All language subtitles for How Its Made S23E04 Railway Bridge Ties; Membrane Filters; Hydrolic Post Drivers; Bi-Planes

-- Captions by VITAC --
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CAPTIONS PAID FOR BY
DISCOVERY COMMUNICATIONS

Narrator:
THE DECK OF A RAILWAY BRIDGE

IS TYPICALLY BUILT OF
WOOD-TIMBERS CALLED BRIDGE TIES.

THEY'RE BOLTED
TO STEEL SUPPORT BEAMS

LOCATED ON CONCRETE PIERS
OVER THE WATER OR GULLY BELOW.

THE RAILS
ON WHICH THE TRAIN TRAVELS

ARE BOLTED TO THE WOODEN TIES.

WOOD ABSORBS THE NOISE
AND VIBRATION

OF THE PASSING TRAIN.

THE LOAD
THE RAILWAY BRIDGE WILL CARRY

DETERMINES THE SIZE OF ITS TIES.

TO CALCULATE THE LOAD,

ENGINEERS FACTOR IN
THE NUMBER OF TRACKS,

VOLUME OF TRAFFIC,
WEIGHT OF THE TRANSPORTED CARGO,

AND WHETHER THE BRIDGE
IS STRAIGHT OR CURVED.

A CURVE WILL PUT ADDITIONAL
STRESS ON THE STRUCTURE.

THE WOOD OF CHOICE IS OAK
BECAUSE IT'S HARD AND STRONG.

WHEN THE LOGS
ARRIVE AT THE SAWMILL,

THEY COME FACE-TO-FACE
WITH A MENACING-LOOKING DEVICE

CALLED A DEBARKER.

A CONVEYOR MOVES THE SHIPMENT
TOWARD THE DEBARKER,

THEN DROPS A SINGLE LOG IN FRONT
OF IT ONTO SPINNING ROLLERS.

THE ROLLERS ROTATE THE LOG,

WHILE THE DEBARKER MAKES ITS WAY
FROM ONE END TO THE OTHER.

IT CHEWS OFF THE BARK
WITH ITS SHARP-TOOTHED BLADES.

WHAT THE DEBARKER SHAVES
OFF IS PUT TO GOOD USE.

THE BARK GETS PROCESSED
INTO GARDENING MULCH

AND THEY BURN THE SAWDUST
IN THE WOOD-FIRED BOILER

THAT RUNS ANOTHER PART
OF THE PLANT.

NEXT, ONE LOG AT A TIME
DROPS INTO A MOBILE CARRIAGE

THAT RUNS IT
THROUGH A CIRCULAR SAW.

THE CARRIAGE HAS SENSORS

WHICH DETECT
THE LOG'S EXTREMITIES

AND REPORT ITS DIMENSIONS

TO A CONSOLE LOCATED
IN THE OPERATOR'S CAB.

THE OPERATOR
INTERPRETS THE DATA.

USING A JOYSTICK CONTROLLER,

HE FLIPS THE LOG
INTO WHICHEVER POSITION

MAXIMIZES THE YIELD.

THE FIRST FEW RUNS

TRIM OFF THE ROUGH SURFACE
AND SQUARE THE SHAPE.

THE NEXT RUNS CUT BOARDS,

WHICH THE SAWMILL
SELLS TO FLOORING PLANTS.

THIS CONTINUES UNTIL THE LOG
IS THE EXACT DIMENSIONS

OF THE BRIDGE TIE.

AGAIN, NOTHING IS WASTED.

THE SAWMILL PROCESSES
THE CUTOFFS INTO WOOD CHIPS,

WHICH IT THEN SELLS TO COMPANIES
THAT MAKE PARTICLE BOARD,

STRAND BOARD, AND SIMILAR
CONSTRUCTION MATERIALS.

THE SAWMILL STACKS THE TIES

FOR TRANSFER
TO THE BRIDGE MILL NEXT DOOR.

THE ROLE OF THE BRIDGE MILL
IS TO FRAME THE BRIDGE,

ALSO KNOWN AS DAPPING.

THAT'S THE PROCESS
OF MAKING THE SPECIFIC HOLES

AND NOTCHES IN EACH TIE

FOR ATTACHING IT TO THE STEEL
BEAM ON WHICH IT WILL SIT.

AT THE BRIDGE MILL,

THE BRIDGE LAYOUT SUPERVISOR
PROCESSES ONE TIE AT A TIME.

