Take-off Distance Research Articles

Changes in Kinematics During Repeated Jumping

IntroductionKinematic studies allow the assessment of variations in body position during jumping. This study evaluated changes in kinematic variables in horses during a jumping test.MethodsEight horses equipped with reflective skin markers were submitted to a jumping test consisting of 70 jumps in 4 series of 10, 15, 20 and 25 times each over a 1.10 m vertical obstacle. Six jumps per series were recorded; a heart rate of ≤ 90 bpm was the criterion to begin the next series. A 25 Hz calibrated camera was placed 10 m from the fence, and 2D images were analyzed. The variables were: overtracking at jumping; take‐off and landing distances; jump length; distance between lowest point of the fore and hind limb and the fence; height of head, withers and croup in relation to the ground when passing the fence; and maximum withers height at jumping. Data were analysed with an ANOVA with a post‐hoc Tukey test (P<0.05).ResultsThere was a reduction in take‐off distance (1.65 m to 1.46 m, P = 0.03), landing distance (1.99 m to 1.71 m, P = 0.001), jump length (4.51 m to 4.11 m, P = 0.005), left forelimb distance height above the fence (9.4 cm to 5.1 cm, P = 0.03) and maximum withers height at jumping (2.0 m to 1.95 m, P = 0.001) from the first to the third series. Overtracking before jumping increased from 32 cm to 48 cm (P = 0.003) and there was a reduction of right forelimb height above the fence from 7.3 cm to 2.9 cm (P = 0.04), and of withers and croup height above the fence from 2.0 m to 1.95 m (P = 0.001) and 1.93 m to 1.86 m (P<0.0001) respectively from the first to fourth session.ConclusionsThe increase in the number of jumps resulted in a decrease of take‐off and landing distances, and in the distance between forelimb and fence and the withers and croup height, all indicating decreased jumping efficiency.Ethical Animal ResearchThe research was approved by UFRRJ Ethics Committee on Animal Research: UFRRJ/ COMEP‐UFRRJ: 263/2012. Sources of funding: CNPq, CAPES and FAPERJ. Competing interests: none.

Estimating returns to scale of Chinese airport airside activities using the CCR-0-objective RTS method

The returns to scale (RTS) nature of 41 Chinese airport airsides is investigated in this paper. We introduce take-off distance available and landing distance available into RTS estimation. To deal with the existence of multiple optimal solutions when estimating RTS using the CCR (Charnes, Cooper and Rhodes) RTS method in Data Envelopment Analysis, we introduce the CCR-0-objective RTS method. The empirical study shows that all those airsides with two runway operate under decreasing RTS. Those airsides with only one runway either show constant RTS or show increasing RTS.

Optimal aircraft take-off with thrust vectoring

AbstractThe short take-off capability is of paramount importance for a fighter airplane to enable its operation from short and damaged runways. This paper analyses the airplane take-off process from the viewpoint of reducing the ground roll/take-off distance with the use of thrust vectoring. The airplane take-off is modelled incorporating the ground reactions on the landing gear and the thrust vector forces and moments. The take-off problem is formulated as an optimal control problem with appropriate constraints. Though many researchers have applied optimal control techniques for designing airplane manoeuvres, its application to the airplane take-off problem is rarely available in the open literature. It is expedient to use such methodology to understand the use of thrust vectoring features of an aircraft to maximise the benefits in shortening the ground roll/take-off distance. An optimal control methodology has been applied in this paper with the objectives stated above to a twin-engine fighter nonlinear aircraft model popularly known as F-18/HARV. Computation of flight path and control schedules using optimal control has been carried out with and without the use of vector nozzles. A reduction of about 6% in take-off distance and about 29% in ground roll distance is obtained with the use of thrust vector for the configuration studied.

