Helicopter Main Rotor Conceptual Design - Application to a Westland Lynx Helicopter

Helicopter design requires from the designers to make a lot of compromises and choices, sometimes affecting on positive parameters in order to improve global capabilities and performance. If these choices are made well, based on detail calculations and reliable input data, flight performances should be good and helicopter should be able to satisfactory sustain all the missions and tasks for which it is designed for. The following paper describes a shorter version of the initial design philosophy with an application to the Westland Lynx helicopter. This philosophy, of course with some specifics, could be applied in Croatia, in terms of determination of basics requirements and assumptions for making the right decision in selecting a specific type of an aircraft – both for the military and for civilian sector

Aircraft performance monitoring from flight data

Poznavanje stvarnih performansi zrakoplova bitno je za učinkovitu eksploataciju i pravovremeno održavanje. Performanse su određene fizikalnim karakteristikama zrakoplova. U Priručniku za letenje opisane su teorijske performanse određene od proizvođača nakon proizvodnje zrakoplova i testiranja u letu. Komercijalni zrakoplovi su tijekom svog operativnog ciklusa uglavnom izloženi predviđenim uvjetima eksploatacije. Unatoč predviđenim uvjetima eksploatacije i redovnom održavanju, starenje materijala i velika opterećenja na strukturu zrakoplova kod leta visokim podzvučnim Machovim brojem, mogu dovesti do promjene temeljnih fizikalnih faktora koji određuju performanse. Zbog toga se stvarne performanse zrakoplova nerijetko razlikuju od teorijskih. Zračni prijevoznici prate stanje zrakoplova i njegove stvarne performanse tijekom korištenja. U ovom radu prikazan je pregled dosadašnjih metoda praćenja performansi i mogućnosti istraživanja na području određivanja fizikalnih parametara zrakoplova u eksploataciji prema podacima iz leta.To ensure timely maintenance and efficient aircraft operations, it is necessary to know and keep track of aircraft’s actual performance. Flight performance is determined by aircraft\u27s physical characteristics. Theoretical aircraft performance, obtained after manufacturing and flight testing, are described in flight manual. Transport aircraft in operation is usually exposed to standard operational conditions. Despite the standard operational conditions and regular aircraft maintenance, structure aging and high dynamic loads due to high subsonic Mach number could lead to changes of main physical factors that determine flight performance. For this reason actual aircraft performance often differs from theoretical. Commercial airlines monitor true performance of aircraft in operation. This paper presents an overview of existing performance monitoring methods as well as first indications for new research possibilities regarding physical characteristics determination for aircraft in operation using flight data

The Influence of Human Factor in Aircraft Maintenance

Human factor is one of the safety barriers which is used in order to prevent accidents or incidents of aircraft. Therefore, the question is to which extent the error caused by human factor is included into the share of errors that are madeduring aircraft maintenance. In the EASA approved aircraft maintenance organisation, which includes in its working system the human factor as well, the tendency is to apply the approach by continuous monitoring and analysis of errors in aircraft maintenance. Such approach achieves advance prevention or reduction of the occurrence of harmful events, such as accidents, incidents, injuries and in a wider sense damages related to aircraft operation and maintenance. The research presented in this paper is a result of gathering and systematization of errors caused by human factors over the last five years in one organisation for aircraft maintenance certified according to the European standards. The study encompasses an analysis of 28 (twenty-eight) investigations of individual cases and provides insight into the main factors of errors. The results of analyses on the cause of occurrence of human error show similar results like the Boeing study which was carried out for the world fleet. </p

