İki Kişilik Hafif Askeri Eğitim Uçaği Ana İniştakimi

dc.contributor.advisor Yüksel, Ahmet Nuri tr_TR
dc.contributor.author Keskin, Zeki tr_TR
dc.contributor.authorID 56004 tr_TR
dc.contributor.department Uçak ve Uzay Mühendisliği tr_TR
dc.contributor.department Aeronautics and Astronautics Engineering en_US
dc.date 1996 tr_TR
dc.date.accessioned 2018-12-10T08:39:41Z
dc.date.available 2018-12-10T08:39:41Z
dc.date.issued 1996 tr_TR
dc.description Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1996 tr_TR
dc.description Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 1996 en_US
dc.description.abstract Yapılan bu çalışma iki kişilik bir askeri eğitim uçağının ana iniş takımlarının dizynında yapılmış olan çalışmaların temel olarak alınması ile oluşturulmuştur. Çalışmada belli bir aşamaya gelmiş olması gereken öndizayn verileri başlangıç verileri olarak gerekir. Bu önverilere şunlar örnek verilebilir; uçak kalkış ağırlığı, uçak kanat alanı, uçak kanat ve kuyruk boyutları, uçak gövde genel taslağı, uçak kanopi dizaynı ve mürettebat ve yolcunun yerleştirilme düzenlemesi, motor seçimi ve yerleştirimi. Çalışma sonucunda ise seçilecek olan lastik ve tekerlek standardı, şok absorbe edicinin boyu, iniş takımlarının genel yerleştirimi, geriçekilebilme durumu ve nasıl geri çekileceği, fren seçimi gibi sonuçlar elde edilmektedir. Yapılan ilk aşama dizayn kararlarının mukavemet ve mekanizma tasarımı açısından bir optimizasyon ve karışıklık durumu oluşturup oluşturmadığı ise IDEAS adlı bilgisayar destekli dizayn programı ile kontrol edilmiştir ve detay incelemeleri tezden bağımsız olarak sürdürülmektedir. Çalışmada izlenen temel metod, iniş takımı dizaynının sınıf I ve sınıf II metodları ile incelenmesidir. İlk metod nisbeten kaba bir yaklaşım sunar fakat genel düzenlemeyi verir. İkinci metod ise bu genel düzenleme içinde daha ayrıntılı hesaplamaları ve seçimleri içerir. Sınıf I metodunda öncelikle uçak lastiğinin uçak ağırlığı cinsinden seçimi yapılır. Seçilmiş lastik genel boyutları yerleştirildikten sonra uçak ağırlık merkezinin sınıf I analizi yapılır. Bu analizde uçağın en ön ve en arka ağırlık merkezleri belirlenir. Bu ağırlık merkezlerine ve gövde yapısına göre uçağın yanal devrilme, boylamasına devrilme ve yer aralıkları kriterleri uygulanır. Bu kriterlerin uygulanması ile genel olarak uçak tekerlek açıklığı, uçak teker izi, iniş takımı dikme boyutları belirlenir. Sınıf II dizaynında ilk önce tekerlek dizaynı tekrar ele alınır ve herbir tekerleğe ait gelen yükler belirlenir ve bunlara göre tekerlek standart boyutları belirlenir. Daha sonra elde edilen bu boyutlar için lastik aralık gerekleri uygulanarak çevresi ile olan mesafe belirlenir. Daha sonra FAR 23 nizannamelerine göre dikme yükleri belirlenir ve iniş takımı strok boyu ve dikme çapı belirlenir. Bunlara göre genel iniş takım piston düzenleme standartlarına göre ve yapılan seçimlere göre iniş takımının diğer parçalarının tasarımı yapılır. Bu tasanlar birebir çizimler ile sonuçlandırılır. Bu çalışma, öncelikle burun iniştakımı dizaynı ile ilgilenen Ercan GÜNDOGDU ve gövde ve kanat dizaynları ile ilgilenen Hüsamettin PAYAT ve Selami KORKMAZ'ın çalışmaları ile paralellik arzeder, birbirini tamamlar. tr_TR
dc.description.abstract The Main Landing Gear Design of Light Aircraft Main landing gear design or light aircraft is very complex design and influenced from every step of progress of aircraft design sequences. In our study we applied some sources that have gotten great importance on their scope. In design we provide two methods; class I and class II methods. Class I Method: The purpose of class I method is to provide a rapid method to determine the following landing gear characteristics. 1. Number, type, and size of tires 2. Length and diameter of strut(s) 3. Preliminary disposition 4. Retraction feasibility In class I design steps, we firstly decide which landing gear system to use: retractable or non retractable. As a general rule, if the cruise speed of airplane is above 150 knots, a fixed gear imposes an unacceptably high drag penalty. So we choose the retractable gear. After that we decide which landing gear configuration will use on aircraft. From an ease of ground maneuvering viewpoint as well as a ground looping viewpoint the nose wheel configuration is to be preferred. One after step is decide how can we dispose the landing gears. In this stage, some of the criteria must be satisfy. For example; longitudinal tip-over criteria, lateral tip over criteria, longitudinal ground clearance criteria, lateral ground clearance criteria. After satisfying these criteria, the maximum static load per strut can be calculated. The continuous step is choose the number of wheels to be used. After that, P"/Wto and nsPmAVro ratios and approximate tire size are selected from standard tire data tables. At this stage of the preliminary design process it is useful to verify the retraction capability with the help of a so-called 'stick diagram'. With the gear layout defined, we perform the weight and calculations and if necessary, iterate back to first step until the gear location satisfies all criteria. Class II Method The class II method is provide methods and data to assist in preparing satisfactory landing gear design layouts. Firstly we define