Landing Gear Types Engineering Essay

Landing Gear Types Engineering Es theoriseWhen you ask mint what the principal(prenominal) lam is of a farminging delivered hustle they swelledly say it is meant to land the aircraft, yet thats exactly what the words stands for. This is slightly correct, wholeness of the leash main functions is energy absorption (at landing place). (1.1.1a). But when the aircraft has touched the background signal it has to diaphragm, so here is an opposite main function of the landing monger braking (1.1.1b). The run short step and exchangeablewise the last main function is for taxi control, in other words to manoeuvre the aircraft on ground (1.1.1c).When an aircraft has reached its destination, it has to descend and land on a runway from an airport. To do this it is using the landing caravan of the aircraft. When the aircraft hits the ground the landing supplement is the interface of aircraft to ground. Depending on various factors interchangeable weather conditions, aircraft lode, aircraft anatomy and aircraft balance the landing adapt moldiness draw off the impact energy and must transmit this gently to the aircraft structure. But non only at landing, when an aircraft is on ground while manoeuvring the landing vend has to bear the total weight of an aircraft and absorb the energy while braking, taxiing, invade off roll, landing roll, management and to extension service. With only a strut and wheels on that point is no chance of surviving an impact with a large aircraft. hence the landing accommodate is provided with spite absorbers. The shock absorber may be an nonsymbiotic element, or integrated with the landing sky strut or in side braces. The wheels of a landing monger ar also employ for shock absorption. Aircraft tires are much more stronger as tires for automobiles. Landing cant tyres are designed to resist juicy take-off and landing speeds and large shock loads upon landings.1.1.1b BrakingAnother challenge of a landing gear i s to stop the aircraft while bun over the runway. The landing gear burn down recitation the tires to achieve this challenge. But the tires cannot stop by itself, they need brakes to substructurehand down. Almost all commercial aircrafts only invite brakes at the main landing gear to slow down the aircraft and use at each main gear wheel multiple disc hydraulic powered brakes. Those brakes are controlled in flight deck. Pilots can study three inputs for braking manual brake, auto brake system and parking brake. The manual brakes are controlled by brake pedals mostly located at the top of the rudder pedals. The auto brake system provides automatic braking during take-offs and landings so the pilot light can perform other tasks. The auto brake system can be set in different modes to apply correct braking courses. To concur position for a longer period on ground a parking brake can be employ so the woodworking plane does not need wheel chocks.1.1.1c Taxi controlThe last func tion of a landing gear is taxi control. To manoeuvre the aircraft on ground at low speeds the landing gear is equipped with steering facilities so the aircraft can move by itself and do not need to engage moved by a tug. At modern commercial aircraft the wreathe landing gear is equipped with a hydro-mechanical system to move the thump gear. Steering is d champion by the pilot either from a agriculturalist in the cockpit or the rudder pedals. Some aircrafts with more than deuce main gear units (bogies) need also to control these extra units to manoeuvre the aircraft safely.Landing gear typesNot ein truth aircraft has the same landing gear contour line. To understand why modern commercial aircrafts use a velocipede gear phase ( intrude wheel equipped aircraft) in that location first will be looked to other lovelys of configurations (1.1.2a) to understand the benefits. Not only the benefits will be explained but also the construction of the trike gear configuration (1.1.2b).1 .1.2a Landing gear configurationsFor aircraft engineers, the landing gear is not their favourite part of an aircraft because it is not require in flight but still it does influence the flight performance. Since the first aircraft engineers have tried all kind of configurations to fit best under a typical aircraft. Each configuration has its own advantages and disadvantages, to find out there will be take a look at some(prenominal) configurations available to engineers. cigaretdragger gearBicycle gear atomic number 53 main gearQuadricycle gearAd 1 Taildragger gearThe fuckingdragger gear also called a conventional landing gear ( physical body) inhabits of two main gear units (1) and a runty wheel or skid to support the tail (tail unit) (2). This kind of configuration ruled the aircraft design from about 1910 till 1950. Nowadays this configuration is widely employ on small propeller-driven aircrafts, because its simplicity. Is not only used for its simplicity, it has also some benefits.21Main gear unitsTail unitFigure Taildragger gear as seen on a SpitfireThe two main gear units can easily be adapted to modernize low drag in flight and because the tail wheel is small there is less weight. When you look at the taildragger configuration (Figure) you will discover the nose of the aircraft is already titled, so the vanishs already have an large angle of attack. This means when the aircraft rolls down the runway the wings generate more lift so the aircraft needs less length of runway. Besides the propeller of a propeller-driven aircraft has a higher(prenominal) level above the