Air, Low Pressure, High Pressure, Lateen Sail, Flight, Wing, Lift, Drag, Leading Edge Slats, Trailing Edge Flaps and Angle of Attack

Posted by PITHOCRATES - October 10th, 2012

Technology 101

There’s more to Air than Meets the Eye even though it’s Invisible

When you take a shower have you noticed how the shower curtain pulls in towards you?  Have you ever wondered why it does this?  Here’s why.  Air has mass.  The water from the showerhead sends out a stream of water drops that also has mass.  So they fall to the floor of the shower.  Pushing air with it.  And pulling air behind it.  (Like drinking through a straw.  As you suck liquid out of the straw more liquid enters the straw.)  So you not only have a stream of water moving down alongside the shower curtain.  You also have a stream of air moving down alongside the shower curtain.

As the falling water sweeps away the air from the inside of the shower current it creates a low pressure there.  While on the outside of the curtain there is no moving water or air.  And, therefore, no change in air pressure.  But there is a higher pressure relative to the lower pressure on the inside of the shower curtain.  The low pressure inside pulls the curtain while the high pressure outside pushes it.  Causing the shower curtain to move towards you.

There’s more to air than meets the eye.  Even though it’s invisible.  It’s why we build modern cars aerodynamically to slice through large masses of invisible air that push back against cars trying to drive through it.  Making our engines work harder.  Consuming more gas.  And reducing our gas mileage.  While race cars will use spoilers to redirect that air up, forcing the weight of the car down on the tires.  To help the tires grip the road at higher speeds.  We even design skyscrapers to be aerodynamic.  To split the prevailing winds around the buildings to prevent large masses of air from slamming into the sides of buildings, minimizing the amount buildings sway back and forth.

We put the Engines on, and the Fuel in, the Wings to Counteract the Lifting Force on an Aircraft’s Wings

Air can be annoying.  Such as when the shower curtain sticks to your leg.  As it steals miles per gallon from your car.  When it shakes the building you’re in.  But it can also be beneficial.  As in early ship propulsion before the steam engine.  Large square-rigged sails that pushed ships along the prevailing winds.  And triangular lateen sails that allowed us to travel into the wind.  By zigzagging across the wind.  With the front edge of a lateen sail slicing into the wind.  The sail redirects the wind on one side of the sail to the rear of the boat that pushes the boat forward.  While the wind on the other side follows the curved sail creating a low pressure that pulls the boat forward.  Like the inside of that shower curtain.  Only with a lot more pulling force.

Harnessing the energy in wind let the world become a smaller place.  As people could travel anywhere in the world.  Of course, some of that early travel could take months.  And spending months on the open sea could be very trying.  And dangerous.  A lot of early ships were lost in storms.  Ran aground on some uncharted shoal.  Or simply got lost and ran out of drinking water and food.  Or fell to pirates.  So it took a hearty breed to travel the open seas under sail.  Of course today long-distant travel is a bit easier.  Because of another use for air.  Flight.

Like a lateen sail an aircraft wing splits the airflow above and below the wing.  And like the lateen sail an aircraft wing is curved.  The air pushes on the bottom of the wing creating a high pressure.  While the air passing over the curve of the top of the wing creates a low pressure.  Pulling the wing up.  In fact, it’s the wind passing over the top of the wing that does the lion’s share of lifting airplanes into the air.  The low pressure on top of the wing is so great that they put the engines on the wings, and the fuel in the wings, to counteract this lifting force.  To prevent the wings from curling up and snapping off of the plane.  Planes with tail-mounted engines have extra reinforcement in the wings to resist this bending force.  So those lifting forces only lift the plane.  And not curl the wing up until it separates from the plane.

