Aircraft range equation
Aircraft range equation
(OP)
hi all,
Im currently a aerospace engineering and I have some questions that I have been wondered about the range equation.
I just studied about the breguet range equation (R=v/sfc L/D ln(wi/wf)). The equation is pretty simple within many assumptions such as constant speed constant L/D... How can the manufacturer such as Boeing or Airbus come up with the quoted range in the aircraft's specification? Since the breguet's equation is quite ideal and far from realistic, should there be a better way to determine the range?
is there a more precised formula has been developed? or the value just comes from the flight test alone?
I also think that there are many conditions of payload/fuel load, but how come the manufacturer come up with only 1 range in the specification? what condition do they usually use?
I know there are many questions and takes long to answer, if anyone could suggest me articles or books would be already much appreciated.
thanks
Im currently a aerospace engineering and I have some questions that I have been wondered about the range equation.
I just studied about the breguet range equation (R=v/sfc L/D ln(wi/wf)). The equation is pretty simple within many assumptions such as constant speed constant L/D... How can the manufacturer such as Boeing or Airbus come up with the quoted range in the aircraft's specification? Since the breguet's equation is quite ideal and far from realistic, should there be a better way to determine the range?
is there a more precised formula has been developed? or the value just comes from the flight test alone?
I also think that there are many conditions of payload/fuel load, but how come the manufacturer come up with only 1 range in the specification? what condition do they usually use?
I know there are many questions and takes long to answer, if anyone could suggest me articles or books would be already much appreciated.
thanks





RE: Aircraft range equation
To an aspiring aeronautical engineer I can do no more than recommend the NASA/LARC archive of papers, which will give you a great historical perspective, and an appreciation of the level of analysis people did in the years BC.
http://ntrs.nasa.gov/?method=aboutntrs
Cheers
Greg Locock
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RE: Aircraft range equation
http://www.amazon.com/gp/search?index=books&li...
RE: Aircraft range equation
RE: Aircraft range equation
rb1957, is that what the manufacturer really do to estimate the range. do know have any paper or ref i can look at?
RE: Aircraft range equation
a piece-wise discrete segmentation of an overall flight is an easy way to restrict the simplifying assumptions (constant this, constant that) that you'd get a reasonably accurate answer.
i'd expect that they run flight simulations that either are piece-wise discrete segments, or continuously varying varibles.
Raymer might go into this in more detail, or other Flight Performance texts.
RE: Aircraft range equation
Also look at Jan Roskam, Aircraft design, vol 1, preliminary sizing. Worked examples in both, IIRC.
Both show the method of writing several design flight segments using simplifying assumptions and performance/weight estimates based on trade studies. The product of all your segment fuel fractions gives you your takeoff weight over structure & payload fraction.
RE: Aircraft range equation
Lefteris
Dep. of Mechanical Engineering and Aeronautics
RE: Aircraft range equation
TTFN

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RE: Aircraft range equation
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