An integrated conceptual design study using span morphing technology

A comprehensive conceptual design study is performed to assess the potential benefits of span morphing technology and to determine its feasibility when incorporated on medium altitude long endurance unmanned air vehicles. A representative medium altitude long endurance unmanned air vehicle based on the BAE Systems Herti unmanned air vehicle was selected. Stability and control benefits are investigated by operating the morphing span asymmetrically to replace conventional ailerons. The Tornado vortex lattice method was incorporated for aerodynamic predictions. The sensitivity of rolling moment generated by span morphing for different flight parameters (instantaneous vehicular weight and angle of attack) is studied. The variation of roll rate (steady and transient response) with span morphing (for constant rolling moment) for different rolling strategies (extension and retraction) is investigated. It turns out that the optimum rolling strategy is to extend one side of the wing by 22% while retract the other by 22%. Operational performance benefits are investigated by operating the morphing span symmetrically to reduce drag, increase endurance and reduce take-off and landing distances. Twenty-two per cent symmetric span morphing reduces the total drag by 13%, enhances the endurance capability by 6.5% and reduces the take-off field length and landing distance by 28% and 10%, respectively.

Conceptual Design of an Aircraft with Maglev Landing System

The accelerated growth in aircraft industries desire effectual schemes, programs, innovative designs of advanced systems to accomplishing the augmenting need for home-free air transportation. In this paper, a contemporary conceptual design of an airplane has been proposed without landing gear systems in order to reducing accidents, time consumption, and to eliminating drawbacks by using superconducting levitation phenomenon. This invention of an airplane with superconductive material coating, on the solar plexus region assist to reduce weight by approximately 4% of the total takeoff weight, and cost effective. Moreover, we conjectured that superconductor landing system reduces ground friction, mission fuel, total drag, take-off and landing distance. Keywords—Aircraft landing system, Magnetic levitation, Superconductors, Take-off and landing.

Design and Computational Studies on Plain Flaps

In this paper, Computational fluid Dynamics (CFD) is used to predict accurately the incremental lift due to use of passive lift -augmentation device 'Flap'. In a 2-D wing, lift at a given angle of attack can be increased by increasing camber. In aircraft design, values of Maximum Lift Coefficient (CL max ) are used to determine the take-off and landing distances, on the assumption of usage of some type of lift- enhancing device. Passive lift enhancement device, such as a trailing edge plain flap, is relevant to most of the aircraft designs except Short Take Off and Landing (STOL) However, accurate analytical solutions to complex non linear equations of aerodynamics are a far cry and one has to depend largely on support from experimental results. It is here that CFD analysis makes the task simpler. Computational study of a typical plain flap with NACA (National Advisory Committee for Aeronautics) 0012 airfoil is taken up to predict its influence on incrementing the lift during critical phases of flight at low speed. The flow analysis is done using CFD tool FLUENT 6.3 along with GAMBIT 2.2. Effect of Plain flaps on basic aerodynamic parameters such as CP, CL , CD are studied by analyzing the flow over an airfoil with plain flap. The results obtained from the analysis are compared with analytical solutions to establish the influence and relevance of flap as an effective high lift device.

Understanding Change of Direction Performance: A Technical Analysis of a 180° Ground-Based Turn and Sprint Task

This study aimed to identify the key technical features that are consistently present in superior 180° ground-based change of direction performances (180gbCOD), but lacking in lesser skilled performances. Twenty-two national under 21 level netball players performed three trials of a 180° turn from a static start, followed by a 2.5 m straight sprint. High-speed video of the movement was recorded for each trial. A qualitative analytic approach was used to analyze the technical strategies employed by players throughout the movement task. Five key technical features were identified that were consistently observed in superior 180gbCOD performances (first foot ground contact was parallel to the new direction): 1) shallow squat combined with backward-moving centre of mass; 2) head leading the body through the turn; 3) arms and legs close to the body through the turn; 4) full extension of the takeoff leg (trail leg) at first takeoff; and, 5) large takeoff distance (distance from the foot of the trail leg to the center of mass) at first takeoff. These features provide coaches with valuable insight into the technical cues that appear to contribute to a superior 180gbCOD performance.