the function of the landing gear components. There are fife reasons for incorporating landing gears in airplanes. These are; to absorb landing shocks and taxiing shocks, to provide ability for ground maneuvering, to provide for breaking capability, to allow for airplane towing, to protect the ground surface. XI Landing gear type will be discussed for continued step. Two major decisions which must be made before the landing gear layout process can be started are; decide on a fixed or a retractable gear and decide on use of a tricycle, bicycle, tail wheel or unconventional gear. The first decision is a trade off between gear induced aerodynamic drag, weight and complexity (or cost). Second decision depends strongly on the airplane mission. The tricycle gear configuration has become the most frequently used gear layout. Important reasons are: good visibility over the nose during ground operation, stability against ground loops, good steering characteristics, level floor while on the ground. Compatibility of landing gear and runway surface is discussed. The load on each landing gear strut as well as the load on each tire may not exceed values which: cause structural damage to the gear or to the airplane, cause tire damage, cause runway damage or excessive surface deformations. To allow for adequate nose wheel steering, a minimum normal force must act on the nose gear so that the approximate levels of friction forces needed for steering can be generated. The normal force on the nose gear should not be less than 0.08 Wto for adequate steering. For tree types runway, discussion is completed. These runways are; runways with unprepared or simply prepared surfaces, runways with flexible pavement, runways with rigid pavement (concrete). After that, discussion about tire and wheels is completed. The following information is presented in this section: a discussion of tire types, tire construction, and tire descriptions, a discussion of tire performance, load deflection and shock absorption capability, a discussion of tire clearance requirements, a method for determining the correct tire size for airplane applications, tabulated data on tire geometry, tire load carrying capability and tire applications. Tire manufacturers rate tires in terms of play rating, maximum allowable static loading, recommended inflating pressure, maximum allowable runway speed. The ply rating or tires identifies the tire with its maximum recommended static load and corresponding inflation pressure when used in a specific type of operation. The ply rating is an index of tire strength and does not indicate the actual number of fabric core plies. Tires participate significantly in the process of shock absorption following touchdown. [low much the tires participate, depends on the design of the shock absorbers. In selecting airplane tires, it is usually a good idea to keep future airplane growth capabilities in mind. It is recommended to allow for 25 percent growth in tire load in selecting tires for a new airplane. The following tire clearance requirements must be observed; wheel well clearance (after retraction), tire-to-fork and/or tire to strut clearance. The physical reasons for these tire clearance requirements are; tires grow in size during their service life and tires grow in size under influence of centrifugal forces. This type of growth depends on the maximum tire operating speed on the ground In preliminary design purposes it is acceptable to account for the following tire clearances, in width: 0.04w + xii lateral clearance due to centrifugal forces + 1 inch, in radius: 0. 1 do + radial clearance due to centrifugal forces + 1 inch. Wheels used with the single disk brakes are manufactured of magnesium or aluminum alloy and are of the divided type. The two wheel sections are held together by bolts secured with self locking nuts. Each wheel has two tapered roller bearings which are seated in hardened steel bearing cups. The brake side of wheel is equipped with hardened steel disc drive keys, secured by bolts or screws or with cast gear teeth to drive the rotating brake disc. Key drive wheels are designed to accommodate disc clips which are used to eliminate the noise and rattle of the disc. These clips also align and retain the disc in the wheel. A disc retaining ring is available as an accessory which can be used to retain the disc in the wheel when severe service conditions are encountered. When we select the tire of an airplane then we can choose the brake of wheels. The brake of an airplane have to meet several requirements, such as; stop the aircraft during the landing run at reasonable rate of deceleration with minimum friction material wear, prevent the wheels form rolling on a paved runway with takeoff power on the critical engine (but they need not prevent movement of the airplane with wheels locked), steer the aircraft on the ground without excessive pedal loads, limit the taxi speed with engines idling, parking. Modern light aircraft utilizes the caliper/disc brake which consists of a caliper containing one or more pistons forcing friction pads of organic material against a steel disc, often chrome-plated to give smoother operation and to reduce pad wear. The consequent reduction in friction coefficient due to