Ultralight Aircraft Research Articles

Drivetrain Noise of The Gyroplane I-28

Abstract Gyroplanes, as ultralight aircraft, are popular transport vehicles recently. Ultralight aircraft flights take place at a low altitude – their noise is not without effect on people and nature. The localization of the sources of noise and a possibility to decrease the noise of an gyroplane are described in this paper. The rules of design and exploitation of gyroplanes do not define the limits of emitted noise. Gyroplanes are not noisy aircraft vehicles but for their silencing the knowledge about the sources and frequency range of noise is necessary. The goal of the conducted measurement was to determine the gyro-plane noise properties and the noise measurement methods. The evaluation of the noise sources was made by acoustic beamforming and the directional emission with single microphones at various engine speeds. The supplement of these tests should be the rotor noise measurement but that investigation should be performed on a special stand, on which the rotor propulsion noise would not disturb the measurement.

Roll performance assessment of a light aircraft: Flight simulations and flight tests

A methodology is presented for the roll performance assessment of a light aircraft. The study is based both on flight simulations and flight tests, focusing on the accurate determination of the lateral control power. The chosen test airplane was a Tecnam P92, a two-seat ultralight aircraft which was specifically equipped with a lightweight and accurate instrumentation for the planned set of flight data measurements. A matrix of flight experiments for the test campaign was established with the support of 6-degree-of-freedom simulations, implementing a carefully constructed baseline dynamic model of the aircraft. The article discusses first the general problem of a reliable evaluation of aircraft roll performance indicators, i.e. the estimation of the aerodynamic derivatives that mainly influence the airplane ability to roll. Next, the results of extensive flight test activities are presented. The analysis of several roll maneuvers performed at different flight speeds and with different aileron maximum deflections showed interesting rolling characteristics for this non-aerobatic aircraft. One notable finding was a clear nonlinear dependency of the aileron efficiency index on aileron deflection amplitude. A control power derivative extracted from flight data in the form of lookup table was used to correct the baseline flight dynamics model. Flight simulations outputs based on the updated model showed a satisfactory agreement with experimental time histories. According to this, the present effort proposes a new method to estimate the aileron control derivative in whole the flight envelope for light aircraft.

Raman lidars for a better understanding of pollution in the Arctic System (PARCS)

The development of oil and gas drilling and the opening of new shipping routes, in the Barents and Norway seas, poses new challenges for the Arctic environment due to the impact of air pollution emissions on climate and air quality. To improve our knowledge of the interactions between aerosols, water vapor and cloud cover, within the French PARCS (Pollution in the ARCtic System) project, Raman lidar observations were performed from the ground and from an ultra-light aircraft near the North Cape in northern Norway, and coupled with measurements from a 95 GHz ground-based Doppler radar.

Estimation of the Spatial and Habitat Distribution of Anseriformes in the Yamal-Nenets and Khanty-Mansi Autonomous Regions (Experience from the Use of Ultralight Aircrafts)

In Russia, the conservation of anseriformes is possible through the creation of temporary huntingfree zones during hunting season, especially in spring. A justification for creating such zones and outlining their boundaries (by analogy with the experience derived from the countries on North America) each season must be based on data on annual waterfowl monitoring. The present paper describes census experience drawn from the use of ultralight aviation for further delineating the key staging sites of waterfowl in western Siberia. To refine the duration of monitoring, observation data were combined with those derived from geese equipped with GSM-GPS transmitters. In the spring and autumn of 2012–2014, we covered over 50000 km of aerial surveys of 25 waterfowl species. A new method is advanced for assessing their numbers based on visual observations, flock photography, and modern statistics. We estimated the species densities in 16 habitat types delineated on the basis of Landsat imagery. In terms of this, a system is proposed for extrapolating the survey data on 25 waterfowl species onto model sites in western Siberia. Drops in the numbers of several mass game species were noted. Based on an evaluation of the habitat quality, ten waterfowl hunting-free zones were suggested and delineated. A GIS project was launched that incorporated the main migration routes, boundaries of the key sites, places of mass bird aggregations, and sites for the observation of rare, Red Data Book. A program of long-term monitoring and sustainable use of waterfowl in the study region is offered. Such an approach must also be applied to other regions of Russia.