Take-off and landing of aicraft

In this paper, the take-off and landing segments of an airplane trajectory are studied. The equations of motion for the ground run are derived and solved for distance. Then, specific formulas are obtained for the take-off ground distance and time and the landing ground distance and time. Transitions from take-off to climb and descent to landing are investigated so that take-off distance and landing distance and time can be estimated. The run distances and the run times for take-of and landing dependent of altitude, speed wing, temperature, the coefficient of rolling friction. In conformity with mathematical model, programs of calculation were elaborated. Also interfaces of calculations were elaborated for programs of calculation. 1. NOMENCLATURE Exyz = ground axes system is fixed to the surface of the earth at mean sea level, and the ax plane is the vertical plane. It is an approximate inertial reference frame, Fig. 3.3 h h h z y Ox = local horizon axes system moves with the airplane (Os the airplane center of gravity), but its axes remain parallel to the ground axes, Fig. 3.3. w w w z y Ox = wind axes system moves with the airplane, and the axis is coincident with the velocity vector, Fig. 3.3. w x

Research on Improving Take-Off Characteristics of Fly Wing with a New Constitution

The take-off control of UAV with fly wing layout is limited by its relatively lower pitch moment. This paper gained the state parameters of a few groups of taking off model by means of numerical simulation. The influence of different models on take-off distance, take-off angle of attack (AOA), take-off safe speed and c.g. location was then analyzed. Based on the analysis, a new fly wing constitution was designed and the corresponding take-off control scheme was suggested as well. Finally, the flight test results shows that this fly wing constitution can gain better take-off control characteristics.

Evaluating the technical efficiency of Chinese airport airside activities

This paper evaluates the technical efficiency of 37 Chinese airport airsides. We introduce take-off distance available, landing distance available, and aircraft-parking position as inputs into the efficiency evaluation. This study also estimates the input excess and output shortfalls. Benchmarks are identified for those technically inefficient airsides.

Development of fighter aircraft flight procedures for reduced noise impact.

Lockheed Martin engineers have recently developed a unique process to rapidly develop realistic and community‐friendly fighter aircraft procedures for use near airports. The process integrates known aircraft performance (takeoff distance, rate of climb, etc.) with community noise estimation tools (Noisemap, INM), allowing rapid calculation of the changes in community noise impact due to proposed changes in flight procedures or the integration of new aircraft. Automated performance calculations capture the effects caused by changes in aircraft weight, external loading, and airfield density altitude. Operational pilots from the airport under study validate each proposed procedure in a realistic flight simulator (with performance matching the actual aircraft). These “flights” ensure that each proposed profile is safe, realistic, and reasonable for that base. The process has been applied to contemporary fighter (F‐16) operations, as well as those for aircraft entering service soon (F‐35). When necessary, the newly developed process can be used to create flight procedures which reduce the aircraft noise impact in nearby communities. Initial studies have demonstrated that the community area significantly impacted by noise (i.e. that within the 65 DNL contour) can be significantly reduced through judicious control of power settings, climb angles, and other flight parameters, without modification of the aircraft.

The development of probabilistic models to estimate accident risk (due to runway overrun and landing undershoot) applicable to the design and construction of runway safety areas

The risks of landing overrun (LDOR – LanDing OverRun), Take-off Overrun (TOOR – Take-Off OverRun) and landing undershoot (LDUS – LanDing UnderShoot) are dependent on multiple factors related to operating conditions. These include wind, runway surface conditions, landing or take-off distances required, the presence of obstacles, runway distance available, the existence and dimensions of runway safety areas. In this paper we propose risk models for runway overrun and landing undershoot, using a probabilistic approach. These models are supported by historical data on accidents in the area around the runway and will enable us to determine if the risk level is acceptable or whether action must be taken to mitigate such risks at a given airport. Furthermore, these models permit comparison of the results of different risk mitigation actions in terms of operational risk and safety. The principal advantage of this method is the high quality results obtained for a limited investment in terms of time, computing power and data. As such the method is extremely practical and easy to apply in aerodrome planning, development and operation.

Flight Tests, Performances, and Flight Certification of a Twin-Engine Light Aircraft

This paper deals with flight test activities performed on P2006T, a twin-engine light aircraft recently designed and produced by Tecnam. Research activities and flight tests have been conducted during the flight certification of P2006T for the normal category under CS23. All the acquired data and flight results presented have been focused on both aircraft certification and on aircraft performances, stability and flight qualities measurement. The data have been acquired through a light, accurate and reliable flight instrumentation available at DIAS (Department of Aerospace Engineering). Some flight data about aircraft leveled speed, stall speed, climb characteristics and ground performances (take-off and landing) will be presented. After preliminary flight tests, winglets have been designed and added to the final configuration in order to obtain good climb performances also in OEI (One Engine Inoperative) conditions. Accurate stall tests have been performed in all configurations and influence of both entry-rate and load factor on stall speed have been highlighted. Excellent ground performances have been measured with short take-off and landing distances compared with similar airplanes. All measured flight performances can be considered very good for this aircraft category and have been used to demonstrate aircraft safety and to obtain CS23 certification.

