Take-off Distance Research Articles

장애물 높이에 따른 만성 뇌졸중 환자의 보행 특성

Purpose: The present study investigated the obstacle avoidance strategies of patients with chronic stroke according to the height of the obstacle when obstacle crossing. Methods: For this purpose, Nine healthy older (control group) and 10 chronic stroke patients (experimental group) participated in the study. The kinematic characteristics of obstacle avoidance strategies according to two obstacle height conditions (i.e., 5cm and 15cm) were measured with the take-off distance, toe clearance, and landing distance during obstacles crossing. Results: The results showed that chronic stroke patients had relatively shorter take-off distances and landing distances during obstacles crossing than healthy older adults. Chronic stroke patients also had a higher toe clearance when passing obstacles compared to healthy older adults. Conclusion: The results suggests that compensation and avoidance strategies for stroke patients to prevent falls and perform effective during obstacle crossing. In conclusion, these results indicate that changes in motor ability to overcome movement restrictions appeared to influence the planning of stepping strategies rather than the execution for obstacle crossing performance in healthy older adults.

Improving the efficiency of an aircraft power plant with a turboprop engine based on water-methanol mixture injection

This paper considers a technique for modernizing the power plant (PP) of a regional aircraft. The modernization is based on the injection of water or a water-methanol mixture into the compressor or combustion chamber of a turboprop engine (TPE). An algorithm has been developed for the thermodynamic calculation of TPE parameters, taking into consideration the injected mixture; the mathematical model (MM) has been improved. Methodical studies of the operability and range of application of the improved MM were carried out. The results of mathematical modeling were validated. For verification, the AI-450M turboshaft engine produced by GP Ivchenko-Progress (Ukraine) was used as an object of research. Based on the improved MM, a software module has been developed to study the performance characteristics of a regional aircraft with a TPE. The influence of water injection and a water-methanol mixture on the TPE operating process and the operational characteristics of a regional passenger aircraft has been studied. The proposed measures could be implemented in existing TPEs. This would allow the operation of aircraft without significant modernization of the airport infrastructure. For TPE, the injection of water and a water-methanol mixture is an alternative way of boosting in order to temporarily improve performance. A given modernization technique could improve the TPE power up to ~10 %, as well as reduce the amount of harmful emissions. The results obtained showed a satisfactory convergence of estimated and experimental data. The error of the results under the accepted assumptions does not exceed 3 %. The calculation results demonstrate the advantages of injection at the take-off stage of the aircraft to reduce the take-off distance (up to 45 % in hot conditions TAMB=+30 °C) and reduce the time of climbing the echelon (~10 %)

Kinematics of the Final Approach and Take-Off Phases in World-Class Men and Women Pole Vaulters

The pole vault is a highly technical event where the athletes must successfully convert horizontal velocity during the run-up to vertical velocity at take-off. The aim of this study was to compare the kinematics of men's and women's world-class pole vaulting. Video data were collected of the best clearances by 14 men and 11 women at the 2018 IAAF World Indoor Championships using three high-speed cameras (200 Hz). Running velocity, step lengths, step times, and pole angles were measured during the run-up; during take-off, distance from the plant box, angle and velocity of take-off, and relative positions of the foot and hands were measured. Men achieved greater clearance heights with faster run-ups, faster take-off velocities and higher hand grip positions (all p < 0.001), with each of the last three steps longer for men when expressed as absolute values (all p < 0.001), but not when expressed relative to stature. There were no differences in run-up pole angles, step times, take-off angle, take-off contact time or time from pole plant to take-off. Women differed in their approach and take-off for characteristics affected by stature and strength, such as fewer run-up steps, shorter take-off distances, and lower grip heights. These lower grips result from a shorter, lighter pole, and this disadvantage was greater than slower run-up velocities. Coaches should therefore note that sex-based differences occur in the pole vault that result from anthropometric differences, but which do not negate the adoption of similar technical models of vaulting.