Estimation of Aerodynamic Coefficients in a Small Subsonic Wind Tunnel

To apply the experimental data measured in a wind tunnel for a scaled aircraft to a free-flying model, conditions of dynamical similarity must be met or scaling procedures introduced. The scaling methods should correct the wind tunnel data regarding model support, wall interference, and lower Reynolds number. To include the necessary corrections, the current scaling techniques use computational fluid dynamics (CFD) in combination with measurements in cryogenic wind tunnels. There are a few methods that enable preliminary calculations of typical corrections considering specific measurement conditions and volume limitation of test section. The purpose of this paper is to present one possible approach to estimating corrections due to sting interference and difference in Reynolds number between the real airplane in cruise regime and its 1:100 model in the small wind tunnel AT-1. The analysis gives results for correction of axial and normal force coefficients. The results of this analysis indicate that the Reynolds number effects and the problem of installation of internal force balance are quite large. Therefore, the wind tunnel AT-1 has limited  usage for aerodynamic coefficient determination of transport airplanes, like Dash 8 Q400 analyzed in this paper

Genre Characteristics of Sanje Lovrenčić "In Seach of Ivana"

Ovaj rad analizira djelo U potrazi za Ivanom Sanje Lovrenčić koji je primjer romaneskno opisanoga života Ivane Brlić-Mažuranić, a koji je autorica kompozicijski podijelila u sedam poglavlja koja su posvećena godinama umjetničina života i rada. Osim romaneskne strukture u tekstu se nalazi i autobiografski pristup tj. odnos autorice sa svojim sinom te njihova potraga za detaljima iz života Ivane Brlić-Mažuranić kojima se prikazuje sadašnjost, a što je u suprotnosti od biografskog pristupa. Kako bi se shvatio širi kontekst u kojem je djelo nastajalo u radu su izloženi biografski i bibiliografski podaci o samoj autorici te njezina preciznost i studioznost pri istraživanju predmeta. Ovo djelo ima karakteristike romana, autobiografije i dnevnika stoga su u radu definicijski određene karakteristike ovih žanrova. U djelo je uneseno povijesno ozračje koje obogaćuje priču i čini je zanimljivijom.This master's thesisanalyses Sanja Lovrenčić's book U potrazi za Ivanom (In search of Ivana) which is an example of novelisticly described life of Ivana Brlić-Mažuranić. The author compositionaly splits her life into seven different chapters which are dedicated to the years of the artist's work.Apart from novelistic structure, in the text also occurs an autobiographical approach ,that is, relationship of the author and her son and their search for the details of Ivana's life. Details portray thepresent, which is opposit of the biographical approach. In order to understand the broader context in which the work originated, the master's thesispresents biographical and bibliographical information about the author herself, as well as her precision and sophistication in her research of the subject. This book has the characteristics ofnovels, autobiographies and diaries, so the characteristics of these genres are definitely defined in the master's thesis. A historical atmosphere is added to the novel, which enriches the story and makes it more interesting

Genre Characteristics of Sanje Lovrenčić "In Seach of Ivana"

Ovaj rad analizira djelo U potrazi za Ivanom Sanje Lovrenčić koji je primjer romaneskno opisanoga života Ivane Brlić-Mažuranić, a koji je autorica kompozicijski podijelila u sedam poglavlja koja su posvećena godinama umjetničina života i rada. Osim romaneskne strukture u tekstu se nalazi i autobiografski pristup tj. odnos autorice sa svojim sinom te njihova potraga za detaljima iz života Ivane Brlić-Mažuranić kojima se prikazuje sadašnjost, a što je u suprotnosti od biografskog pristupa. Kako bi se shvatio širi kontekst u kojem je djelo nastajalo u radu su izloženi biografski i bibiliografski podaci o samoj autorici te njezina preciznost i studioznost pri istraživanju predmeta. Ovo djelo ima karakteristike romana, autobiografije i dnevnika stoga su u radu definicijski određene karakteristike ovih žanrova. U djelo je uneseno povijesno ozračje koje obogaćuje priču i čini je zanimljivijom.This master's thesisanalyses Sanja Lovrenčić's book U potrazi za Ivanom (In search of Ivana) which is an example of novelisticly described life of Ivana Brlić-Mažuranić. The author compositionaly splits her life into seven different chapters which are dedicated to the years of the artist's work.Apart from novelistic structure, in the text also occurs an autobiographical approach ,that is, relationship of the author and her son and their search for the details of Ivana's life. Details portray thepresent, which is opposit of the biographical approach. In order to understand the broader context in which the work originated, the master's thesispresents biographical and bibliographical information about the author herself, as well as her precision and sophistication in her research of the subject. This book has the characteristics ofnovels, autobiographies and diaries, so the characteristics of these genres are definitely defined in the master's thesis. A historical atmosphere is added to the novel, which enriches the story and makes it more interesting

