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Author Topic: Will flying eastwards save on aeroplane fuel?  (Read 3552 times)

Offline acsinuk

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Will flying eastwards save on aeroplane fuel?
« on: 14/05/2015 10:29:04 »
The Coriolis effect is a new physics explanation of earths rotation
. If the flight route distance is 11,000km and aircraft speed is 880 kph in classical physics terms it should take 12.5 hours each way which is confirmed for north/south routes. But due to Coriolis 3D rotation effect the east/west routes in fact takes only 12 hours from London to Malaysia but the return flight from Malaysia to London takes 13 hours as witnessed in flight schedules.  To save fuel; fly east into the sunrise.
Happy Whitsun landings
« Last Edit: 14/05/2015 15:07:52 by chris »


 

Offline evan_au

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Re: To save fuel fly eastwards
« Reply #1 on: 14/05/2015 12:09:31 »
The example of London to Malaysia is a very small sample, and by itself does not create a general rule.

The predominant direction of winds is different at different latitudes. So if you want to go faster on average, go with the direction of the tradewinds.
 
However, most people don't want to fly directly east-west. Airlines don't want to fly east-west, either - to save time and fuel, they want to go by the shortest-distance path, which is a "great circle" path, which often cuts across the tradewinds.
 
 

Offline alancalverd

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Re: To save fuel fly eastwards
« Reply #2 on: 14/05/2015 12:47:47 »
London - Boston is about 6 hours going west, at least 18 hours going east, in an airliner. OK if you like airline food, but no fuel saving.

I often fly Cambridge-Dublin in a Cessna 172: 2 hours or so going west, the adventure of a lifetime going east. Must try it sometime - if I can afford the fuel.

I am planning to fly round the British Isles for fun and will definitely take the anticlockwise route. Nothing to do with fuel saving or the Atlantic cyclone, but a desire to "Pass the Duchy on the left Hand Side", literally. Fly mellow! 
 

Offline Colin2B

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Re: To save fuel fly eastwards
« Reply #3 on: 14/05/2015 12:50:07 »
The Coriolis effect is a new physics explanation of earths rotation
This is untrue. The Coriolis effect does not explain the earth's rotation, nor is it  new unless you think 1830s is new! It actually explains an effect of the earth's rotation in which air does not flow directly from high pressure to low but follows a curved path causing rotating wind systems, hence has a significant effect on daily weather. Coriolis force, like centrifugal force is an apparent force.

Evan_au is correct when he says flight differences are due to winds. Sailing clippers used to make use of the contrary direction of trade winds and westerlies, but aircraft can also use the jet stream.
Note: the westerlies actually blow east as sailors are more interested in where the wind is coming from!
 

Offline PmbPhy

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Re: To save fuel fly eastwards
« Reply #4 on: 14/05/2015 13:35:45 »
The Coriolis effect is a new physics explanation of earths rotation
. If the flight route distance is 11,000km and aircraft speed is 880 kph in classical physics terms it should take 12.5 hours each way which is confirmed for north/south routes. But due to Coriolis 3D rotation effect the east/west routes in fact takes only 12 hours from London to Malaysia but the return flight from Malaysia to London takes 13 hours as witnessed in flight schedules.  To save fuel; fly east into the sunrise.
Happy Whitsun landings
I don't see where you're getting all of this from. Please post the calculations that you went through in order to arrive at your results. The Coriolis effect is so small as to be negligible. There's no reason why the flight times should be any different. That's why I want to see your calculations.
 

Offline alancalverd

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Re: Will flying eastwards save on aeroplane fuel?
« Reply #5 on: 14/05/2015 17:35:13 »
The coriolis force is what determines the initial circulation of large weather systems such as the Atlantic Low. Once the system has started rotating, always anticlockwise in the northern hemisphere (Buys Ballott's Law) it can intensify into the series of depressions that dominates the weather of the north Atlantic and the British Isles. At sub-arctic latitudes this is characterised by strong winds blowing from 190 to 350 degrees, so nonpolar flights and sea crossings are nearly always faster from west to east, and the more so at higher altitiudes where the jet stream dominates.
 

Offline acsinuk

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Re: Will flying eastwards save on aeroplane fuel?
« Reply #6 on: 15/05/2015 15:31:15 »
There is no calculation possible as the standard model calcs are for static and not dynamic air space.  But contact any airline and ask for nonstop schedule flight time for London to Malaysia and then from Malaysia to London and you will establish that it is a fact!
 

Offline alancalverd

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Re: Will flying eastwards save on aeroplane fuel?
« Reply #7 on: 15/05/2015 19:36:17 »
There is no calculation possible

I hate to disabuse you but I did exactly that caculation this morning and, in consequence, arrived at both today's destinations precisely as planned.
 

Offline Bill S

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Re: Will flying eastwards save on aeroplane fuel?
« Reply #8 on: 17/05/2015 18:29:43 »
Quote from: Alan
"Pass the Duchy on the left Hand Side"

For the record; we Cornish are not a "Nation" of pot smokers.  Tiz them furreners as come down-long from up country as bring that stuff down yer. Bl**dy Emmets!
 

Offline Ophiolite

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Re: Will flying eastwards save on aeroplane fuel?
« Reply #9 on: 19/05/2015 07:33:06 »
There is no calculation possible as the standard model calcs are for static and not dynamic air space.  But contact any airline and ask for nonstop schedule flight time for London to Malaysia and then from Malaysia to London and you will establish that it is a fact!
No one with any knowledge of long haul flights would dispute the observations. However, are you still maintaining that this is due to the Coriolis effect, rather than the benefit/detriment of the jet stream?

As a further example, the Houston-London flight takes about one hour more going west, than east. This is an effect of adverse, or beneficial winds, a point often made by the pilots in their comments to passengers. I recall one such flight where, with the benefit of a 250 mph jet stream we had a "supersonic" ground speed.

It would be nice to see you acknowledge the error of your claim.
 

Offline syhprum

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Re: Will flying eastwards save on aeroplane fuel?
« Reply #10 on: 19/05/2015 16:09:53 »
I to have gone supersonic in a 747 flying back to LHR from south Korea we had a ground speed of 760 MPH and were able to miss out a stop at FRA (the only trip I have had a second meal).
 

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Re: Will flying eastwards save on aeroplane fuel?
« Reply #10 on: 19/05/2015 16:09:53 »

 

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