Re: Angle of attack - Relative wind

Dan_Thomas_nospam@xxxxxxxxx wrote in
news:5f123f64-94d3-42f1-b19a-557daf3ad64e@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

On Dec 29, 9:34 am, Bertie the Bunyip <S...@xxxx> wrote:
jon <newb...@xxxxxxxxxx> wrote
innews:22e28c5c-e179-4dd3-a61a-81cb0a268909
@t1g2000pra.googlegroups.com:



On 22 Dec, 19:07, Bertie the Bunyip <S...@xxxx> wrote:
jon <newb...@xxxxxxxxxx> wrote
innews:3f2b8fc7-9928-43b0-9c45-25f68517b7c4
@q70g2000hsd.googlegroups.com:

On 22 Dec, 05:37, Bertie the Bunyip <S...@xxxx> wrote:
jon <newb...@xxxxxxxxxx> wrote
innews:4d1b53a6-6781-4e34-93db-a31cf387fcc8
@i12g2000prf.googlegroups.com:

On 17 Dec, 22:55, Bertie the Bunyip <S...@xxxx> wrote:
jon <newb...@xxxxxxxxxx> wrote
innews:55750ab5-8c12-4dd8-9664-7b25b07fcdbc
@b40g2000prf.googlegroups.com:

On 15 Dec, 16:01, Michael Henry
<michael.k.henry_nos...@xxxxxxxxx> wrote:
OK, I've just got home from my Christmas party and I'm
quite drunk so I should probably wait until tomorrow to
reply but this seems to be a simple mis-understanding.

Camber increases the effective AOA, so that at "zero
angle" the effective AOA is still positive.

No, this is wrong. To repeat from my last post:

"There's no "effective AOA" or "real AOA" other than
the
ang
le
formed between the chord line and the relative
wind."

At "zero angle" of attack the angle of attack is: zero!

Take a look at this image of the venerable Clark Y
airfoil:

http://en.wikipedia.org/wiki/Image:Clark_y.JPG

Looking at the image, what would you say is it's angle of
attack assuming a perfectly horizontal relative wind
coming from the left of the screen? Based on your comment
I suspect you think the angle of attack is zero because
the bottom of the airfoil (which happens to be flat) is
horizontal.

However if you re-read the definition of chord line
you'll see that the airfoil in this picture actually has
a positive angle of attack because the leading edge is
above the trailing edge with respect to the relative
wind.

So for this shape to have zero angle of attack you need
to tilt it down a couple of degrees (I have no idea what
the exact amount is). It will still produceliftat that
angle, however. For it to produce zerolift you'll need to
tilt it down another couple of degrees so that it will
have a negative angle-of-attack.

Regards,

Michael

All new airliners from Boeing and Airbus use the
Supercritical wing, with almost flat uppersurface.

http://en.wikipedia.org/wiki/Supercritical_wing

It looks like a Clark-Y turned upside down.

There's more to it than just being upside down. And only the
center section has that. F you notice, it has a guppy shape.
that bulge is for recovery and helps offset the buffet
brought on by area rule.

All aircraft fly due to angle of attack (AOA), even
aircraft with the Clark-Y wing.

Earth gravity force sucks them all down and to counteract
that force one need AOA and downwash airmasses.

Nope.

Bertie

- Dölj citerad text -

- Visa citerad text -- Dölj citerad text -

- Visa citerad text -

More pages with Supercritical wing history:


http://oea.larc.nasa.gov/PAIS/Concept2Reality/supercritical.htm
l

B747-400 could save 15-20% drag, with a new "flat upper
surface wing"!

A. it alread has what you call a "flat upper surface wing" and
has done since it first flew forty years ago.
B. it's not a "flat upper surface" wing in practice.

Bertie- Dölj citerad text -

- Visa citerad text -

Boeing was about to make newer models of 747 with the same
"supercritical wing" like the B777 and C17!

Were they?

So waht?

What happened with that project?

Dunno, maybe it fell dwon between the Schnitzelbank and the wall.
Have look maybe they'll give you clue as a reward for finding it.

And Bertie, where from to get the velocity V to put
intoBernoulli equation for the calculation of the pressure
difference?

Dunno, where from you get notion that one persone gives two kronas
what you think, k00kie boi?

Bertie- Dölj citerad text -

- Visa citerad text -

Do we agree that " different airflow path around wing" does not
give you the answer?

Nothing you post gives an answer.

I'll talk to you when you answer the last quetion I posed.

Why the cloud on top of the wing in those pics?

Bertie

Direct him to this website, tell him to read the WHOLE thing
and report back:
http://www.av8n.com/how/



So many of these guys don't want to read. They know it all
already.

And for that reason he either won't go there or he'll go and twist
everythign he saw to suit himself.

Bertie>

.

Relevant Pages

  • Re: would an AOA indicator be helpful in a glider?
    ... Every book on airfoils from the venerable Abbot's "Theory of Wing ... airfoils coefficient of lift vs. angle of attack. ... their time flying near stall don't have them has always puzzled me. ...
    (rec.aviation.soaring)
  • Re: Flatboarding: the sailing style
    ... A symmetrical wing at zero angle of attack has zero lift. ... it will have no lift - it will be in a zero-G flight path. ...
    (rec.skiing.alpine)
  • Re: Wind on the Wing
    ... > attack is shown. ... > And in fact the heating of air by the underside of the ... > working wing is seen. ... > At some angle of attack a force of drag increases ...
    (sci.physics)
  • Re: Flatboarding: the sailing style
    ... With a symmetrical airfoil, angle of attack is required for lift. ... It changes the flow of air over and under the wing, ...
    (rec.skiing.alpine)
  • Re: McLarens "horns"
    ... incidence of the wing to the aircraft, which is somewhat akin to the hand out ... it demonstrates the stall angle of an airfoil (usually around 16 ... your "angle of attack" theory ...
    (rec.autos.sport.f1)