47402725 aircraft landing gear

7/29/2019 47402725 Aircraft Landing Gear

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AIRCRAFT LANDINGAIRCRAFT LANDING

GEARGEAR


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LANDING GEARLANDING GEAR

is a structure which installed on the aircraft for theis a structure which installed on the aircraft for theground and alsoground and alsoallows the aircraft to land safely. Landing gear alsoallows the aircraft to land safely. Landing gear alsoprovides mobility to theprovides mobility to the

aircraft purpose to support the weight of the aircraftaircraft purpose to support the weight of the aircraftwhiles it on ground or water.whiles it on ground or water.

Aircrafts require landing gear for taxiing, takeoff, andAircrafts require landing gear for taxiing, takeoff, andlanding. Initially aircrafts used skids as its landing gear.landing. Initially aircrafts used skids as its landing gear.Times after times, wheels were attached to the skids.Times after times, wheels were attached to the skids.

Since that time, various arrangements have been usedSince that time, various arrangements have been usedfor wheels and structures to connect them to thefor wheels and structures to connect them to theairplane.airplane.


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TYPES OF LANDING GEARTYPES OF LANDING GEAR

Conventional landing gearConventional landing gear

Tricycle landing gearTricycle landing gear

Tandem landing gearTandem landing gear


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Conventional landing gearConventional landing gear

consists of two wheels forward of the aircraft'sconsists of two wheels forward of the aircraft's

center of gravity and a third small wheel at thecenter of gravity and a third small wheel at the

tail. This type of landing gear is most often seentail. This type of landing gear is most often seen

in older general aviation airplanes. The two mainin older general aviation airplanes. The two mainwheels are fastened to the fuselage by struts.wheels are fastened to the fuselage by struts.

Without a wheel at the nose of the plane, itWithout a wheel at the nose of the plane, it

easily pitches over if brakes are applied tooeasily pitches over if brakes are applied too

soon. Because the tailwheel is casteredsoon. Because the tailwheel is castered----free tofree tomove in any directionmove in any direction----the plane is very difficultthe plane is very difficult

to control when landing or taking off.to control when landing or taking off.


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HistoryHistory

In early aircraft, a tail skid made of metalIn early aircraft, a tail skid made of metal

or wood was used to support the tail onor wood was used to support the tail on

the ground. In most modern aircraft, athe ground. In most modern aircraft, asmall, articulated wheel assembly issmall, articulated wheel assembly is

attached to the rearmost part of theattached to the rearmost part of the

airframe in place of the skid. This wheel isairframe in place of the skid. This wheel is

steered by the pilot through a connectionsteered by the pilot through a connectionto the rudder pedals, allowing the rudderto the rudder pedals, allowing the rudder

and tail wheel to move together.and tail wheel to move together.


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AdvantagesAdvantages

tailwheel has less parasite dragtailwheel has less parasite drag

less expensive to buy and maintainless expensive to buy and maintain

Tailwheel aircraft are easier to manTailwheel aircraft are easier to man--handle onhandle on

the ground and, due to their lower tail, they willthe ground and, due to their lower tail, they will

fit into some hangars more easilyfit into some hangars more easily

If a tailwheel fails on landing, the damage to theIf a tailwheel fails on landing, the damage to the

aircraft will be minimal. This is not the case inaircraft will be minimal. This is not the case inthe event of a nosewheel failure, which usuallythe event of a nosewheel failure, which usually

results in propeller damage.results in propeller damage.


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DisadvantagesDisadvantages

Tail wheel aircraft are much more subject to "noseTail wheel aircraft are much more subject to "nose--over"over"accidents, due to main wheels becoming stuck in holesaccidents, due to main wheels becoming stuck in holesor injudicious application of brakes by the pilotor injudicious application of brakes by the pilot

Conventional geared aircraft are much more susceptibleConventional geared aircraft are much more susceptible

to ground looping. A ground loop occurs when directionalto ground looping. A ground loop occurs when directionalcontrol is lost on the ground and the tail of the aircraftcontrol is lost on the ground and the tail of the aircraftpasses the nose, in some cases completing a full circle.passes the nose, in some cases completing a full circle.This event can result in damage to the aircraft'sThis event can result in damage to the aircraft'sundercarriage, tires, wingtips and propeller. Avoidingundercarriage, tires, wingtips and propeller. Avoiding

ground loops requires increased pilot training and skill.ground loops requires increased pilot training and skill.


