Horizontal Takeoff Research Articles

A Multi-Modal Tailless Flapping-Wing Robot Capable of Flying, Crawling, Self-Righting and Horizontal Take-Off

A Multi-Modal Tailless Flapping-Wing Robot Capable of Flying, Crawling, Self-Righting and Horizontal Take-Off

The Effects of Differential Learning on the Standing Broad Jump.

In this investigation, we examined the influence of two approaches of motor skill learning (differential learning and repetition-based) for an explosive motor skill. Twenty-seven individuals completed four training sessions of a standing broad jump task, presented with either differential training or a repetition-based approach. We collected pre-and post-training assessments that included maximal jump distances used to index performance and the recording of ground reaction forces to determine potential biomechanical changes (normalized vertical ground reaction force - GRFvert, rate of force development - RFD, and horizontal take-off velocity - Vhor). Results showed that differential training exhibited greater jump distances than repetition-based training (p < .001) but no training effect was found for jump distances between pre- and post-assessments for either training approach (p = .15). However, a significant increase occurred for Vhor with greater velocities achieved following training (p = .03). Overall, differential training failed to show the expected performance enhancements for a discrete, explosive motor task; this may be related to limited exposure and task specific demands of the movement. Further research is needed to better understand the task factors influencing skill acquisition from differential training.

Optimum Design of a Reusable Spacecraft Launch System Using Electromagnetic Energy: An Artificial Intelligence GSO Algorithm

Due to its advantages of high acceleration, reusability, environmental protection, safety, energy conservation, and efficiency, electromagnetic energy has been considered as an inevitable choicefor future space launch technology. This paper proposes a novel three-level orbital launch approach based on a combination of a traditional two-level orbital launch method and an electromagnetic boost (EMB), in whichthe traditional two-level orbital launch consists of a turbine-basedcombined cycle (TBCC) and a reusable rocket (RR). Firstly, a mathematical model of a multi-stage coil electromagnetic boost system is established to develop the proposed three-level EMB-TBCC-RR orbital launch approach, achieving a horizontal take-off–horizontal landing (HTHL) reusable launch. In order to optimize the fuel quality of the energy system, an artificial intelligence algorithmparameters-sensitivity-basedadaptive quantum-inspiredglowworm swarm optimization (AQGSO)is proposed to improve the performance of the electromagnetic boosting system. Simulation results show that the proposed AQGSO improves the global optimization precision and convergence speed. By using the proposed EMB-TBCC-RR orbital launch system and the optimization approach, the required fuel weight was reduced by about 13 tons for the same launch mission, and the energy efficiency and reusability of the spacecraft was greatly improved. The spacecraft can be launched with more cargo capacity and increased payload. The proposed novel three-level orbital launch approach can help engineers to design and optimize the orbital launch system in the field of electromagnetic energy conversion and management.

Model, Control, and Realistic Visual 3D Simulation of VTOL Fixed-Wing Transition Flight Considering Ground Effect

The research topic of VTOL (vertical take-off and landing) fixed wing (VFW) is gaining significant attention, particularly in the transition phase from VTOL to fixed wing and vice versa. One of the latest and most challenging transition strategies is the bird take-off mode, where vertical and horizontal take-off is carried out simultaneously, mimicking the behavior of birds. The condition that is rarely considered when taking off is the ground effect. Under natural conditions, a ground effect is bound to occur, which can significantly impact the stability of the transition when the VFW is close to the ground. This paper addresses this issue by proposing a model and control strategy and conducting realistic visual 3D simulations of the VFW transition that incorporates ground effect using full complex aerodynamic parameters. This research represents a novel approach, using the robot operating system (ROS) and Gazebo to conduct realistic visual 3D simulations for VFW transition. The linear quadratic regulator (LQR) control method is used to manage the transitions and compensate for any disturbances. The flight tests demonstrate the effectiveness of the proposed model and controller in executing flight missions using the bird take-off mode transition. Moreover, the controller has demonstrated reliability and robustness in compensating for attitude errors induced by ground effects and external disturbances.

Hyplane: a single-stage suborbital aerospaceplane.

This paper has the aim to report the status of the HYPLANE project to date. HYPLANE is a horizontal take-off and landing Mach 4.5 bizjet-size aerospaceplane conceived by Trans-Tech and University Federico II of Naples and under study within the industrial-academic ecosystem of the Campania Aerospace District (DAC). HYPLANE has the aim to offer very fast suborbital flight for space tourism, microgravity experimentation and training, and also shortening time to connect two distant airports within a door-to-door scenario. The concept is based on the access to stratospheric altitudes (30km) for either point-to-point stratospheric or suborbital flights as safe as today's commercial air transportation, by integrating enhanced state-of-the-art aeronautical and space technologies. Essentially, HYPLANE is mostly based on already relatively high TRL technologies which guarantees a sufficiently short time to market. The low wing loading configuration and designed ability to manoeuvre along the flight trajectories at small angles of attack, allow HYPLANE to guarantee accelerations and load factors of the same order as those characterizing the present civil aviation aircraft (FAA/EASA specifications). Thanks to its technical features, it may operate from/to more than 5000 airports all over the world needing short runways to take-off and land, which for point-to-point business aviation is paramount. Furthermore, characteristics such as small dimension, configuration and high cruising altitude determine reduced noise in the airports surrounding and low sonic boom impact on ground. These conditions will further facilitate not only the development of the commercial use of such kind of transportation mean, but also its social acceptability.

