Conceptualizing Naval Helicopter Landing Gear Engineering Essay

Conceptualizing Naval Helicopter land Gear Engineering EssayThe get gear is an important part of an aircraft as march onmost as the take-offs and landings ar concerned. The landing gear machines (or structures) are pretty simple in nerve of the commercial cleaver as compared to the commercial airplanes. But, that is not the case for the naval helicopters. Because of the not-so-friendly landing pre delays, the naval helicopter must have sophisticated landing gear chemical mechanism connected with its fuselage. The design of the landing gear mechanism for the naval helicopter should be such that the helicopter merchant ship land safely in aircraft carrier as well as in backdrop also, the mechanism should not fail under the sea wave excitation, while in ground condition.b. Research on landing gearDuring the initial age of the human flying history, the flyers apply to have the Skids as landing gears. The skids are still very much in use for commercial helicopters. But, for the airplanes and for the naval helicopters wheels are used mostly for the landing gears. The wheels are connected with the shock absorbers to form the landing gears. The landing gear, then, get connected with the fuselage in various fashions based upon the sizing of the aircraft.All the wheel based landing gears can broadly be categorized in terce main categoriesConventionalTri-cycleTandemFig.1 Showing three basic types of wheel based landing gearsTwo front wheels and a evoke tail wheel are used to form the conventional landing gear. The older aircrafts still have this type of landing gear. Ground handling is bit difficult here.The tri-cycle configurations has cardinal (or multiple of two) wheels at rear and minimum of angiotensin-converting enzyme nose wheel (s) at front. It gives better ground handling comfort and used widely for sm every sized aircrafts. On the basis of the wheel arrangements, diametrical types of tri-cycle arrangements are possible (as shown down the st airs)Fig.2 Showing different types of Tri-Cycle configurations (as per Federal Aviation Administration nomenclature)The multiples of landing gears are placed in line to form a compound tandem landing gear system. Different combinations of tandem are possible (as shown below)Fig.3 Showing different types of Tandem configurations (as per Federal Aviation Administration nomenclature)c. Conceptualizing Naval helicopter Landing GearAfter studying different types of available landing gears configurations, I have decided to develop the landing gear opinion of case-by-case wheel main gear with dual wheel nose gear configuration. It s a kind of tri-cycle configuration.Fig.4 Showing the rough landing gear conceptI have decided to use only contortion spring as shock absorbing elements for the concept.d. Preliminary Design CalculationsIn order further developing the concept, I have used the following dataTotal mass of the helicopter = 5126 KgSprung mass on each spring, m = 2563 KgDistance b etween the front and rear gear = 5 mDistance between the two rear gears= 2mNormal landingVertical channel run of the helicopter = 0.5 m/ second baseVertical ball over speed = 0So, the congeneric speed between the knock down and the helicopter, v =0. 5 m/sec=500 mm/secSo, the kinetic energy of the helicopter, KE = 0.5*m*v2 = 320375000 kg-mm2/sec2The energy stored in the tortuousness spring, SE= 0.5*k*r2 =0.5*kWhere, k= spring rate in N-mm/ percentage pointr=deformation of the spring =1 degree (assumed)Now, asKE = SE .eqn.1So, k= 640750000 N-mm/DegreeI will use this spring rate for rest of the two landing conditions to find out the deformations of the torsion springs.Hard landingVertical descent speed of the helicopter = 3 m/secVertical deck speed = -3 m/secSo, the congenator speed between the deck and the helicopter, v =6 m/sec=6000 mm/secK= 640750000 N-mm/degreeSo, by using the eqn.1r= 12 degreeCrush landingVertical descent speed of the helicopter = 15 m/secVertical deck spee d = 0m/secSo, the relative speed between the deck and the helicopter, v =15 m/sec=15000 mm/secK= 640750000 N-mm/degreeSo, by using the eqn.1r= 30 degreeSo, I will start my ADAMS design with the treasures obtained from this hand calculation and gradually fine tune the values in order to wreak the landing criteria.e. Converting the Conceptual Design to ADAMS MechanismsI have used the MSC ADAMS software for preparing two landing gear mechanism design options out of the abstract design and the hand calculations. The two design options differ in terms of heights. Parametric design advantage of the ADAMS software is utilized for creating the two design options. magical spell creating the two mechanism design options, the following ADAMS options are utilizedPoint Points are used for creating basic locations of all the important elements of the design (like centre of the wheels etc.) toroid Wheels of the landing gears are created using the torus option.Link