A dumb doubt on stalls

Matt Whiting wrote in news:Sf_lg.9891$lb.874408
@news1.epix.net:

Skywise wrote:

Bob Moore wrote in
. 122:


Dylan Smith wrote

Snipola

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

This Wikipedia article leaves a lot to be desired.

Snipola

The beauty of Wikipedia is that YOU can change it.

Brian

Which is why it leaves a lot to be desired.

Matt

I have heard more than once that a collection of average
people is smarter than a few experts. If no one corrects
the data then it will continue to be wrong. I've been
seriously thinking of getting an account so I can make
changes as I see the need. Mostly minuscule stuff, but
every bit would help. The only concern I have is time.

I find it fascinating, the human capacity to bitch about
something, yet not have the willingness to actually DO
soemthing to fix the problem. I'll admit up front I've
done that myself, and it's something I should change.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?

Dylan Smith wrote:
Conventional light planes should not do that (i.e. certified, non-canard
designs).

A Morane Saulnier Rallye is a conventional certified light plane and it
just drops with its nose up and tail down when stalled.
But I suppose it is an exception to the rule.

-Kees.

wrote in
oups.com:


Dylan Smith wrote:
Conventional light planes should not do that (i.e. certified, non-canard
designs).

A Morane Saulnier Rallye is a conventional certified light plane and it
just drops with its nose up and tail down when stalled.
But I suppose it is an exception to the rule.

-Kees.



In the Rallye 235E, power off, as you reach full back on the yoke, you will
encounter mild buffet and descend in a level flight attitude at slightly
over 1,000 fpm with an IAS of about 40 MPH. Aerilons are still effective
and you can easily turn in this configuration without using your rudder.
(You will get a very nice adverse yaw demonstration doing this). Just relax
slightly from full back on the yoke and the nose drops immediately. For
more fun, keep the yoke back and slowly add power and watch your VSI jump
past +500 fpm while you are still encountering mild buffet.

--
Marty Shapiro
Silicon Rallye Inc.

(remove SPAMNOT to email me)

Hi Marty,

Rallyes are really fun, I miss mine from time to time. :-(

-Kees (D-EHNE)

wrote:
Hi Marty,

Rallyes are really fun, I miss mine from time to time. :-(

Great short field performance especially the 885

On 20 Jun 2006 03:30:46 -0700, wrote:

Is it possible for an aircraft to stall and sink nose-up tail-down
instead of pitching nose-down? Or does aircraft design inherently
preclude that?

Thanks in advance,

Ramapriya

Thinking about it simply, if the airplane is not generating lift, it should
fall with the heaviest end down. For most light GA a/c, the engine is up
front, so that end goes down first.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Ron Rosenfeld wrote:
Thinking about it simply, if the airplane is not generating lift, it should
fall with the heaviest end down. For most light GA a/c, the engine is up
front, so that end goes down first.


The wing's center of pressure moves forward as the stall is
approached, as the laminar flow over the top of the wing breaks up
toward the trailing edge and lift is lost over the aft area of the
wing. At the stall, the center of pressure moves aft as the whole
laminar flow goes turbulent, and the CP shift lifts the tail.
The loss of effective downforce on the stabilizer as speed
decreases contributes to the nose drop. That's the "heavy end down"
effect you speak of.

Dan

On Tue, 20 Jun 2006 07:36:13 -0400, Ron Rosenfeld
wrote in
::

On 20 Jun 2006 03:30:46 -0700, wrote:

Is it possible for an aircraft to stall and sink nose-up tail-down
instead of pitching nose-down? Or does aircraft design inherently
preclude that?

Thanks in advance,

Ramapriya

Thinking about it simply, if the airplane is not generating lift, it should
fall with the heaviest end down. For most light GA a/c, the engine is up
front, so that end goes down first.

You may recall, that Galileo Galilei (1564-1642) performed experiments
to verify that heavier bodies do not fall faster than lighter ones,
rather that they fall at the same rate, therefore your analysis is
incorrect.

While it is true, that an airplane in a vacuum will fall in any
orientation, in the atmosphere, it is practically impossible to
prevent the falling airplane's wings from providing some lift. Given
an airplane correctly loaded within its weight and balance envelope,
when the wing is generating lift, the center of lift is located behind
the aircraft's center of gravity. The center of gravity acts as a
fulcrum, and the lifting force aft of the CG is acting in the
direction roughly upward, while the gradational force acts uniformly
on the entire airplane in a downward direction resulting in the nose
dropping as the aircraft was designed.

On Tue, 20 Jun 2006 14:00:39 GMT, Larry Dighera wrote:

On Tue, 20 Jun 2006 07:36:13 -0400, Ron Rosenfeld
wrote in
::

On 20 Jun 2006 03:30:46 -0700, wrote:

Is it possible for an aircraft to stall and sink nose-up tail-down
instead of pitching nose-down? Or does aircraft design inherently
preclude that?

Thanks in advance,

Ramapriya

Thinking about it simply, if the airplane is not generating lift, it should
fall with the heaviest end down. For most light GA a/c, the engine is up
front, so that end goes down first.

You may recall, that Galileo Galilei (1564-1642) performed experiments
to verify that heavier bodies do not fall faster than lighter ones,
rather that they fall at the same rate, therefore your analysis is
incorrect.

While it is true, that an airplane in a vacuum will fall in any
orientation, in the atmosphere, it is practically impossible to
prevent the falling airplane's wings from providing some lift. Given
an airplane correctly loaded within its weight and balance envelope,
when the wing is generating lift, the center of lift is located behind
the aircraft's center of gravity. The center of gravity acts as a
fulcrum, and the lifting force aft of the CG is acting in the
direction roughly upward, while the gradational force acts uniformly
on the entire airplane in a downward direction resulting in the nose
dropping as the aircraft was designed.

You're both getting into a more complicated, thoughtful (and accurate)
analysis than I.
Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

The location of the center of gravity directly relates to an
aircraft's dynamic and static stability. Stall behavior
with a CG aft of the center of pressure on a wing will cause
the stalled aircraft to pitch deeper into the stall. The
stall buffet comes from disturbance of the air flow over the
wing root, but the actual stall comes from the tail.


--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


wrote in message
oups.com...
| Is it possible for an aircraft to stall and sink nose-up
tail-down
| instead of pitching nose-down? Or does aircraft design
inherently
| preclude that?
|
| Thanks in advance,
|
| Ramapriya
|