Mini N2-Raman Lidar Onboard Ultra-Light Aircraft for Aerosol Measurements: Demonstration and Extrapolation

Few airborne aerosol research experiments have deployed N2-Raman Lidar despite its capability to retrieve aerosol optical properties without ambiguity. Here, we show the high scientific potential of this instrument when used with specific flight plans. Our demonstration is based on (i) a field-experiment conducted in June 2015 in southern France, involving a N2-Raman Lidar embedded on an ultra-light aircraft (ULA); and (ii) an appropriate algorithmic approach using two-level flight levels, aiming to solve the notorious instability of the airborne Lidar inversion for the retrieval of aerosol optical properties. The Lidar measurements include the determination of the aerosol extinction coefficient along ~500 m horizontal line of sight, and this value is used as a reference to validate the proposed algorithm. The Lidar-derived vertical profiles obtained during the flights are used as an input in a Monte Carlo simulation in order to compute the error budget in terms of biases and standard deviations on the retrieved aerosol extinction coefficient profile, as well as the subsequent optical thickness. The influence of the Lidar ratio (i.e., between aerosol extinction and backscatter) on the error budget is further discussed. Finally, from this end-to-end modeling, an optimal N2-Raman Lidar is proposed for airborne experiments, adapted to both small and large carriers.

Electrohydrodynamic Thrust for In-Atmosphere Propulsion

The electrohydrodynamic thrust generated by wire–cylinder electrodes under high dc voltage is experimentally analyzed. Some recent experimental studies have shown that electrohydrodynamic thrusters produced by corona discharge and ionic wind are able to deliver high thrust-to-power ratio, which reopens prospects for electrohydrodynamic propulsion. From simple considerations based on ultralight aircraft mass, aerodynamics, battery mass, and experimental electrohydrodynamic thrust densities, their potential for applications is showcased. Furthermore, an experimental study is performed, for which the experimental observations are presented in terms of electric field and thrust density. This allows a simplified and synthetic presentation of propulsive properties. Various experimental biases have been identified and corrected. The measure of time-periodic oscillations of the airflow in the back of the thruster pinpoints a possible wake effect due to the impact of ionic wind on electrodes. The variations of the associated drag are studied when varying the position of the collecting electrodes. It is shown that aerodynamic losses can be significant in experimental electrohydrodynamic thrusters.

Numerical and experimental investigations of the propeller characteristics of an electrically powered ultralight aircraft

The performance and efficiency of a propeller is crucial for electrically powered propulsion systems. Since the energy of the batteries is limited, it is important to develop propellers with high efficiency. Therefore, numerical and experimental investigations of the propeller characteristics are performed. The wind tunnel experiments are performed on a fuselage–propeller configuration. The electrical motor, batteries, and control units are designed to be integrated in the fuselage. Furthermore, force measurements are conducted to provide a data base for the validation of the numerical results. Two different numerical approaches are presented. First, the propeller is fully resolved by applying a rotational domain and a sliding mesh interface. Second, an actuator disk approach including blade element theory with a panel method one-way coupled with a boundary layer integration method is presented. The latter shall be used to reduce computational and mesh generation costs. The thrust, efficiency as well as pressure distribution and the flow field downstream of the propeller are analyzed. The obtained numerical results show a good agreement with the experimental data for the integral values over a wide operating range. Moreover, the results of the inter-method comparison of the two numerical approaches are in a good accordance regarding the local effects for the two highlighted operating points.

The usefulness of low-altitude aerial photography for the assessment of channel morphodynamics of a lowland river

Abstract The paper presents examples of using low-altitude aerial images of a modern river channel, acquired from an ultralight aircraft. The images have been taken for two sections of the Vistula river: in the Małopolska Gorge and near Dęblin and Gołąb. Alongside with research flights, there were also terrestrial investigations, such as echo sounding of the riverbed and geological mapping, carried out in the river channel zone. A comparison of the results of aerial and terrestrial research revealed high clarity of the images, allowing for precise identification of the evidence that indicates the specific course of river channel processes. Aerial images taken from ultralight aircrafts can significantly increase the accuracy of geological surveys of river channel zones in the Polish Lowlands due to low logistic requirements.