HE CAREFULLY REVIEWS
THE ENGINEER'S BLUEPRINTS,

WHICH ASSIGN A NUMBER
TO EACH AND EVERY TIE.

THESE NUMBERS SPECIFY PRECISELY
WHERE THE SAW HAS TO CUT NOTCHES

AND WHERE THE DRILL
HAS TO BORE HOLES.

THE LOCATIONS OF THESE NOTCHES
AND HOLES VARY,

DEPENDING ON THE TIE'S POSITION
ON THE BRIDGE.

SO, HE MUST FOLLOW
THE BLUEPRINTS METICULOUSLY.

AFTER MEASURING
AND MARKING IT ALL OUT,

HE SENDS THE TIE TO THE DAP SAW.

THE OPERATOR SETS UP EACH CUT,

LINING UP THE MARK
WITH LASER-LIGHTS,

WHICH INDICATE THE LOCATION
AND THE CUTTING DEPTH

OF THE BLADE.

THE NOTCHES ARE JUST THE RIGHT
SIZE TO FIT OVER THE STEEL BEAM

ON WHICH THE TIE WILL LIE.

NEXT,
A WORKER USING A DRILL PRESS

BORES HOLES FOR HOOK BOLTS,
WHICH GO THROUGH THE TIE

TO SECURE IT
ONTO THE STEEL BEAMS.

EACH TIE RECEIVES A METAL
IDENTIFICATION TAG,

WHICH INCLUDES THE BRIDGE
AND TIE NUMBERS.

ON EACH END,
WORKERS NAIL ON A MESH PLATE,

MADE OF RUST-PROOF
GALVANIZED STEEL.

THE PLATE HAS TEETH DESIGNED
TO GRASP AND HOLD TOGETHER

THE WOOD FIBER TO PREVENT
THE END FROM SPLITTING.

AFTER NAILING THE ID TAG
TO ONE OF THE END PLATES,

WORKERS FORCE IN BOTH PLATES
WITH A PRESS.

THE TIE'S LAST STOP
IS THE ADJACENT TREATMENT PLANT.

THEY SPEND 24 HOURS
INSIDE A HIGH-TEMPERATURE,

HIGH-PRESSURE CHAMBER

WHICH PENETRATES THEM
WITH A CREOSOTE-BORATE SOLUTION.

THIS PROTECTS THE WOOD
FROM ROT AND INSECT DAMAGE

AND EXTENDS THE TIE'S LIFE-SPAN

FROM ABOUT A DECADE
TO AT LEAST 25 YEARS.

Narrator:
WHEN FILTERING LIQUIDS,

IT'S ALL ABOUT THINKING SMALL.

MEMBRANE FILTERS CAN SEPARATE
THE TINIEST SOLIDS FROM FLUIDS,

WHICH PURIFIES THE LIQUIDS
AND RECOVERS THE SOLIDS.

ONCE SEPARATED,
THE TWO SUBSTANCES

MAY THEN BE REUSED
SO THAT NOTHING GOES TO WASTE.

MEMBRANE FILTERS CAN TURN MURKY
WATER CLEAR, ALMOST MAGICALLY.

TO DEMONSTRATE, A TECHNICIAN
INSTALLS A SPIRAL-WOUND MEMBRANE

IN THE HOUSING
OF A PUMPING SYSTEM,

WHICH IS A SMALL-SCALE VERSION

OF WHAT YOU WOULD SEE
IN A FACTORY.

SHE TURNS ON THE TAP,
AND WATER FLOWS INTO A TANK.

SHE ADDS LATEX PAINT
TO PURPOSELY SULLY THE WATER.

THE SYSTEM PUMPS
THE CONTAMINATED WATER

THROUGH A STRAINER

AND THEN THE MEMBRANE FILTER
WHILE METERS MEASURE THE FLOW.

WITHIN MINUTES, THE PAINT
HAS BEEN FILTERED OUT,

AND THE WATER IS CLEAR.

THE MAKING OF A MEMBRANE FILTER
BEGINS WITH POLYPROPYLENE MESH.

AN AUTOMATED SYSTEM UNWINDS
THE MESH AND CUTS IT TO LENGTH.

THESE MESH SHEETS
WILL BE USED AS SPACERS.

THEY'LL CREATE GAPS
FOR THE LIQUID

TO FLOW THROUGH THE FILTER
AND OVER THE MEMBRANE.

