Beam, Fulcrum, Torque, Law of the Lever and Mechanical Advantage

Posted by PITHOCRATES - April 30th, 2014

Technology 101

(Originally published May 1st, 2013)

A Lever is a Rigid Beam on a Fulcrum

Archimedes said, “Give me a place to stand, and I shall move the Earth with it.”  At least we think he did.  Archimedes of Syracuse was a Greek genius.  Mathematician.  Physicist.  Engineer.  Inventor.  And astronomer.  One of many of the ancient Greeks who advanced modern civilization.  By using math and science.  He did a lot.  And explained why things worked the way they did using math.  Like the Law of the Lever.

In the days before the twist-off bottle cap we used bottle openers.  Because try as we might we could not pry a bottle cap off with our hands.  Most grown men just didn’t have the strength to do that.  But a child could open a bottle if that child used a bottle opener.  For that bottle opener is a lever.  Giving the child leverage.  The ability to use a little bit of force to do a lot of work.

A lever is a rigid beam on a fulcrum.  Like a seesaw.  A common playground fixture.  If two kids of equal weight are on either end of the seesaw and the fulcrum is in the center these kids can effortless push up and down.  But if a grown adult sits on one end and a child is on the other the weight of the adult will drop his side of the seesaw down.  Leaving the child up in the air on the other side.

As the Lever increases in Length the more it will Amplify the Input Force we Apply

Now that’s no fun.  Having the seesaw permanently tipped in one direction.  However, even two people of different weights can enjoy playing on the seesaw.  All they have to do is move the fulcrum towards the heavier person until the seesaw balances.  So that there is a short length of seesaw between the fulcrum and the heavy person.  And longer length of seesaw between the fulcrum and the lighter person.  This creates the same amount of torque on both side of the fulcrum.

Torque is the turning force created by a force acting about a fulcrum.  The force in this case is the weight of the people on the seesaw.  Which we calculate by multiplying their mass by the force of gravity.  With the force of gravity being constant the greater the mass the greater the weight.  This weight pressing down on the beam creates torque.   And the further away from the fulcrum the greater the turning force.  Such that a lighter weight at a greater distance from the fulcrum can balance a greater weight at a shorter distance from the fulcrum.  Allowing a child to play on a seesaw with someone of far greater mass.  Because the lever amplified the smaller force of the child.  Allowing the child to move a heavier weight.  To illustrate this consider the following table.

Lever

This is just a visual aid.  The numbers don’t represent anything.  It just shows a relationship between force and the length of the lever.  In this example we need 1000 units of force to move something.  If we use a lever that is 10 units from the fulcrum we need to apply 100 units of force.  If we have a lever that is 40 units from the fulcrum we only need to apply 25 units of force.  If we have a lever that is 80 units from the fulcrum we only need to apply 12.5 units of force.  As the lever increases in length the more it will amplify the input force we apply.  Which is why a child can open a bottle with a bottle opener.

A Wheelbarrel combines the Lever with the Wheel and Axle

A lever gives us mechanical advantage.  The amplification of a small input force into a larger output force.  Such as a hand-held bottle opener.  But what about the kind that used to be fastened to pop machines?  When you bought a glass bottle of pop out of a vending machine?  The fulcrum is the fixed bottle opener.  And the lever is the bottle.  A can opener was often on the other end of a bottle opener.  Instead of a grip to latch onto a bottle cap this end had a triangular knife.  When we lifted up on the lever it pressed down and pierced a hole in a can.

A wheelbarrel allows us to move heavy loads.  This device combines two simple machines.  A wheel and axle.  And a lever.  The wheel and axle is the fulcrum.  The lever runs from the fulcrum to the handles of the wheelbarrel.  We place the load on the lever just before the axle.  When we lift the far end of the lever we can tilt up the load and balance it over the axle.  The lever amplifies the force we apply.  And the wheel and axle reduce the friction between this load and the ground.  Allowing us to move a heavy load with little effort.

Today’s pop bottles have screw-top caps.  Some people still use a lever to help open them, though.  A pair of pliers.  We use the pliers because we don’t have the strength to grip the cap tight enough to twist it open.  The pliers are actually two levers connected together at the fulcrum.  The pliers amplify our hand strand-strength to get a very secure grip on the bottle cap.  While our hands compress the two levers together getting a firm grip on the cap we can then use our arm to apply a force on the handles of the pliers.  Providing a torque to turn the bottle cap.  Very simple machines that make everyday life easier.  Thanks to the knowledge Archimedes handed down to us.

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First Electric Cars now an Electric Helicopter

Posted by PITHOCRATES - December 1st, 2013

Week in Review

The federal government is doing everything it can to stimulate electric car sales.  Because they’re so green.  But despite huge government subsidies for both manufacturers and buyers people just aren’t buying them.  In large part because of their limited range.  Keeping away potential buyers.  And filling electric car owners with range anxiety.  That dread that fills them when they start worrying whether they have enough battery charge to get home.  And getting stranded a long way from home.  Of course, this range anxiety could be worse (see 18-rotor electric helicopter makes maiden flight by Tim Hornyak posted 11/25/2013 on CNET).

The VC200, however, has a proper cockpit for two, and is described as a vertical take-off and landing (VTOL) manned aircraft that doesn’t quite fit into any traditional category of flying machine.

It has 18 zero-emission, battery-powered electric motors for propulsion instead of the traditional combustion engines of helicopters. A frame and branching supports for rotors are made of carbon fiber help keep the weight down.

E-volo says the Volocopter VC200 can offer passengers a quiet, smooth, green ride. The vehicle is also easy to fly by joystick, and will have low operating and maintenance costs.