Design of the crashworthy structure of an urban aircraft

With the development of general aviation, the urban aircraft is around the corner. The urban aircraft with composite is considered as an ultralight vehicle and the crashworthiness is of vital importance for such an ultralight aircraft. Composites are being widely and increasingly used in the aerospace industry because of their advantages that include the high specific strength and stiffness over traditional metallic materials. Besides, composites have the potential for absorbing the energy in a crash event. The crashworthiness of the cockpit section is analyzed in this paper and some modifications in the subfloor have been made to improve the survivability of the pilot. Advances in commercial softwares have enabled engineers to simulate crash events. The three-dimensional structure model is established by use of CATIA software and the crash process is simulated by MSC/DYTRAN. By comparing the crashworthiness of composite structures, reliable basis is provided for the design of a safe and sound structure.

Validation of nonlinear integrated navigation solutions

There exist numerous navigation solutions already implemented into various navigation systems. Depending on the vehicle in which the navigation system is used, it can be distinguished in most cases among; navigation, tactical, and commercial grade categories of such systems. The core of these systems is formed by inertial sensors, i.e. accelerometers and angular rate sensors/gyros. Navigation and tactical grade systems commonly rely on fiber optic/ring laser gyros and servo/quartz accelerometers with high resolution, sensitivity, and stability. In the case of cost-effective navigation systems, for example piloted light and ultralight aircraft, usually use commercial grade sensors, where the situation differs. The sensor outputs are less stable and sensitive, and suffer from manufacturing limits leading to temperature dependency, bias instability, and misalignment which introduces non-negligible disturbances. These conditions commonly limit the applicability of the navigation solution since its stand-alone operation using free integration of accelerations and angular rates is not stable. This paper addresses a cost-effective solution with commercial grade inertial sensors, and studies the performance of different approaches to obtain navigation solution with robustness to GNSS outages. A main goal of this paper is thus comparison of a nonlinear observer and two extended Kalman filter solutions with respect to the accuracy of estimated quantities and their sensitivity to GNSS outages. The performance analyses are carried out on real flight data and evaluated during phases of the flight when the solutions are challenged by different environmental disturbances.

MIRANDA 35 GHz SAR Based Non-Coherent Change Detection

AbstractUp to now, the high effort involved with airborne Synthetic Aperture Radar (SAR) systems has led to the effect that SAR image processing is mostly restricted to single images of a scene. Recent developments like the MIRANDA 35 and its matching flight platform allow for frequent revisits of the same scene at very high repeatability. MIRANDA 35 has been designed as a lightweight and compact SAR sensor for altitudes of up to 1 km while providing a resolution of 15 cm. In combination with a highly flexible ultralight aircraft we have recently obtained 28 measurements of a scene within 2 h of flight time at very high repeatability. Two sets of flight courses, each with 7 flyovers of the reference scene and 7 of a modified change scene, are investigated here using statistical change detection methods like Informational Difference and Universal Image Quality Index.

Flow bench testing of prototype intake manifolds for ultralight aircraft engine

The article describes the research on the intake manifold for ultralight aircraft engine Vaxell 100i. It presents the actual and new redesigned manifold construction and points out the design requirements. The results of previously made numerical simulation of air flow inside the manifold are discussed. Computer analysis confirmed the appropriateness of internal guide vanes usage to improve the uniform air distribution between cylinders. For verification, a flow bench test stand was made for multicylinder intake manifold testing. A prototype manifold was built with the possibility of guide vane adjustment. The best variant had almost 5 times better uniformity of air distribution comparing to variant without the guide vane. Flow bench results confirmed the conclusions from numerical simulations.

FEM simulation research of natural frequency vibration of crankshaft from internal combustion engine

The article presents vibration simulation studies of a crankshaft used in internal combustion engine. The simulation was performed using FEM method. The study was conducted in Abaqus software, and a shaft model was implemented in Catia v5. The influence of a mesh element size on the results of obtained calculations was analysed. A shaft which will be used in the ultralight aircraft engine was the subject of research. Results show the first 10 frequency modes and 12 grid examples for various element sizes, from 9 to 1.3 mm. Moreover, the effect of mesh size on the obtained results is presented. It has been proven that the maximum error for two extreme results (the densest and sparsest grid) is approximately 1.4%; therefore, it is justified to carry out calculations of own vibration on a fatal grid. Results presented herein will be used in the future work on the crankshaft geometry modifications.

