Mxsmanic , IFR sensations, and some other stuff

On Thu, 22 May 2008 10:52:15 -0500, Michael Ash wrote:

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?

Because I eat beans?

writes:

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

Simple action and reaction.

BDS writes:

I agree that a flat wing will produce lift at a positive AOA even without an
airfoil shape - it just won't be as efficient as it would otherwise be if it
were shaped like an airfoil, and talk about pitch divergent...

Non-flat airfoil shapes help to increase the range of usable AOAs and reduce
drag, but a positive AOA is still required to generate lift.

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

It is a common misconception.

Stealth Pilot writes:

downwash occurs after the wing has passed.

Downwash is the result of the wing's passing. The wing accelerates air above
it downwards. That downward movement continues after the wing has passed, and
it is called downwash. It is the acceleration that produces the downwash that
is responsible for lift.

Gig 601Xl Builder writes:

If that were the case a 747 would have to be producing over 250,000
pounds of force straight down.

It does. The downward force is equal to the weight of the aircraft.

Why then am I not crushed when a 747 flies over me?

Because the entire force is not concentrated on the top of your head.

Jim Stewart writes:

I'm wondering why the airlines, FAA and the
military don't seem to be particularly
concerned about this....

It's too difficult to enforce in a culture where this type of substance abuse
is an institution.

Mxsmanic wrote:
Gig 601Xl Builder writes:

If that were the case a 747 would have to be producing over 250,000
pounds of force straight down.

It does. The downward force is equal to the weight of the aircraft.

Why then am I not crushed when a 747 flies over me?

Because the entire force is not concentrated on the top of your head.

Chuckle for the day :-)

--
Dudley Henriques

Mxsmanic wrote:
Jim Stewart writes:

I'm wondering why the airlines, FAA and the
military don't seem to be particularly
concerned about this....

It's too difficult to enforce in a culture where this type of substance abuse
is an institution.

Don't fsking quote me out of context.

wrote:
On May 22, 8:20 am, Stealth Pilot

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.

EXACTLY! GOD, somebody FINALLY nailed it. The ones that can't hang on
slam into the elevator and produce downwash.

-c

Jim Stewart writes:

Don't fsking quote me out of context.

I quote as I see fit.