During the 9/11 aircraft grounding, climatologists had a pretty unique chance to measure temperature variance compared to historical data.
Just the few days of data showed that days became warmer and nights became cooler. I pretty much had no idea that just trails could impact weather so noticeably until I read up on this experiment.
As a european citizen I’d vote for all subsidies that go towards intra-European air travel to go towards railway traffic.
The US should so something serious about plane travel as well. At least we have the excuse of completely separate governmental entities that built different railway infrastructure. The US is probably lacking behind China who practically just began connecting their nation through high-speed railways.
The other thing astonishing about 9/11 was how quiet it was. The ambient white noise of aircraft was non-existent, and it is considerable in any major urban area.
I think there is probably some low-hanging fruit with airplane design. Techniques to prevent or reduce contrails by modifying the engines or the flight times or flight paths of planes.
Really interesting that certain types of cloud formation (including those created by aircraft) can actually increase mean surface temperature. I had always assumed that the reflection of sunlight outweighed the insulating effect. Does anyone have a link to some kind of model that explains the factors in this?
A large part of the propulsion of a modern turbofan jet plane is provided by so-called "bypass" air, air that flows around the core of the engine. If you can spin those turbine blades electrically you can get nearly as much thrust as the jet version.
The challenge is in finding out how to do this. You could do this with some other mechanism if you can come up with a way of storing lots of energy in a liquid or solid that isn't too heavy.
Most of the visible contrail seems to come from engine emissions, though you can also see condensation effects purely from the dynamic pressure changes around the plane. Those are more obvious with fighter jets and acrobatic planes though, where they are generating more severe aerodynamic effects rather than sustained level flight.
Assuming the visible contrail correlates well with the part causing climate effects, an electric ducted fan might be a big improvement, by removing the combustion emissions. I don't know if some other fuel-burning engine could be combined with a ducted fan and sufficient emission controls to also serve this purpose.
Aren’t those less efficient and less reliable as well? I don't see going back to props. What's the mean time before overhaul on both? Also lower ceiling.
Propellers have a fundamental speed limit on them, the tips can not exceed the speed of sound or else shock waves form which cause the efficiency to drop off sharply, as well as creating massive noise pollution from the sonic boom constantly coming off the propeller. Todays commercial "jet" engines are actually closer related to propeller planes than pure jets, turbofans provide the majority of their thrust from the ducted fan rather than the jet exhaust coming out the back.
Just the few days of data showed that days became warmer and nights became cooler. I pretty much had no idea that just trails could impact weather so noticeably until I read up on this experiment.
As a european citizen I’d vote for all subsidies that go towards intra-European air travel to go towards railway traffic.
The US should so something serious about plane travel as well. At least we have the excuse of completely separate governmental entities that built different railway infrastructure. The US is probably lacking behind China who practically just began connecting their nation through high-speed railways.