NEXT, THE SYSTEM
CUTS SHEETS OF POLYESTER FABRIC.

THESE WILL FORM CHANNELS

THROUGH WHICH THE FILTERED
MATERIAL WILL TRAVEL.

THESE SHEETS ARE KNOWN
AS PERMEATE SPACERS.

AN EMPLOYEE STACKS
THE POLYESTER FABRIC SHEETS.

USING HIGH-FREQUENCY
SOUND WAVES,

SHE WELDS ONE SHEET TO THE NEXT
AT JUST ONE END.

SHE LAYERS AND WELDS
A TOTAL OF 15 SHEETS,

AND THEN APPLIES
DOUBLE-SIDED TAPE.

THE TAPE IS FOR ATTACHING
THE PACKET TO A CENTRAL TUBE,

AND IT WILL ALSO SERVE AS
A GUIDE TO CORRECTLY ALIGN IT.

NEXT, THE MEMBRANE SOUP
FLOWS INTO A LONG TROUGH.

IT'S A MIX
OF MELTED PLASTICS AND SOLVENTS.

PAPER BACKING UNWINDS
INTO THE TROUGH

AND IS COATED WITH THE SOUP
ON ONE SIDE.

THE COATED PAPER THEN TRAVELS
THROUGH TWO QUENCH TANKS,

AND THE PLASTIC COMPONENTS
SOLIDIFY

AS THE SOLVENTS ARE DRAWN OUT.

THE EXITING SOLVENTS
CREATE A UNIQUE CORE STRUCTURE

IN THE REMAINING
WHITE PLASTIC MEMBRANE.

THE MEMBRANE NOW
TRAVELS BY A LIGHT BOX,

WHICH ILLUMINATES
ANY VISUAL DEFECTS.

AN APPLICATOR ALSO DRIPS A
PRESERVATIVE ONTO THE MEMBRANE.

A TEAM UNROLLS THE MEMBRANE
ONTO A WORK TABLE.

THEY LAY A SHEET
OF THE POLYPROPYLENE MESH,

WHICH WE SAW CUT TO SIZE
EARLIER, ON THE MEMBRANE.

THE EMPLOYEE
THEN CUTS THE MEMBRANE

TO TWICE THE LENGTH OF THE MESH.

THEY FOLD THE MEMBRANE
OVER THE MESH,

CREATING A MEMBRANE ENVELOPE.

THE MESH SERVES AS A PATHWAY
FOR FLUID

TO FLOW BETWEEN THE MEMBRANES.

MEANWHILE, ANOTHER WORKER

APPLIES EPOXY
TO PERFORATED PLASTIC TUBE.

HE ATTACHES
THE PERMEATE SPACERS TO IT

WITH THE DOUBLE-SIDED TAPE,

GIVING THE EPOXY TIME TO CURE
FOR A PERMANENT SEAL.

HE AND A COLLEAGUE
APPLY MORE EPOXY

TO THE PERIMETER
OF THE BOTTOM SHEET.

THEY TRANSFER
THE MEMBRANE ENVELOPE TO IT

AND CONTINUE TO LAYER,

MAKING A PERMEATE FABRIC
AND MEMBRANE SANDWICH.

THE WORKER THEN WINDS
THE GLUED LAYERS SNUGGLY

TO A PERFORATED PLASTIC CORE,

FORMING
THE SPIRAL MEMBRANE FILTER.

HE TAPES THE MULTI-LAYERED WAD
FROM ONE END TO THE OTHER.

THE TAPE HOLDS EVERYTHING
TIGHTLY IN PLACE

AS THE EPOXY CURES OVERNIGHT.

THEY LEAVE THE TAPE
ON AFTER THE CURE,

AND A MACHINE WINDS
EPOXY-DRENCHED FIBERGLASS ROPE

AROUND THE ENTIRE FILTER.

AS THE EPOXY CURES,

THE ROPE WILL FORM A HARD SHELL
AROUND THE MEMBRANE FILTER.

PARTWAY THROUGH,

THEY APPLY THE LABEL
WITH A COMPANY NAME.

THE OPERATOR CAPTURES THE GLUE
RUNOFF DURING THE WIND.

AND IT'S A WRAP,
SO HE CUTS THE ROPE.

FROM THE SIDE,
YOU CAN SEE THE FLOW CHANNELS

BETWEEN THE LAYERS.