Contribution of high-resolution remotely sensed thermal-infrared imagery to high-throughput field phenotyping of an apple progeny submitted to water constraints

The genetic variability of fruit trees in response to drought stress is scarcely studied. As adaptation of scion cultivars to abiotic constraints constitutes a new challenge for fruit production, in particular where water scarcity is likely to occur, development of high-throughput phenotyping strategies applicable in the field to assess the tree response to soil drought among large populations is needed, overcoming the limitations of usual in-planta measurements. In this research, remotely sensed images were acquired by ultra-light aircraft (ULA) and an unmanned aerial vehicle (UAV) during 4 years in a field trial where an apple progeny (122 hybrids) was studied under contrasted summer irrigation regimes. Ortho-images were simultaneously acquired in visible (RGB), near-infrared (NIR) and thermalinfrared (TIR) bands. After rthorectification, georeferencing and mosaicking, RGB and NIR images were used to compute different vegetation indices over the field trial, while TIR imaging allowed extraction of the vegetation surface temperature (Ts), which was calibrated at ground level by using hot and cold reference targets. The Morans'f water deficit index (WDI), which combines the surface minus air temperature (Ts-Ta) and the normalized difference vegetation index (NDVI), was used as a stress phenotypic variable. WDI estimates the ratio of actual to maximal evapotranspiration (WDI=1.ETact/ETmax) in discontinuous plant covers. Like the Ts-Ta variable, it significantly discriminated the tree water statuses and genotypes. On the basis of different plant- and image-based indices, individual tree behaviour trends (isohydric vs. anisohydric) can be distinguished among the progeny, irrespective of tree vigour. This opens potential applications for plant breeding, and genetic bases of apple tree response to water stress are currently investigated through quantitative trait locus (QTL) detection. Making use of ULA with flights performed at 40-60 m altitude made it possible to strongly improve the TIR image resolution ('10 cm) and to limit the number of vegetation/soil mixed pixels. However, it will require careful image posttreatment, possibly including classification and/or segmentation.

Exceptional aerosol pollution plume observed using a new ULA-lidar approach

An exceptional particulate pollution event was sampled in June 2005 over the Ardèche region in Southern France. Airborne (at the wavelength of 355 nm) and ground-based (at the wavelength of 532 nm) lidars performed measurements simultaneously. Airborne observations were performed from an ultra-light aircraft (ULA); they offer an opportunity to test a new method for inversing lidar profiles which enables their quantitative use while the airplane flies in a scattering layer. Using the results of this approach and the ground-based lidar measurements, the aerosol plumes have been optically quantified and the diversity of particle sources (from Western Europe, North Africa and even North America) which contributed to the event has been highlighted using both spaceborne observations and multiple air mass back-trajectories.

A Study on History of the Development of Domestic Aviation Sports and the Trends of Research

본 연구는 국내 항공 스포츠의 도입과 전개의 과정을 역사적으로 살펴보고, 아울러 관련 연구물을 종합적으로 고찰하여 항공스포츠의 미래 과제를 조명해 보고자 했다. 항공스포츠의 기록을 추적한 결과 1945~1970년대까지를 태동기로, 1980~1990년대까지를 확산기로, 2000년대 이후를 도약기로 구분할 수 있었다.BR 1945년 조직된 조선항공회 창설, 1957년 국제항공연맹 총회 정회원국 가입, 1976년의 이사국 승격 등 조직 구성은 태동기의 기반이 된 일들이다. 1981년 민간항공 첫 운행 이후 국제항공연맹 총회의 대표단 파견 및 각국 민간항공단체와의 친선교류, 1991년 한국활공협회의 지도자 연수회, 초경량항공기협회의 세미나, 본격적인 항공스포츠 관련 조직의 구체적 활동은 확산기로서의 체계를 구축하는 결과를 가져왔다.BR 최근 정부의 본격적인 지원으로 말미암아 항공스포츠는 도약기로서의 출발점에 놓여있다고 하겠다. 항공스포츠 관련 연구의 대부분은 항공기 자체의 공학적 연구나 항공 기술 연구에 치우쳐 있다. 미미하게나마 여가·레저스포츠로서의 관련 연구가 이루어져 있지만, 향후 모험스포츠로서의 항공스포츠가 갖는 의미와 가치, 인식, 행정 개선 등의 대중화를 기반으로 한 학문적 연구가 지속적으로 이루어져야 할 것이다.BR

