21x11 - Cast Iron Stoves/Ultra Light Aircraft; Snow Groomers/Rubber Bands

[bunniefuu]

Narrator:
cast-iron stoves have been
adding warmth to people's lives

For more than three centuries.

Today there are new reasons
to cozy up to this invention.

It's had a major update.

Modern stoves burn wood
more cleanly and efficiently,

Providing heat

Without the dirty fallout
from the chimney.

Modern cast-iron stoves
hardly resemble

Their smoke-belching,
soot-spewing predecessors.

The design creates
a hotter fire,

So it requires less fuel
and releases little smoke.

It all starts
with a pile of iron scrap,

Things like old stoves, sinks,
brake drums, and rotors.

A magnetized crane
transfers the scrap

To a propane-fired preheater.


Spent in the preheater

Removes moisture
from the iron scrap.

The scrap iron
spills into a hopper

That funnels it
into an electric furnace.

The temperature in the furnace

Is a blistering


And the iron melts
into a fiery liquid.

The furnace tilts
to pour the molten iron

Into a ladle for transfer.

Next, they make the molds
of the stove parts,

Using a mix of sand, clay,
water, and coal.

They blow the ingredients
between the aluminum patterns.

A hydraulic system squeezes
the patterns together.

The sand mix compacts and takes
the shape of the patterns.

They now have sand molds.

The molten iron arrives

And flows into a channel
leading to the molds.

As the liquid metal cools,

It solidifies into the shape
of the mold.

A vibrating conveyor shakes
and breaks the sand molds

To reveal
the cast-iron stove parts.

A worker knocks off
unwanted bits,

And then
it's into a blast cleaner.

Inside the blast cleaner,

Steel grit bombards
the stove parts

To remove remnants
of the sand molds

And expose the metal.

Essentially it blasts the dirt
off, and they come out clean.

An employee grinds the edges
of the metal stove parts.

He blends in the line created

Where the two parts of the mold
came together during casting.

It takes 40 parts to make
one woodburning stove,

And each one is cast in
a sand mold made from a pattern.

Next, a worker drills threads
for the bolts

That will hold all the parts
of the stove together.

Once the surface of the parts
has been prepped,

They spray an enamel coating
onto them and bake it on.

A laser then cuts out
a steel heat shield

For the back of the wood stove.

The intricate cuts
are computer driven.

An employee bends the
heat shield to fit the stove.

Next, a worker packs
a kind of mortar

Into a silicone mold
of the firebox.

The table its on vibrates
to settle the material

And eliminate air pockets

So the firebox will be able
to withstand high temperatures.

The shape of the firebox

Is crucial to the stove's
energy efficiency,

And so are the holes
that have been molded into it.

These strategically
located holes

Will introduce fresh air

To burn gases that would
otherwise go up in smoke,

Preventing energy loss
and pollution at the same time.

The parts
have all been fabricated,

And they're ready
to put the pieces together.

They assemble the stove
from the bottom up.

They bolt the parts and seal the
joints to make them airtight.

The assembly takes
about an hour.

This cast-iron stove
is now ready

To keep these fires burning
for many years to come.

Narrator:
an ultralight aircraft

Is a lightweight,
motorized flying machine

That looks like a hang glider.

Hang gliding inspired
the invention of ultralights

Back in the late 1970s.

The idea was to create

A slow but affordable method
of motorized flight

Subject to minimal
aerospace regulations.

They're called ultralights
or microlights.

This made-in-france 2-seater
model weighs about 485 pounds.

To be classified
as an ultralight

By the international
air sports federation,

Takeoff weight
can't exceed 990 pounds

And minimum speed can't surpass


The wing surface,
called the sail,

Is made of a sturdy
polyester-based material

Treated with a special coating

That protects it
from the sun's ultraviolet rays.

They unroll different colors
of this fabric

Onto a cutting table
marked with patterns

For the four separate
sail sections.

They staple the fabrics
to the table

To hold them steady
while tracing the patterns.

Once they finish tracing,
they cut out the pieces,

Then connect them
with double-sided adhesive tape

To position them correctly
for sewing.

They reinforce select areas

With adhesive-backed
polyester mesh fabric.

Then a sewer stitches
the pieces together

With high-strength,
u.v.-Resistant thread.

In this first stage
of the sewing process,

They stitch together


In the second stage of sewing,

They sew together the top
and undersurfaces of each side.

Then, in the final stage,

They stitch
the right and left together.

In another part of the factory,

The body of the aircraft
begins taking shape.

It's called the trike
because it sits on three wheels,

Like a tricycle.

They build it in sections,

Welding together
several stainless-steel tubes.

