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1

The influence of the blades leading edge anti-erosion protection on main rotor performances

Wojtas M., Czajkowski Ł., Sobieszek A.

Journal of KONES

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2018

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Vol. 25, No. 2

409--414

EN

This article presents the influence of rotor blade airfoil shape on main rotor performances. In this case, we analysed the influence of anti-erosion tape, which is applied to the leading edge of the blade to protect the blades from environmental conditions. In Gyro-Tech Innovation an Aviation Company and Institute of Aviation the independent tests of helicopter and gyroplane main rotors were performed. Research includes: bench tests, on the test stand for dynamic testing of insulated rotors and tests on two flying constructions, gyroplane Cavalon produced by AutoGyro GmbH Company and ultralight helicopter Dynali H3. On the test bench, a two-blade rotor, used in ultralight and unmanned helicopters, was tested. In article, the authors present importance of the proper selection and application of anti-erosion coatings on rotor blades. Discuss the behaviour of the above-mentioned constructions with main rotor blades leading edge covered anti-erosion tape, during flight tests. The results of bench tests, including the comparison of polar curves of the main rotor with anti-erosion coating and without were also presented and discussed. In the summary of this article among others the solution of technological pocked introduced in the rotor blade, corresponding to the thickness of the anti-erosion tapes, in such way that after tape is applied it does not change the contour of the blade airfoil were presented.

2

Strain gauge pin based force measurement

Skorupka Z., Sobieszek A.

Journal of KONES

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2018

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Vol. 25, No. 2

335--340

EN

In this article authors present force measurement method based on strain gauge measuring system installed inside pin, which is a part of light helicopter Main Landing Gear Shock Absorber. Strain gauges in full bridge configuration were installed inside the mounting pin (upper one – fuselage side). Placement and type of strain gauges were selected during the preliminary tests, which verified the validity and conditions of the force measurement. Preliminary tests allowed verification and selection of an optimal measurement system by testing two types of them. The impact on force according to the angle of force vector direction was also verified. Preliminary tests of the strain gauges equipped pin were performed using quasistatic tests stand – 40 T hydraulic press for applying force acting on shock absorber and pin. Whole measuring system is planned to be used in real time analysis of shock absorber force acting on fuselage mounting node. The strain gauges allows measurement of force in any place of the structure, the article presents the advantages of the system located inside pin. Additionally, the installation technologies of strain gauges in hard-to-reach places are presented. The article is summed up with an analysis of the problems, which arise during the installation and measurement process using strain gauges installed in such a specific place.

3

Strain gauge measuring plate for dynamic tests

Sobieszek A., Skorupka Z.

Journal of KONES

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2018

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Vol. 25, No. 4

399--404

EN

In dynamic tests, especially landing gears, it is necessary to measure and record load levels. In this article, authors present measurement methods used in the landing gear tests on the 10-Ton Drop Test Machine, which is capable of simulating conditions similar to real landing in landing energy dissipation tests. Possible test objects include dampers, shock absorbers, and crash structures and devices. In described case load measurement can be done by several methods where one of them is strain-gauge plate based load measurement. This type of measurement is weighting system under the test object where all forces acting on it are measured. Strain gauge plate is usually tailormade measurement system, which is composed out of mechanical device (plate itself) equipped with strain gauge force sensors, strain gauge amplification system and recording system. In addition, differences between static and dynamic measurements are described as well as influence of dynamic test conditions on strain gauges behaviour. In the article, authors describe general layout of the system, advantages and disadvantages of the test stand and problems that may appear during measuring. Authors also emphasize how the accuracy of the design affects to the quality of measurement. At the end of the article, advantages and disadvantages of the test stand and problems that may appear during measuring are described.

4

Innovative composite gyroplane rotor blades : fatigue tests

Wojtas M., Sobieszek A., Szczepanik T.

Journal of KONES

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2018

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Vol. 25, No. 4

447--453

EN

The paper presents test bench method for verifying the fatigue life of the rotor blades, working in operating conditions in a position steady flight (autorotation), on the aviation construction called the gyroplane. One of the critical elements of this design is the main rotor, which in its modern versions takes the form of advanced composite structures subjected to loads in flight complex variable, the nature of which differs from the well-known operating conditions of helicopter rotors. The article includes a description of the test object, which are composite rotor blades designed specifically to work in autorotation, the specificity of loads of autorotation rotor, and method of implementation of the gyroplane rotor work cycles in the test bench. The main aim of this research is to evaluate the sustainability of the composite blades under the gyroplane operating loads with the goal to allow the rotor to operate in the air. The tests were carried out for 100 hours of gyroplane flight at loads do not exceed the maximum operating loads, and for several hours under a load higher than operating. During test for the evaluation of composite structure, the infrared camera with dedicated software IRNDT was used. The reached showed structural integrity in critical mounting section of the blade.

