Stealth Pilot wrote in
:

On Fri, 25 Apr 2008 13:20:48 +0000 (UTC), Bertie the Bunyip
wrote:

es330td wrote in
news:bb48d3a5-08b9-4a54-a836-
:

Fortune magazine online has a photo essay about their new 787. On
one
page,

http://money.cnn.com/galleries/2008/....boeing_dreaml
i
ner.fortune/16.html, they make this statement:

The Dreamliner's wingspan is 197 feet, or about 25% longer than a
similar-sized plane, which increases lift and reduces drag.

I thought that lift, in addition to causing a net upward force on
the
wing, also contributes to the drag force on the wing as well. If
this
is the case then increasing lift should also increase drag. Did I
misunderstand?


Well, it's a trade off. it's possible to do both by various means.
arifoil selection, planform and so forth. It'd be more correct to say
that they're eliminating unneccesary drag.


Bertie

no.
it would be valid to say that they were using a geometry with less
induced drag. drag isnt necessary or unnecessary it is drag.


Well, by unneccesary drag I mean stuff that is not as a result of
creating lift. Improved fillets and seals, for instance. I agree, the
planform and airfoil sections are designed to do what they do and
collect drag as they do

you cant eliminate it, all you can do is try hard to find the design
shape that has the least of it.

...got you on a slip of the keyboard :-)


Yeah, you did. i didn't mean for the one thought to relate to the other.
Having said that, airliner wings are really complicated. Boeing wings
are a marvel to look at. The 757 wing is simply mindboggling. The center
section has a supercritical section in order to ammelorate drag induced
by the shick wave at high mach numbers. I'd say the 787 is going to
carry on that tradition with further refinements in that direction.


you'll hate me now. :-)

No, I only give a hard time to cretins!



Bertie