No One Can Explain Why Planes Stay in the Air

[Halbhh]

If the force on the wing is upward, why can planes fly upside down?

Good question. By keeping the nose up and increasing the angle of attack enough, deflection can push air downward, similar to how a rudder works. So its a 2nd way to get lift, different from the more efficient (lower drag) airliner airfoil using the Bernoulli effect with little or no needed angle of attack. In cruising flight that is. For climbing both would happen, but especially brute force angle of attack, with flaps.

It's an interesting topic. Now I'm wondering about new stuff, like what about supersonic, and what about sails (both effects or just one?).

 

[Ricky M]

Whatever do you mean there?

The post I quoted said there are two competing theories as to why planes fly.

I was just commenting on how polarized we are when we think everything has to compete instead of working together.

 

[sjastro]

What legend!
That's what I call "puttin ya money where ya mouth is"!

Lord Cherwell using the Australian vernacular might have been a daredevil but was also a bit of a drop kick.

Lindemann believed that a small circle of the intelligent and the aristocratic should run the world, resulting in a peaceable and stable society, "led by supermen and served by helots."[6] Some sources claim that he was Jewish,[7][8] but Frederick Smith's biography and David Irving's second book on Churchill[9] declare that he was not.[10] Lindemann supported eugenics and held the working class, homosexuals, and blacks in contempt and supported sterilisation of the mentally incompetent.

I recall his exploits from a book that also takes the mickey out of scientists.

 

[Ophiolite]

I was just commenting on how polarized we are when we think everything has to compete instead of working together.

I don't agree!

 

[Halbhh]

I don't agree!

Well, also consider, as in post 21 above, that usually both things are happening: both a nice Bernoulli effect for the efficient (low drag configuration) airliner airfoil during level flight cruising...

...and then in contrast the same airplane was during takeoff and especially initial climbing using just brute force deflection in a large degree, with the big flaps down, just deflecting a huge amount of air just downward, akin to a rudder, with a lot of drag, inefficient but rapid, to gain altitude quickly.

So then these 2 effects are both key and routine for typical flights.

And then also next it's possible to just explain the Bernoulli effect as just mechanics, as I tried to convey earlier in my first and third posts, though I doubt it would be accepted as a 'one-liner' (or thereabouts, like 3 or 5 lines) explanation, heh heh, that many would accept. (I mean I accept it, but does anyone else? lol)

 

[Halbhh]

Did you read the OP linked article?

Yesterday could not open the article (not subscribing at this time), but then today I could open it using a different way to go to the site and I did finally skim through past the intro (skimmed because much of it was old to me, as I once got interested in this before the internet, and also a 2nd time after the internet), and I did like 2 things: the nice hand waving explanation from Mark Drela of how the angle of attack for instance of the wing causes a a low pressure above the wing -- because using Drela's nice hand waving, we can also use that same hand waving also for level flight with zero angle of attack by just substituting in that the curved front surface of the wing will deflect air hitting (and air redirected by the pressure wave) and going over the wing upward (that's much of the work against drag the engines are doing in cruising I bet btw), so that it will again result in the same observed low pressure, even in level flight, due to airfoil shape.

So, that's a very handy visualization! (I think that's an easier to understand wording than my own way of visualizing little balls in motion from the collision with the wing).

Also, a lot of fun was the anecdote of Einstein's 1917 airfoil design and how it was like a "pregnant duck" in the air. That was just fun!

 

[Ophiolite]

Well, also consider, as in post 21 above, that usually both things are happening: both a nice Bernoulli effect for the efficient (low drag configuration) airliner airfoil during level flight cruising...

...and then in contrast the same airplane was during takeoff and especially initial climbing using just brute force deflection in a large degree, with the big flaps down, just deflecting a huge amount of air just downward, akin to a rudder, with a lot of drag, inefficient but rapid, to gain altitude quickly.

So then these 2 effects are both key and routine for typical flights.

And then also next it's possible to just explain the Bernoulli effect as just mechanics, as I tried to convey earlier in my first and third posts, though I doubt it would be accepted as a 'one-liner' (or thereabouts, like 3 or 5 lines) explanation, heh heh, that many would accept. (I mean I accept it, but does anyone else? lol)

My post failed in its intent.

@Ricky M said "I was just commenting on how polarized we are when we think everything has to compete instead of working together."

My response, "I don't agree", was offered as an example of a exactly that: in this instance a competitive remark, rather than a cooperative one. The smilie was meant to convey that my disagreement was for effect only. Ah well!

 

[SelfSim]

... and I did like 2 things: the nice hand waving explanation from Mark Drela of how the angle of attack for instance of the wing causes a a low pressure above the wing -- because using Drela's nice hand waving, we can also use that same hand waving also for level flight with zero angle of attack by just substituting in that the curved front surface of the wing will deflect air hitting (and air redirected by the pressure wave) and going over the wing upward (that's much of the work against drag the engines are doing in cruising I bet btw), so that it will again result in the same observed low pressure, even in level flight, due to airfoil shape.

So, that's a very handy visualization! (I think that's an easier to understand wording than my own way of visualizing little balls in motion from the collision with the wing).

Hmm .. I personally don't think Bernoulli's principle is flawed, per se, but the usual Bernoulli explanations typically leave out sources of pressure on the wing which are not caused by the static pressure of the airflow, in particular, pressure caused by deflection of the flow by the surface itself .. you appear to be going along similar lines of thinking(?)

 

[Ricky M]

My post failed in its intent.

@Ricky M said "I was just commenting on how polarized we are when we think everything has to compete instead of working together."

My response, "I don't agree", was offered as an example of a exactly that: in this instance a competitive remark, rather than a cooperative one. The smilie was meant to convey that my disagreement was for effect only. Ah well!

I got it

 

[Lazarus Long]

Yes they can

 

[SLP]

In Germany, one of the scientists who applied themselves to the problem of lift was none other than Albert Einstein. In 1916 Einstein published a short piece in the journal Die Naturwissenschaften entitled “Elementary Theory of Water Waves and of Flight,” which sought to explain what accounted for the carrying capacity of the wings of flying machines and soaring birds. “There is a lot of obscurity surrounding these questions,” Einstein wrote. “Indeed, I must confess that I have never encountered a simple answer to them even in the specialist literature.”

No One Can Explain Why Planes Stay in the Air

What is the implication?
Jesus?

If so, why wasn't flight a reality in ancient times?

Not having an airtight explanation for something does not mean 'magic' is the answer.

 

[Sabertooth]

If so, why wasn't flight a reality in ancient times?

Birds, bats & bumblebees still flew.

 

[chilehed]

No One Can Explain Why Planes Stay in the Air

Please, what load of nonsense. We know full well how aerodynamic lift works and why.

And yes, I read the linked article. It's rubbish.

 

[SLP]

Birds, bats & bumblebees still flew.

Clever.