To make Flying Safe at Slow Speeds they add Leading Edge Slats and Trailing Edge Flaps to the Wing

Sails can propel a ship because a ship floats on water.  The wind only propels a ship forward.  On an airplane the wind moving over the wings provides only lift.  It does not propel a plane forward.  Engines propel planes forward.  And it takes a certain amount of forward speed to make the air passing over the wings fast enough to create lift.  The faster the forward air speed the greater the lift.  Today jet engines let planes fly high and fast.  In the thin air where there is less drag.  That is, where the air has less mass pushing against the forward progress of the plane.  At these altitudes the big planes cruise in excess of 600 miles per hour.  Where these planes fly at their most fuel efficient.  But these big planes can’t land or take off at speeds in excess of 600 miles per hour.  In fact, a typical take-off speed for a 747-400 is about 180 miles per hour.  Give or take depending on winds and aircraft weight.  So how does a plane land and take off at speeds under 200 mph while cruising at speeds in excess of 600 mph?  By changing the shape of the wing.

We determine the amount of lift by the curvature and surface area of the wing.  The greater the curvature the greater the lift.  However, the greater the curvature the greater the drag.  And the greater the drag the more fuel consumed at higher speeds.  And the more stresses placed on the wing.  Also, current runways are about 2 miles long for the big planes.  That’s when they land and take off at speeds under 200 mph.  To land and take off at speeds around 600 mph would require much longer runways.  Which would be extremely costly.  And dangerous.  For anything traveling close to 600 mph on or near the ground would have a very small margin of error.  So to make flying safe and efficient they add leading edge slats to the front edge of the wing.  And trailing edge flaps to the back edge of the wing.  During cruise speeds both are fully retracted to reduce the curvature of the wing.  Allowing higher speeds.  At slower speeds they extend the slats and flaps.  Greatly increasing the curvature of the wing.  And the surface area.  Providing up to 80% more lift at these slower speeds.

At takeoff and landing pilots elevate the nose of the aircraft to increase the angle of attack of the wing.  Forcing more air under the wing to push the wing up.  And causing the air on top of the wing to turn farther away for its original direction of travel as it travels across the top of the up-tilted wing.  Creating greater lift.  And the ability to fly at slower speeds.  However, if the angle of attack it too great the smooth flow of air across the wing will break away from the wing surface and become turbulent.  The wing will not be able to produce lift.  So the wing will stall.  And the plane will fall out of the sky.  With the only thing that can save it being altitude.  For in a stall the aircraft will automatically push the stick forward to lower the nose.  To decrease the angle of attack of the wing.  Decrease drag.  And increase air speed.  If there is enough altitude, and the plane has a chance to increase speed enough to produce lift again, the pilot should be able to recover from the stall.  And most do.  Because most pilots are that good.  And aircraft designs are that good.  For although flying is the most complicated mode of travel it is also the safest mode of travel.  Where they make going from zero to 600 mph in a matter of minutes as routine as commuting to work.  Only safer.

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Airbus proposing Measures to Reduce the Aviation Carbon Footprint that may make Flying more Dangerous

Posted by PITHOCRATES - September 9th, 2012

Week in Review

Airplanes are very complex machines.  They fly at speeds 3-4 times the speeds they land and take off at.  Which requires leading edge slats and trailing edge flaps to curve the wing more at low speed to increase lift.  While flattening it out more at high speeds to reduce drag.  When landing pilots put the engines into reverse thrust to help slow the plane down.  So they even use fuel to slow down.

And speaking of fuel it’s expensive.  Airlines carry as little of it as possible in their airplanes to reduce weight which reduces costs.  Sometimes bad weather forces planes to go to an alternate airport.  Sometimes there are strong headwinds.  Sometimes they fly into Heathrow and have to circle for a half hour or so to land.  Because they only have two runways.  Compounding this problem planes are getting lighter and engines are getting more efficient.  Allowing airlines to carry even less fuel.  So it is not uncommon for a pilot to declare a fuel emergency because of unexpected additional flying time.

When flying in the air highways air traffic controllers keep airplanes separated by large distances.  To keep them from running into each other.  The more distance the better so they can take evasive actions to avoid bad weather cells.  Or allow a plane some leeway in case they have a system malfunction (like plugged pitot tubes feeding false air speed and altimeter readings into the autopilot) that takes the plane off course.  Or in case a plane flies into some clear air turbulence (CAT) and it drops out of the sky 1,000 feet or so.  Or rises 1,000 feet or so.  Two things that allow a plane to recover from unplanned events like these are empty skies around you and altitude.

