Mxsmanic , IFR sensations, and some other stuff

"Maxwell" luv2^fly99@cox.^net wrote in news:ymVZj.1162$v94.724
@newsfe14.lga:


"Bertie the Bunyip" wrote in message
...

Good link but I think he kind of munged up the lift/drag thing as
being
seperate entities, when they're inextricably linked. IOW you create
lift
and drag is a by product. Not to say, BTW, that the correlation is
rigid!


Bertie

Posted by a forger.






Snort!



Bertie

wrote:
On May 22, 5:36 pm, Some Other Guy wrote:
BDS wrote:
There is an interesting article in Flying magazine by Peter Garrison that
talks about lift theory.
I thought that one of the most interesting points he made was that the
lift force generated by an airfoil is greater at the optimum angle of
attack than would be the force imparted to it if you were to move it
through the air perpendicular to the air flow at the same speed.
I first experienced this as a kid, sticking my hand out the car window with
the thumb as a leading edge, forming a crude airfoil.

When at the right shape and angle of attack, the lift is amazingly strong.
I always found it remarkable that when my hand was completely
perpendicular to the wind, the force didn't seem as strong.

Definitely a visceral lesson in lifting versus stalling.

I have a copy of that article here. Very, very good. The
coefficient of lift, as he described it, was a ratio related to the
lift generated by a unit area of wing compared to the flat-plate drag
created by the same unit area perpendicular to the airflow. The Wright
brothers did this in their wind tunnel, so they were able to develop
efficient airfoils. A common airfoil (NACA 23012, IIRC) has a max lift
coefficient of 1.8 , which means that it generates 1.8 times the lift
as the drag of the perpendicular surface of the same area.
He made things really clear when he pointed out that this is why
boats and ships no longer use paddlewheels. The wheel will produce
forward thrust equivalent to the power required to force the paddle
back through the water, while the propeller (they call it a "screw")
will produce much more forward thrust for the same torque required by
the paddlewheel.
So it's a process to cause the air to exert a force in a
direction perpendicular to the airflow. It fools the air, if you like,
which is why we call it an "air foil." A foil is a device to deceive.
Bernoulli is right, and so is Newton. There's a pressure
difference because of the difference in airspeeds between top and
bottom, and there's a movement of air downward to which there's an
upward reaction. The equal-transit time theory is bogus, since the
airfoil is much more efficient than that theory would imply. See this
page:
http://www.av8n.com/how/htm/airfoils.html
And, again, Mxmanic has declared, for about the 12th time, that
positive AOA is necessary for lift. If this was so, and it isn't, and
he has been shown many times that it isn't, then airfoils like the
Clark Y wouldn't generate lift at AOAs as low as -4 degrees. That's
negative 4 degrees, airfoil chord pointing downward. A graph can be
found a third of the way down this page: http://lpmpjogja.diknas.go.id/kc/a/air/airplane.htm
That page also deals properly with both Newton and Bernoulli.

Dan



Perhaps if we stray from a Clark Y and discuss symmetrical
airfoils............... :-))

--
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

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.

writes:

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

Simple action and reaction.

On May 22, 1:08 pm, Mxsmanic wrote:
writes:
What about rocket propulsion in a vacuum? How does that work?

Simple action and reaction.

Mmmm...but your action has nothing to react against, there's nothing
to push down on like you said with downwash producing lift for an
airplane wing.

On Fri, 23 May 2008 12:59:08 -0700 (PDT), wrote:

On May 22, 1:08 pm, Mxsmanic wrote:
writes:
What about rocket propulsion in a vacuum? How does that work?

Simple action and reaction.

Mmmm...but your action has nothing to react against, there's nothing
to push down on like you said with downwash producing lift for an
airplane wing.

huh??? the push is against the inside top of the rocket.
the hole at the bottom where all manner of stuff rushes out is in
reality the part where the push is missing. ...thats for a gunpowder
rocket.

for a nasa fuel rocket the push is against the conical part of the
rocket motor because of the way the pressure is generated.

....its not rocket science you know!

Stealth Pilot