Design and analysis of power supply and information transfer to three-axis gyroscope stabilizer platform

The paper focuses on problems of the engineering implementation of 3-axis gyrostabilizer of the camera for orthophotography performed from light and ultralight aircrafts. The functional diagram of gyrostabilizer is characterized by a lighter ball-bearing having a large inner diameter used for the platform suspension on its internal (vertical) axis. The problem is to transfer the supply voltage to the platform and the electric signals to and from the platform. Design solutions concerning the power supply and information transfer are supported by the experimental techniques suggested in this paper, namely: the use of the rolling contact; three-phase gyro motor power supply replaced by that from the single-phase network; signal transmission from the precession angle sensor using the air transformer; current and voltage frequency division; DC mode selection for the torquer. The results obtained prove the efficiency of the suggested design solutions.

STUDY OF THE INFLUENCE OF A GAP BETWEEN THE WING AND SLOTTED FLAP ON THE AERODYNAMIC CHARACTERISTICS OF ULTRA-LIGHT AIRCRAFT WING AIRFOIL

The purpose of the study is to assess what the influence of the distance of the gap is between the wing and slotted flap on the aerodynamic characteristics of ultra-light aircraft wing when the flap is retracted. It has been elected numerical approach to the study and it is been realized through applied numerical model of the wing airfoil NACA 2412 for three different lengths of slotted gap size, whose length is expressed as percentages of the airfoil chord. The code ANSYS FLUENT has been applied, as it has been determined RANS (Reynolds-averaged Navier-Stokes) equations and DES (detached-eddy simulation) turbulent model has been used.

Energy Expenditure and Metabolic Changes of Free-Flying Migrating Northern Bald Ibis.

Many migrating birds undertake extraordinary long flights. How birds are able to perform such endurance flights of over 100-hour durations is still poorly understood. We examined energy expenditure and physiological changes in Northern Bald Ibis Geronticus eremite during natural flights using birds trained to follow an ultra-light aircraft. Because these birds were tame, with foster parents, we were able to bleed them immediately prior to and after each flight. Flight duration was experimentally designed ranging between one and almost four hours continuous flights. Energy expenditure during flight was estimated using doubly-labelled-water while physiological properties were assessed through blood chemistry including plasma metabolites, enzymes, electrolytes, blood gases, and reactive oxygen compounds. Instantaneous energy expenditure decreased with flight duration, and the birds appeared to balance aerobic and anaerobic metabolism, using fat, carbohydrate and protein as fuel. This made flight both economic and tolerable. The observed effects resemble classical exercise adaptations that can limit duration of exercise while reducing energetic output. There were also in-flight benefits that enable power output variation from cruising to manoeuvring. These adaptations share characteristics with physiological processes that have facilitated other athletic feats in nature and might enable the extraordinary long flights of migratory birds as well.

Aircraft health and usage monitoring system for in-flight strain measurement of a wing structure

This paper presents an aircraft health and usage monitoring system (HUMS) using fiber Bragg grating (FBG) sensors. This study aims to implement and evaluate the HUMS for in-flight strain monitoring of aircraft structures. An optical-fiber-based HUMS was developed and applied to an ultralight aircraft that has a rectangular wing shape with a strut-braced configuration. FBG sensor arrays were embedded into the wing structure during the manufacturing process for effective sensor implementation. Ground and flight tests were conducted to verify the integrity and availability of the installed FBG sensors and HUMS devices. A total of 74 flight tests were conducted using the HUMS implemented testbed aircraft, considering various maneuvers and abnormal conditions. The flight test results revealed that the FBG-based HUMS was successfully implemented on the testbed aircraft and operated normally under the actual flight test environments as well as providing reliable in-flight strain data from the FBG sensors over a long period of time.