Link of the day: Why did the half-plane, half-helicopter not work?
For quite a while now I have been thinking about green air travel. The thing that has been bugging me the most is that air travel doesn’t necessarily have to be as detrimental to the environment as it is right now. One big reason for the high environmental impact is the speed at which we travel (around 750-900 km/h for commercial airliners), as air friction increases quadratically with speed (of course, altitude and air density also plays a large role). But in principle, airplanes could fly at around 300 km/h, which would however not be commercially viable. There are other concepts to make air travel greener. I especially like the half-plane, half-helicopter. Give it a read.