Individuology

 

June 24, 2007

The Myth of Lift

Continuing with negative models…

Some myths persist for centuries, like the earth being the center of the universe. Some for only a century, like ‘lift’, which supposedly keeps airplanes in the air. Let us look at this carefully, and also trust both our senses, and our minds.

Some theoreticians have created an abstract notion called ‘lift’. I consider it bogus, and here’s why. By the way, I’ll also show why it’s safe to fly.

Let’s look at a few of their definitions:

Lift: The lift force, lifting force or simply lift is a mechanical force generated by a solid object moving through a fluid.

The first red flag: It seems to me that a moving object doesn’t generate force; rather a force is need to make the object move.

The second red flag, air is a gas not a fluid!
Gases compress rather easily, and when compressed try to decompress, liquids or fluids, except under some extreme conditions do not.

Do try this at home:
Blow up a balloon. The tension of the balloon skin, compresses the air, keeping it from decompressing. Stick a pin in the balloon. The compressed air, given an opportunity decompresses very rapidly!

Here’s some help, I found. which is as clear as mud:
Sometimes the term dynamic lift or dynamic lifting force is used for the perpendicular force resulting from motion of the body in the fluid, as in an aerodyne, in contrast to the static lifting force resulting from buoyancy, as in an aerostat.

Again, air is a gas not a fluid!

Much of the supposed ‘lift’ of an aerodynamically shaped wing is attributed to Bernoulli’s principle which states: that in fluid flow, an increase
in velocity occurs simultaneously with decrease in pressure.

Yet again, air is a gas not a fluid!

They’ve even created wind tunnels where they blow air, with big fans past a stationary wing to determine its aerodynamic behavior. But that’s not what happens when you fly a plane. The air is sitting there rather happy, and undisturbed, and all of a sudden, you come along with your plane’s wing and try to penetrate the air. If you’re going slowly, say less than 60 mph, the air simply gets out of your way since it’s a rather flexible gas, almost fluid. But when you go faster than say 70+ mph, the air can’t get out of the way quick enough, so it compresses! Now it doesn’t take much compression for the air to get very firm, perhaps spongy is a better word. A mere 30 lbs. of pressure, can keep a 3000 lb. car off the ground.

So as a pilot, you look for air that you can ‘push against’. You compress it with your wing using speed, and as it tries to de-compress it pushes you up. Just like the dense cold air pushing the lighter hot air upwards. There is no mysterious force called ‘lift’, with a motor or batteries of it’s own that ’sucks’ you upward.

Regardless of the ‘aerodynamic shape’ of a wing, you can flip a plane upside down and continue to fly quite normally! acrobatic planes do it all the time. Indeed the shape of their wings is symmetric (same on top and bottom), not the popular ‘aerodynamic’ wing.

To see a diagram of an aerodynamic wing see:
Diagram of an aerodynamic wing

If you like this topic, here are some excellent pictures, see:
Blaniks-1
Blaniks-2

Supporting articles:
Newton on hot air

Another explanation, with fantastic pictures is at:

Air-balloons

Gravity pushes flames and hot air up:


Gravity

Naturally, if I ever have to take an FAA exam to get some sort of flying certificate, I’ll swear allegiance to the lie of lift, to get my license. But when caught in a micro burst, or spiraling to where my plane does not behave like a plane, but more like a rock, I’ll look for some air to ‘push against’!

No worries…

As I promised…

Flying is safe, or at least far safer than driving. The most dangerous part of any flight is driving to the airport, you can get yourself killed on the highway. But if lift is a myth, and the aircraft industry relies on it, why is it safe to fly? Mathematically, the same forces exist in the real world, regardless of how you describe them. Just as with hot air rising, whether the ‘lift’ sucks the plane upward or pushes it upwards, the same forces are at play, just the explanations are different, one easy and natural, one abstract and difficult.

Please DO try this at home:
When you’re driving in a car down a highway, put your hand out of the window. First, put it out flat, with your thumb facing the wind. Then turn it slightly, raising your thumb, and feel what you experience. I feel a compression of air on the underside, which tries to push my hand upwards. I do not feel any suction from above pulling the skin on the back of my hand upwards. But that is only my experience, you try it, and decide for yourself.

Further thoughts:

Does the same or a similar principle apply for water when skipping a stone across it! Why for the first 2-3 skips does the water not allow the stone to penetrate it, but by the 4-5 skip it does allow it to penetrate the surface of the water and sink to the bottom?

Filed under: Individuology — Bob Gorman @ 9:33 pm

June 19, 2007

On the Use of Negative models

We have so many negative models around that it is hard to think accurately sometimes. What I mean by negative forces, is explanations that propose a mysterious force, which can’t be measured, pushing, or more often pulling things around.

Case 1: Hot Air
Some people claim that ‘hot air rises’.
It’s as if the hot air has a little motor in it, or perhaps a battery that enables it to propel itself upwards. I doubt that.

A more useful model, for the real world, is that cold air, being more compressed, hence heavier, falls to the ground. We see this when we open a freezer and see the heavy cold air tumble out.

Now when that heavy, cold, compressed air pushes downward, due to gravity, it squeezes the lighter less compressed hot air out of it’s way, thus giving the illusion that hot air rises, when in fact, the cold air, as a side effect of its falling, due to gravity, pushes the hot air upward.

Try it yourself.

Filed under: Individuology — Bob Gorman @ 2:56 pm

June 16, 2007

Experiential and Abstract worlds

We all live in multiple worlds. There is the one shared world of everyday experience, where we bump into trees and get a lump on our heads. There is also the worlds we create in our heads, our own personal map of that shared world. To capture the entire experiential would overwhelm us, so we only capture those parts that we are interested in. We construct our personal worlds, or maps, based on our values, priorites, and expectations. This serves us well by reducing the ‘noise’ of the the full ‘real’ experiential world.

Then, since we all want to make things better in some way, we manipulate our private worlds, and refine them, and generate hypothesis, and test them, all with the single goal of making things better, in some way, for our selves and others, those we care about.

To understand others, who have created different maps of our common experiential world, we need to understand that they, like us, act based on their maps, not on the experiential territory.

This distinction, first made by Alfred Korzybski in 1933, is so fundamental to many of my ideas that I want to remove it from long fancy, technical words and make it very real for us ordinary folk. Since we have different individual preferences, here are 3 examples.

Visual example:

To make this clear, visually, here is a picture of a local airport both as the world is,

(Google Satellite photograph) and as we see it (Google Map View):

TerritoryMap

 

 

 

 

 

 

 


Clearly there is a difference, and when we think about things we must be clear about which world we are talking about. Confusing one with the other has caused countless mis-understandings.The really important rule is that:

We, and others, ACT based on our private maps of the world, NOT on the shared territory!

Audio example: The difference between a bird singing, and a recording of that bird singing.

Kinesthetic example: The difference between flying an airplane, and reading about how to fly a plane.

Filed under: Individuology — Bob Gorman @ 9:47 pm

June 1, 2007

Respect for Individuals counts…

This blog has one central theme. To improve many of the worlds most pressing human problems, we must start with total & complete Respect for Individuals.

Filed under: Individuology — Bob Gorman @ 7:40 pm

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