Lift-to-Drag Ratio?

"Toks Desalu" wrote in
news:ikurb.154486$Tr4.407177@attbi_s03:

Guys-
If we have higher L/D, we need higher thrust to maintain lift equal
weight. Am I reading this correctly? In this case, you would need higher
horsepower?

I'm not entirely sure I understand what you are trying to say. The higher
the L/D ratio, the *less* thrust is needed to maintain the same lift.

Look at 1920's aircraft. Very anemic engines, so they have high lift wings
(and usually biplanes - double wings to boot). Not very good for going
fast (because parasitic drag goes up with speed), but great for getting
enough lift to become airborne without much HP.

OTOH, look at an F-16 fighter. Virtually no "lift" from the airfoil design
at all. The lift comes from Angle of Attack (AOA), which causes induced
drag. So how does it get airborne (not to mention fly so well at
supersonic speeds)? LOTS and LOTS of thrust!

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James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
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