Mxsmanic , IFR sensations, and some other stuff

wrote:
Dudley Henriques wrote:

Any article that "discounts Bernoulli" as having anything to do with
lift is incorrect. I just can't understand why there is so much trouble
in the pilot community understanding that Newton and Bernoulli do NOT
conflict in any way whatsoever, and that each explanation is correct in
itself. Newton AND Bernoulli are BOTH present simultaneously on th wing
at any moment lift is being created. EACH creates the other and EACH is
a complete explanation for how lift is created.

You can use either Newton or Bernoulli to explain lift, but the correct
way to explain it is to explain how both are correct.
In other words, anytime you have lift being created you have a Newton
explanation AND a Bernoulli explanation occurring at the SAME TIME!

Most people seem to want simple, one size fits all answers to
everything and forget that most real life things, e.g. what causes
lift and what causes cancer, are complex and can't be boiled down
into a 10 second sound bite.


This is exactly correct.

Lift explanation in it's true form is an extremely complicated issue.
Attempts to explain it in one simple sentence is usually very confusing
to a new student pilot.
The closest thing to a one sentence explanation I have seen is that lift
is created by turning an airflow.
Of course this covers Newton and leaves Bernoulli out there to be
discovered later on as one finally comes to realize that you can't turn
the airflow without having the pressure difference :-)

The best way to handle the lift question is to openly discuss both
Newton and Bernoulli and how they interact to create each other while
creating what we call lift.

--
Dudley Henriques

"Dudley Henriques" wrote

Lift explanation in it's true form is an extremely complicated issue.
Attempts to explain it in one simple sentence is usually very confusing
to a new student pilot.
The closest thing to a one sentence explanation I have seen is that lift
is created by turning an airflow.
Of course this covers Newton and leaves Bernoulli out there to be
discovered later on as one finally comes to realize that you can't turn
the airflow without having the pressure difference :-)


I hadn't looked into this much in recent years and the article rekindled
some interest. I hadn't even heard of the "equal transit theory" before you
mentioned it, but a short search brought up a detailed explanation of
exactly what you are talking about, and turning the airflow is ultimately
what it's all about for both Bernoulli and Newton.

BDS

In rec.aviation.student Gig 601Xl Builder wrote:
Mxsmanic wrote:
Stealth Pilot writes:

aeroplanes fly because of lift generated by pressure differences on
the wing surfaces.

Airplanes fly because the wings divert the air through which they pass
downwards, creating a downwash and exerting a force in doing so that engenders
an opposite force that is lift.

... these pressure differences are caused by the shape
of the aerofoil of the wing ...

The air is diverted because the wing has a positve angle of attack. It can be
perfectly flat and it will still generate lift.

If that were the case a 747 would have to be producing over 250,000
pounds of force straight down. Why then am I not crushed when a 747
flies over me?

At sea level the atmosphere pushes down with about 14.7 pounds of force
for every square inch of exposed surface. On the average man, this works
out to about 43,000 pounds, all the time. Why aren't your crushed by this?

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon

Michael Ash wrote:


At sea level the atmosphere pushes down with about 14.7 pounds of force
for every square inch of exposed surface. On the average man, this works
out to about 43,000 pounds, all the time. Why aren't your crushed by this?


I don't know about you but Celine Dion gave me an invisible force-field.

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums...ation/200805/1

BDS wrote:
"Dudley Henriques" wrote
Lift explanation in it's true form is an extremely complicated issue.
Attempts to explain it in one simple sentence is usually very confusing
to a new student pilot.
The closest thing to a one sentence explanation I have seen is that lift
is created by turning an airflow.
Of course this covers Newton and leaves Bernoulli out there to be
discovered later on as one finally comes to realize that you can't turn
the airflow without having the pressure difference :-)


I hadn't looked into this much in recent years and the article rekindled
some interest. I hadn't even heard of the "equal transit theory" before you
mentioned it, but a short search brought up a detailed explanation of
exactly what you are talking about, and turning the airflow is ultimately
what it's all about for both Bernoulli and Newton.

