Browse Topic: Pitot-static instruments
Air data measurement and calibration are fundamental components in the pursuit of accurate and reliable aerodynamic assessments. The systematic collection of essential data regarding air properties are important for evaluating aircraft performance under various conditions and configurations. The scope is to achieve a comprehensive understanding of airflow characteristics, which is fundamental for design improvements and operational strategies, contributing to safer and more efficient flight operations in a several range of scenarios. This type of data measurement is even more challenging for the AW609 Tiltrotor which combines vertical take-off technology capabilities with the fixed-wing flight efficiency. The activity starts from known pitot-static system calibration methodologies for conventional applications and shows what were the difficulties encountered in a non-conventional Tiltrotor approach. The paper goes through the presentation of the original Pitot-Static and Air Data
FAA rotorcraft airworthiness regulations require calibration of pitot-static systems in all flight regimes. Of all methods commonly used, none has been applied in a manner showing full compliance, specifically in the takeoff phase and in determining CG (Center of Gravity) effects. A review of accepted Position Error Correction methods identifies the GPS-based true airspeed method, with an adapted execution and analysis technique, as the most practical in terms of equipment and efficiency to provide a complete airspeed system calibration. The level flight limitations of the GPS method are solved by a combination of flight profiles, continuous data recording and reduction technique. The GPS horseshoe method and the ORBIS constant turn radius method are expanded by varying the airspeed, altitude, and heading as required to provide an equation set solved for the wind components and true airspeed. The new variable parameter methods minimize wind variability effects and flight test time.
Bell Helicopter's 525 Relentless will be the world's first commercially certified fly-by-wire helicopter. As a fully computer controlled aircraft, the design aims at higher safety through reduced pilot workload, increased situational awareness, and improved handling qualities. The flight control system that achieves these results operates with numerous redundant sensors that provide flight data and feedback to the flight control logic. This paper describes the development of the Bell 525's redundant Pitot static airspeed system, showing how computational fluid dynamics (CFD) models were used to perform initial calibration of the triplex system far ahead of first flight. Since air data readings interact with the flight control logic, it was important to have a reasonable airspeed calibration available for first flight. The Bell 525 aerodynamics team developed an analytical approach to model the triplex airspeed system to account for position error across the flight envelope. The
In efforts to increase the accuracy and reliability of altimetry, speed measurement and other aspects of air data, a great deal of attention and money have been expended on new and refined pressure transducing and computing systems and on the standards by which they are calibrated. So much progress has been made in this that the limiting factor is, or may soon be, the sensing and transmitting in the aircraft of the pressures to be transduced. Until the appearance of References 1-13 and 18 there was little guidance available on the maintenance of pitot and static systems. This report presents what information is available, suggests limits, and lists the principal original papers on the subject.
The four engined Upper Surface Blowing (USB) STOL research aircraft ASKA was developed by National Aerospace Laboratory of Japan and has been in the flight test phase to provide various kinds of flight data. The position error in airspeed and angle of attack is discussed, and the low speed performance demonstrated in the flight test is provided by the figures of lift/drag coefficient curves and V-Gamma plot. Several indications of powered lift and dynamic stability derivatives obtained from the V-Gamma plot are discussed. The flight measured pitching moment shows the distinctive features such as pitch up tendency. The wing-body pitching moment and the downwash angle are analyzed from the flight load measurments of the horizontal tail. The ground effect of the ASKA is also presented quantitatively in this paper. THE QUIET SHORT TAKE-OFF AND LANDING (STOL) capability is very beneficial for the Japanese domestic aviation, since airports have short runways in the vicinity of the
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