On drag

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Is it a fair assumption that at best L/D speed the drag will be the
least?

Thanks in advance,

Ramapriya

[Jim Macklin]

No, because it is a ratio of lift over drag. You could
reduce lift and also reduce drag.

L/D Ratio Because lift and drag are both aerodynamic forces,
the ratio of lift to drag is ... Aerodynamicists call the
lift to drag ratio the L/D ratio, pronounced "L ...
www.grc.nasa.gov/WWW/K-12/airplane/ldrat.html - 13k -
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aero This phenomenon is called (aerodynamic) ground effect.
.... values could be reached, his X-112 achieved an L/D value
as high as 23 in ground effect flight. ...
www.se-technology.com/wig/html/main.php?open=aero -
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High-Lift Aerodynamics, Tables of Lift-to-Drag Ratios On
Table 1 we have a summary of aerodynamic efficiency L/D (for
high speed flows, transonic as well as supersonic, the
efficiency is ML/D, ...
www.aerodyn.org/HighLift/ld-tables.html - 6k -
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[PDF] Efficient Aerodynamic Shape Optimization File Format:
PDF/Adobe Acrobat - View as HTML
Efficient Aerodynamic Shape Optimization. Antony
Jameson ... Wing L/D. Wing L/D vs. Mach at fixed CL.
Baseline. Redesign. - - - : Baseline. -- : Redesign ...
aero-comlab.stanford.edu/Papers/jameson.iowa.add.2005.pdf
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Aerospaceweb.org | Hypersonic Waveriders - Vehicle
Characteristics Hypersonic vehicle design issues,
configuration, aerodynamic behavior, compression lift ...
Maximum lift-to-drag ratios for hypersonic vehicles and the
"L/D ...
www.aerospaceweb.org/design/waverider/design.shtml -
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Aerospaceweb.org | Ask Us - Ground Effect and WIG Vehicles
The aerodynamic efficiency of an aircraft is expressed
through a quantity called the lift-to-drag ratio, or L/D. In
steady, level, non-accelerating flight, ...
www.aerospaceweb.org/question/aerodynamics/q0130.shtml
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Aerodynamics for Students Again assuming approximate steady
conditions where velocity and propulsion performance is kept
constant and that the aerodynamic parameter L/D is
maintained ...
www.aeromech.usyd.edu.au/aero/perf/range/ - 10k -
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> wrote in message
ps.com...
| Is it a fair assumption that at best L/D speed the drag
will be the
| least?
|
| Thanks in advance,
|
| Ramapriya
|

[Marc J. Zeitlin]

Jim Macklin wrote:

>> > wrote in message
>> ps.com...
>> | Is it a fair assumption that at best L/D speed the drag
>> will be the least?

> No, because it is a ratio of lift over drag. You could
> reduce lift and also reduce drag.

For a given aircraft flying straight and level, lift=weight. Unless
the weight's changing (or you accelerate the aircraft by turning), the
lift doesn't change as you change speed - it still has to equal the
weight to keep the plane in the air.

Given that, then yes - maximizing L/D minimizes drag.

Obviously there are many cases where this won't be true, but for the
most part, it is.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006