Measurement of aircraft ground roll distance during takeoff and landing on a grass runway

The aim of this study was to develop a method for airplane ground roll distance measurement. This method is based on measurements of aircraft accelerations, magnetic field vector, as well as Global Positioning System (GPS) position. A convolution neural network was developed in this study and it recognizes characteristic moments of flight during takeoff: longitudinal acceleration, nose wheel up (rotation), and liftoff, as well as during landing: approach, touchdown, rollout, and stop. The developed neural network includes two filters that enable collection of input data from both the total dataset as well as from data portions for information about the occurrence of a peak at the time of touchdown and the change of acceleration at the time of takeoff.The distance traveled by the plane on the ground during takeoff or landing is then calculated using the GPS coordinates, measured simultaneously. The method uses a sensor system consisting of accelerometers, magnetometers, and a GPS receiver; a prototype hardware was based on a single-board miniature computer. The hardware is small in size and fits anywhere in the aircraft cockpit. The method has been practically examined by means of flight tests and it was concluded that it performs well: the mean difference in the measured take-off and landing distances from the results obtained with the reference method was 2,92 % and 6,31 % respectively. The method was not sensitive to airplane design type: low wing vs. high wing. Also, the method has been tested for two different pilots and no significant difference in the results of measurement was observed.

Kinetics, Kinematics, and Fixed Postures: An Exploration of How Attentional Focus Manipulation Enhances Movement

ABSTRACT There is debate in the literature regarding how manipulating the focus of attention (FOA) influences ground reaction forces during the standing long jump (SLJ) and gaps in understanding as to which phases of the SLJ are affected (takeoff, flight, and landing) and whether FOA manipulation benefits remain when tasks are performed in fixed body postures. P urpose: This study compared SLJ performance under external (EXT) and internal (INT) FOA conditions with free and fixed postures. M ethods: Twenty participants performed SLJs under EXT and INT FOA conditions while being allowed to swing arms freely and having to keep hands on their hips. Kinematics and kinetics were recorded using 3D-motion capture and force plates. Jump distances, projection angles, and ground reaction forces and impulses were compared across conditions using a 2 × 3 repeated measures ANOVA. R esults: Jump distances were significantly further with EXT FOA (p < .001). These differences were due to increases in the takeoff distance (p < .001) and landing distances (p < .001), with flight distances not being different between the conditions (p = .061). Peak horizontal ground reaction forces (p < .001) and impulses (p < .001) were both greater, while projection angles were lower (p = .002) in the EXT FOA condition. Co nclusions: Improvements in SLJ distance with an EXT FOA are due to the takeoff and landing phases; manipulating FOA does change forces during the SLJ; and that benefits of an EXT FOA are realized even when movements are performed with constrained body postures.

Do Different Hurdle Heights Alter Important Spatiotemporal Variables in Hurdle Clearance?

The aim of this study was to determine whether important spatiotemporal variables in hurdle clearance change with different hurdle heights. Twelve male hurdlers (mean height, 1.75 ± 0.04 m) cleared hurdles set at different heights [10% higher (High) and 10% lower (Low) than the center of mass (CM)]; images were captured by six high-speed cameras, and each spatiotemporal variable was calculated. Thereafter, the difference in each spatiotemporal variable between High and Low and the relationship between the mean horizontal velocity from takeoff to landing [Hurdle clearance velocity (HC-v)] and each spatiotemporal variable were examined. Our findings indicated that values for flight time, flight time from hurdle to landing (2nd flight time), clearance time, release height on takeoff, peak height of the CM, and the difference in landing distance were greater in the High condition than in the Low condition. Moreover, a low rate of deceleration on takeoff and short 2nd flight time, clearance distance, and takeoff distance were more strongly related to HC-v in the condition High, whereas a low rate of deceleration on landing, short flight time from takeoff to hurdle (1st flight time), high release height on landing, and touchdown height on landing were more strongly related to HC-v in the Low condition. Therefore, coaches should consider these changes in spatiotemporal variables when changing hurdle heights based on age group or event. It should also be noted that, even when the hurdle heights are the same, the spatiotemporal variables that should be considered may differ depending on the height of the hurdler.