The VC200 flew to a height of some 70 feet during its test flights, which were recorded in the video below, which is pretty noisy but that may be due to the camera position.

It can fly for about 20 minutes with current battery technology, but E-volo hopes that will improve to allow for flights of an hour or more.

Really?  An electric helicopter?  It’s bad enough having your electric car coast to a stop on the road after your battery dies.  But to fall out of the sky?

Before a commercial jetliner flies it calculates how much fuel they need to get them to their destination.  To get them to an alternate destination in case something prevents them from getting to their primary destination.  And a reserve amount of fuel.  For the unexpected.  They are very careful about this because a plane cannot coast to a stop on a road.  If they run out of fuel they tend to fall out of the sky.  So the FAA is pretty strict on fuel requirements.  Can you imagine them certifying an electric helicopter that can carry only one battery charge?  That has to power the craft regardless of the weight of the air craft?

On the one hand pushing the bounds of technology is a good thing.  We can develop better batteries to use in our mobile devices and tablet computers.  But electric cars and electric flight?  The very design requires solving a paradox.  To get greater range we need more/bigger batteries.  But more/bigger batteries means greater weight.  And greater weight means reduced range.  That is, the very thing that increases range also reduces range.  The current technology just isn’t good enough to give us electric cars or electric flight at this time.  And any tax dollars that go to subsidize it is tax money poorly spent.

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Pendulums, Springs and Timekeeping

Posted by PITHOCRATES - September 25th, 2013

Technology 101

A Swing is a Pendulum that loses Energy due to Air Resistance and Friction

Remember what it was like to swing on a swing?  You sat down on a seat supported by two chains that connected to a bar above you.  When you were real young your mom or dad may have pushed you to get you started swinging back and forth.  As we got older we didn’t need Mom or Dad anymore.  We just pushed back with our feet.  Picked up our feet.  Pulled back on the chains as we swung forward.  As our forward momentum petered out we swung backwards.  Until that backward momentum petered out.  As we swung forward again we’d pull back on those chains again.  Until we began to fly.

Well, not fly literally.  But we’d swing back and forth, getting pretty high before we started swinging back in the other direction.  Going pretty fast as we swung through the bottom.  We could do this for hours because it hardly took any effort.  Most of the work was done by gravity pulling our weight back down to the ground.  Gravity made us go faster as we swung towards the bottom.  And slowed us down after we passed through the bottom.  Which is why few kids, if any, were ever able to wrap the swing around the overhead bar like in the cartoons.  As they could never build up enough speed to escape the pull of gravity.

But we could maintain that back and forth motion almost forever.  The only thing stopping us was a bathroom break.  Stopping to eat.  Stopping to go to bed.  Or stopping because we got bored.  If we sat still on the swing the distance we swung back and forth would get smaller and smaller.  Coming to a full stop if we let it.  Why?  Because the swing loses a lot of energy.  Though kids are small they catch a lot of air.  This air resistance slows down their motion.  There is friction where the chains connect to the overhead bar.  And with two chains our pulling would be uneven and twist the swing from side to side.  Creating more friction in the chain as the links twist against each other.

A Constant Period at Small Amplitudes makes the Pendulum Ideal for Timekeeping

The pendulum is probably the closest we’ve come to achieving perpetual motion.  In ideal conditions where there was no friction or air resistance the back and forth motion (oscillation) of pendulum would go on forever.  Even in the ideal conditions it would still take an energy input to begin the oscillation.  But even though we can’t create the ideal conditions for a pendulum we can get close enough to make the pendulum do useful work for us.

The parts of a pendulum are a suspended weight (bob) and a pivot point.  The weight of the bob and the distance between the bob and the pivot determine the distance the pendulum travels (amplitude).  One swing back and forth is one period.  The greater the amplitude the greater the period and the slower the oscillation.  The smaller the amplitude the smaller the period and the faster the oscillation.  The greater the distance between the bob and the pivot the greater the period and the slower the oscillation.  The smaller the distance between the bob and the pivot the smaller the period and the faster the oscillation.

Pendulums with small swings have a very useful feature.  The period will remain the same even if the amplitude does not.  So the effects of friction and air resistance will be negligible for small swings.  Making the pendulum ideal for timekeeping.  Such as in a grandfather clock.  Where the bob is suspended on a long rod from the pivot.  That oscillates in small swings back and forth.  When this period is one second it can advance a minute hand one minute with 60 periods.  And with gears and cogs connecting the axle of the minute hand to the axle of the hour hand 60 revolutions of the minute hand will move the hour hand one hour.  Gears and cogs make the minute and hour hands move.  But it’s the pendulum that actually keeps time with its constant period.  With one other element.

Early Marine Chronometers replaced the Pendulum with a Wound Spiral Spring in the Escapement

So what actually makes the hour and minute hands move?  Gravity.  Wrapped around one of these axles is a cable.  At the end of this cable hanging down in the clock body is a weight.  Think of a fishing rod when a fish strikes.  The fish will pull the line out of the reel until you start reeling it in.  This is what gravity does.  It pulls that weight down pulling the cable off of the main drive axle causing it to spin.  But it doesn’t spin out of control.  In fact, it moves in very short, discrete steps.  Because of the escapement at the heart of a pendulum clock.

An escapement is a gear and a locking mechanism.  The locking mechanism attaches to the pendulum and looks a little like an inverted letter ‘V’.  As this rocks back and forth with the pendulum it moves two teeth (at each tip of the ‘V’) into and out of the gear.  As it rocks one way one tooth moves out of the gear.  Releasing it and allowing the gear to turn.  At the same time the other tooth moves into the gear.  Locking it and stopping the gear from turning.  When the pendulum swings the other way the locking tooth releases, allowing the gear to turn.  Until the other tooth moves into the gear and locks it again.  This happens with every swing of the pendulum, giving it that characteristic tick-tock sound.

