122,202 research outputs found
LIGHT AIRCRAFT FLIGHT TESTS: PERFORMANCES, STABILITY AND FLYING QUALITIES MEASUREMENT
No full textThe present paper deals with flight test activities performed on light aircraft at University of Naples, Dipartimento di Progettazione Aeronautica (DPA) by the ADAG (Aircraft Design and Aeroflightdynamics Group) research group. Flight tests performed on a Brasilian light aircraft called Curumin and on G97 Spotter ultralight aircraft (ULM) will be presented. An accurate and complete flight test equipment and instrumentation has been designed and assembled by the research group. A complete set of sensors and instruments (pressure transducers, inertial platform, GPS, pitot probe used for angle of attack and sideslip measurement etc.) has been integrated and used to measure flight data and an accurate A/D converter and a flight data logger system has been set up for flight data acquisition. The complete on-board system is light and compact since it is also used for model aircraft (RPV or UAV) flight tests. The flight data are stored on board and sent to the ground where a ground control station is used for real-time monitoring. The ground station allows real-time ground visualization of all flight data parameters and aircraft position and attitude. In the paper all the advantages (i.e. fast evaluation of dynamic stability characteristics of the aircraft) in using a telemetry system for flight test activities will be highlighted. The complete instrumentation constitutes a valid tool for light aircraft flight tests and is also extensively used at our University for teaching purposes. The paper presents some flight test procedures and results concerning light aircraft aerodynamics and performances estimation. The paper will also present our current methodology based on Maximum Likelihood Method (MLM) for aerodynamic and dynamic parameter estimation. This allows the build-up of the complete aircraft aerodynamic data-base to be used for flight simulation. For the prediction of performances and dynamic behaviour of the airplane in flight, specific and detailed maneuvers have been designed and executed in order to excite dynamics modes. Comparison between simulated and measured maneuvers will be performed. Examples of linear and non-linear flight parameters estimation such as longitudinal non-linear aerodynamics from stall maneuver will be presented
Flying qualities and performances estimation of three surfaces aircraft RPV model with and without canard from flight test
No full text
Multi-step strategy for rotorcraft model identification from flight data
No full textThe availability of suitable methods for system identification from flight data of rotorcraft models is a key factor to enhance the competitiveness of the rotorcraft industry in the development process of new vehicles. Indeed, reliable simulation models provided by the identification techniques can be used for the design and validation of the vehicle flight control system. It allows minimizing the number of in flight experimental tests and consequently reducing costs and risks related to flight testing. Identification methodologies generally fall into two categories: frequency-domain and time-domain. Each approach has inherent strengths and weaknesses. Much of the published works on rotorcraft identification deals primarily with frequency-domain methods, which work well at mid and high frequencies associated with the dynamics of the vehicle control inputs and the aero-elastic behaviour of the blades. On the other hand, time-domain methods, which are well assessed for the identification of fixed wing aircraft, provide accurate models at the low frequency scale that is related to the vehicle flight mechanics. In this paper a hybrid time-frequency identification approach is described. The identification process was carried out in the framework of a multi-step strategy and a specific methodology was selected to comply with each step objective. The hybrid time-frequency approach allowed exploiting the advantage of both time and frequency methods, maximizing the information content extracted from the flight data and obtaining an identified model applicable in the whole frequency range of interest. Furthermore the multi-step strategy decomposed the complex starting problem in simplified sub-problems, which are easier to be solved. The proposed methodology was applied to simulated data of the UH60 Black Hawk, generated using the FLIGHTLAB multi-body simulation environment. Preliminary results showed the effectiveness of the proposed identification strategy in terms of convergence and capability of extracting from flight data relevant information on the vehicle dynamic behaviour. Future works will be focused on the refinement of the structure of the rotorcraft model used for identification purpose and on the application of the proposed methodology to set of data gathered during actual rotorcraft flight tests
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