Studying and Optimizing the Take-Off Performance of Three-Surface Aircraft

In the quest for making aircraft more energy-efficient, configuration, and primarily the arrangement and quality of aerodynamic surfaces, play a relevant role. In a previous comparative study by the authors, it was shown how to obtain a significant increase in cruise performance by adopting a three-surface configuration instead of a classical pure back-tailed design. In this paper, an analysis of the same configurations in take-off is carried out, to assess through a fair comparison the potential effect of a three-surface one especially on take-off distance. Take-off is mathematically described by means of a sound analytic approach. Take-off distance is computed for a baseline two-surface aircraft, and in a later stage on a three-surface one. In addition to exploring the performance, a numerical optimization is also deployed, so as to find the best use of both configurations analyzed (i.e., baseline and three-surface) in take-off, and the corresponding top performance. The quality of the optimum, as well as the practical realization of a control link between the yoke and both control surfaces in the three-surface configuration, are analyzed in depth. The paper describes the advantage which can be attained by selecting a three-surface configuration, and proposes some remarks concerning the practical implementation of the maneuver to actually capture an optimal performance.

CFD Wind Tunnel Assessment on the case study of the MOTHIF Blown Flap

The increasing interest in Small Air Transportation (SAT), to enhance global connectivity, is highlighting the need for reducing take-off distance: lift coefficient has to be increased without penalizing the configuration drag, weight and complexity.Within the EU Clean Sky 2 projects, a blown flap configuration has been developed to allow STOL capabilities of a future affordable and green commuter belonging to EASA CS 23.The blowing system design choice is aimed at keeping the inevitable associated increase in pitching moment very low, and not penalizing performance when blowing fails.In collaboration between Piaggio Aerospace and the MOTHIF consortium, a wing model was designed, built and tested in the VKI’s large subsonic L1-A wind tunnel, reproducing bi-dimensional preliminary results obtained during the design phase.In order to reduce and predict three dimensional and blockage effects, CFD has been used extensively to obtain a proper test chamber configuration and to reproduce some wind tunnel test results, so that both the accuracy of wind tunnel and design methodology can be assessed.This work presents the comparison between experimental data and CFD simulations to demonstrate the usefulness of simulations to reduce both the risk for erroneous results in experimental activities and their related cost.

The Influence of Climate Change and Variability on Aircraft Take-off and Landing Performance; a Case Study of the Abeid Amani Karume International Airport-Zanzibar

Climate change (CC) and variability have been world widely reported to pose number of risks in aviation industry including accidents, astray, and other operational difficulties. The impact of weather on landing and take-off performances has been several times experienced at Abeid Amani Karume International Airport (AAKIA); however, the influence of climate change and variability to the aircraft performance needs to be assessed. Thus, this study investigated the influence of climate change and variability on aircrafts take-off and landing performances. Specifically, the study investigated; i) the influence of climate change on Take-off Distance Required (TODR) and Maximum Take-off Mass (MTOM) for different types of aircraft; ii) the influence of climate variability to the aircraft landing performance on light, medium and heavy aircraft and lastly, iii) the study investigated the seasonal and annual variability on aircraft landing performance due to climate variability. The datasets used in this study include the eight years (2014-2021), aircraft operational records (diversion and missed approach events) and Aviation Routine Weather Reports (METAR) records which were utilized as the indicators for landing performance, the long-term (1990-2020) annual maximum temperatures (Tmax) which was used to determine the TODR and MTOM. Statistical tools including mean, percentage changes, correlations, regression, and the chi-square test were used for analysis and hypotheses testing. The results revealed that light and medium aircraft categories were significantly most affected on diversion events as compared to the heavy categories; however, for the missed approach events the impact was vice versa. Moreover, the seasonal and annual variability on diversion and missed approach events were significantly different (at p ≤ 0.001). As for the take-off performance, results show that the TODR and MTOM were significantly increasing and decreasing (at p ≤ 0.001), based on increasing air temperatures. Therefore, the study concludes that the changing climate has significantly affected aircraft by increasing the TODR and decreasing the MTOM, while the climate variability has significantly affected landing performance by influencing the diversion and missed approach events. Thus, the study recommends (i) further research works including the feasibility study on runway extension for the safety of future aircraft operations at the AAKIA and (ii) proper maintenance and improvement of the Instrumental Landing Systems (ILS) as an adaptation measures to the landing aircraft during bad weather events.

Comparison of Vertical and Horizontal Reactive Strength Index Variants and Association With Change of Direction Performance.