After the sections receive
a baked-on coat of paint,

Workers assemble them
to each other

Around the fuel tank.

The 17-gallon tank is made
of lightweight polypropylene,

A type of plastic
that's u.v. Resistant

And impact resistant.

Once the trike
is fully assembled,

They mount
the three small wheels,

Similar to those
on motorized scooters.

Next, they bolt a 100-horsepower
gasoline engine,

Similar to a full-sized
motorcycle engine,

To the back of the trike.

On the front of the trike,
they install pedals

For propelling the craft
on the ground...

And a motorcycle-style plastic
console with windshield.

The console houses
the instrumentation panel.

They mount the radiator
in the center of the trike,

Cover it with foam and fabric,

Then install
a pair of upholstered seats

For pilot and passenger.

Then they protect the engine
with a plastic housing.

They mount an aluminum-
and-carbon-fiber propeller

On the shaft of the gearbox
connected to the engine.

Now for the wing.

Its main structure is made up
of hinged aluminum tubes

Which fold for transport.

Aluminum is lightweight
and rustproof,

Which is essential for flight.

They slip the sail over the
tubing, then unfold the wing.

Thin aluminum tubes provide
crosswise structural support.

A system of cables keeps
the wing in the open position.

Another system of cables,
called the corset,

Manipulates
the billowing of the sail.

This enables the pilot
to alter the aerodynamics

To increase or reduce speed.

Under the wing,
they install the a-frame,

The ultralight's
steering mechanism.

The pilot manipulates the
a-frame with a horizontal bar,

Changing the trike's
body position under the wing.

The last step is to bolt the
front of the trike to the wing

And hook up
the safety backup cables.

The pilot steers the ultralight

By weight-shifting
with the a-frame bar,

Tilting the trike
toward the front to descend,

To the right to veer right,
and so on.

Typical cruising speed
is around 75 miles per hour.

With an open c*ck,

Air temperature
and oxygen levels

Limit how high
an ultralight aircraft can fly.

Maximum altitude
is about 3,300 feet,

High enough for a thrill ride

Yet still low enough
for a spectacular view.

Narrator: after a busy day
of skiing and snowboarding,

Ski slopes get worn down

And develop ruts, bumps,
ice, and bare spots.

Ski resorts typically refresh
the slopes overnight

By grooming the snow
with specialized track machines.

By morning,
the runs are as good as new.

A snow groomer is like
a bulldozer on tracks,

Except instead of pushing dirt,
it pushes snow.

It uses grooming implements
mounted to the front and back.

To build a snow groomer,

Workers begin by aligning
front and rear frames

With the vehicle's main frame

With the help
of positioning jigs.

Then a welder gets to work.

First,
he tacks everything together.

Then, with a mechanical lift,

He raises and tilts
the tacked frame

To gain access
from various angles.

After welding on
additional parts,

Including 10 axles,

They prime and paint the frame.

Then a mechanic installs
a heavy-duty suspension system

Designed to automatically adapt

To the type and shape
of terrain,

Maximizing traction.

Next, he greases the 10 axles

And installs a wheel hub
and bearings on each one.

He then mounts the wheel,

Tightening the bolts
to a specified torque

To ensure optimal performance
and durability.

Meanwhile, another mechanic
installs the hydraulic hoses.

These control
the grooming implements

And the sprocket
on which each track turns.

Then he connects the hoses
to the main hydraulic valve.

At another workstation,

A mechanic assembles
the diesel engine,

The transmission,
and four hydraulic pumps.

Two of these pumps drive oil
to the hydraulic motors,

Which propel the vehicle
forward and backward.

The two others
pump hydraulic fluid

To operate the implements
and the cooling system.

They lower this assembled unit
into the frame

And make the required electrical
and hydraulic connections.

Meanwhile, another team prepares
the next unit,

Starting
with the cooling system,

Two powerful fans
which cool the engine

And hydraulic fluid.

Next, they install
the exhaust system

And two batteries
to power the engine.

They mount this assembled unit
above the transmission

And make
all the necessary connections.

They lower the cab
onto the frame,

Connect more electrical
and hydraulic lines,

And fill all systems
with their respective fluids.

The vehicle now undergoes
extensive testing

In a dynamometer,

Which operates the engine
and hydraulic components

At maximum capacity.

If all systems perform according
to engineering specifications,

The vehicle gets the go-ahead

To receive
the snow-grooming implements.

The rear implement is a tiller,

Which breaks up the snow
into small particles

And shapes narrowly spaced
parallel lines

On the trail surface.

A powerful,
built-in hydraulic motor

Spins the steel-toothed rotors
at speeds

Of up to 1,350 revolutions
per minute.