Genre Characteristics of Sanje Lovrenčić "In Seach of Ivana"

Ovaj rad analizira djelo U potrazi za Ivanom Sanje Lovrenčić koji je primjer romaneskno opisanoga života Ivane Brlić-Mažuranić, a koji je autorica kompozicijski podijelila u sedam poglavlja koja su posvećena godinama umjetničina života i rada. Osim romaneskne strukture u tekstu se nalazi i autobiografski pristup tj. odnos autorice sa svojim sinom te njihova potraga za detaljima iz života Ivane Brlić-Mažuranić kojima se prikazuje sadašnjost, a što je u suprotnosti od biografskog pristupa. Kako bi se shvatio širi kontekst u kojem je djelo nastajalo u radu su izloženi biografski i bibiliografski podaci o samoj autorici te njezina preciznost i studioznost pri istraživanju predmeta. Ovo djelo ima karakteristike romana, autobiografije i dnevnika stoga su u radu definicijski određene karakteristike ovih žanrova. U djelo je uneseno povijesno ozračje koje obogaćuje priču i čini je zanimljivijom.This master's thesisanalyses Sanja Lovrenčić's book U potrazi za Ivanom (In search of Ivana) which is an example of novelisticly described life of Ivana Brlić-Mažuranić. The author compositionaly splits her life into seven different chapters which are dedicated to the years of the artist's work.Apart from novelistic structure, in the text also occurs an autobiographical approach ,that is, relationship of the author and her son and their search for the details of Ivana's life. Details portray thepresent, which is opposit of the biographical approach. In order to understand the broader context in which the work originated, the master's thesispresents biographical and bibliographical information about the author herself, as well as her precision and sophistication in her research of the subject. This book has the characteristics ofnovels, autobiographies and diaries, so the characteristics of these genres are definitely defined in the master's thesis. A historical atmosphere is added to the novel, which enriches the story and makes it more interesting

Optimal Replacement Policy of Jet Engine Modules from the Aircarrier's Point of View

A mathematical model for optimising preventive maintenanceof aircraft jet engine was developed by dynamic programming.Replacement planning for jet engine modules is regardedas a multistage decision process, while optimum modulereplacement is considered as a problem of equipment replacement.The goal of the optimal replacement policy of jet enginemodules is a defined series of decisions resulting in minimummaintenance costs. The model was programmed inC++ programming language and tested by using CFM56 jetengine data. The optimum maintenance strategy costs werecompared to costs of simpler experience-based maintenancestrategies. The results of the comparison j usti.JY further developmentand usage of the model in order to achieve significant costreduction for airline carriers

PLANNING OF TRAINING AIRCRAFT FLIGHT HOURS

Maintenance of the training aircraft causes downtime of operations and thereby reduces the operational availability, which is crucial for flight planning in a training organisation. Manual daily planning within the fleet delivers suboptimal results and often causes discontinued flight of several aircraft that have to be maintained at the same time. Optimal maintenance schedule of training aircraft can be obtained by a sliding scale method. This paper presents a mathematical model of the sliding scale formulated by a mixed integer linear problem. Allocation of flight hours is optimised by using AMPL programming language, assuring that a sufficient number of aircraft are always available for training. The model can be used by a flight dispatch department in a training organisation as a basis for optimised planning and reduction of maintenance downtime