Šarabon, N, Kozinc, Ž, and Bishop, C. A comparison of vertical and horizontal reactive strength index variants and association with change of direction performance. J Strength Cond Res 37(1): 84-90, 2023-This study sought to investigate the interrelationship between different vertical and horizontal variants of reactive strength index (RSI) and change of direction (CoD) performance. Thirty-one male volleyball players (age: 22.4 ± 3.9 years) performed bilateral drop jumps (DJs), bilateral and unilateral countermovement jumps (CMJs), and triple hops for distance. The RSI was calculated as the ratio of jump height and contact time (DJ), jump height and time to takeoff (CMJ), flight time or hop distance and contact time (triple hop), and 505 CoD test. Reactive strength index obtained from DJ and CMJ tasks exhibited excellent trial-to-trial reliability (intraclass correlation coefficient [ICC] = 0.91-0.94), whereas triple hop-based RSI had only moderate reliability (ICC = 0.67-0.74). The relationships among different RSI variants were moderate to high (i.e., DJ to CMJ: r = 0.57-0.69, p ≤ 0.004; DJ to triple hop: r = 0.54-0.66, p ≤ 0.021; and CMJ to triple hop: r = 0.42-0.63, p ≤ 0.037). For the triple hop, the associations between RSI based on hop flight time and RSI based on hop distance were high for hop 1-2 (r = 0.77-0.83; p < 0.001) and very high for hop 2-3 (r = 0.91-0.92; p < 0.001). All RSI variants were in small to moderate negative correlation with 505 test performance (r = -0.38 to -0.45; p ≤ 0.042). The agreement in interlimb asymmetry direction between RSI from unilateral CMJ and triple hop RSI variables was slight to moderate (kappa coefficient = 0.06-0.36). In conclusion, although interrelationships between RSI variants were moderate to high, the direction of interlimb asymmetry was inconsistent, highlighting the notion of movement variability in limb dominance.

Spatiotemporal factors affecting a single hurdle clearance technique: is “faster” the same as “increased technique efficiency”?

ABSTRACT This study aimed to identify the spatiotemporal characteristics in technical hurdle clearance considering differences in centre of mass (CM) height and sprint ability. Spatiotemporal variables were calculated for 13 male hurdlers by capturing hurdle clearances at the same height as their respective CM and hurdle-free sprints with a high-speed camera. Relationships between each variable and the horizontal velocity during hurdle clearance (HC-v), ratio of HC-v to sprint velocity without hurdles (HC-index), rate of deceleration on takeoff (D-takeoff), and rate of deceleration on landing (D-landing) were examined. Results showed that the support time on takeoff was not significantly correlated with the HC-index, and the correlation coefficient with the release height of CM at landing was significantly higher for the HC-index than for the HC-v. After stepwise multiple regression analysis, the following explanatory variables were selected as promising: clearance time for HC-v, long release distance on takeoff and high release height of CM at landing for HC-index, short touchdown distance on takeoff and long release distance on takeoff for D-takeoff, and takeoff–landing distance ratio for D-landing. These results suggest that the spatiotemporal variables that are important for speed, technicality, and low deceleration on takeoff versus on landing during hurdle clearance are different.

Reviewing the impacts of climate change on air transport operations

AbstractClimate change is increasing global-mean tropospheric temperatures, but the localised trends are uneven, including cooling the lower stratosphere and lifting the tropopause. The wind speeds are also being modified, both at the surface and aloft. A further effect, additional to wind and temperature alone, is of increasing fluctuations and severity of extreme weather. These are impacting air transport, and this will continue. The effects are known to include increased take-off distances where excess runway lengths exist and reduced payloads where they do not, increased en-route flight times, increased frequency and severity of encounters with clear air turbulence in some regions, changed patterns of wildlife — particularly bird — activity in some regions (potentially also for other anthropogenic reasons) are shifting locations of flight safety hazards, and increased burdens upon airport and associated infrastructure. There is increasing understanding and acknowledgment by companies and authorities of these effects and the importance of mitigating them, although this is not universal and there are as yet no universally understood best practices for air transport climate change mitigation.