All the structural members (like top frame, axels etc) are created using this option.Box This tool is used for creating the landing deck of the air craft carrier.Torsion Spring This is for creating the front and rear torsion springs.Hinge Joint This option is for creating all the revolute joints of the mechanism.Translational Joint This option is used for creating the translational joints.Contact The contacts between the wheels and the deck are created using this option.e.1. ADAMS Mechanism Option-1The mechanism option-1 looks like belowFig.5 Showing the ADAMS Mechanism option-1 ArrangementThe points table for the mechanism option-1 looks like belowFig.6 Showing the point table for the mechanism option-1e.2. ADAMS Mechanism Option-2The mechanism option-2 looks like belowFig.7 Showing the ADAMS Mechanism option-2 ArrangementThe points table for the mechanism option-2 looks like belowFig.8 Showing the point table for the mechanism option-2e.3. Selecting the Optimum ADAMS Landing Gear MechanismThe selection of the best design out of the two options is done by observing the speedup values. The acceleration plots for the hard landing conditions (descent velocity of the helicopter = 3 m/sec and upward deck speed = 3m/sec) for both the concepts are shown belowFig.9 Showing the hard landing condition acceleration plots for both the conceptsThe above plot is display that the level best acceleration value for the design -2 is more than50 m/sec2.The acceleration plots for the crush landing condition (descent velocity of the helicopter =15 m/sec and upward deck speed = 0 m/sec) for both the options are shown belowFig.10 Showing the crush landing condition acceleration plots for both the conceptsThe above plot is showing that the maximum acceleration value for the design option-2 is much higher in case of the crush landing condition.So, on the basis of the above two tests, it can be concluded that the design option-1 is better among the two options. Hence, I have selected the design option-1 for further analysis.f. Testing the Selected ADAMS mechanism (design option-1) Against the Specified Landing ConditionsNormal Landing Condition The acceleration plot for normal landing condition (descent velocity of the helicopter = 0.5 m/sec and upward deck speed = 0m/sec) for the design option-1 is shown belowFig.11 Showing the normal landing condition acceleration plots for the Design Option-1The above plot is showing that the maximum acceleration value for normal landing condition for the design option-1 is 7.5 m/sec2.Hard Landing Condition The acceleration plot for normal landing condition (descent velocity of the helicopter = 3 m/sec and upward deck speed = 3m/sec) for the design option-1 is shown belowFig.12 Showing the hard landing condition acceleration plots for the Design Option-1The above plot is showing that the maximum acceleration value for hard landing condition for the design option-1 is 48.1 m/sec2.Crush Landing Condition The acceleration plot for normal landing co ndition (descent velocity of the helicopter = 15 m/sec and upward deck speed = 0m/sec) for the design option-1 is shown belowFig.13 Showing the crush landing condition acceleration plots for the Design Option-1The above plot is showing that the maximum acceleration value for hard landing condition for the design option-1 is 119.6 m/sec2.g. Running the Vibration analysis for the Selected ADAMS MechanismThe vibration analysis is performed for the Design option-1 using the ADAMS vibration plug-in. For simulating the sea wave oscillations, two acceleration actuators are used at front and the rear axles. One output channel is created at the COG of the top frame. The output channel is used for measuring the acceleration at the COG of the frame.Fig.14 Showing the frequency Response Analysis plot for the Design Option-1The pick of the above frequency response plot indicates the resonating frequency for the design option-1. So, the resonating frequency here is 64.5 Hz.h. Consolidated Result s for Design Option-1Parameters ValuesMaximum Normal Landing quickening (m/sec2) 7.5Maximum Normal Landing Acceleration (m/sec2) 48.1Maximum Normal Landing Acceleration (m/sec2) 119.6Resonating Frequency (Hz) 64.5i. DiscussionTask-1 This task is covered in the section-c and section-d.Task-2 This task is covered in Section-f.Task-3 This task is covered in section-g.Task-4 This task is covered in section-e.j. ConclusionThe ADAMS is a powerful tool for creating and testing a mechanism under specified conditions. The parametric feature of ADAMS helps creating different design iterations easier.The design option-1 passed all the landing conditions specified for the assignment. Also, the resonating frequency observed for the design option-1 is 64.5 Hz.k. Referenceshttp//www.faa.gov/airports/resources/publications/orders/media/Construction_5300_7.pdfhttp//www.allstar.fiu.edu/aero/flight14.htmhttp//www.helis.com/howflies/skids.phphttp//www.aoe.vt.edu/mason/Mason_f/M96SC.html