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Elimination of adverse meteorological conditions during takeoff and landing
Published in Vladimír. Socha, Lenka Hanáková, Andrej Lališ, New Trends in Civil Aviation, 2018
If there is a head wind during takeoff, this speed is added to the speed of the aircraft moving in relation to the runway, the so-called ground speed (GS). The greater the head wind is, lower the speed of the airplane needed toward the runway to reach the Indicated Air Speed (VR) velocity – the rotation speed. That is the speed at which the elevator becomes efficient enough and the pilot can start to rotate the airplane by upward movement of the control wheel to lift it off the runway and climb. If there is a head wind component during takeoff, then it is enough for the airplane to develop lower ground speed than in case of windlessness. This difference is equal to the size of the head wind component. The lower the required airplane speed to the ground, the shorter rolling time is needed to lift off and thus shorter takeoff distance.
Airport Planning and Design
Published in Dušan Teodorović, The Routledge Handbook of Transportation, 2015
Headwinds will add to the aircraft’s airspeed, whereas tailwinds will subtract from it. As an example, an aircraft flying at a ground speed of 250 km/h with a headwind of 20 km/h will have an airspeed of 270 km/h, whereas the same aircraft at the same ground speed but with a tailwind of 25 km/h will be flying at an airspeed of 225 km/h. For this reason, take-offs and landings should always be performed with either headwinds or calm winds. The direction the wind is blowing from will then determine the direction of take-off and landing operations on a runway.
Straight-level flight
Published in Mohammad H. Sadraey, Aircraft Performance, 2017
In Chapter 2, the term “airspeed” was introduced. Aircraft airspeed is not affected by any wind, while wind affects the ground speed. A headwind decreases the aircraft ground speed, but a tailwind increases the aircraft speed relative to the ground. Since the range is calculated relative to the ground, the ground speed is employed instead of airspeed. This is the reason why the range is influenced by wind.
Computational analysis of skid resistance of aircraft tire on wet runway pavement with different groove depths
Published in Road Materials and Pavement Design, 2023
Baiyu Jiang, Xiao Chen, Hao Wang
The dimensions of squared grooves in the current FAA standards are 6.4-mm width, 6.4-mm depth, and 31.2-mm edge-to-edge spacing (FAA, 1997). It is expected that the groove depth would affect water flow and hydrodynamic pressure at tire-pavement contact as the water is squeezed under the tire at high speed. Therefore, the effect of water film depth on friction coefficient is evaluated using the developed tire-water-pavement interaction model. It is expected that the skid resistance decreases as the speed increases. The analysis speed is selected to be 56 m/s in this study, which is a common speed ground speed after aircraft touchdown (maximum speed after touchdown). The initial friction coefficient in the wet condition is 0.49 based on the field measurement at 56m/s (Agrawal, 1983). The tire load and pressure are kept at 156 kN and 966 kPa in all analyses.
Calibration of smartphone sensors to evaluate the ride quality of paved and unpaved roads
Published in International Journal of Pavement Engineering, 2022
Xinyi Yang, Liuqing Hu, Hafiz Usman Ahmed, Raj Bridgelall, Ying Huang
Table 3 shows part of the data collected using the RIVET app on the Android phone operating system (Google Pixel in this study). The column ‘Time’ stored the epoch time of the sampling instant in milliseconds. The columns labelled ‘Lat’ and ‘Lon’ stored the GPS coordinates of latitude and longitudinal in decimal degrees. The ‘v’ column stored the ground speed of the vehicle speed in units of . The variables ax, ay, az stored the accelerometer lateral, longitudinal, and vertical accelerations in units of . Yaw, Pitch, and Roll stored the azimuth, pitch, and roll angles, respectively, recorded from the gyroscope in decimal degrees. Rx, Ry, Rz stored the rotation rates around the x-axis, y-axis, and z-axis, respectively. Mx, My, Mz stored the magnetic field strength along the x-, y-, z-axis, respectively, in units of micro-Tesla . The RIVET app directly collected the accelerations of the smartphones without using Equation (2). Thus, in the post data analysis, Equation (2) needs to be applied to compute the g-force (gz) before estimating RIF using Equation (1).
Head-up displays assist helicopter pilots landing in degraded visual environments
Published in Theoretical Issues in Ergonomics Science, 2018
Neville A. Stanton, Aaron P. Roberts, Katherine L. Plant, Craig K. Allison, Catherine Harvey
The development of the HUD was part of a larger research project in which the concept was designed with the aid of Cognitive Work Analysis (see Stanton and Plant 2010, 2011; Stanton et al. 2016). The requirement was that the HUD would be capable of assisting the pilot with performing approach and landing in a degraded visual environment. In line with potential future cockpit capabilities, the HUD was developed in a full-colour system with an extended field-of-view (e.g. future windshield displays). To assist with the landing task, the HUD included a flight path vector, which represented the point on the ground that would be hit if velocity was maintained (see Figure 1, #1). Perspective view augmented reality ‘trees’ were located in a fixed position at the landing site starting at 150 ft, providing a visual reference point when landing (see Figure 1, #2). The arrows on the trees moved in accordance to aircraft's altitude, to provide intuitive information concerning height and rate of descent (see Figure 1, #3). The HUD concept was created using GL Studio. A two-way data interface was developed to allow flight data to be transferred from Prepar3D and synchronised symbology to be transferred from GL studio. During the flight conditions with the HUD, the concept was overlaid onto the simulated environment using an open source ghost window application. The HUD contained the following 2D flight instruments: conformal compass, heading readout, airspeed indicator, gull wing horizon line, attitude indicator, vertical speed indicator, air speed indicator, wind direction and strength indicator, ground speed and distance to go (see Figure 1).