Effect of hurdling step strategy on the kinematics of the hurdle clearance technique

ABSTRACT Athletes use either an eight-step or a seven-step strategy to reach the first hurdle in the 110 m hurdles event. This study investigates the effect of step strategy on the hurdle clearance technique and spatio-temporal parameters of the four steps prior to hurdle clearance. Two-dimensional video data were collected in the sagittal plane from 12 male sprinters, grouped as seven-step (n = 6) or eight-step (n = 6) strategists. The take-off distance was 0.20 m further from the hurdle and the touchdown was 0.42 m closer to the hurdle for seven-step athletes. Additionally, seven-step athletes reduced the length of the final step before hurdle take-off by 0.14 m compared with the previous step, whereas the eight-step athletes extended their final step by 0.17 m. There was negligible difference between the mean horizontal velocities of the two groups throughout the hurdle clearance (0.02 m/s) or the approach time to the first hurdle from the block clearance (0.01 s). This presents an important first insight into the effect of the step strategy on the first hurdle kinematics. Our findings identify the take-off and touchdown distance parameters of the hurdle clearance technique, and approach step characteristics for a successful seven- or eight-step approach strategy to be employed.

Flight-Test Validation of a Takeoff Performance Uncertainty Model

A Monte Carlo model designed for fixed-wing aircraft takeoff performance uncertainty quantification is benchmarked. The uses of an efficient takeoff simulator of this type range from rapid design variable and constraint sensitivity studies and large-scale conceptual level analyses to operational performance planning and real-time anomaly detection. The accuracy of the model is assessed against high-resolution flight-test data obtained through a campaign consisting of eight takeoffs flown with a specially instrumented commuter category transport aircraft: a BAe Jetstream Series 3100 twin turboprop. On all but one of the takeoffs, a close agreement is seen in terms of the takeoff distance, as predicted vs as observed, at the point of passing a 35 ft screen height; for the outlier, evidence of a sudden change in wind speed is presented as the probable cause of the discrepancy. Such studies are subject to many other sources of error and uncertainty, which are inherent in both flight-test data analysis and simulation, stemming from the highly dynamic and complex nature of this phase of the flight. The analysis presented also proposes to be a template for dealing with these issues, in a way that is applicable to other benchmarking studies.

Take off simulation and analysis of aircraft with twin floats

Amphibious aircraft is a multi-function aircraft which can be operated on land and water. This type of aircraft helps transportation sector due to its ability to reach remote areas. Indonesia as the largest archipelago in the world has problems in connecting remote areas. Land transportations and conventional aircraft have difficulties to reach remote areas due to lack of facility. Hence, small aircraft capable of operating on land or water with take off and landing distance less than 1000 m are required. This study conducted take off simulation and analysis for DHC-6 Twin Otter Series 400 equipped with twin float. It tries to propose a simpler method to initiate the analysis of take of performance for float planes with limited data constraints. Several programs were used to generate required data, such as DatCom and SolidWorks. Float plane take-off simulation used in this research utilized Gudmundsson’s method. Results showed that the method is suitable and correctly produce take off distance and time similar to those of the real aircraft. Aircraft weight and thrust affect take-off distance and required time, as well as hydrodynamic forces produced. Reduction of weight 10% reduces the distance approximately 17%, while 10% thrust reduction increases take off distance about 15%. In the future this research will be expanded to include other float shapes and sizes, as well as flying boats.

Approaching wildlife with drones: using scientific literature to identify factors to consider for minimising disturbance

ABSTRACT Drones are a modern alternative to manned aircraft for aerial surveys, however approaching wildlife with drones may still cause disturbance. Understanding the factors influencing animal responses to drone flights is fundamental for informing guidance on lowest-impact flight practices. We reviewed scientific literature on drone flights conducted to approach wildlife and collated and quantified references to factors that should be considered in the development of guidelines and policies. The most referenced controllable factors were approach distance, noise emissions and airspeed. Other frequently referenced controllable factors included drone type, take-off distance, flight pattern, pilot experience and competence, whether consecutive flights were conducted and flight duration. The most referenced environmental factors were animal taxa, biological state of animals and ambient noise, followed by whether conspecifics are present, weather variables, habitat variables, whether animals have received previous exposure to anthropogenic settings, animals’ behaviour prior to drone flights and whether predators are present. Policies and protocols that address these factors have an increased probability of minimising disturbance of drone flights. The variability in animal responses across different taxa, different ways drone flights are performed and the different circumstances they are deployed in highlights the need for taxa-specific protocols that also account for geographical and biological variations.