Before the pendulum clock the existing mechanical clocks of the day were accurate to about 15 minutes a day.  The pendulum clocks, though, were accurate to within 15 seconds a day.  Making it the most accurate time piece for about 300 years until the advent of the quartz clock around 1930.  One of the drawbacks of the pendulum clock was that it needed to be stationary.  Which made it poorly suited for ships which could get tossed around in rough seas.  Which was a problem.  For telling time was crucial for navigation.  As ships traveled away from the coastline they needed to find their position on a chart.  They could use a sextant to find what line of latitude (north-south location) they were at.  But to determine what line of longitude (east-west location) they were at they needed an accurate time piece.

Early marine chronometers used an escapement.  But replaced the accurate pendulum and weight with a less-accurate wound spiral spring.  Which found their way into wristwatches.  Before there were batteries.  They weren’t as accurate as a pendulum clock.  And you had to wind them up every day whereas a grandfather clock will keep time for about a week.  But a spring allowed miniaturization.  And the ability to tell time when you didn’t have the ideal conditions a pendulum requires.  Such as on a ship navigating across rough seas.

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Trucks, Trains, Ships and Planes

Posted by PITHOCRATES - August 21st, 2013

Technology 101

Big Over-the-Road Tractor Trailer Trucks have Big Wheels so they can have Big Brakes

If you buy a big boat chances are you have a truck or a big SUV to pull it.  For rarely do you see a small car pulling a large boat.  Have you ever wondered why?  A small car can easily pull a large boat on a level (or a near level) surface.  That’s not the problem.  The problem is stopping once it gets moving.  For that is a lot of mass.  Creating a lot of kinetic energy (one half of the mass times velocity squared).  Which is dissipated as heat as brake shoes or pads rub against the wheels.  This is why you need a big truck or SUV to pull a boat.  So you can stop it once it gets moving.

Big trucks and big SUVs have big wheels and big brakes.  Large areas where brake pads/shoes press against a rotating wheel.  All of which is heavy duty equipment.  That can grab onto to those wheels and slow them down.  Converting that kinetic energy into heat.  This is why the big over-the-road tractor trailer trucks have big wheels.  So they can have big enough brakes to stop that huge mass once it gets moving.  Without the brakes turning white hot and melting.  Properly equipped trucks can carry great loads.  Moving freight safely across our highways and byways.  But there is a limit to what they can carry.  Too much weight spread between too few axles will pound the road apart.  Which is why the state police weighs our trucks.  To make sure they have enough axles supporting the load they’re carrying.  So they don’t break up our roads.  And that they can safely stop.

It’s a little different with trains.  All train cars have a fixed number of axles.  But you will notice the size of the cars differ.  Big oversized boxcars carry a lot of freight.  But it’s more big than heavy.  Heavy freight, on the other hand, like coal, you will see in smaller cars.  So the weight they carry doesn’t exceed the permissible weight/axle.  If you ever sat at a railroad crossing as a train passed you’ve probably noticed that the rail moves as the train travels across.  Watch a section of rail the next time you’re stopped by a train.  And you will see the rail sink a little beneath the axle as it passes over.

If a Ship is Watertight and Properly Balanced it can be covered in Green Water and Rise back to the Surface

So the various sizes of train cars (i.e., rolling stock) keeps each car from being overloaded.  Unlike a truck.  Steel haulers and gravel trains (i.e., dump trucks) have numerous axles beneath the load they’re carrying.  But these axles are retractable.  For the more wheels in contact with the road the more fuel is needed to overcome the friction between the tires and the road.  And the more tires in contact with the road the more tire wear there is.  Tires and fuel are expensive.  So truckers like to have as few tires in contact with the road as possible.  When they’re running empty they will have as many of these wheels retracted up as possible.  Something you can’t do with a train.

That said, a train’s weight is critical for the safe operation of a train.  In particular, stopping a train.  The longer a train is the more distance it takes to stop.  It is hard to overload a particular car in the string of cars (i.e., consist) but the total weight tells engineers how fast they can go.  How much they must slow down for curves.  How much distance they need to bring a train to a stop.  And how many handbrakes to set to keep the train from rolling away after the pressure bleeds out of the train line (i.e., the air brakes).  You do this right and it’s safe sailing over the rails.  Ships, on the other hand, have other concerns when it comes to weight.

Ships float.  Because of buoyancy.  The weight of the load presses down on the water while the surface of the water presses back against the ship.  But where you place that weight in a ship makes a big difference.  For a ship needs to maintain a certain amount of freeboard.  The distance between the surface of the water and the deck.  Waves toss ships up and down.  At best you just want water spray splashing onto your deck.  At worst you get solid water (i.e., green water).  If a ship is watertight and properly balanced it can be covered in green water and rise back to the surface.  But if a ship is loaded improperly and lists to one side or is low in the bow it reduces freeboard.  Increases green water.  And makes it less likely to be able to safely weather bad seas.  The SS Edmund Fitzgerald sank in 1975 while crossing Lake Superior in one of the worst storms ever.  She was taking on water.  Increasing her weight and lowering her into the water.  Losing freeboard.  Had increasing amounts of green water across her deck.  To the point that a couple of monster waves crashed over her and submerged her and she never returned to the surface.  It happened so fast that the crew was unable to give out a distress signal.  And as she disappeared below the surface her engine was still turning the propeller.  Driving her into the bottom of the lake.  Breaking the ship in two.  And the torque of the spinning propeller twisting the stern upside down.