5

Strength analysis of the magnesium alloy control system lever of the ILX-27 unmanned helicopter

Wojtas M., Sobieszek A., Żurawski R.

Journal of KONES

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2017

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Vol. 24, No. 2

293--300

EN

The article presents the potential use of magnesium alloys in the aerospace industry. In this project the static strength analysis of magnesium alloy AZ31 of the control – system lever of the ILX-27 unmanned helicopter was carried out. Control-system levers are located between the swash plate and an actuator. The aim of the tests was to confirm the strength properties of the magnesium alloy control-system lever for their implementation on the ILX-27 unmanned helicopter. Strain gauge sensor was used during the tests. Strain gauges installation on easily corrodes surface requires special method. The laboratory tests were proceeded by the lever static strength calculations in the computing environment ANSYS Inc. Additionally, a geometry measurement of the control-system lever at CMM equipped with a laser scanner head was made to compare with the lever CAD model to assess the quality and method of conformance. Unmanned helicopter ILX-27 is being developed through the introduction new materials and technologies. Tests of control system lever have shown if it is possible to use lighter materials than aluminum alloy to provide sufficient strength properties while reducing the mass of the object. Analysis of the available materials used in aerospace engineering allowed selecting the best of magnesium alloy.

6

Weryfikacja możliwości wzmocnienia nasady łopaty wirnika nośnego wiatrakowca

Wojtas M., Sobieszek A., Szczepanik T.

Technologia i Automatyzacja Montażu

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2016

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nr 1

34--38

PL

W publikacji przedstawiono zagadnienie wzmocnienia nasady łopaty wirnika nośnego wiatrakowca przez wklejenie kieszeni łopaty. Technologia klejenia jaką zastosowano została opracowana dla stopu aluminium 6005 T6, z którego wykonane zostały łączone elementy. W celu opracowania optymalnych parametrów klejenia przeprowadzono szereg badań, w wyniku których dobrano substancję klejącą oraz sposób przygotowania powierzchni, zapewniający największą wytrzymałość statyczną połączenia. Obiekt badań stanowi łopata wirnika nośnego wiatrakowca oraz kieszeń będąca łącznikiem między łopatą a głowicą wirnika wiatrakowca. Oba elementy zostały zaprojektowane w ramach projektu „Nowoczesny wirnik autorotacyjny”. W celu opracowania metody wklejania kieszeni na nasadę łopaty sprawdzono wytrzymałość połączenia dla różnych wariantów montażu kieszeni. Pierwszy wariant polegał na nasunięciu kieszeni na łopatę, w drugim natomiast wykorzystano kieszeń przecięta wzdłuż krawędzi natarcia. Drugi wariant powstał po wstępnych próbach, które ujawniły wady nasuwania kieszeni na jej nasadę niezależnie od kierunku nasuwania. Wyniki badań zostały zestawione z wynikami zrywania nasady łopaty, na którą nie naklejano kieszeni (kieszeń była montowana tylko śrubami). Zestawienie wyników zweryfikowało możliwość wzmocnienia nasady łopaty przez wklejanie kieszeni, stopień wzmocnienia i określiło optymalne rozwiązanie montażu kieszeni na nasadzie łopaty. Zrealizowany proces badawczy może stanowić zarówno próby dowodowe wytrzymałości nasady łopaty wirnika wiatrakowca i podstawę do wprowadzenia wdrożenia opracowanej technologii klejenia dla wykorzystywanego do produkcji łopat stopu aluminium.

EN

The paper presents the issue of strengthening the gyroplane rotor blade base by bonding the blade socket to it. Adhesive technology for aluminum alloy 6005 T6 has been developed. In order to develop optimal bonding parameters, a number of tests has been conducted, which resulted with selecting the best adhesive and the best method of surface preparation that provides the highest static strength. The test objects are, the gyro rotor blade and socket which is the link between the blade and the hub of gyroplane rotor, both elements were designed in Modern Autorotating Rotor Project. In order to develop a method of bonding a socket on the blade base the joint strength was tested for different way of socket installation. The first variant was pushing socket on the base of rotor blade, and another which uses the pocket cut along the leading edge. The second variant was created after initial tests that revealed defects in the socket docking on the rotor blade base, regardless of the direction of the docking. The results are compared with results of strength tests of the rotor blade base, where socket was only mount by screws. Summary of results verified the possibility to strengthen the rotor blade base by bonding socket and identified the optimal socket mounting solution on rotor blade base. Carried out the research process can be evidence strength test of gyroplane rotor blade base as well as basis for the implementation of bonding technology to use in the production of aluminum alloy rotor blades.