CONCENTRATED CONTAMINANTS WILL
TRAVEL THROUGH THEM AND OUT.

THE FILTERED LIQUID WILL SEEP
INTO THE CORE AND EXIT,

CLEARLY IMPROVED.

Narrator: THE INVENTION
OF THE HYDRAULIC POST DRIVER

IN THE 1960s

ALLOWED WORKERS TO DROP
THEIR SHOVELS AND SLEDGEHAMMERS

AND LET A MACHINE DO THE JOB
OF POUNDING FENCE AND SIGN POSTS

INTO THE GROUND.

WHEN IT COMES
TO LABOR-SAVING INVENTIONS,

THIS ONE IS DEFINITELY
A STRIKING EXAMPLE.

THE POST DRIVER

RAISES HEFTY FENCE
OR SIGN POSTS INTO POSITION,

AND THEN SLAMS THEM
INTO THE GROUND.

INSIDE A VERTICAL CASE,
A HYDRAULIC SYSTEM

DROPS A 300-POUND WEIGHT
TO DRIVE THE POST,

AND THEN LIFTS IT
FOR ANOTHER HIT.

THIS MACHINE DOES THE WORK
OF TWO OR MORE BRAWNY HUMANS

WITH JUST ONE PERSON
AT THE CONTROLS.

TO MAKE IT, THEY START WITH
A VERTICAL CASE FOR THE WEIGHT.

A HIGH-PRECISION PLASMA TORCH

CUTS STEEL
INTO A RECTANGULAR SHAPE

AND MAKES HOLES FOR COMPONENTS.

THEY INSERT THE RECTANGLE
INTO A BREAK-PRESS REPEATEDLY

TO BEND IT
INTO A THREE-SIDED PART.

THE PROFILE INCLUDES FLANGES

FOR WELDING IT
TO THE BACK WALL OF THE CASE.

HE FITS THE PART
TO THE BACK WALL

AND WELDS THEM TOGETHER,
COMPLETING THE POST DRIVER CASE.

AN EMPLOYEE BUILDS
THE POST DRIVER WEIGHT

WORKING WITHIN A WELD FIXTURE.

IT'S A BOX-SHAPED WEIGHT,
AND HE WELDS IT AT THE SEAMS.

HE TAPS THE CORNERS
BETWEEN THE WELDS

TO MAINTAIN
A TIGHT CONFIGURATION.

THIS 300-POUND WEIGHT CAN LATER
BE FILLED WITH STEEL SHOT

TO MAKE IT EVEN HEAVIER
FOR GREATER IMPACT.

THE NEXT WORKER ASSEMBLES
YELLOW STEEL JAWS TO A HUB

TO PRODUCE THE GRAPPLE.

THIS IS THE PART
THAT GRIPS THE FENCE POST

AND RAISES IT INTO POSITION.

HE STICKS A DANGER LABEL
ONTO THE HUB

TO WARN PEOPLE TO STAY CLEAR
OF THESE POWERFUL JAWS.

HE ATTACHES
A HYDRAULIC CYLINDER,

WHICH WILL MAKE
THE JAWS OPEN AND CLOSE.

HE CONNECTS THE CYLINDER
TO THE GRAPPLE JAW.

NEXT,
THEY MOVE ON TO THE METAL PLATE

THAT WILL BE USED TO MOUNT
THE POST DRIVER TO A VEHICLE,

LIKE A SKID-STEER LOADER.

IT INCLUDES
A HYDRAULIC MECHANISM

FOR TILTING THE FENCE POST
LEFT OR RIGHT.

THE EMPLOYEE INSTALLS A CONTROL
VALVE NEXT TO THE CYLINDER

AND LINKS THE TWO WITH HOSES.

HE'LL ALSO CONNECT THE GRAPPLE

AND WEIGHT HYDRAULICS
TO THIS VALVE.

BACK TO THE POST DRIVER CASE
NOW -- IT'S BEEN PAINTED,

AND THEY'RE READY TO INSTALL
THE HYDRAULIC MOTOR.

THE WORKER CONNECTS IT
TO THE SPROCKETS AND CHAINS

THAT WILL LIFT THE WEIGHT.

HE PINS THE SPROCKETS INTO PLACE

AND INSTALLS TENSIONING RODS
ON EITHER SIDE.

