Airplane Pilot's As Physicists

Phil wrote in news:1192037923.115677.275220
@o3g2000hsb.googlegroups.com:

On Oct 9, 6:15 pm, Ray Vickson wrote:
Heh. I know the argument. I think it's broken out here (sci.physics)
many times.

(a) It's the Bernoulli effect due to the shape of the
wing cross-section, the way we were all taught as kids.

(b) No, it's just the angle of attack.

Probably true, in large part anyway. Just consider that aerobatics
pilots can fly their planes upside-down over considerable distances.
If Bernoulli were the sole factor this couldn't happen.

R.G. Vickson

It doesn't have to be either-or. Both Bernoulli and angle of attack
are at work in generating lift.


That's right, but what's more is that Bernoulli is strengthened by angle of
attack and it's that which provides most of the increase n lift at higher
angles.
Even with a flat bottom wing being flown inverted, most of the lift is
still coming from Bernoulli.



Bertie

On Oct 9, 7:33 pm, Bertie the Bunyip wrote:
Ray Vickson wrote in news:1191971717.488856.299560
@g4g2000hsf.googlegroups.com:







On Oct 9, 1:22 pm, Randy Poe wrote:
On Oct 9, 4:08 pm, Le Chaud Lapin wrote:

Hi All,

There is a long discussion ongoing in rec.aviation.piloting about
what
causes lift on a plane.

Heh. I know the argument. I think it's broken out here (sci.physics)
many times.

(a) It's the Bernoulli effect due to the shape of the
wing cross-section, the way we were all taught as kids.

(b) No, it's just the angle of attack.

Probably true, in large part anyway. Just consider that aerobatics
pilots can fly their planes upside-down over considerable distances.
If Bernoulli were the sole factor this couldn't happen.

Bernoulli still works when you're upside down.

Even with a flat bottomed wing..

Doesn't work so good, BTW, which only strengthens the bernoulli
position, but it does work.

But the Bernoulli position works best with helicopters.
That's why they were invented for winged weirdos,
who know kust about nothing about Bernoulli.
Other than he once made a principle for
Newton idiots.
c


Bertie



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" wrote in
ups.com:

On Oct 9, 7:33 pm, Bertie the Bunyip wrote:
Ray Vickson wrote in news:1191971717.488856.299560
@g4g2000hsf.googlegroups.com:







On Oct 9, 1:22 pm, Randy Poe wrote:
On Oct 9, 4:08 pm, Le Chaud Lapin wrote:

Hi All,

There is a long discussion ongoing in rec.aviation.piloting
about
what
causes lift on a plane.

Heh. I know the argument. I think it's broken out here
(sci.physics)
many times.

(a) It's the Bernoulli effect due to the shape of the
wing cross-section, the way we were all taught as kids.

(b) No, it's just the angle of attack.

Probably true, in large part anyway. Just consider that aerobatics
pilots can fly their planes upside-down over considerable
distances.
If Bernoulli were the sole factor this couldn't happen.

Bernoulli still works when you're upside down.

Even with a flat bottomed wing..

Doesn't work so good, BTW, which only strengthens the bernoulli
position, but it does work.

But the Bernoulli position works best with helicopters.
That's why they were invented for winged weirdos,
who know kust about nothing about Bernoulli.
Other than he once made a principle for
Newton idiots.
c



I see

Bertie

"Mxsmanic" wrote in message
...
CWatters writes:

Nope. That wouldn't explain how wing sections for tailless planes work.
The
sections for those curve up towards the trailing edge. The leading edge
produces lift but the trailing edge produces a _downward_ force to
counter
the pitching moment. Example section...


http://www.desktopaero.com/appliedae...image13_43.gif

The first thing I saw in this image was "Angle of attack 5.50." Case
closed.

So what's that got to do with anything. You can simulate the performance of
a section at any AOA you like. Try it yourself at AOA = 0 degrees. You might
be surprised.

"Mxsmanic" wrote in message
...
CWatters writes:

How come most wing sections still produce lift at ZERO degrees AOA?..

They don't do that.

Yes they do. Almost any wing that has camber generates lift at zero degrees
AOA. The more camber a wing has the more pronounced this effect is

The very first polar plot google finds shows this...

http://www.mh-aerotools.de/airfoils/images/hdi_pol3.gif

Notice how Cl is about 0.45 when the AOA is zero.

"Mxsmanic" wrote in message
...
Le Chaud Lapin writes:

Even though this (new) thread is not about what causes a wing to lift,
I just wanted to say for the record that I agree with this answer,
that it is both AoA and curvature of the wing.

It's just AOA.

Ok so explain how we measure the AOA of the ball in this video...

http://uk.youtube.com/watch?v=Vg-_nn...elated&search=

CWatters wrote:
"Mxsmanic" wrote in message
...
Le Chaud Lapin writes:

Even though this (new) thread is not about what causes a wing to
lift, I just wanted to say for the record that I agree with this
answer, that it is both AoA and curvature of the wing.

It's just AOA.

Ok so explain how we measure the AOA of the ball in this video...

http://uk.youtube.com/watch?v=Vg-_nn...elated&search=

And if that one doesn't do it for you here's another.

http://uk.youtube.com/watch?v=5YHqCkCJbWQ&NR=1

http://uk.youtube.com/watch?v=KCcZyW-6-5o

Enjoy!!!






Ok so explain how we measure the AOA of the ball in this video...

http://uk.youtube.com/watch?v=Vg-_nn...elated&search=

And if that one doesn't do it for you here's another.

http://uk.youtube.com/watch?v=5YHqCkCJbWQ&NR=1

"ABLE_1" wrote:
http://uk.youtube.com/watch?v=KCcZyW-6-5o

Enjoy!!!

Here's something that flies which doesn't rely on Bernoulli's theorem:

http://uk.youtube.com/watch?v=1T2gg4zpyuo

Enjoy!

(By my estimate, at Akron's max speed of 72 knots it would travel its own
length in about 6.5 seconds. That's roughly in range of how fast its shadow
appears to cross points on the clouds, so IMHO the Youtube poster who said
it appeared to be traveling 500 mph is wrong.

Anyway, it's nice to imagine the 8 Maybach engines sounding about like that
at full throttle.)

Jim Logajan wrote:
Here's something that flies which doesn't rely on Bernoulli's theorem:

http://uk.youtube.com/watch?v=1T2gg4zpyuo

Correction - should have used past tense.