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>I know volumes have been written about best/optimal fuel management and
>aircraft operation with regard to climb speed, cruise level and speed and
>descent profiles, etc etc

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>Can anybody point me to a good site that easily explains the easiest way to
>work out the best altitude to fly at with regard to varying head winds with
>altitude.

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>I know that generally it is best to fly quite high due to reduced air
>density and that optimal altitude is calculated by the fmc in the pmdg 737.
>
>However often I will cruise at the optimum altitude as calculated by the fmc
>but I will get a better Ground Speed (GS) if I fly a lower flight level
>where the head wind is less. Add on programs like active sky will give me
>the flight level wind strength and direction, but how do I work out what
>flight level gives me the best GS.

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>David
>

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>...Can anybody point me to a good site that easily explains the easiest way
>to work out the best altitude to fly at with regard to varying head winds
>with altitude....
>...often I will cruise at the optimum altitude as calculated by the fmc but
>I will get a better Ground Speed (GS) if I fly a lower flight level where
>the head wind is less. Add on programs like active sky will give me the
>flight level wind strength and direction, but how do I work out what flight
>level gives me the best GS.
>
> David
>

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>
> "David" <drdavid32@hotmail.com> wrote in message
> news:42e8d1de$0$5404$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
> I don't have a site to recommend, but I wanted to make a comment (you may
> already know this but it may benefit others). It really depends on what
> you consider "best" altitude. To most airlines, the best altitude is the
> one that gives you the best fuel economy, and I imagine this is how the
> FMC's calculate it. In this case the higher the better is the usual rule
> of thumb because the thinner air produces less drag at constant TAS. But
> IIRC, if you want the best ground speed without regard to fuel consumption
> the highest altitudes are not best in an airliner because you run into
> your Mach limits (the higher you go the lower the speed of sound, so your
> Mach speed is higher at the same airspeed as in a lower altitude). So
> your best ground speed will come at the altitude where your best airspeed
> intersects your Mach limit (say density altitude of 28000' for example,
> but depends on aircraft). Now factor in winds and that may shift your
> altitude for best GS a few thousand feet either way.
>
> Well, I'm no expert, but just wanted to point out that most economical
> altitude and your fastest altitudes are going to be different, have to
> decide which you prefer.
>

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> On Thu, 28 Jul 2005 22:38:26 +1000, "David" <drdavid32@hotmail.com>
> brought the following to our attention:
>
>
> David.. am responding because of interest in the same thing.. although
> may not know precisely what I'm [talking] about, and some may chuckle.
> If you've got an FMC (built in computer).. its like having a flight
> engineer sitting there with notebooks full of charts and tables.
>
> The FMC has performance data stored in look-up tables or math
> functions and can return LOTS of useful info about the flight.. etc.
> Otherwise for older jets.. it would be necessary to have a number of
> FM (manual) sheets for the particular aircraft that you're operating.
>
>
> you mean a general site for airspeed/headwinds? or for specific type?
>
>
> wait till John hears this.. could always make a Spreadsheet for your
> plane.. and lets' not forget the FDE must be designed correctly or the
> Sim won't perform like the real thing!!
>
> If you'd like to work the `atmosphere' numbers.. see this page:
>
> http://www.aerospaceweb.org/questio...ere/q0049.shtml
>
>
> -g
>
>

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> On Thu, 28 Jul 2005 19:34:03 +0200, "Oskar Wagner"
> <rengaw@swissonline.ch> brought the following to our attention:
>
>
>
> splendid idea.. Sa!!
>
>
> -g
>

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> Hi Gregory,
>
> Did you say Spreadsheet??!! */_*
>
> Some of the technical stuff sends me cross-eyed, mate :-)), but
> co-incidentally, I was reading up on X Plane yesterday, and noticed the
> following:
>
> http://www.x-plane.com/cruisealt.html
>
> I'm not sure whether it's relevant, or useful, or just a flat-out
> nuisance, but there it is anyway!
>
> Regards,
> John Ward
> "Gregory" <flightsim.maps@bkwds.comcast.net> wrote in message
> news:p5ohe1l379epo618khd5h6q8o07qpjapv1@4ax.com...
>
>

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> Thanks for the replies, the x-plane site discussed what I was sort of
> wanting to know.
>