7

Opracowanie technologii klejenia anodowanego stopu aluminium 6005 T6 stosowanego w lotnictwie

Sobieszek A., Wojtas M., Szczepanik T.

Technologia i Automatyzacja Montażu

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2016

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nr 1

48--52

PL

W artykule opisano przebieg badań doświadczalnych, mających na celu określenie technologii klejenia dla stopów aluminium. Proces opracowania technologii oparto na badaniach anodowanego stopu aluminium 6005 T6. Z wybranego stopu aluminium wykonuje się elementy wirnika nośnego wiatrakowca tj. łopaty oraz kieszenie łopat. We wstępie artykułu przedstawiono zalety procesu klejenia w zastosowaniach lotniczych. Opisano warianty przygotowania powierzchni i dobór substancji klejącej, spośród dedykowanych aluminium, dwuskładnikowych klejów epoksydowych oraz żywicy epoksydowej z wypełniaczem. Omówiono kolejne etapy przygotowania każdej z czterech z zaproponowanych metod przygotowania powierzchni. Opisano przebieg badań oraz stanowisko badawcze zapewniające czyste ścinanie połączeń klejonych. System akwizycji danych zapewnił rejestracje przebiegu siły w funkcji przemieszczenia. Przeanalizowano zalety i wady wybranych wariantów połączeń w odniesieniu do zastosowań w lotnictwie, uwzględniając warstwę anody, która nie powinna być naruszona podczas przygotowania powierzchni. Na podstawie wytrzymałości statycznej na ścinanie oraz pozostałych kryteriów (tj. łatwość przygotowania mieszanki klejącej i aplikacji kleju, pracochłonność przygotowania powierzchni oraz minimalizacja ingerencji w warstwę anodowaną, koszty, czas potrzebny do pełnego utwardzania) określono optymalne parametry klejenia dla duralu 6005 T6. Przeprowadzone prace badawcze i otrzymane wyniki wytrzymałości statycznej połączeń klejonych stanowią podstawę do wykorzystania opracowanej technologii na rzeczywistym obiekcie. Analiza wyników uwzględniająca wszystkie zawarte w pracy badawczej kryteria pozwoliła na określenie optymalnych parametrów połączenia klejonego, tj. konkretnej mieszanki klejącej przy jednej z przebadanych powierzchni klejenia.

EN

This article describes the testing process to determine bonding technology for aluminum alloys, this process was developed based on anodized 6005 T6 aluminum alloy research. The components of gyro rotor ie. the blades and blades pockets are made of that aluminum alloy. In the introduction of this paper advantages of the bonding process in aerospace industry are presented. Variants of surface preparation and selection of the adhesive (dedicated to aluminum two-component epoxy adhesives and epoxy resin with the filler) were described. Discussed the steps of preparing each of four of the proposed methods of surface preparation. The conduct of the study and test stand to provide a pure shear bonded joints were describes. The data acquisition system assured the registration course of force versus displacement. The advantages and disadvantages of selected variants joints for uses in aviation, taking into account the anode layer, which should not be violated during surface preparation were analyzed. On the basis of static shear strength and other criterias (ie. the ease of adhesive mixture preparation, adhesive application, surface preparation workload to minimize interference with the anodized layer, costs and time needed for a full curing) for optimal adhesion for 6005 T6 aluminum alloy were determined. Conducted research and the results of bonded joints static strength provide a basis for the use technology to the real object. Analysis of the results, taking into account all included criteria allowed to define optimum conditions for adhesive connection, selected adhesive for one of the tested bonding surface.

8

Composite rotor blades tests essential before mounting on gyroplane

Sobieszek A., Wojtas M.