NEXT, A COVER PLATE
PROTECTS THE SPROCKETS.

THE TENSIONING RODS
PROTRUDE THROUGH IT.

HE SLIDES SPRINGS
ONTO THOSE TENSIONING RODS

AND COMPRESSES THE SPRINGS
TO MAINTAIN THE TENSION.

HE NOW ATTACHES THE GRAPPLE
TO THE POST DRIVER CASE.

HE LOCKS IT INTO PLACE
WITH A LONG PIN.

HE LINKS THE GRAPPLE HYDRAULICS
TO THE CONTROL VALVE.

AND IT'S READY TO GRAB
BIG FENCE POSTS

AND HOLD ON TIGHT.

THEY ATTACH THE METAL MOUNTING
PLATE TO THE POST DRIVER CASE.

THE WORK TABLE TILTS BACK
TO MOVE THE POST DRIVER

INTO AN UPRIGHT POSITION.

WITH THE HELP OF A CRANE,

THE NEXT WORKER
MOVES THE WEIGHT INTO POSITION

AND LOWERS IT INTO THE CASE.

HE SLIDES A PIN INTO THE TOP END

TO KEEP THE WEIGHT
FROM FALLING OUT

WHEN THE POST DRIVER
IS ON AN ANGLE.

ONE DAY IN THE MAKING,

THIS HYDRAULIC POST DRIVER IS
READY FOR YEARS OF HEAVY LABOR,

TAKING OVER FOR HUMANS SO THEY
DON'T HAVE TO MOVE A MUSCLE.

Narrator: A BIPLANE
IS A VINTAGE-STYLE AIRCRAFT

WITH TWO PAIRS OF WINGS
SITTING ONE ABOVE THE OTHER.

THE TOP WINGS ARE TYPICALLY
RAISED ABOVE THE FUSELAGE

WITH VERTICAL STRUTS BRACING
THEM TO THE BOTTOM WINGS.

DATING BACK TO THE EARLIEST DAYS
OF AVIATION,

THEY'RE STILL POPULAR
FOR PERFORMING AEROBATICS.

A BIPLANE'S LOWER WINGS
HAVE AILERONS,

WHICH BANK THE AIRPLANE
TO THE RIGHT OR LEFT.

ON THE PLANE'S TAIL,

ELEVATORS PITCH THE PLANE'S NOSE
UP OR DOWN

WHILE A RUDDER STEERS IT
LEFT OR RIGHT.

A PROPELLER
PROVIDES THE PROPULSION.

THE PLANE HAS FOUR WINGS.

EACH WING HAS TWO SPARS,

WOODEN BEAMS
AT THE FRONT AND REAR,

WHICH FORM
THE PERIMETER STRUCTURE.

A CRAFTSMAN SKILLFULLY FASHIONS
THESE SPARS OUT OF SITKA SPRUCE.

THIS WOOD IS EXCEEDINGLY LIGHT,
YET EXCEPTIONALLY STRONG,

MAKING IT ONE
OF ONLY A FEW WOODS

APPROVED FOR STRUCTURAL USE
IN AIRPLANES.

AFTER SAWING THE WOOD
TO THE SPAR'S SHAPE,

HE MOUNTS ATTACHMENT PLATES
MADE OF SITKA SPRUCE

AND MAHOGANY PLYWOOD.

THESE ARE THE END STRUTS,

STEEL VERTICAL BARS
WHICH WILL CONNECT THE UPPER

AND LOWER WINGS.

HE FINISHES THE SPAR
BY REFINING ITS CONTOUR,

FIRST WITH A HAND PLANE,
THEN AN ELECTRIC PLANE.

USING STRIPS OF SITKA SPRUCE,

HE CONSTRUCTS 15 STRUCTURAL RIBS
FOR EACH WING.

HE BEGINS WITH LONG STRIPS,

WHICH HAVE BEEN SOAKING IN WATER
FOR A WEEK TO MAKE THEM PLIABLE.

HE INSERTS ONE END
INTO A CURVED FIXTURE

AND LEAVES THE STRIPS TO DRY.

WHEN HE REMOVES THEM A COUPLE
OF DAYS LATER,

THEY HAVE A PERMANENT
AERODYNAMIC CURVE.

HE GLUES
TWO CURVED STRIPS TOGETHER

TO FORM THE PERIMETER
OF ONE RIB.

IN BETWEEN, HE GLUES SHORT
DIAGONAL STRIPS CALLED TRUSSES.