Airplanes are the only Mode of Transportation that has two Systems to Carry their Load

One of the worst maritime disasters on the Great Lakes was the sinking of the SS Eastland.  Resulting in the largest loss of life in a shipwreck on the Great Lakes.  In total 844 passengers and crew died.  Was this in a storm like the SS Edmund Fitzgerald?  No.  The SS Eastland was tied to the dock on the Chicago River.  The passengers all went over to one side of the ship.  And the mass of people on one side of the ship caused the ship to capsize.  While tied to the dock.  On the Chicago River.  Because of this shift in weight.  Which can have catastrophic results.  As it can on airplanes.  There’s a sad YouTube video of a cargo 747 taking off.  You then see the nose go up and the plane fall out of the sky.  Probably because the weight slid backwards in the plane.  Shifting the center of gravity.  Causing the nose of the plane to pitch up.  Which disrupted the airflow over the wings.  Causing them to stall.  And with no lift the plane just fell out of the sky.

Airplanes are unique in one way.  They are the only mode of transportation that has two systems to carry their weight.  On the ground the landing gear carries the load.  In the air the wings carry the load.  Which makes taking off and landing the most dangerous parts of flying.  Because a plane has to accelerate rapidly down the runway so the wings begin producing lift.  Once they do the weight of the aircraft begins to transfer from the landing gear to the wings.  Allowing greater speeds.  However, if something goes wrong that interferes with the wings producing lift the wings will be unable to carry the weight of the plane.  And it will fall out of the sky.  Back onto the landing gear.  But once the plane leaves the runway there is nothing the landing gear can gently settle on.  And with no altitude to turn or to glide back to a runway the plane will fall out of the sky wherever it is.  Often with catastrophic results.

A plane has a lot of mass.  And a lot of velocity.  Giving it great kinetic energy.  It takes long runways to travel fast enough to transfer the weight of the aircraft from the landing gear to the wings.  And it takes a long, shallow approach to land an airplane.  So the wheels touch down gently while slowly picking up the weight of the aircraft as the wings lose lift.  And it takes a long runway to slow the plane down to a stop.  Using reverse thrusters to convert that kinetic energy into heat.  Sometimes even running out of runway before bringing the plane to a stop.  No other mode of transportation has this additional complication of travelling.  Transferring the weight from one system to another.  The most dangerous part of flying.  Yet despite this very dangerous transformation flying is the safest mode of traveling.  Because the majority of flying is up in the air in miles of emptiness.  Where if something happens a skilled pilot has time to regain control of the aircraft.  And bring it down safely.

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Beam, Fulcrum, Torque, Law of the Lever and Mechanical Advantage

Posted by PITHOCRATES - May 1st, 2013

Technology 101

A Lever is a Rigid Beam on a Fulcrum

Archimedes said, “Give me a place to stand, and I shall move the Earth with it.”  At least we think he did.  Archimedes of Syracuse was a Greek genius.  Mathematician.  Physicist.  Engineer.  Inventor.  And astronomer.  One of many of the ancient Greeks who advanced modern civilization.  By using math and science.  He did a lot.  And explained why things worked the way they did using math.  Like the Law of the Lever.

In the days before the twist-off bottle cap we used bottle openers.  Because try as we might we could not pry a bottle cap off with our hands.  Most grown men just didn’t have the strength to do that.  But a child could open a bottle if that child used a bottle opener.  For that bottle opener is a lever.  Giving the child leverage.  The ability to use a little bit of force to do a lot of work.

A lever is a rigid beam on a fulcrum.  Like a seesaw.  A common playground fixture.  If two kids of equal weight are on either end of the seesaw and the fulcrum is in the center these kids can effortless push up and down.  But if a grown adult sits on one end and a child is on the other the weight of the adult will drop his side of the seesaw down.  Leaving the child up in the air on the other side.

As the Lever increases in Length the more it will Amplify the Input Force we Apply

Now that’s no fun.  Having the seesaw permanently tipped in one direction.  However, even two people of different weights can enjoy playing on the seesaw.  All they have to do is move the fulcrum towards the heavier person until the seesaw balances.  So that there is a short length of seesaw between the fulcrum and the heavy person.  And longer length of seesaw between the fulcrum and the lighter person.  This creates the same amount of torque on both side of the fulcrum.

Torque is the turning force created by a force acting about a fulcrum.  The force in this case is the weight of the people on the seesaw.  Which we calculate by multiplying their mass by the force of gravity.  With the force of gravity being constant the greater the mass the greater the weight.  This weight pressing down on the beam creates torque.   And the further away from the fulcrum the greater the turning force.  Such that a lighter weight at a greater distance from the fulcrum can balance a greater weight at a shorter distance from the fulcrum.  Allowing a child to play on a seesaw with someone of far greater mass.  Because the lever amplified the smaller force of the child.  Allowing the child to move a heavier weight.  To illustrate this consider the following table.

Lever

This is just a visual aid.  The numbers don’t represent anything.  It just shows a relationship between force and the length of the lever.  In this example we need 1000 units of force to move something.  If we use a lever that is 10 units from the fulcrum we need to apply 100 units of force.  If we have a lever that is 40 units from the fulcrum we only need to apply 25 units of force.  If we have a lever that is 80 units from the fulcrum we only need to apply 12.5 units of force.  As the lever increases in length the more it will amplify the input force we apply.  Which is why a child can open a bottle with a bottle opener.