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Tail wheel aircraft are more difficult to taxiTail wheel aircraft are more difficult to taxiduring high wind conditions, due to theduring high wind conditions, due to thehigher angle of attack on the wings. Theyhigher angle of attack on the wings. They

also suffer from lower crosswind capabilityalso suffer from lower crosswind capabilityand in some wind conditions may beand in some wind conditions may beunable to use crosswind runways orunable to use crosswind runways orsinglesingle--runway airports.runway airports.

Conventional geared aircraft require moreConventional geared aircraft require moretraining time for student pilots to master.training time for student pilots to master.


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TRICYCLE LANDING GEARTRICYCLE LANDING GEAR

Tricycle gear is the most popular landingTricycle gear is the most popular landing

gear arrangements. The tricyclegear arrangements. The tricycle

undercarriage includes two main gearsundercarriage includes two main gears

just aft of the center of gravity and ajust aft of the center of gravity and a

smaller auxiliary gear near the nose.smaller auxiliary gear near the nose.


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AdvantagesAdvantages

It allows more forceful application of the brakesIt allows more forceful application of the brakesduring landings at high speeds without causingduring landings at high speeds without causingthe aircraft to nose over.the aircraft to nose over.

It permits better forward visibility for the pilotIt permits better forward visibility for the pilotduring takeoff, landing, and taxiing.during takeoff, landing, and taxiing.

It tends to prevent ground looping (swerving)It tends to prevent ground looping (swerving)by providing more directional stability duringby providing more directional stability duringground operation since the aircrafts center ofground operation since the aircrafts center of

gravity (CG) is forward of the main wheels.gravity (CG) is forward of the main wheels.The forward CG keeps the airplane movingThe forward CG keeps the airplane movingforward in a straight line rather than groundforward in a straight line rather than groundlooping.looping.


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TANDEM LANDING GEARTANDEM LANDING GEAR

is used for very large aircraft like the Bis used for very large aircraft like the B--5252bomber and the Ubomber and the U--22reconnaissance/research aircraft. Thereconnaissance/research aircraft. The

main landing gear is in two sets that aremain landing gear is in two sets that arelocated one behind the other on thelocated one behind the other on thefuselage. The tandem landing gear allowsfuselage. The tandem landing gear allowsthe use of a highly flexible wing, but it maythe use of a highly flexible wing, but it mayalso require the use of small wheels on thealso require the use of small wheels on thetips of the wings to keep the wings fromtips of the wings to keep the wings fromscraping the ground.scraping the ground.


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Another Types of Landing GearAnother Types of Landing Gear

QuadricycleQuadricycle

UnconventionalUnconventional

BogeyBogey


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QUADRICYCLEQUADRICYCLE

Quadricycle gear are also very similar to theQuadricycle gear are also very similar to thetricycle arrangement except there are four maintricycle arrangement except there are four maingear roughly equal in size and mounted alonggear roughly equal in size and mounted alongthe fuselage. Like tricycle gear, the quadricyclethe fuselage. Like tricycle gear, the quadricycle

undercarriage also requires a very flat attitudeundercarriage also requires a very flat attitudeduring takeoff and landing. This arrangement isduring takeoff and landing. This arrangement isalso very sensitive to roll, crosswinds, andalso very sensitive to roll, crosswinds, andproper alignment with the runway. The mostproper alignment with the runway. The mostsignificant advantage of quadricycle gear is thatsignificant advantage of quadricycle gear is that

the plane's floor can be very close to the groundthe plane's floor can be very close to the groundfor easier loading and unloading of cargo.for easier loading and unloading of cargo.However, this benefit comes at the price of muchHowever, this benefit comes at the price of muchhigher weight and drag than bicycle gear.higher weight and drag than bicycle gear.


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UNCONVENTIONALUNCONVENTIONAL

Aircraft that have to land on water areAircraft that have to land on water are

fitted with skids rather than wheels.fitted with skids rather than wheels.

These skids are the unconventionalThese skids are the unconventional

landing gears for the aircraft. Somelanding gears for the aircraft. Some

planes had interchangeable skids andplanes had interchangeable skids and

wheels so that the plane could be usedwheels so that the plane could be used

to land both on land and on water. Otherto land both on land and on water. Otherthan skids, skis and floats also thethan skids, skis and floats also the

unconventional gears.unconventional gears.