Optimization of the Slotted Gurney-Flap geometry applied to NACA 0012 airfoil for aerodynamic performance improvement

The salient aim of this paper is the shape optimization of an airfoil equipped with Gurney-Flap for aerodynamic performance improvement. The optimization of the slotted Gurney-Flap for improving the aerodynamic efficiency and increasing the lift force of NACA 0012 is the novelty of this research. The Genetic Algorithm, Artificial Neural Network, and Computational Fluid Dynamics are employed for shape optimization. The optimization variables include the height and thickness of the GF; also, the thickness and position of the slot. All analyses have been conducted at Re=0.45×106 and AOA=8o to simulate the take-off phase. After validating numerical results, the optimization process was conducted with two different fitness functions of lift force and aerodynamic efficiency. According to the results, the geometry representing an optimized lift coefficient compared to the geometry with optimized aerodynamic efficiency has a considerably higher height. Furthermore, the thickness of the slot in the first geometry is lower than the second geometry. The first optimized geometry leads to a 21.64 percent lift coefficient increment; there is a 293 percent increment in aerodynamic efficiency due to the second optimized geometry. As a result, it can be indicated that the help of slotted optimized Gurney-Flap can provide the required lift force for Short Take-Off Landing distance.

Acute Effects of Handheld Loading on Standing Broad Jump in Youth Athletes.

The study aimed to investigate the acute effects of handheld loading on standing broad jump (SBJ) performance and biomechanics. Fifteen youth male athletes (mean age: 14.7 ± 0.9 years; body mass: 59.3 ± 8.0 kg; height: 1.73 ± 0.07 m) volunteered to participate in the study. Participants were assigned to perform SBJ with and without 4 kg dumbbells in a random order. Kinematic and kinetic data were collected using 10 infrared high-speed motion-capture cameras at a 250 Hz sampling rate and two force platforms at a 1000 Hz sampling rate. A paired t-test was applied to all variables to determine the significance between loading and unloading SBJs. Horizontal distance (p < 0.001), take-off distance (p = 0.001), landing distance (p < 0.001), horizontal velocity of center of mass (CoM; p < 0.001), push time (p < 0.001), vertical impulse (p = 0.003), and peak horizontal and vertical ground reaction force (GRF; p < 0.001, p = 0.017) were significantly greater in loading SBJ than in unloading SBJ. The take-off vertical velocity of CoM (p = 0.001), take-off angle (p < 0.001), peak knee and hip velocity (p < 0.001, p = 0.007), peak ankle and hip moment (p = 0.006, p = 0.011), and peak hip power (p = 0.014) were significantly greater in unloading SBJ than in loading SBJ. Conclusions: Acute enhancement in SBJ performance was observed with handheld loading. The present findings contribute to the understanding of biomechanical differences in SBJ performance with handheld loading and are highly applicable to strength and conditioning training for athletes.

CIVIL FLIGHT GUIDE WHEN TAKE OFF FROM THE GADING FIELD

Until now, Gading Airfield cannot be used for commercial flights. However, in the future, along with the increasing number of commercial and training flights, Gading Airfield will continue to be developed to help smooth flights in DI Yogyakarta. Thus some flight guidelines for civil aviation must be made. Several analysis and calculation methods are carried out starting from general analysis of the airfield, counting and design of the takeoff guide patron starting from two sides of the runway, namely from RWY 10 and 28. The calculation consists of MTOW calculation which is limited by PCN, calculation of takeoff path, calculation Takeoff distance requirement, calculation of climb segment up to 1.500 feet, calculation of flight turn 1.500 feet, to design patron takeoff path guidance.

Morphing wingtip structure based on active inflatable honeycomb and shape memory polymer composite skin: A conceptual work

Morphing wingtip technology could improve the reduction of the induced drag, fuel consumption, and take-off and landing distances in fixed wing configurations. We describe in this work a morphing winglet concept based on active inflatable honeycombs and Shape Memory Polymer Composite (SMPC) skins. The combination of the two materials and structural subsystems allow the winglet deployment, with a morphing skin able to withstand the aerodynamic loading, also through the use of distributed pneumatic muscle fibers. An actuation geometric and mechanical model that represents the morphing wingtip concept is developed and analyzed. A morphing wingtip prototype is also fabricated to demonstrate the kinematics and actuation of the concept. Experiments and simulations show agreement about the output angle/input pressure relationship necessary for the wingtip deployment.