A Wheelbarrel combines the Lever with the Wheel and Axle

A lever gives us mechanical advantage.  The amplification of a small input force into a larger output force.  Such as a hand-held bottle opener.  But what about the kind that used to be fastened to pop machines?  When you bought a glass bottle of pop out of a vending machine?  The fulcrum is the fixed bottle opener.  And the lever is the bottle.  A can opener was often on the other end of a bottle opener.  Instead of a grip to latch onto a bottle cap this end had a triangular knife.  When we lifted up on the lever it pressed down and pierced a hole in a can.

A wheelbarrel allows us to move heavy loads.  This device combines two simple machines.  A wheel and axle.  And a lever.  The wheel and axle is the fulcrum.  The lever runs from the fulcrum to the handles of the wheelbarrel.  We place the load on the lever just before the axle.  When we lift the far end of the lever we can tilt up the load and balance it over the axle.  The lever amplifies the force we apply.  And the wheel and axle reduce the friction between this load and the ground.  Allowing us to move a heavy load with little effort.

Today’s pop bottles have screw-top caps.  Some people still use a lever to help open them, though.  A pair of pliers.  We use the pliers because we don’t have the strength to grip the cap tight enough to twist it open.  The pliers are actually two levers connected together at the fulcrum.  The pliers amplify our hand strand-strength to get a very secure grip on the bottle cap.  While our hands compress the two levers together getting a firm grip on the cap we can then use our arm to apply a force on the handles of the pliers.  Providing a torque to turn the bottle cap.  Very simple machines that make everyday life easier.  Thanks to the knowledge Archimedes handed down to us.

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Boeing’s 787 Battery Solution illustrates why the All-Electric Car remains more of a Novelty than a Legitimate Car

Posted by PITHOCRATES - April 7th, 2013

Week in Review

The problem with the all-electric car is the battery.  To get a decent range requires a large battery.  But a large battery adds weight.  The heavier the car is the more battery power it takes to drive the car.  Which, of course, decreases the range.  So the only solution to this problem is to come up with a better battery.  One that is smaller and lighter that can charge quickly and provide great range.  Currently, that battery is the lithium-ion battery.  The same technology Boeing used on their new 787 Dreamliner.  Those same planes that showed the drawbacks of getting more energy out of a smaller and lighter battery.  They generate a lot of heat.  And can burst into flames (see Boeing has “good” Dreamliner battery plan fix: official by Doug Palmer and Alwyn Scott posted 4/5/2013 on Reuters).

Boeing Co (BA.N) has a “good plan” to fix the battery problem that has grounded its 787 Dreamliner jets, U.S. Transportation Secretary Ray LaHood said on Friday as the company prepared for a test flight to check the battery system revamp…

It’s still unknown what caused the two batteries to overheat, and the National Transportation Safety Board is investigating. Boeing came up with measures it says make the battery safe. It put more insulation in the battery, encased the battery in a steel box, changed the circuitry of the battery charger and added a titanium venting tube to expel heat and fumes outside the plane.

This is a good fix for an airplane.  For if there is a fire in the battery compartment you want to vent the heat and fumes outside of the airplane.  So the airplane doesn’t catch on fire.  Of course, this solution is not a very good one for an all-electric car that parks in attached garage plugged in overnight.  For there will be no freezing air blowing across that titanium tube like a plane flying at 40,000 feet.  That intense heat just may start the car on fire.  Or the garage.

To increase sales of the all-electric car they need to increase the range.  Even if you’re driving at night in winter with the heater and lights on.  And get stuck in stop and go traffic that adds an hour to your drive-time home.  But to do this you need to put more energy into a smaller package.  Which is often not the safest thing to do.  As Boeing learned.  So until they can come up with a battery that can give people the range to make it home safely without the car (or garage) catching on fire the all-electric car will remain more of a novelty than a legitimate car.

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One Passenger Airline charging by the Passenger’s Weight may offer new Funding Idea for Obamacare

Posted by PITHOCRATES - April 7th, 2013

Week in Review

When the price of oil soars it doesn’t affect the railroads that much.  Because fuel costs are not their greatest cost.  Maintaining that massive infrastructure is.  For wherever a train travels there has to be track.  It’s different for the airlines.  The only infrastructure they have is at the airports.  And the traffic control centers that keep order in the sky.  Once a plane is off the ground it doesn’t need anything but fuel in its tanks to go somewhere.  And because the flying infrastructure is so much less than the railroad infrastructure fuel costs are a much larger cost.  In fact, it’s their greatest cost of flying.  So when fuel costs rise ticket prices rise along with them.  And they start charging more bag fees.  As well as any other fee they can charge you to offset these soaring fuel costs.

Boeing made their 787, the Dreamliner, exceptionally light.  To reduce flying costs.  They used a lot of composite materials.  Two large engines because they’re lighter than 4 smaller engines.  They even used a new lithium-ion battery system to start up their auxiliary power unit.  And made it fly-by-wire to eliminate the hydraulic system that normally operates the control surfaces.  They did all of these things to fight the biggest enemy they have in flying.  Weight.  For the greater the weight the more fuel they burn.  And the less profitable they are.

Freight airlines charge their customers by the weight of the freight they wish to ship.  Because there is a direct correlation between the weight of their freight and the amount of fuel they have to burn to carry that freight.  In fact, all shippers charge by the weight.  Because in transportation weight is everything.  But there is one mode of transportation that we don’t charge by the weight.  Passenger air travel.  Until now, that is (see A tax on overweight airline passengers: a brutal airline policy by Robin Abcarian posted 4/3/2013 on the Los Angeles Times).

When teensy-weensy Samoa Airlines debuted its pay-by-the-kilo policy in January, I doubt it expected to set off an international controversy about fat discrimination.