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BOGEYBOGEY

Another type of landing gear is the use of multipleAnother type of landing gear is the use of multiplewheels per landing gear strut. It is especially common towheels per landing gear strut. It is especially common toplace two wheels on the nose strut of the tricycleplace two wheels on the nose strut of the tricyclearrangement to provide safety and steering control inarrangement to provide safety and steering control in

case of a tire blowout. This additional tire is particularlycase of a tire blowout. This additional tire is particularlyuseful on carrieruseful on carrier--based aircraft where two nose wheelsbased aircraft where two nose wheelsare a requirement. When multiple wheels are placedare a requirement. When multiple wheels are placedon the same gear unit, they are attached together on aon the same gear unit, they are attached together on astructural device called a bogey. The heavier the aircraftstructural device called a bogey. The heavier the aircraft

becomes, the more wheels are typically added to thebecomes, the more wheels are typically added to thebogey to spread the plane's weight more evenlybogey to spread the plane's weight more evenlyacross the runway pavement.across the runway pavement.


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Classification of Landing GearClassification of Landing Gear


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NonNon--Absorbing Landing gearAbsorbing Landing gear

Includes Rigid landing gear, ShockIncludes Rigid landing gear, Shock--cordcord

landing gear, Spring landing gearlanding gear, Spring landing gear

Rigid:Rigid: helicopters, sailplanes.helicopters, sailplanes. No flexingNo flexing

other than the structure.other than the structure.

Shock cord system:Shock cord system: uses Bungee cordsuses Bungee cords

Spring type uses spring steel (someSpring type uses spring steel (some

Cessnas)Cessnas)


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Images of Non absorbing landingImages of Non absorbing landing

geargear

**RIGID** *Shock cord* **spring type***RIGID** *Shock cord* **spring type*


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ShockShock--Absorbing Landing GearAbsorbing Landing Gear

Dissipates landing energies by forcing fluid through aDissipates landing energies by forcing fluid through arestrictionrestriction

This fluid generates heat, dissipated into the atmosphereThis fluid generates heat, dissipated into the atmosphere

Two types:Two types: Spring Oleo, and AirSpring Oleo, and Air--Oil OleoOil Oleo

Spring Oleo is history by nowSpring Oleo is history by now

Air Oleos are all very similar:Air Oleos are all very similar: a needle valve restrictsa needle valve restrictsfluid flowfluid flow

Air in the oleo holds the weight of the a/c on the groundAir in the oleo holds the weight of the a/c on the ground

Air Oleos present in both retractable and fixed gearsAir Oleos present in both retractable and fixed gears


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Images of shockImages of shock--absorbing landingabsorbing landing

geargear

Spring oleo AirSpring oleo Air--Oil OleoOil Oleo


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Fixed GearFixed Gear

Non retractable, usually bolted on to theNon retractable, usually bolted on to the

structurestructure

Often uses fairings or wheel pantsOften uses fairings or wheel pants

Advantages:Advantages:

Lighter weightLighter weight

Least costlyLeast costly


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Images of Fixed gearImages of Fixed gear


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Retractable GearRetractable Gear

Designed to eliminate drag (the greatestDesigned to eliminate drag (the greatest

advantage)advantage)

Can be either fully or partially retractableCan be either fully or partially retractable

Direction of retraction depends on airframeDirection of retraction depends on airframe

modelmodel

Methods of retraction:Methods of retraction: hydraulic, electric,hydraulic, electric,

mechanical, pneumaticmechanical, pneumatic Critical area of aircraft maintenance for safetyCritical area of aircraft maintenance for safety

reasonsreasons


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Images of Retractable landing gearImages of Retractable landing gear


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Hulls and FloatsHulls and Floats

Can be single float, or multipleCan be single float, or multiple

Definition may include floating hulls (ex. LakeDefinition may include floating hulls (ex. Lake

aircraft)aircraft)

Floating hulls may only require wing tip floatsFloating hulls may only require wing tip floats

Skis used for snow and ice (wood, metal,Skis used for snow and ice (wood, metal,

composites)composites)

Skis are mounted on the same strut as tiresSkis are mounted on the same strut as tires


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Hulls and FloatsHulls and Floats


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ENDENDLANDING GEARLANDING GEAR

Cast of CharactersCast of Characters

Jaysser FuentesJaysser Fuentes

Johnzel VasquezJohnzel Vasquez

Raffy ZaraRaffy Zara

InstructorInstructor Christopher LingaChristopher LingaStunt MenStunt Men

ALL AMT 4ALL AMT 4--11

47402725 aircraft landing gear

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