Journal of KONES

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2016

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Vol. 23, No. 4

487--494

EN

The article presents the course of the composite rotor blades tests. Object of study was designed in Institute of Aviation, new airfoil for gyroplane rotors and technology of manufacturing carbon rotor blades were made. When the test program was developed, we focused for special test to check not only typical rotor blades properties but also composite structures thereby technology of manufacturing. One of the basic rotor blades test is to determine the breaking force, which, taking into account the safety factor, cannot exceed the maximum centrifugal force occurring on the rotor blades during flight. The first step of rotor blades tests was static test, which gave us answer about stiffness in plane of low stiffness and torsional stiffness, it’s very important properties related to vibrations. Another mechanical properties measured during tests were centre of gravity and mass moment of inertia in rotor blade. Next step was dynamic test – tracking and balancing verification. After static and dynamics, which has proper results – good balance and no vibration on the entire range of rotational speed – rotor blades can be use on fly object. After getting proper results of static and dynamic test next step was a specially prepared test, which defined the time needed for delamination to take place. During the delamination tests, the rotor blade was subjected to adequate loads that occur in horizontal flight. That kind of test is basis to determine service life of rotor blades.

9

Assessment of feasibility the use of infrared techniques in aviation : testing structures and aviation parts

Sobieszek A.

Journal of KONES

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2016

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Vol. 23, No. 4

479--485

EN

This paper presents the use of infrared thermography in aviation. Each of the described applications has been proved experimentally and revealed the advantages and disadvantages of the thermography method. Thermography is a discipline of research that allows observation of many phenomena, e.g. simple temperature analysis, defectoscopic tests and actions of aerodynamic. Its use in aviation is multidirectional therefore; thermography is an attractive method for research. Thermal techniques seem simple; however require extensive knowledge of infrared radiation, the areas in which this technique is used, the influence of camera parameters on its capabilities and software knowledge applied depending on the purpose. This paper undertakes the verification of temperature analysis method, which is based on the tests of whole machine assembly and its parts during their operation - widely known as passive thermography. Another raised issue is defectoscopic study which aim is to detect structural defects by non-destructive testing (NDT) - active thermography. Several types of sandwich and composite materials were selected, and on the basis of the test results the limitations and possibilities of thermography in the field of active thermography were concluded. The last application considered in this study is the use of thermography for aerodynamic testing, i.e. verification transition point, laminar to turbulent layer on the aerodynamic profile.

10

Proces certyfikacji podzespołów statku powietrznego na przykładzie

Sobieszek A., Wojtas M.

Prace Instytutu Lotnictwa

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2015

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Nr 4 (241)

73--86

PL

W artykule przedstawiono proces przygotowawczy certyfikacji, metodologie i przebieg badań weryfikujących podstawowe założenia konstrukcji lotniczej na przykładzie innowacyjnej głowicy wiatrakowca. Przeprowadzono badania czterołopatowej głowicy wiatrakowca weryfikujące wytrzymałość statyczną przy obciążeniach dopuszczalnych, określonych przez siły występujące przy manewrze wyrwania. Scharakteryzowano przebieg badań, metody badawcze oraz weryfikowane parametry. Opisano aspekty prawne dopuszczenia do lotu oraz uzyskania certyfikatu uwzględniając przepisy CS 27, podczęść C - Badania Wytrzymałościowe, według których prowadzono badania. Przedstawione wyniki i wnioski były podstawą do dopuszczenia obiektu do prób w locie przez Urząd Lotnictwa Cywilnego.

EN

This paper describe the preparatory process of certification, methodology and tests which verify the assumptions of aeronautical construction based on innovative gyroplane rotor hub. Presented legal aspects of admission to the flight tests and the Type Certification (TC) taking into account legislation (CS 27 Subpart C - Strength Requirements). In this paper presented tests of innovative four - rotor blades rotor hub which verify static strength up to limit loads. The loads during "pull-up from level flight" maneuver are limit loads. Discussed are tests process, methodology of tests and verified parameters. The results and conclusions were the basis the admission object for flight testing by the Civil Aviation Authority.

11

Landing gear dynamic tests with strain gages

Sobieszek A., Paprzycki I., Tywoniuk A.

Journal of KONES

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2015

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Vol. 22, No. 3

221--227

EN

Strain gage sensing is widely used method for measurements conducted during dynamic tests. This article describes electrical resistance strain gages performing force measurement during the tests of main and nose landing gear of medium-lift civil aircraft. It is the most common method used for measuring mechanical properties like force, pressure, stress, strain, etc. Strain gages were installed in selected areas of the Drop Test Stand. The paper presents advantages of strain gage measuring method in regards to commercially available, ready-made force sensors. Furthermore, it describes the process of selecting strain gage and load cell measurement systems (bridge, half bridge, quarter bridge) and its influence on the test results. What is more the technological process is presented, taking into account the strain gage installation adhesive technology and sensor protection against external conditions, performance of the measurement system and connection to the data acquisition system. Continuing with the process description of calibrating a load cell system for measuring the occurring forces. The article is summed up with an analysis of the problems which arise during the installation and measurement process using strain gages, and includes a description of advantages and disadvantages that occur while applying strain gages while preforming force measurement.

