Performanse helikoptera u autorotaciji

master's thesis

• Title (english): Helicopter performance in autorotation
• Author: Josipa Vukelić
• Mentor: Milan Vrdoljak (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2014-12-03, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Aviation, Rocket and Space Technology

Abstract

Ovaj diplomski rad bavi se temom performansi helikoptera u autorotaciji kao izvanrednom režimu leta u slučaju otkaza motora. Na samom početku dan je teorijski uvod što je to autorotacija i računski opis modela gibanja helikoptera: pretpostavka za vertikalni let. Napravljen je analitički proračun performansi helikoptera u autorotaciji koji se koristi kao podloga za usporedbu tri konfiguracije helikoptera korištenih u proračunu i analizi. Pri tom proračunu uvedene su određene pretpostavke kao što su parametri standardne atmosfere na 0m nadmorske visine, utjecaj stlačivosti je zanemaren, krakovi rotora se razmatraju kao kruta tijela, uzima se u obzir cjelokupna težina letjelice,a ne samo glavnog rotora, nisu se razmatrala gibanja lopatica rotora kao što su mahanje, zabacivanje i uvijanje. Nakon teorijskog razmatranja ovog manevra i danih performansi helikoptera, opisan je postupak koji se koristi za izradu H/V dijagrama koji je bitan za praktičnu primjenu helikoptera u letu kada nastupi otkaz motora. Dan je računski opis dobivanja kritičnih točaka dijagrama te je opisan postupak crtanja dijagrama. Nakon toga se postavio proračun za sva tri tipa helikoptera, nacrtani su dijagrami i napravljena je analiza prema stvarnim H/V dijagramima. Usporedba helikoptera prema performansa u autorotaciji je opisan preko indeksa autorotacije prema kojemu je napravljena i analiza sva tri helikoptera. Na kraju ovog diplomskog rada dana je komparativna analiza svih dobivenih rezultata proračuna i teorijskog razmatranja te je napravljena usporedba na temelju zaključka svih rezultata.

Abstract (english)

The topic of this thesis is performance of helicopter in autorotation as emergency maneuver in case of engine failure. In introduction, a definition of what is autorotation and a computational description of the model of the helicopter with assumption for vertical ight is given. Further, an analytical calculation of helicopter's performance in auto-rotation has been made; this calculation was used as input used in further calculation and analytics for comparison of three configurations of a helicopter. During calculation the following assumptions were taken: parameters of standard atmosphere at 0 m at sea level, the infuence of compressibility has been neglected, the wings of the rotor is considered as a rigid body, the whole weight of the aircraft and not just the main rotor have been taken into account and finally the motion of the rotor blades such as ap,lag and feather were not taken into consideration. After a theoretical consideration of this maneuver and given performance of the helicopter, the procedure on how to construct H/V diagram was explained, as an essential part of a practical application of a helicopter in ight when engine failure occurs.The thesis continues with a description of determining the critical points of the diagram and the procedure for drawing a diagram, which was made with the software package MATLAB. After that, calculation for the H/V diagram for all three types of helicopters was set and were made with MATLAB, followed by the comparison with the actual H/V diagrams. The method used to compare helicopters with each other with respect to their performance in autorotation is given in the description of the characteristics of the authoritative index. The thesis concludes with a comparative analysis of all of the results of the conducted calculation as well as the theoretical view of the results and conclusions made from them.

• Keywords: Autorotacija; helikopter; performanse; brzina spušstanja; H/V dijagram; indeks autorotacije
• Keywords (english): Autorotation; helicopter; performance; rate of descent; H/V diagram; autorotative index
• Language: croatian
• URN:NBN: urn:nbn:hr:235:085078
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2019-05-28 10:18:23