But that’s what happened when news seeped out this week after the airline’s chief executive, Chris Langton, told ABC News radio in Australia that the system is not only fair but destined to catch on.

“Doesn’t matter whether you’re carrying freight or people,” explained Langton. “We’ve amalgamated the two and worked out a figure per kilo.”

Samoa Air, he added, has always weighed the human and non-human cargo it carries. “As any airline operator knows, they don’t run on seats, they run on weight,” said Langton. “There’s no doubt in my mind this is the concept of the future because anybody who travels has felt they’ve paid for half the passenger that’s sitting next to them…”

“Samoa Air, Introducing a world first: ‘Pay only for what you weigh’! We at Samoa Air are keeping airfares fair, by charging our passengers only for what they weigh. You are the master of your Air’fair’, you decide how much (or little) your ticket will cost. No more exorbitant excess baggage fees, or being charged for baggage you may not carry. Your weight plus your baggage items, is what you pay for. Simple. The Sky’s the Limit..!”

One bright note to this policy: Families with small children, who often feel persecuted when they travel, stand to benefit most from this policy. Since Samoa no longer charges by the seat, it will cost them a lot less to fly than it did before.

The appeal of this policy depends on your perspective.  If you’re of average weight sitting next to someone spilling over their seat into yours it may bother you knowing that you each paid the same price for a seat and resent the person encroaching on your seat.  But if you paid per the weight you bring onto the airplane then that person paid for the right to spill over into your seat.  Which they no doubt will do without worrying about how you feel.  As they paid more for their ticket than you paid for yours.  So the person who weighs less will get a discount to suffer the encroachment.  While the person who weighs more will have to pay a premium for the privilege to encroach.

Under the current system the people who weigh less subsidize the ticket prices of those who weigh more.  It’s not fair.  But it does save people the embarrassment of getting onto a scale when purchasing a ticket.  So should all airlines charge like all other modes of transportation?  Or should they continue to subsidize the obese?  Should we be fair?  Or should we be kind?

Chances are that government would step in and prevent airlines from charging by the weight.  Calling it a hate crime.  Even while they are waging a war on the obese themselves. Telling us what size soda we can buy.  And regulating many other aspects of our lives.  Especially now with Obamacare.  Because the obese are burdening our health care system with their health problems the government now has the right to regulate our lives.  And they have no problem calling us fat and obese.  But a private airline starts charging by the weight of the passenger?  Just don’t see how the government will allow that.  For it’s one thing for them to bully us.  But they won’t let these private businesses hurt people’s feelings by being fair.  So the people who are not overweight will continue to subsidize the flying cost of those who are overweight.

Until the government determines obese people are causing an unfair burden on society.  The obese have more health issues.  Which will consume more limited health care resources.  Also, flying these heavier people around will burn more fuel.  Putting more carbon emissions into the air.  Causing more breathing problems for everyone else.  As well as killing the planet with more global warming.  So while the airlines may not want to weigh people when selling them a ticket because of the potential backlash, the government won’t have a problem.  To cut the high cost of health care and to save the planet from global warming caused by carbon emissions they may even introduce a ‘fat’ tax.  Like any other sin tax.  To encourage people to choose to be healthier.  And to punish those who choose not to.  If they can force us to buy health insurance what can stop them from accessing a ‘fat’ tax?  Especially when they do have the right to tax us.

This is where national health care can take us.  When they begin paying the bill for health care they will have the right to do almost anything if they can identify it as a heath care issue.  Because it’s in the national interest.  They’ve painted bulls-eyes on the backs of smokers.  And drinkers.  With tobacco and alcohol taxes.  And you know they would love to tax us for being fat.  Perhaps even having our doctors file our weight with the IRS.  So they can bump our tax rates based on how obese we are.  If the tax dollars pay for health care they will say they have that right.  As the obese consume an unfair amount of those limited tax dollars.  Anything is possible with an out of control growing federal government faced with trillion dollar deficits.  Especially when they can call it a health care issue.

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Thrust, Drag, Lift, Weight, Concorde, Center of Pressure, Center of Gravity, Boeing 747, Slats and Flaps

Posted by PITHOCRATES - January 16th, 2013

Technology 101

The Drawback to increasing Thrust and Lift with more Powerful Engines is the Weight of Greater Fuel Loads

To get an airplane off of the ground requires two things.  To produce thrust that is greater than drag.  And to produce lift that is greater than weight.  You do this and you’ll get any airplane off of the ground.  Of course, getting these two things is not the easiest thing to do.  Primarily because of the purpose of airplanes.  To move people and freight.  People and freight add weight.  Which increases the amount of lift needed.  And they make the plane bigger.  A bigger object displaces more air increasing drag.  And thus requiring more thrust.

Engines provide thrust.  And wings provide lift.  So the obvious solution to overcome greater drag is to produce greater thrust.  And the solution to overcome greater weight is to produce greater lift.  And we do both with fuel.  Greater amounts of fuel can power bigger engines that can produce more thrust.  And larger wings can produce greater lift.  But larger wings also produce more drag.  Requiring additional thrust.  And fuel.  Or, we can produce greater lift by moving air over the wings faster.  Also requiring additional thrust.  And fuel.

