Physical Description of Flight

[hilgert]

Found this out on the Web yesterday (was listening to a NPR show that mentioned it). It's a more obvious discussion of how plane wings (fixed and rotating) actally work to create lift. It explains why the popular Bernoulli explanaition does not fully explain things such as inverted flight, etc.

-Hilgert

A Physical Description of Flight (PDF) (http://home.comcast.net/~clipper-108/lift.pdf)

A Physical Description of Flight (HTML) (http://home.comcast.net/~clipper-108/lift.htm)

[kcaldwel]

Nice article, thanks!

Kevin

[Brandano]

The Bernoulli principle still holds true, even in inverted flight, even when you have a ducted fan VTOL plane. AND it works moving a mass of air downwards, or generating a low pressure above the wing... this sort of religious wars upsets me. Each "theory" is right for a specific method of observation, the same way Newton's principles are right even if "proved" wrong by relativistic and quantum theory. The pressure doesn't lower because the air accelerates, and the air doesn't accelerate because the pressure lowers. The two phenomena are interconnected, and are just a form of conservation of energy.

[vintage1]

Bernoulii is a simplified approach, and although its correct as far as it goes, it doesn't go far enough: In particular it doesn't 'do' turbulent flow.

It does do inverted tho. What counts there is where the streamlines start to diverge above and below the wing, so that the upper path is still 'longer'.

[Brandano]

Bernoulii is a simplified approach, and although its correct as far as it goes, it doesn't go far enough: In particular it doesn't 'do' turbulent flow.
The same way as Newton doesn't 'do' near light speed, my thought exactly. And neither explanation really works for ballistics, that state where the laminar flow detaches completely from the plane, typical of supersonic flight, or cavitation in denser fluids.

[Daddio]

No matter what we think is "really" going on, Newton can probably explain it.