12

Spectral analysis of the EEG-signal registered during anaesthesia induced by propofol and maintained by fluorinated inhalation anaesthetics

Olejarczyk E., Sobieszek A., Rudner R., Marciniak R., Wartak M., Stasiowski M., Jałowiecki P.

Biocybernetics and Biomedical Engineering

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2010

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Vol. 30, no. 1

55-70

EN

The aim of this study was to identify the effects of different volatile anaesthetics (isoflurane, desflurane or sevoflurane) on the spectro-temporal pattern of EEG during all of the stages of anaesthesia recorded at the frontal derivations in 64 adult patients. The relative powers of EEG for delta, theta, alpha and beta frequency bands as well as the characteristics of their time evolution and their relationships with the concentrations of anaesthetics were used as the EEG spectra indices. The time evolutions of the individual wave powers in 75% of patients were similar for all the anaesthetics used in this study at the same method of administration. Well correlated biphasic changes in the slow and fast wave powers emerged after propofol induction as well as in association with the volatile anaesthetics action. Wave powers as well as their relationships with the anaesthetic concentrations were not hampered by the variability across the patients and anaesthetics used in this study. Comparing the branches of increasing and decreasing concentration, the hysteresis phenomenon, i.e. systematic decrease or increase of each wave power, was observed at the end of anaesthesia for each of the volatile anaesthetics. A rapid increase of sevoflurane concentration at the initial phase of anaesthesia caused more effective attenuation of beta waves than in the case of gradual anaesthetic administration but it happened at the cost of the intensification of delta waves.

13

Evaluation of the EEG-signal during Volatile Anaesthesia: Methodological Approach

Olejarczyk E., Sobieszek A., Rudner R., Marciniak R., Wartak M., Stasiowski M., Jałowiecki P.

Biocybernetics and Biomedical Engineering

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2009

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Vol. 29, no. 1

3-28

EN

The presence of the EEG patterns showing some similarities with epileptiform activity as well as epileptic EEG discharges and motor seizures observed in some people during anaesthesia conducted with volatile anaesthetics is now well-recognized. Nevertheless the practical as well as theoretical implications indicate for the necessity of better understanding of the nature and mechanism of these patterns. The aim of this study was to verify the usefulness of some methods of the EEG analyses to characterize the atypical forms of EEG. It was shown that the estimation of Higuchi's fractal dimension and mean phase coherence as well as the analysis of time-frequency distributions (spectrograms and scalograms) revealed the quantitative features of atypical patterns and their relationships with the depth of anaesthesia.

14

Frequency analysis of ictal EEG neocortical epileptic discharges in cats: comparison between potassium and penicillin induced seizures

Sobieszek A., Tarnecki R., Zalewska E.

Biocybernetics and Biomedical Engineering

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2005

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Vol. 25, no. 1

37-47

EN

Results of this research illustrate similarities as well as differences between patterns of the cortical EEG ictal discharges and their frequency spectra recorded in two experimental, animal models of epilepsy in cats. Localized bioelectric discharges were evoked in animals with permanently implanted electrodes either by local, subdural. epicortical application of penicillin or subdural perfusion of the parietal cortex with artificial cerebrospinal fluid (aCSF) with elevated concentration of potassium ions up to 16 mM/dcm3. Three classes of components were distinguished: low frequency surface negative spikes and surface positive waves with subsequent negativity, appearing at theta-delta frequencies (2-4 Hz), recorded in both experimental conditions and high frequency component in beta frequency range (13-35 Hz) recorded after administration of penicillin. A typical pattern of spike and slow wave complexes was characteristic for ictal discharges evoked by high potassium aCSF. High frequency "beta" component was observed after topical administration of penicillin and was preserved after administration of substances belonging to the two classes of potent antiepileptic drugs: barbiturates and benzodiazepines. The results provide experimental evidence linking disturbances of the neuronal potassium ion homeostasis in the cerebral cortex with the appearance of EEG spike and slow wave pattern characteristic for absence epilepsy.