty neat, but looks like watching traffic in the rear will be a pain in the same:-)
Hopefully, machines like the following wearable motorcycle will give us the comfort of climate-controlled enclosure at a two-wheeler fuel efficiency, in the near future. It appears pretty neat, but looks like watching traffic in the rear will be a pain in the same:-)
While looking at this machine, got curious about the fuel efficiency of Jumbo Jets. On a quick and dirty back-of-the-envelope calculation, noticed that in spite of hauling large amounts of fuel, these air crafts are comparable* in efficiency to cars; about 8% of energy is used for hauling passengers, while 92% of energy is used for hauling the plane and fuel. Even though planes appear to be energy efficient (due lesser friction and thinner air, I imagine) when compared to cars, we need to factor-in the energy costs of maintaining airports and ground crew.
Quick estimates
Weight of Boeing 747-100: 395,000 lbs
Volume of Jet Fuel: 57,285 gals
Average specific gravity of jet fuel: 0.75
Weight of the fuel: 57,285 gals x 8.34 lbs/gallon (water) x 0.75 = about 358,000 lbs
Weight of passengers: 416 passengers x 140 lb/passenger = about 58,240 lbs
% of fuel used for hauling passengers: 58240/(358000+395000)= about 8%
Weight of luggage: 416 passengers x 50 lbs/passenger = 20,800 lbs (not included in calculation)
2 comments:
Thanks, Gopa; loved that.
Just wondering what would happen if you take out one of those on Indian roads. Guys would be trying to overtake you by sneaking under the wings of that BatMo gizmo. Its byline in India could be:
~~~~~
Buy one; get an Indian under your wings free ;-)
~~~~~
HA! HA! Raama. You have a point! I noticed that when there are no traffic jams, the traffic in India looks like chaos with a certain degree of order! Every driver keeps calculating all the time - is the gap big enough to squeeze in? how fast is the vehicle coming from the other side? how big is it? Does that lorry driver look like the kind of guy who gives way to people? All those micro-second management decisions!
Post a Comment