Aviation has come a long way.  And Boeing and Airbus are making some incredible airplanes.  So they know a thing or two about flying an airplane.  And it shows in their planes.  Which makes it hard to take them seriously when they talk about ways to reduce their carbon footprint by making flying more risky (see Airbus To Present Measures To Reduce Industry’s Environmental Footprint by Jens Flottau posted 9/6/2012 on Aviation Week).

Airbus on Sept. 6 will unveil five measures it says will make the aviation industry environmentally sustainable by 2050 despite projected growth for global air transport…

Airbus also foresees a new method for takeoff, with renewably powered propelled acceleration allowing aircraft to climb steeper and reach cruise altitude faster. This in turn would allow airports to build shorter runways and minimize land use.

Once in cruise, aircraft should be able to self-organize and select the most efficient routes, says Airbus. On dense routes, aircraft could fly in formation, like birds, to take advantage of drag reduction opportunities.

In Airbus’ vision, aircraft will descend without using engine power or air brakes and would be able to decelerate quicker and to a lower final approach speed enabling them to use shorter runways…

Fuel is a key component of Airbus’ proposal, and the manufacturer says the use of biofuels hydrogen, electricity and solar energy will be required to reduce the industry’s environmental footprint.

You simply can’t build shorter runways.  Because planes aren’t perfect.  Sometimes things happen.  If we had shorter runways what would happen to a plane landing with damaged leading edge slats or trailing edge flaps?  And they have to land at a higher speed than normal because they can’t curve the wing to create more lift at lower speeds?  And what if a plane’s thrust reversers failed to deploy?  This is why we have long runways.  To give planes with problems a better chance to land safely.

Flying commercial jets in formation?  Not a good idea.  One of the most dangerous things to do in the Air Force is aerial refueling.  Where two large planes get real close to each other.  If they bump into each other they could cause some damage.  Even cause them to crash.  Flying in formation would be exhausting for a pilot.  Or they could entrust their formation flying to an autopilot.  But if they hit some CAT and get thrown around in that airspace they could get thrown into each other.  Even while flying on autopilot.  Planes also make their own turbulence.  Which is why there are larger distances between the big planes (i.e., the heavies) and the small ones.  So the small ones don’t get flipped over by some spiraling wingtip vortex turbulence off the heavy in front of it.

Solar energy?  Really?  How?  It’s not going to propel a jumbo jet.  And if they think they’re going to save on engine emissions by using solar panels on the wings to produce electricity for the cabin lights and electronics I don’t think that will work.  The emissions from the electrical load on those engines may be negligible compared to emissions they make producing thrust for flight.  And if they add more weight (solar panels) that will only take more fuel for flight.  Which will release more emissions.  Finally, a lot of planes fly at night.  When there is no sunshine.  What then?

Trying to reduce a plane’s carbon footprint will only make flying more dangerous.  It’s one thing to throw money away building solar panels and windmills on the ground.  For that’s just ripping the people off.  But applying this nonsense to aviation may end up killing people.  It’s hard to believe that Airbus is serious with these suggestions.  One wonders if they’re just proposing this to get those proposing that carbon trading scheme to back off as it will increase the cost of flying.  Which will reduce the number of people flying.  And reduce the number of planes Airbus can sell.  Perhaps by dangling this green future of aviation they may buy some time before the carbon trading scheme kills the aviation industry.

Fighting nonsense with nonsense.  It’s just as good an explanation as any.

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Property Rights and Contracts

Posted by PITHOCRATES - March 26th, 2012

Economics 101

We put a lot of Money and Time into Maintaining Property we Own so we can Enjoy it Exclusively

Have you ever bought the Brooklyn Bridge?  I hope not.  For if you have someone probably conned you.  Unless you bought it from the New York City Department of Transportation (DOT).  Because they currently own the Brooklyn Bridge.  And are the only ones who can sell it.  But the last I checked they weren’t selling.  So I doubt they sold it to you.  If you are about to enter into negotiations to buy the Brooklyn Bridge I suggest you do a title search first.  To verify that the seller in fact owns the property.  Has the right to sell the property.  And that the seller is selling the property ‘free and clear’.  To make sure you don’t have to pay any outstanding construction bills for work completed on the bridge that the DOT didn’t pay.  Then and only then should you buy your bridge.  So you can enjoy the pride of bridge ownership.  While charging tolls.  And getting rich.