BDS



It's a complicated issue that many in aviation accidentally make even
more complicated by delving too deeply into their physics books instead
of learning to shave with Occam's Razor :-))

--
Dudley Henriques

wrote:
On May 21, 12:56 pm, Mxsmanic wrote:
Stealth Pilot writes:
aeroplanes fly because of lift generated by pressure differences on
the wing surfaces.
Airplanes fly because the wings divert the air through which they pass
downwards, creating a downwash and exerting a force in doing so that engenders
an opposite force that is lift.

So you're saying the sky does suck after all?

What about rocket propulsion in a vacuum? How does that work?

I've repeatedly explained to these guys that camber was just a
conspiracy by the aluminum industry to sell more metal.

I don't know why Boeing, Cessna, Piper, Beechcraft and everybody else
don't listen to Mxmaniac. CAMBER IS A LIE!!!

-c

"BDS" wrote:
There is an interesting article in Flying magazine by Peter Garrison
that talks about lift theory.

[...]

Oh yeah, the article also pretty much discounts Bernoulli as having
anything to do with why a wing produces lift.

The Bernoulli equations aren't wrong. It is a simply a case that they apply
ONLY to a set of streamlines. Once the streamlines are determined, the
Bernoulli equation should be able to tell you the lift of an airfoil.
Explanations that point to Bernoulli and then fail to discuss how and
whence the streamlines are determined for a problem are bound to lead to
confusion and misunderstanding.

On May 22, 10:15 am, wrote:
Dudley Henriques wrote:
Snipped

Most people seem to want simple, one size fits all answers to
everything and forget that most real life things, e.g. what causes
lift and what causes cancer, are complex and can't be boiled down
into a 10 second sound bite.

--
Jim Pennino

Remove .spam.sux to reply.

Careful there; next you'll be telling us that we shouldn't nationalize
the oil companies, tax all profits and generally use a Marxist
economic system in an effort to 'simplify' our complex energy issues.

On May 22, 11:51 am, gatt wrote:
wrote:
On May 21, 12:56 pm, Mxsmanic wrote:
Stealth Pilot writes:
aeroplanes fly because of lift generated by pressure differences on
the wing surfaces.
Airplanes fly because the wings divert the air through which they pass
downwards, creating a downwash and exerting a force in doing so that engenders
an opposite force that is lift.

So you're saying the sky does suck after all?

What about rocket propulsion in a vacuum? How does that work?

I've repeatedly explained to these guys that camber was just a
conspiracy by the aluminum industry to sell more metal.

I don't know why Boeing, Cessna, Piper, Beechcraft and everybody else
don't listen to Mxmaniac. CAMBER IS A LIE!!!

-c

No no, aluminium was a conspiracy by Westinghouse and Edison (and
proly Tesla too) to sell more electricity via the Bayer process! Or
was it the other way 'round? Westinghouse was a conspiracy by the
electricity conglomerates to produce more beer cans? Hmmm....let me
adjust my Reynolds Cap.

On May 22, 8:20 am, Stealth Pilot
wrote:
On Wed, 21 May 2008 19:56:35 +0200, Mxsmanic
wrote:

Stealth Pilot writes:

aeroplanes fly because of lift generated by pressure differences on
the wing surfaces.

Airplanes fly because the wings divert the air through which they pass
downwards, creating a downwash and exerting a force in doing so that engenders
an opposite force that is lift.

... these pressure differences are caused by the shape
of the aerofoil of the wing ...

The air is diverted because the wing has a positve angle of attack. It can be
perfectly flat and it will still generate lift.

downwash occurs after the wing has passed. how does it transmit its
effect to the wing? magnetism?

Sorta. The girl lift fairies push from underneath whilst the boy lift
fairies pull from up top. The obese lift fairies just hang on and
thus produce drag.