Jumper Kinematics on Terrain Park Jumps: Relationship between Takeoff Speed and Distance Traveled

Abstract The performance of individuals jumping tabletop features in terrain parks has not been widely studied. A field study was conducted to measure the takeoff speed and horizontal distance achieved by jumpers at two tabletop style jump features: A smaller jump at Snow Summit, CA and a larger jump at Mammoth Mountain, CA, USA. Analyses were also conducted to determine the effects of equipment type (skis versus snowboard) on jumper kinematics. Before each data collection session, the physical dimensions of the jump were measured and recorded. For consecutive jumpers, the speed parallel to the ramp was measured at the end of the takeoff by using a laser speed trap accurate to 0.11 m/s. The landing zone was marked at 3.0 m intervals with colored dye, beginning just past the flat deck portion of the jump. A high-definition video camera was used to record the landing of each jumper, and the landing point of the projected center of mass was determined by using photogrammetry, accurate to within 5 cm. The actual landing distances measured in the field were compared to predicted landing distances by using ordinary ballistic equations. A total of 280 jumps was observed on the two features: 105 on skis and 175 on snowboards. The correlation coefficients between the square of the takeoff speed and the landing distance for the smaller and larger jumps were 0.75 (R2=0.56) and 0.41 (R2=0.16), respectively. The measured landing distances differed significantly from those predicted by models using the ballistic equations of motion. The average landing distance beyond the knuckle was 2.4 m on the smaller jump and 2.1 m on the larger jump. For both features, skier and snowboarder jumpers did not differ in average landing distance.

Analysis of Hurdle Running at Various Inter-hurdle Distances in an Elementary School PE Class

The present study examined relationships between hurdle running performance of elementary school students at various inter-hurdle distances and measurement items such as body characteristics and take-off distance. Subjects were 30 6th-grade students in an elementary school physical education class. Each student freely selected one of four inter-hurdle distances (4.5, 5.0, 5.5, or 6.0 m) based on their ability to run the inter-hurdle distances in a three-step rhythm, and hurdle running record was measured. Body height in the 6.0-m inter-hurdle distance group was significantly higher than that in the other groups, and hurdle running record, sprint record, and hurdle loss time in the 6.0-m group were significantly shorter than those in the other groups. In contrast, no significant differences in body height, weight, hurdle running record, sprint record, or hurdle loss time were observed in the 4.5-, 5.0-, and 5.5-m groups. These results suggest that the 6.0-m group comprised early-maturing students. Thus, subjects were reclassified into two groups: the 6.0-m group and the 4.5-5.5-m group. In the 4.5-5.5-m group, in which there were no differences in maturity level, hurdle running record was not significantly correlated with body height or weight, suggesting that the influence of body characteristics on hurdle running in elementary school PE classes can be reduced by shortening the inter-hurdle distance. In both the 6.0- and 4.5-5.5-m groups, hurdle loss time was not affected by take-off distance and landing distance. In addition, students did not attempt to lower hurdle clearance height in order to improve hurdle loss time.

Combined Effects of Bag Holding and Obstacle Avoidance on Gait Characteristics: A Kinematic Study in Healthy Young Adults

Objective This study examined the influence of holding a bag with one hand on a walkway with an obstacle on gait characteristics. Methods Ten healthy male students walked 5 m on obstructed and unobstructed walkways while holding loads corresponding to 0%, 10% and 20% of their body weights. General gait parameters (gait velocity, step length, etc.), the toe-obstacle clearance and the minimum toe clearance, the hip, knee and ankle joint angles of both limbs, and take-off and landing distances were analysed. Results With heavier loads, the step length, velocity and landing distance decreased, and flexion angles of the knee and ankle of the support limb increased on both walkways. Clearances were maintained constantly by flexion of the ankle joint in unobstructed trials and by flexion of the hip joint in obstructed trials. Conclusion Even in healthy adults, gait properties remarkably change owing to holding loads that equal to 10–20% of body weight on obstructed and unobstructed walkways. Clearance between toe and an obstacle/floor are maintained by using different strategies.