This illustrates a central point about buying and selling things.  Property rights.  Which lets us buy things.  And sell them.  For to sell something we must first own it.  And to buy something we must know that we can own it.  Because if we’re not sure we can own it we’re not going to exchange our hard-earned money for it.  And once we own something we’re going to use it however we wish to use it.  At least that’s what we expect to do.  If we buy a house with a pool in the yard we’re going to want to use that pool exclusively.  Because we paid for it.  And keep it clean.  By maintaining the pool filters and pumps.  Adding chlorine.  Vacuuming the bottom.  We’re going to put a lot of money and time into maintaining that pool so we can enjoy it.  Our little tropical paradise in our own backyard.  But we’re not going to do all of that if just anyone can walk into our yard and use our pool whenever they damn well please.  For if that were the case we wouldn’t spend the time and money in the first place.  We’d look for a pool we could use for free.  Like everyone else who thought they could walk into our yard and use our pool whenever they damn well please.

Or would we?  Let’s say someone in your neighborhood just moved in.  They put in a nice in-the-ground pool.  Spent a fortune on it.  Kept it pristine.  And used it exclusively.  They were happy.  Until the subprime mortgage crisis hit.  And all of a sudden they owed far more on their mortgage than the house was worth.  So one night they just disappeared.  And let the bank have the house.  Once you notice their house is empty you think about that pool.  And decide what could it hurt if you went over for a swim?  You go there.  Notice they left the pumps and filters on.  And the pool is still pretty clean.  So you enjoy a swim or two.  Others find out.  And go over for a swim.  A lot of them.  The pool is crowded.  And not so clean anymore.  No one is skimming the garbage out of it.  Or maintaining the chlorine level.  Some of the kids are even peeing in the pool instead of getting out of it.  Soon the pool begins to smell bad.  Algae is growing.  The filters plug up.  With the water flow blocked the pumps strain and trip the circuit breaker.  Stopping the pumps.  And the filtering.  The crud they filtered out backs up into the pool.  Soon the water turns a greenish gray.  And looks more like a stagnant pond where dead fish float on the surface than the pristine tropical paradise it once was.

We can trace most Pollution and Environmental Damage back to the Tragedy of the Commons

Economists call this the Tragedy of the Commons.  Which is what happens when we poorly define our property rights.  In our example the pool was clean and enjoyable when someone owned the pool.  When no one owned the pool (after the previous owners abandoned it) the pool became dirty and no longer enjoyable.  Why?  Because when we own something we have an incentive to take care of it.  For our long-term enjoyment.  When no one owns it no one has an incentive to take care of it.  Some may try but others will continue to pollute.  Because they don’t own it.  And have no incentive to spend the time and money to keep it clean.  Especially when others are still polluting.  So no one tries to keep the pool clean.  They’ll enjoy it while they can.  And when the pollution gets so bad they will move on and find something else to enjoy. 

We can trace most pollution and environmental damage back to the Tragedy of the Commons.  If you love the beach so much that you buy a house on it you will keep your beach clean.  You’re not going to litter it with cigarette butts, empty bottles, food wrappers, used condoms, etc.  A public beach, on the other hand, is a different story.  Just as people will take their trash to a public field to dump it.  Because they don’t own that land and have no incentive NOT to pollute it.  And it’s cheaper than taking their trash to the private landfill that charges a fee.  Who helps to keep America beautiful by burying our trash.  And when the landfill is full someone else will buy it and make a beautiful golf course out of it.  Or something else.  As long as someone owns it something nice will happen with that land.  To maintain the value of that land to the landowner.

When you own something it has value to you.  Such as a logging company cutting down trees on land they own.  Because this land has value they will not over-log it.  And when they cut down trees they will plant new seedlings.  So the land continues to have value.  Because they will be able to cut down these seedlings after they grow into trees.  Or the future owner of that land will be able to.  Who will buy that land because it has value.  Whereas there is no incentive for a private logger working on public land NOT to over-log it.  Or to plant seedlings.  Because they don’t own that land.  Anything they don’t cut down some other logging company will.  And without any property rights to that land they won’t plant any seedlings.  Because nothing will prevent anyone else from cutting these down once they grow into trees.