This ensures
even grooming throughout.

The groomer's tracks are made
of ultra-durable steel.

A mechanic guides
the edge of each track

Onto a high-strength
urethane sprocket

Bolted to the rear of the frame

While another mechanic slowly
drives the vehicle forward

To pull the track
over the wheels.

Then they clamp the two ends
together

And join them with giant hinges,
closing the loop.

It's time to mount
the snow-grooming implements.

They attach the tiller
to the rear mechanism,

Which carries
the hydraulic connections

For the implement's
onboard motor.

They attach a blade to
the identical front mechanism.

The blade plows snow

And sculpts features
such as half-pipes,

Those giant,
u-shaped bowls of snow

In which freestyle skiers
and daredevil snowboarders ride.

For safety,
the cabin has a steel skeleton

With roll-over protection
features.

A specially designed joystick

Gives the driver
precision control

Over the blade and tiller.

The state-of-the-art electronics
include three computers,

Which enable the driver

To select and adjust
different functions and modes,

All of it displaying
on a color monitor.

The vehicle
never sinks into the snow

Because its weight is optimally
balanced on the tracks.

This 22,000-pound snow groomer

Actually exerts less pressure
on the snow

Than a single person does
on foot.

Narrator: the rubber band
was invented in england

In the middle
of the 19th century.

The key to its success,
of course, is flexibility.

A rubber band can be stretched

Around items
of various shapes and sizes

To hold them together,

So in the rubber-band industry,

The possibilities for expansion
are numerous.

Rubber bands come in handy
for a whole bunch of things.

If you have a bunch of anything,

A rubber band
can keep it together.

Production of rubber bands
starts with natural rubber.

These spongy slabs
have been made

From the sap of rubber trees.

Natural rubber
has greater elasticity

Than the synthetic kind,

Making it a better choice
for rubber bands.

A worker measures and pours
rubber processing oil

Into a kneader machine.

He adds powdered pigment --
in this case, yellow and white

For a pale yellow shade.

He feeds several rubber slabs

To the kneader's
spiral-shaped jaws.

The spiraling blades intersect
to break up the rubber

And blend in
the other ingredients.

The kneading process generates
heat which softens the rubber,

Making it easier
to form into dough.

The kneader spits out
rubber-dough chunks.

Next, a giant rolling pin
transforms the dough

Into wide, thin pieces.

He slices the strips
and bundles them.

In this form,

It will be easier to control
the weight of the rubber

In relation to chemicals
that are added next.

They roll the rubber

With a precise amount of sulfur
and other chemicals

That strengthen the rubber
and make it more elastic.

They then roll the rubber
very thin.

A worker twists and cuts it
into small bundles

That fit into the opening
of an extruding machine.

It forces the still-warm
and malleable rubber

Through dies to shape it
into long, hollow tubes.

The extruder injects air
and talcum powder into the tubes

To keep the walls
from collapsing

And sticking together
while warm.

The tubes cool down
in a trough of water,

And they deflate
as the injected air dissipates.

Next, these aluminum poles
will serve as molds

For the tubes during curing,

Giving them the correct shape
and diameter.

The worker slides the tubes
onto the molds.

The talcum powder injected into
the tubes during their extrusion

Will also act
as a release agent,

Keeping them from sticking
to the molds during curing.

They load the tubes
into a steam oven,

And the intense heat vulcanizes
the rubber

To boost its tensile strength
and elasticity.

Out of the oven,

Workers inject air between
the tubes and the molds,

Making it easier to peel
the now-vulcanized tubes off.

They rinse the rubber tubes
to remove talcum-powder residue.

There's so much that the water
turns milky white.

They hang the rubber tubes
to drain away some of the water.

By the time they're ready
to cut, they're a bit too dry,

So a worker splashes water
onto them.

With the tubes moistened,

The next operation
will run more smoothly.

He feeds several tubes at once
to a rotating blade

Which carves them.

This creates elastic bands
that are exactly the same width.

In this case,
that's 1.5 millimeters,

An average thickness
for a rubber band.

With this system, they can cut


In an hour.

It doesn't take long
for the inventory to pile up.

There are millions
of rubber bands here.

A worker scoops them up and
examines each one for defects.

Once approved, all that's left
is the packaging.

The rubber bands ride a conveyor

That releases them in increments
into plastic bags.

It has taken about three hours

To produce this bag
of rubber bands.

On a normal day, this factory
generates 40 million elastics.

That's a lot by any stretch
of the imagination.

If you have any comments
about the show,

Or if you'd like to suggest
topics for future shows,

Drop us a line at...