Combined Effects of Bag Holding and Obstacle Avoidance on Gait Characteristics: A Kinematic Study in Healthy Young Adults

Objective This study examined the influence of holding a bag with one hand on a walkway with an obstacle on gait characteristics. Methods Ten healthy male students walked 5 m on obstructed and unobstructed walkways while holding loads corresponding to 0%, 10% and 20% of their body weights. General gait parameters (gait velocity, step length, etc.), the toe-obstacle clearance and the minimum toe clearance, the hip, knee and ankle joint angles of both limbs, and take-off and landing distances were analysed. Results With heavier loads, the step length, velocity and landing distance decreased, and flexion angles of the knee and ankle of the support limb increased on both walkways. Clearances were maintained constantly by flexion of the ankle joint in unobstructed trials and by flexion of the hip joint in obstructed trials. Conclusion Even in healthy adults, gait properties remarkably change owing to holding loads that equal to 10–20% of body weight on obstructed and unobstructed walkways. Clearance between toe and an obstacle/floor are maintained by using different strategies.

A timed method for the estimation of aeroplane take-off and landing distances

AbstractThis paper describes a method by which, without the use of external personnel or equipment, take-off and landing distances of an aeroplane may be estimated. An error analysis for the method, allowing determination of outcome accuracy, is also shown. The method is validated through use of flight test results from two certification programmes: one on a light aeroplane, and one on a microlight aeroplane.

국내외 우수 여자선수 100m 허들동작의 운동학적 비교 분석

The purpose of this study was to analyze kinematic techniques in the woman's 100m hurdle. In order to find the kinematic parameters, a 3-D video system for kinematic analysis-kwon3d 3.1(Kwon3D Motion Analysis Program Version 3.1)-was used. Eight JVC video cameras(GR-HD1KR) were used to film the performance of Lee Yeon-Kyoung at a frame rate of 60fields/s. The kinematic characteristics from the first hurdle to last hurdle were analyzed at the clearing hurdle spots such as distance, velocities, heights and angles. The real-life three-dimensional coordinates of 20 body landmarks during each phases were collected using a Direct Linear Transformation procedure. After analyzing the kinematic variables in the 100m hurdle run, the following conclusion were obtained; Lee Yeon-Kyoung had to maintain constant stride lengths between hurdles and increase takeoff distance before clearance and shorter landing distance after clearance. She also had to hit the correct takeoff point in front of the hurdle and extend the lead leg at the moment of landing in order to minimize the loss of velocity. She had to sprint between hurdles as fast as possible over 8m/s and run powerful first stride and shortened third stride preparing for the following hurdle clearances.

Age-related changes in avoidance strategies when negotiating single and multiple obstacles

The aim of this research was to describe age-related changes in locomotor adjustments during obstructed gait and expand and build from the current body of literature describing single obstacle avoidance strategies by including trials in which the subjects stepped over two identical obstacles placed in series. We observed young adults (YA: N = 8; aged 23.1 +/- 2.0 years) and older adults (OA: N = 8; aged 76.1 +/- 4.3 years) as they walked along a 5 m long instrumented pathway (GAITRite) and stepped over one or two obstacles that were scaled to their lower leg length. Infrared markers, tracked using the Optotrak motion analysis system (60 Hz; Northern Digital Inc, Canada), were fixed to subjects' trunk and feet, and several anatomical landmarks were digitized for each segment (e.g. toes). Data analyses included lead and trail toe clearance values, take-off and landing distance, step time, length, width and velocity, and three-dimensional trunk angles. Both age groups were able to successfully complete the obstacle avoidance task, and the presence of a second obstacle did not affect clearance strategies of either OA or YA. OA crossed the obstacles with a reduced step velocity and stepped closer to the trailing edge, although take-off distances were not different between the age groups. Additionally, OA used similar ranges of trunk motion as YA when crossing the obstacle, but did so while using smaller step lengths and step widths compared to YA, effectively, using a narrower base of support. Together, these findings suggest that older adults adopted a more cautious crossing strategy in that they reduced their crossing step velocity. However, other aspects of the avoidance strategy used by the older adults, specifically the shortened landing distances and the use of similar ranges of trunk motion within a narrowed BOS, could potentially put them at risk for tripping or imbalance when stepping over an obstacle.