HE REINFORCES BOTH SIDES
OF EACH INTERSECTION

WITH A RECTANGULAR PIECE
CALLED A GUSSET.

AN ASSEMBLER MOUNTS THE 15 RIBS
CROSSWISE

ON THE FRONT AND REAR
WING SPARS,

THEN INSTALLS THREE ALUMINUM
TUBES CALLED COMPRESSION RIBS.

THESE ABSORB AIR LOAD
HITTING THE SPARS,

KEEPING THE WOODEN RIBS
FROM FLEXING UNDER PRESSURE.

THE CRAFTSMAN
CONNECTS THE COMPRESSION RIBS

WITH CRISS-CROSSING METAL RODS.

AFTER APPLYING MORE GLUE
TO CRITICAL AREAS,

HE NAILS AN ALUMINUM TRIM

OVER THE FRONT SPAR
AND NOSE OF THE RIBS.

THIS IS CALLED THE LEADING EDGE.

IT'S THE FIRST PART OF THE WING
TO HIT THE WIND,

SO IT TAKES THE BRUNT
OF THE AIR LOAD.

FINALLY, HE LACES REINFORCEMENT
TAPE THROUGH THE RIBS

IN AN X PATTERN.

THE COMPLETED STRUCTURE NOW
MOVES TO THE COVERING DEPARTMENT

WHERE TECHNICIANS DRAPE IT

IN HEAT SHRINKABLE
POLYESTER FABRIC.

THEY CUT THE FABRIC TO SIZE,
GLUE IT TO THE WING PERIMETER,

AND HEAT THE SURFACE
WITH AN IRON

TO SHRINK THE FABRIC
UNTIL IT'S TAUT.

THEN, THEY STITCH OVER THE GLUED
AREAS WITH POLYESTER CORD.

THEY BRUSH ON A CHEMICAL
WHICH SEALS THE PORES

OF THE FABRIC.

THIS PRIMES THE SURFACE
TO RECEIVE A SPRAY COAT

OF POLYURETHANE PAINT,

WHICH IS A SPECIAL FORMULATION
DESIGNED FOR AIRCRAFT BODIES.

TECHNICIANS CONSTRUCT
THE FUSELAGE FRAME

OUT OF HIGH-STRENGTH
STEEL ALLOY TUBES.

THEY USE AN ELECTRIC TORCH TO
SLIGHTLY MELT ADJOINING PIECES

SO THEY FUSE TO EACH OTHER.

BECAUSE THERE'S NO FILLER METAL
BONDING THE PIECES,

THE WELDS DON'T ADD ANY WEIGHT
TO THE STRUCTURE.

AFTER PAINTING THE FRAME,

TECHNICIANS INSTALL ALUMINUM
FLOOR PANELS AND BULKHEADS.

IN THE TAIL, THEY ADD
LIGHTER WEIGHT BULKHEADS

MADE OF MAHOGANY PLYWOOD
AND SITKA SPRUCE.

THEN IT'S TIME
TO BOLT THE ENGINE

TO THE FRONT
OF THE FUSELAGE FRAME.

THE ENGINE DRIVES A PROPELLER

MADE OF EITHER WOOD, ALUMINUM,
OR A COMPOSITE MATERIAL.

PAINTED ALUMINUM BODY PANELS
COVER THE FRAME.

TECHNICIANS
INSTALL THE FUEL TANK

BETWEEN THE FRONT COCKPIT
AND THE ENGINE.

THEN THEY BOLT THE WINGS
TO THE FUSELAGE.

VERTICAL STEEL STRUTS
CONNECT AND REINFORCE

THE TWO LEVELS OF WINGS

BOLTING TO THOSE ATTACHMENT
PLATES ON THE WING SPARS.

NEXT, TECHNICIANS MOUNT
THE PAINTED ALUMINUM AILERONS,

THE TAIL,
WITH ITS ELEVATORS AND RUDDER

MADE OF PAINTED FABRIC
OVER WELDED STEEL,

AND THEN THE ENGINE COVER.

THEY INSTALL A WINDSCREEN

AND INSTRUMENT PANEL
FOR EACH COCKPIT.

THE FRONT SCREEN CAN BE REPLACED
WITH A COCKPIT COVER

TO KEEP THE PILOTS WARM
WHEN FLYING IN COLD WEATHER.

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