Of course, the obvious drawback to increasing both thrust and lift is the added weight of the fuel.  The more fuel carried the more weight lift has to overcome.  Requiring more powerful engines.  Or bigger wings.  Both of which require more fuel.  This is why our first planes were small by today’s standards.  The thrust of a propeller engine could not produce enough thrust to travel at high speeds.  Or operate at high altitudes.  And the first wings were relatively fixed.  Having the same surface area to produce lift at takeoffs and landings.  As well as at cruising altitudes.  Big wings that allowed the lifting of heavier weights produced a lot of drag.  Requiring more fuel to overcome that drag.  And the added weight of that fuel limited the number of people and freight they could carry.  Or they could trade off that fuel for more revenue weight.  The smaller fuel load, of course, reduced flying times.  Requiring an additional takeoff and landing or two to refuel.

A Wing that produces sufficient Lift at 600 MPH does not produce sufficient Lift at Takeoff and Landing Speeds

The supersonic Concorde was basically a flying gas can.  It was more missile than plane.  To travel at those great speeds required a very small cross section to reduce drag.  Limiting the Concorde to about 100 revenue paying passengers.  Its delta wing performed well at supersonic flight but required a drooping nose so the pilot could see over it to land and takeoff due to the extreme nose pitched up attitude.  As Concorde approached supersonic speeds the center of pressure moved aft.  Placing the center of gravity forward of the center of pressure.  Causing the nose to pitch down.  You correct this with trim controls on slower flying aircraft.  But using this on Concorde would create additional drag.  So they trimmed Concorde by pumping the remaining fuel to other fuel tanks to move the center of gravity to the center of pressure.

They designed Concorde to fly fast.  Which came at a cost.  They can only carry 100 revenue paying passengers.  So they can only divide the fuel cost between those 100 passengers.  Whereas a Boeing 747 could seat anywhere around 500 passengers.  Which meant you could charge less per passenger ticket while still earning more revenue than on Concorde.  Which is why the Boeing 747 ruled the skies for decades.  While Concorde flies no more.  And the only serious competition for the Boeing 747 is the Airbus A380.  Which can carry even more revenue paying passengers.  How do they do this?  To fly greater amount of people and freight than both piston-engine and supersonic aircraft?  While being more profitable than both?  By making compromises between thrust and drag.  And lift and weight.

Jet engines can produce more thrust than piston engines.  And can operate at higher altitudes.  Allowing aircraft to take advantage of thinner air to produce less drag.  Achieving speeds approaching 600 mph.  Not Concorde speeds.  But faster than every other mode of travel.  To travel at those speeds, though, requires a cleaner wing.  Something closer to Concorde than, say, a DC-3.  Something thinner and flatter than earlier wings.  But a wing that produces lift at 600 mph does not produce enough lift at takeoff and landing speeds.

Planes need more Runway on Hot and Humid Days than they do on Cool and Dry Days

The other big development in air travel (the first being the jet engine) are wings that can change shape.  Wings you can configure to have more surface area and a greater curve for low-speed flying (greater lift but greater drag).  And configure to have less surface area and a lesser curve for high-speed flying (less lift but less drag).  We do this with leading-edge slats (wing extensions at the leading edge of the wing).  And trailing-edge flaps (wing extensions at the trailing edge of the wing).  When fully extended they increase the surface area of the wing.  And add curvature at the leading and trailing edge of the wing.  Creating the maximum amount of lift.  As well as the greatest amount of drag.  Allowing a wing to produce sufficient lift at takeoff speeds (about 200 mph).  Once airborne the plane continues to increase its speed.  As it does they retract the slats and flaps.  As the wing can produce sufficient lift at higher speeds without the slats and flaps extended.

But there are limits to what powerful jet engines and slats/flaps can do.  A wing produces lift by having a high pressure under the wing pushing up.  And a low pressure on top of the wing pulling it up.  The amount of air passing over/under the wing determines the amount of lift.  As does the density of that air.  The more dense the air the more lift.  The thinner the air the less lift.  Which is why planes need less runway on a cold winter’s day than on a hot and humid summer’s day.  If you watch a weather report you’ll notice that clear days are associated with a high pressure.  And storms are associated with a low pressure.  When a storm approaches meteorologists will note the barometer is falling.  Meaning the air is getting thinner.  When the air is thinner there are fewer air molecules to pass over the wing surface.  Which is why planes need more runway on hot and humid days.  To travel faster to produce the same amount of lift they can get at slower speeds on days cooler and dryer.

For the same reason planes taking off at higher elevations need more runway than they do at lower elevations.  Either that or they will have to reduce takeoff weight.  They don’t throw people or their baggage off of the airplane.  They just reduce the fuel load.  Of course, by reducing the fuel load a plane will not be able to reach its destination without landing and refueling.  Increasing costs (airport and fuel expenses for an additional takeoff and landing).  And increasing flying time.  Which hurts the economics of flying a plane like a Boeing 747.  A plane that can transport a lot of people over great distances at a low per-person cost.  Adding an additional takeoff and landing for refueling adds a lot of cost.  Reducing the profitability of that flight.  Not as bad as a normal Concorde flight.  But not as good as a normal Boeing 747 flight.

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The High Cost of Labor Contracts and Environmental Regulations cause Planes to Run Low on Fuel

Posted by PITHOCRATES - August 26th, 2012

Week in Review

Here is a lesson in basic economics.  There is a tradeoff between costs and safety in aviation.  You could hire thousands of additional mechanics to give an airplane a complete overhaul after each flight.  And double their pay rate just to make sure they are especially happy workers.  You can have a couple of chase planes follow a passenger airliner on every flight to observe the outside of the aircraft so they can warn the pilot of any problems.  And you can top off every fuel tank on an airplane just to be extra safe.  These things would make flying safer.  But they would also make it very expensive to fly.  So expensive that few people would fly.  Thus reducing the amount of airplanes in the sky.  As well as the number of flight and maintenance crews.  Which illustrates the ultimate cost of generous union contracts.  The more they ask for the more they put themselves out of a job.