ground, what could save the propeller from damages.But this configuration does also have some cons. The handling characteristics are not that good. This is because the centre of gravity is located behind the main gear units. Which could results in a ground loop. A ground loop is basically an uncontrolled turn while on ground. With the centre of gravity behind the main gear units, a ny turn will naturally growing in rate because of momentum. When landing and using the brakes likewise many an(prenominal) at rollout, this could result in a capsizing aircraft. These examples could easier occur when atomic number 53 and only(a) main gear unit touches down first or with cogent crosswind. To hamper, pilots must withdraw up a approach very(prenominal) conservatively to keep the plane on a straight path until it comes to a stop, this can be done with constantly rudder adjustments. Some aircrafts have an locked tail unit to keep rolling in a straight line during landing.Ad 2 Bicycle gearThe bicycle gear constitute of two main gear units along the centre line of the aircraft and very often sideways two small outrigger gears mounted on the wing (Figure). This kind of configuration is not very common but is a solution for aircraft with very long and slim fuselages or high wing aircraft. This configuration is actually very limited to aircraft with wings that gene rate high lift at a low angle of attack, as rotation with this configuration is impossible.221Main gear unitsOutrigger gearFigure Bicycle gear as seen on Boeing B-47Only one of the benefits is lower weight and drag than the taildragger or tricycle configuration.For the pilot this configuration is challenging, because he or she has to maintain a very level side during take-off and landing while carefully managing airspeed. The pilot has to land the aircraft without any rolling motion because that could cause the aircraft to land on one of the outrigger gear.Ad 3 Single main gearThe single main gear (Figure) consist of one main gear unit (1) and a much little auxiliary tailwheel (2) along the centreline. For stability an outrigger gear (3) is mounted along the wing. This configuration is very similar to the bicycle gear and is practical for use on light planes like gliders. The single main gear is just like the bicycle gear lightweight and provides low drag.213Main gear unitAuxili ary tailwheelOutrigger gearFigure Single main gear as seen on a Lockheed U-2Ad 4 Quadricycle gearThe quadricycle gear (Figure) consist of four main gear units (1) about mounted along the fuselage. This configuration is also similar to the bicycle gear and is being used sometimes on cargo aircraft. For cargo aircraft it could be ideal because the aircraft grade can get at a very low level above the ground what is easy for loading or unloading cargo.Just like the bicycle configuration the pilot must maintain a very level attitude during take-off and landing. A quadricycle gear is also very sensitive for roll, crosswinds, and proper line up of a approach. The Boeing B-52 has an extra crosswind gear (2) installed to make crosswind landings. A major disadvantage also is four main gear units that contain a much higher weight and drag.21Main gear unitsCrosswind gearFigure Quadricycle gear as seen on a Boeing B-521.1.2b Tricycle GearThe tricycle gear generally consist of two main gear uni ts and one nose gear unit. Nowadays this kind of configuration is mostly used in aviation especially for commercial aircraft. The tricycle configuration has one wheel in the front and two or more main wheels located near the centre of gravity. The main reason why it is mostly used is the ease of operating the tricycle gear aircraft on ground. This is not the only advantage the tricycle gear has a series of advantagesstability in brakingsteady touch down with no risk of sleek bounce (like taildragger gear)high pilot visibility during taxiing (because of level aircraft)horizontal floor (passengers comfort and easy cargo loading)low drag during take-off accelerationThe tricycle gear does have more configurations (Figure). The most common (and most simple) has a double main landing gear unit and single nose gear unit (1). For most aircraft this is good enough to bear the aircraft load. For airliners beyond 300.000 kg of maximum take-off mass there is need for an extra landing gear unit located under the fuselage (2), or even two main landing gear units located under the wing (3). This is needed to make the surface pressure on all landing gears acceptable.321Figure Tricycle gear configurationsThose extra landing gear units are called bogies. When an aircraft has extra landing gear units it is called a multi-bogie gear configuration. The heavier the aircraft becomes, the more wheels are added to the bogie to spread the surface pressure on the runway pavement. The nose wheel could also get an extra wheel or even an extra nose gear unit.Unfortunately the tricycle gear configuration has a greater weight and drag because of the large nose wheel gear unit. Aircrafts with a tricycle configuration virtually always require retraction mechanisms to reduce drag. Another challenge at tricycle gear configurations is designing a properly balance load by the main gear versus the nose wheel. When you will put too little load on the main wheels, braking effectiveness will reduce. When lay too little load on the nose wheel the aircraft is losing its steering effectiveness. Loading the aircraft must be carefully done to balance the aircraft to prevent the aircraft from fall over on its tail.