chrome-plating is made up by the use of higher pressures. This is easily achieved with powered systems, but for light aircraft with no more than one master cylinder to provide the effort, it is sometimes difficult to supply sufficient fluid or pressure to give a high brake force. Aircraft brakes must absorb very high levels of kinetic energy and convert it into heat using a heat sink of minimum weight and volume. High temperatures have always been a factor in the design of brakes. Carbon brakes represent a relatively new technology which permits operation at considerably higher temperatures than conventional materials. Because of simplicity, light weight and reliability, hydraulic brakes are used universally in small and large airplanes. In principle, hydraulic systems interpose a column of fluid between the master cylinder, located near the rudder pedal, and the slave cylinder by the wheel, replacing the cable used in the mechanical systems. In light airplanes the hydraulic brake is closed loop system. The pressure is provided by either a foot pedal or a hand lever. In large aircraft, human effort is sufficient and a force multiplication system is employed utilizing the aircraft hydraulic system pressure (normally 3000 psi). Xlll The maximum vertical load factor encountered on landing depends upon the descent velocity, the shock absorption characteristics of landing gear, including the tire and the attitude of the airplane with respect to the ground, making it necessary to investigate various load conditions to make sure that the landing gear components are sufficiently strong. Wheels, tires and brakes with T.S.O (Technical Standard Order) do not have to be investigated by the aircraft designer, since their strength and shock absorption characteristics have been approved on the basis of the static load shown in the catalogs. The most severe ground loads affecting the landing gear usually occur at the moment of touchdown. Less critical loads generally occur during the landing run, due to application of brakes, an uneven runway or turning the aircraft. The main factors affecting the magnitude of the loads applied to the landing gear are; weight of airplane, landing speed, shock absorber travel, tire deflection, runway surface roughness, angle of approach, angle of drift and/or yaw. The federal aviation regulations, part 23 (FAR 23) for normal, utility and acrobatic airplanes with maximum gross weight of 12,500 lbs. Specify all the requirements that have to be met by USA manufacturers. These regulations also used by many other countries. In FAR 23 the side load conditions defined as: (a) For the side load condition, the airplane is assumed to be in a level attitude with only the main wheels contacting the ground and with the shock absorbers and tires in their static positions. (b) The limit vertical load factor must be 1.33, with the vertical ground reaction divided equally between the main wheels. (c) The limit side inertia factor must be 0.83, with the side ground reaction divided between the main wheels so that- (1)0.5 (W) is acting inboard on one side; (2) 033 (W) is acting outboard on the other side. Under braked roll conditions, with the shock absorbers and tires in their static positions, the following apply: (a) The limit vertical load factor must be 1.33 (b) The attitudes and ground contacts must be those described in 23.479 for level landings. (c) A drag reaction equal to the vertical reaction at the wheel multiplied by a coefficient of friction of 0.8 must be applied at the ground contact point of each wheel with brakes, except the drag reaction need not exceed the maximum value based on limiting brake torque. When investigating landing conditions, the drag components simulating the forces required to accelerate the tires and wheels up to the landing speed XIV must be properly combined with the corresponding instantaneous vertical ground reactions, assuming wing lift and a tiresliding coefficient of friction of 0.8. however, the drag loads may not be less than 25 percent of the maximum vertical ground reactions (neglecting wing lift). The last part of study there is some presentation about application drawings. These drawings based upon before calculations which employed for İTÜE1 basic military trainer aircraft. en_US
dc.description.degree Yüksek Lisans tr_TR
dc.description.degree M.Sc. en_US
dc.identifier.uri http://hdl.handle.net/11527/17167
dc.language.iso tur tr_TR
dc.publisher Fen Bilimleri Enstitüsü tr_TR
dc.publisher Institute of Science and Technology en_US
dc.rights Kurumsal arşive yüklenen tüm eserler telif hakkı ile korunmaktadır. Bunlar, bu kaynak üzerinden herhangi bir amaçla görüntülenebilir, ancak yazılı izin alınmadan herhangi bir biçimde yeniden oluşturulması veya dağıtılması yasaklanmıştır. tr_TR
dc.rights All works uploaded to the institutional repository are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. en_US
dc.subject Uçaklar tr_TR
dc.subject İniş takımı tr_TR
dc.subject Airplanes en_US
dc.subject Landing gear en_US
dc.title İki Kişilik Hafif Askeri Eğitim Uçaği Ana İniştakimi tr_TR
dc.title.alternative The Main Landing Gear Design Of Light Aircraft en_US
dc.type Thesis en_US
dc.type Tez tr_TR
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