But these unions are powerful.  Margins are so thing in aviation that a strike could turn a profitable year into a money losing year.  So to avoid a strike they cut costs where they can.  And the one cost that gives them something to work with is their fuel costs.  Because an airplane only needs enough fuel to fly from point A to point B.  Plus some reserves.  So they are very careful in calculating the fuel requirements to get from point A to point B.  But sometimes weather can enter the picture and add a point C.  And this can sometimes cause a fuel emergency (see Pilots forced to make emergency landings because of fuel shortages by David Millward posted 8/20/2012 on The Telegraph).

Pilots have had to make 28 emergency landings because they were running low on fuel according to figures compiled by the Civil Aviation Authority…

Although the total represents of fuel-related emergency landings is a reduction on 2008-10, when there were 41 such incidents, some pilots have warned the airlines are operating on very narrow margins as they seek to cut operating costs…

One retired pilot told the Exaro website that he and his colleagues were under pressure from airlines because of the industry’s need to keep costs down.

“There is pressure on pilots by airlines to carry minimum fuel because it costs money to carry the extra weight, and that is quite significant over a year…

“The way in which aircraft are being developed in becoming more fuel efficient, there is less need for fuel.

We make jet fuel by refining petroleum oil.  And two things make this an expensive endeavor.  Higher environmental regulations.  And reductions in supply.  Often due to those same environmental regulations.  If they allowed the American oil business to drill, baby, drill, it would be safer to fly.  Because fuel would be less expensive.  And airlines could more easily afford to carry the extra fuel weight.

Airlines don’t have much power over controlling the price of jet fuel.  It is what the market says it is.  They have a little more luck in keeping their capital costs down thanks to the bitter rivalry between Boeing and Airbus.  Who are both eager to sell their airplanes.  Cutting their labor costs is another option they have but it comes with great political costs.  Usually it takes the specter of bankruptcy to get concessions from labor.  So when it comes to cutting their operating costs the least objectionable route to go is to cut fuel costs.  By loading the absolute bare minimum required by regulations.  And for safety.  Airlines want to save money.  But having planes fall out of the sky to save fuel costs will cost more in the long run.  In more ways than one.  (It’s hard to get people to fly on an airline that has a reputation of having their planes fall out of the sky.)

So there are only two practical options to fix this problem of skimping on the fuel load.  Either you drill, baby, drill.  Or you get labor concessions to lower you labor, pension and health care costs.  The very same things that are bankrupting American cities.  So you know the costly union workers are all in favor of drill, baby, drill.  Because the lower the cost of jet fuel the less pressure there is on their pay and benefits.

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Weights and Measures

Posted by PITHOCRATES - November 9th, 2011

Technology 101

Flying Airplanes Require Careful Calculations and Exacting Measurements

How do you buy your gasoline?  Well, if you’re in the U.S., you buy it by the gallon.  And you choose your gas station by the price per gallon.  Typically choosing the cheapest price per gallon you can find.  Even if it means 20 minutes of additional drive time.  Because you want to get as much value as you can when you spend your money.  But have you ever wondered how much gas you’re really getting?

Actually the chances are pretty good that you’re getting what you’re paying for.  The next time you pump gas take a look at the pump.  You should see a tag from the Department of Weights and Measures.  This tag says an inspector filled up a 5-gallon test can and verified the pump metering.  If you see this tag you should be getting what you paid for.  And you should see this tag.  Because they test every gas pump.

Have you ever flown in an airplane?  If you’re a regular flier you probably notice that ticket prices go up when oil prices do.  Why?  Because jet fuel is the greatest expense of flying.  For it takes a lot of jet fuel to make those heavy planes fly.  And one of the heaviest things on a plane is that fuel.  So they try to carry as little fuel as possible.  Which requires some careful calculations.  And some exacting measurements.  Because a jet plane running out fuel while flying can’t continue to fly for much longer.

Egypt, Sumer and Harappa Developed a System of Weights and Measures to Build and Trade

Life as we know it would be pretty difficult without a reliable system of weights and measures.  Something we take for granted these days.  I’m sure you don’t give it a second thought when you pump your gas.  Or sit in an airplane accelerating down a runway.  But none of this would be possible without weights and measures.

There would be no economic activity, either.  Without being able to measure lengths, areas or volumes there would be no building.  And one thing we’ve learned from the Subprime Mortgage Crisis is that building houses IS the U.S. economy.  But it would be hard to build a house if different suppliers sold 2X4s in different lengths.  Or if there were no standard sizes of hot water tanks.  Or if there was no standard size of drywall.  Or no way to measure how much water to mix with gypsum to make wet plaster.

Of course, we would never have gotten to the building process.  Because we couldn’t trade without weights and measures.  We have to measure raw materials before we can trade them.  And assign a unit price.  Calculating prices per unit goes back to the beginning of civilization.  All the way back to Egypt.  Sumer.  And Harappa.  Who all developed systems of weights and measures to build.  And to trade.

Setting Unit Prices for Raw Materials and Finished Goods made Trade Possible and Efficient

Money made trade easier.  But without a system of weights and measures trade would not have been possible.  Even with money.  Because you can’t count everything.  You don’t count grain.  You weigh it in bulk.  You don’t count olive oil.  You measure it by volume.  And you don’t count seed-holes.  You calculate how much seed by weight is required to sow a field based on the calculated area of that field.

Setting unit prices for these goods made trade possible.  And efficient.  It allowed traders to find the best value.  By comparing unit prices.  Much like we do today when choosing a gas station.  All thanks to those reliable weights and measures.

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