Busting an aerodynamic myth -- Planes don't fly due to Bernoulli Effect

[winkosmosis]

If Bernoulli was that powerful, you could take a thin flat plate, pitch it a few degrees so that there would be no attached flow on the bottom rear-facing side, only the top front-facing side. The huge difference between flow speed on top and bottom would let Bernoulli exceed the downforce from turning the flow upwards.

[winkosmosis]

Originally Posted by skyking

you need to get your terms straight. His diagram shows a wing with a line through it. This is the chord line and that is what is used to define angles of attack and angles of incidence.
By definition that wing produces lift at a 0 degree angle of attack.
Many sailplane wings will fly at 0 and slight negative angles of attack.
The angle of attack is the angle formed by the chord line and relative wind.
The angle of incidence if formed by the the chord line and the longitudinal axis of the fuselage.

Yes I know the definition, but what I'm saying is that the effective "flat" angle is different.

I've read elsewhere that most lift, something like 80%, comes from the top of the wing pulling air downward, and remaining lift from the bottom pushing air downward. That makes that rear-facing surface the most important part of the wing. With the wing "horizontal" per the chord line, that surface is still turning flow downward.

[winkosmosis]

An analog would be a car... Remember the Audi TT lift fiasco? Even at zero chord angle, a car can have dangerous lift, necessitating spoilers. It's not because air flows faster over the top of the car, but because of the angle of the sloping windshield and trunk. If it was Bernoulli, the little spoiler that they added to the trunk wouldn't have solved the issue.




Heck... if Bernoulli was that powerful, cars with air dams preventing much airflow underneath would lift off.

[skyking]

The "effective flat angle"? Where did you find that engineering gem?

[winkosmosis]

Originally Posted by skyking

The "effective flat angle"? Where did you find that engineering gem?

Are you really not understanding my point? Look at the wing. See how the top slopes backward? That sloping surface is what creates most of the lift. The chord angle is arbitrary in this discussion if that slope is the most important ****ing surface.




You can't say that since the wing is creating lift when the chord is horizontal, that must mean that the Bernoulli effect is the source of lift. The chord angle and the lift generating surface angle are two different things.

Just because the wing chord is an engineering metric doesn't mean you can't apply common sense and understand how the wing actually works and why a "horizontal" wing is creating lift by pulling air downward.

[winkosmosis]

[dcb]

now, with what you are saying, the tail being the important part and all, wouldn't you think the center of lift for this airfoil in the newtonian only lift theory would be at the trailing edge of the airfoil?

[winkosmosis]

Originally Posted by dcb

now, with what you are saying, the tail being the important part and all, wouldn't you think the center of lift for this airfoil in the newtonian only lift theory would be at the trailing edge of the airfoil?

IF the airfoil is "horizontal" like your diagram, the center of lift would be somewhere between the highest point and the trailing edge

[tjts1]

I thought all this flying business was resolved about 100 years ago. Now I'm starting to wonder if airplane indeed exists.

[Philscar]

Stand on your bathroom scale.
Hold hair dryer in your hand and point it at your forehead.
Run blow dryer on cool setting(don't fry your brain).
Check weight before and after.
If you get lighter with wind blowing over your head,you are developing lift!

Sailboat sails develop lift .
Airplane wings develop lift.
Cars develop lift if they are shaped like a wing.

Tape a sheet of paper to a table edge with most of it hanging down.
Blow some air over the table in the direction of the paper.
Shazam! The paper lifts up!
Lift caused by the airflow faster over the top than the bottom.

I rest my case........

Phil