Naked Science Forum
Non Life Sciences => Technology => Topic started by: Expectant_Philosopher on 17/10/2014 20:13:20
-
Airplanes waste so much fuel on taxiing and trundling around the airport. I think we could have a major redesign of the airport paradigm. The major limiting factor for current design is prevailing wind direction. In zero wind conditions it wouldn't matter which direction the plane would take off. I think we could create a microclimate around the airport. We could create wind baffles and other Metamaterials to cloak the airport from winds. With wind out of the equation airports could place runways in any compass direction, even as spokes from a hub of terminal gates. I think we could even have the runways ramped downwards to provide positive gravity assist on take-offs and negative gravity assist on landings. So in a final vision, the terminal sits on a hill with a flat area around the terminal as a parking apron and gates, then runways at various cardinal directions fanning out pointing downhill from the airport terminal. At the bottom of the hill is a wide safety margin area.
-
I am concerned that in the proposed design, if the plane overshoots the runway, there is no safety margin - the plane plows straight into the terminal building, potentially causing significant loss of life.
Perhaps that is why most airports have terminal buildings somewhere near the center of the runway, but not directly in line with the runway.
While crosswinds and gusty winds can make landings tricky, a strong, steady wind down the runway actually makes landings and takeoffs easier, since the plane can land and take off at a lower ground speed.
(I also think that designing effective wind baffles would be rather challenging - and may pose a risk to any planes that veer off the runway...)
-
I had expected the runway design to include all the recommended safety margins and equipment (safety nets) in addition to the extra margin of the apron leading to the gates. Please refer to the diagrams and discussion of safemargins at this PDF link, http://www.smartcockpit.com/docs/Margin_for_Error.pdf
However if that wasn't enough then the runways could still lead to the flat area surrounding the terminal only offset from the terminal center as tangents to the curve of the circle comprised by the parking apron area.
As for wind baffles, I refer to this 2008 article concerning protection of coastlines from wave action. What science applies to waves would also apply to air as the calculations are both part of fluid dynamics. www.sciencedaily.com/releases/2008/10/081002094842.htm
-
The metamaterial design could either be a purpose built dynamic system to redirect winds to customized directions or a passive system wherein the surrounding buildings developed could adhere to strict design codes wherein the buildings themselves act as the metamaterial grid.
-
It is rarely necessary to have more than one main runway (usually east-west in the UK) and occcasionally a short cross runway for emergency use by light aircraft in strong crosswinds. The length of the runway is determined by the performance of the aircraft you want to use it, but if you have a central terminal and radiating runways you need at least twice as much ground area. It's not a good idea to have multiple landing directions in use at once: you will have half the departing aircraft flying directly towards inbound planes, and in the event of a missed approach you will have to climb and go around through a forest of stuff coming and going all at once.
The dubuious pleasures of instrument landing would be multiplied if you had no idea of the runway bearing from the central beacon (outer markers would of course be useless - you would need hundreds of them) and if you switched on several ILS beams at once, you could end up with more than one plane on any one approach, or none....
Heathrow does quite well with paired runways, landing and taking off in parallel in all weathers
I use a number of small airports where the runway is fitted between mountains or alongside a river: modifying the local weather is the least of your problems in such cases, though Dundee can present a problem for heavily loaded aircraft: I've had to wait a couple of hours in winter until the wind along the river valley was strong enough to take off and clear the hills in the morning. Now if we had a huge fan blowing an artificial wind down the track we could get off the ground very quickly, but as soon as we passed over the fan, the plane would stall and fall out of the sky, to the consternation of people who have paid a lot of money to get to London, not to be strewn over the Scottish countryside.
-
Yes, I would wonder about the interface between the controlled airport environment, and the local winds. Would it be like crossing the bar in a small boat leaving a harbor, but in 3D, of course?
Taxiing can be quick if the runways are clear. Part of the inefficiencies is when planes queue up and wait for a half an hour before getting takeoff clearance. There would be some fuel savings with better logistics allowing the planes to sit at the gates until they are ready to pull out and take off.
One could make greater use of tow vehicles, but at some point, the engines must be fired up and allowed to warm up before takeoff.
-
There's another minor point.
Using the plane's engines to move it round on the ground gives you a chance to check that they are working properly before firing them up for take-off.
I wonder how often the pilot discovers that there's an engine problem while taxiing.
-
Believe me, it's the best time to find out - and the most likely.