Well Defined Property Rights allow Buyers and Sellers to Enter into Contracts with one Another

To do all of this buying and selling we need well defined property rights.  Clearly spelling out what the seller owns.  And what exactly the buyer is buying.  For example, a logging company buying a tree farm may want to drill an exploratory well to see if there is oil or natural gas under that land.  So he or she will want to make sure that the terms of the sale include all mineral rights.  Paying additional for these rights if necessary.  Or getting the tree farm at a lower price than other comparable tree farms because the seller wants to retain the mineral rights.

Well defined property rights allow buyers and sellers to enter into contracts with one another.  Contracts clearly state the terms of sale and any other special provisions.  Such as the seller retaining his or her right to have his or her pick of one tree anywhere on that land once a year in the month of December.  As long as buyer and seller freely enter into these agreements they expect each other to honor the terms of the contract.  And only when both parties honor the terms of the contract does the ownership of property transfer from one party to another.

Property has value.  Even the Brooklyn Bridge.  And well defined property rights protect that value.  Because the DOT owns that bridge they spend money to maintain that bridge.  A well-maintained bridge provides value for those who want to cross the East River.  Currently the various taxes they pay to the city and state make their way to the DOT.  To pay for that maintenance.  But if the city of New York found itself in serious financial trouble they could sell the Brooklyn Bridge.  To a private person.  Who wants to put up toll booths on the bridge.  The city gets a large sum of money to help with their financial trouble.  And the new private owner gets a revenue stream in the form of tolls.  And the city of New York will, of course, screw those crossing the East River.  Because they’ll now have to pay a toll to cross the Brooklyn Bridge.  But they won’t get any of their taxes back.  Because governments rarely if ever cut their taxes.  The city and the private person do well because they both have well defined property rights.  And a contract.  The people using the bridge don’t.  They had no contract with the city that clearly stated the terms for their use of that bridge.  And will continue to pay the taxes that paid their crossing fees.  As well as the new tolls.  Which is business as usual.  Because government always screws the taxpayers.  Who are always at a disadvantage when it comes to property rights and contracts when dealing with the government.  For government has the power to break contracts and take property.  Unlike private persons entering into contracts.  Who only transfer the ownership of property by mutual consent.

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Mounted Knights, Chivalry, Vassalage, Feudalism and Monarchy

Posted by PITHOCRATES - January 5th, 2012

Politics 101

Vassalage bonded the Knight and the Lord together in Mutual Obligations

After the collapse of the Roman Empire land was everything.  You either held land.  Or took land.  Both of which you did with military might.  And during Medieval Europe you did that with cavalry.  Heavy cavalry.  In particular, the mounted knight.  The king of battle.  For few could stand their ground with one to two tons of armored man and horse charging at them.  Where the choices were to be skewered by lance, slashed by sword, trampled by hoof or run away.

This was the age of chivalry.  Of glorious combat.  Where nothing was more gentlemanly than riding bravely into battle.   Suited up in gleaming, and very expensive, armor.  Which made the knight an expensive combat weapon.  Not just anyone could do this.  For you needed wealth.  And the only way to get wealth was by owning land.  Which few owned.

One way to become a landowner was to become a knight.  If you were a gentlemanly warrior who loved to fight you could offer your services to a lord who did own land.  Become his vassal.  In the system of vassalage.  Which bonded the two together in mutual obligations.  The knight agrees to fit horses and men for very expensive mounted warfare.  And the lord provides land for the knight’s use for raw material and wealth to fit his men and horses for battle.

When Knights were not at War they Built their Castles and Managed their Lands

We generally call this arrangement feudalism.  Though definitions vary.  But it’s the vassal relation that’s key.  The knight is bound to the lord and agrees to provide military service.  In exchange the lord provides land for the knight’s use and offers other protections within his powers.  Feudalism is similar to Manorialism.  Where a manor is basically a large farm owned by the Lord of the Manor.  Peasants (i.e., serfs) attached to the land (meaning they are not free to leave) work the land.  The lord provides for them.  And this serfdom provides for their lord.

A lord may own more than one manor.  And have his vassals run these manors.  Or a lord may split up larger landholding to accommodate a new vassal.  Or he could use his military might of mounted knights to conquer neighboring lands and give knights who showed exemplary valor in battle a portion of the newly conquered land.  When knights were not at war they built their castles.  And managed their lands.

Similar systems operated like this in different regions.  A particular region may have a ‘lord’ with large landholdings and military might.  To protect their land from others.  Or to expand their landholdings at the expense of their neighbors.  This was a time before nations.  Even before kings.  Power resided with the landed aristocracy.  Those who owned great tracts of land.  The source of food.  Raw materials.  And wealth.  Land managed by their vassals.  Who answered their call when it was time to strap on the armor and flex some military muscle.

The Many, the Few and the One

Feudalism gave way to monarchy.  Which was similar to feudalism.  Only the lords entered into a vassal relationship with their king.  Who often rose to power to unite and lead his lords to defend against a common enemy.  An enemy that was too great for one lord to fight alone.  Such as the marauding Vikings that the English king Alfred the Great subdued.  Or the spread of Muslim Arabs into southern Gaul (modern day France) that the Carolingian king Charles Martel repulsed.

Kings arose to consolidate power.  Lords continued to own land.  Passing it, and their title, on to their heirs.  Setting the next stage of political governance.  The relationship between the king and the aristocracy.  And their relationship with the people.  The many, the few and the one.

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Hmmm, Help the Economy or Class War?

Posted by PITHOCRATES - September 17th, 2010

Do you know why some Democrats are now urging their leaders to extend the George W. Bush tax cuts?  That’s right, because Bush and the Republicans were right. 

The Democrats want to tax and spend.  But you can’t tax and spend if you don’t win reelection.  And there lies the problem.  They’ve crashed the economy.  Created a permanent underclass.  And shook down the average working stiff to pay for it.  The problem the Democrats have is that there are still too many people who want to have a job.  And until they can take the vote away from these people, they can’t just take their money.  They have to…represent them.  Yeech.  (That would be how these Democrats feel.  Personally, I feel that representing your constituent is a beautiful thing.  So rare these days.)

You see, Democrats are elitists.  They’re part of the Washington aristocracy (which includes RINOs, too).  Life was simpler in the 15th century.  Or so they would think.  And this is what they would say.  If they were honest. 

People knew their places in the 15th century.  The noble classes owned the land.  And the land was everything.  The lord of the manor enjoyed the good life while the peasants worked the land.  Feudalism.  The way it was supposed to be.  Not these days.  This uppity middle class works wherever they want and does whatever they wish.   With no deference to us.  We who are better than they.  No, they act, well, as if they are our equals.  Imagine that!  These impertinent, despicable guttersnipes.

But they’re not honest.  So they don’t say this.  But when they act against the will of the people, they don’t have to.  Their actions speak louder than words.

So now they must deign to listen to these voters.  And these voters want something that’s alien to them.  Jobs.  So they must turn to the alchemy of the Republican Party.  That mysterious witch’s brew.  They have no idea what it is.  But it stimulates the economy.  For real.  It’s one part tax cuts.  Something else.  They don’t know.  It’s all Greek to them.  They don’t know anything about the economy.  But when the Republicans get their way, a crap-load of money comes into Washington.  And they can take it from there.  For they know how to spend that money.  Their money.  So they’ll act like Republicans.  For a little while.  Just long enough to make it through another election cycle.  Then they can stop that nonsense and return to tax and spend.  With a great, big pile of new money.  Their money.  Yeah, that’s right.  To them, it’s all their money.  If only us dunderheads would get it through our thick skulls.

So the Washington aristocracy will call a temporary truce in the class war.  And they will try to stimulate the economy.  And this time it won’t be another spending bill to fund some underfunded union pension plan.  It’ll be something that actually stimulates.  Because it’s for real this time.  It’s election time.

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