Assisted site-dependent selection of the most suitable Airborne Wind Energy system via Fuzzy Analytic Network Process

Over the last decade, the Airborne Wind Energy (AWE) innovation has been evolving with the development of several prototypes by various companies/research institutions. AWE crosswind systems may differ in the electricity generation mode, the wing type, the take-off/landing approaches and the control mechanisms, to name a few. Each system has characteristics which enhance their performance regarding key factors of AWE exploration at the expense of penalizing others. Hence, deciding for the most appropriate system in a possible AWE implementation, targeting a certain location, is a difficult and uncertain scenario. This paper presents a Multi-Criteria Decision Analysis (MCDA) approach, using the Fuzzy Analytic Network Process (FANP), aiming to determine, from nine alternatives, the most suitable AWE crosswind system for two distinct exploration sites: on-shore rural and off-shore. The importance of key selection criteria for AWE is presented and discussed, alternatives in each criterion are evaluated and compared and, finally, a prioritization of both alternatives and criteria is obtained. The FANP methodology indicates rigid wing pumping-cycle systems with horizontal take-off as the most suitable solution for both investigated sites, revealing Aerodynamic Performance, Mass-to-Area Ratio and Controlability as the most relevant factors in the decision.

Design optimization and analysis of HTHL suborbital spaceplanes propelled by hybrid rocket motors

In this paper, a design optimization and parameter analysis of a horizontal takeoff horizontal landing (HTHL) suborbital spaceplane propelled by a hybrid rocket motor (HRM) is proposed. Referenced by a prototype, an integrated design model, including the mass and shape estimation, HRM design, aerodynamic calculation, and trajectory simulation, is established. A series of long burning experimental tests in the reference article is adopted to modify the influence of nozzle erosion on HRM. After modification, the results of HRM design are well fitted with the test ones, which verified the precision of the modified model and revealed the importance of erosion effect on HRM performance. Then, the integrated design process is built and optimized by the multi-island genetic algorithm. The results indicated that the designed HRM-propelled suborbital spaceplane could achieve the target flight height under all the constraints. The parameter analysis (PA) based on optimum result is adopted to analyze the influences of design variables on the performance parameters of the HTHL suborbital spaceplane, and it also gives theoretical reference to the design optimization of the similar aerospace vehicles.

A wide-speed-range aerodynamic configuration by adopting wave-riding-strake wing

The wide-speed-range characteristics of aerodynamic configuration are critical to the design of the horizontal take-off and landing aircraft. To address this problem, the work proposes a wide-speed-range aerodynamic configuration by assembling a waverider to the aircraft with arrow-shaped wing. To enhance the aerodynamic performance of this configuration, surrogate optimization method is applied to the airfoil of the arrow-shaped wing. Thus, the optimized airfoil with double “S” cambers on the lower surface, and a small leading-edge radius is obtained. The aerodynamic performance of the whole aircraft in the wide-speed range has been investigated numerically by means of the three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations coupled with the SST k-omega turbulence model. At subsonic conditions, the waverider can act as a strake-wing to induce vortex from the leading edge of the upper surface. With the large sweep arrow-wing, the subsonic aerodynamic performance is improved by utilizing the vortex lift. At supersonic conditions, wave-riding characteristics as well as the small leading-edge radius wing can effectively reduce the wave-drag. Overall, the lift-to-drag ratio of this configuration is not less than 5.4 at 4-degree angle of attack within Mach number 0.5–7, indicating that this configuration provides outstanding hypersonic aerodynamic performance as well as fairly acceptable subsonic aerodynamic characteristics.

Performance analysis and dynamic optimization of integrated cooling and power generation system based on supercritical CO2 cycle for turbine-based combined cycle engine

Turbine-based combined cycle (TBCC) engines are the most promising propulsion systems for the horizontal takeoff and landing of hypersonic vehicles. However, the high air-inlet temperature, engine-wall temperature, and electrical-energy demand hinder the application of the system. In this study, a novel integrated cooling and power generation system based on a supercritical CO2 recuperative Brayton cycle for hypersonic vehicles was proposed to meet the cooling requirements of each operating stage of a TBCC engine and to provide continuous power. Several optimization parameters able to balance the characteristics of the limited cold source, system weight, and power output of the system, such as the power-to-weight ratio and heat sink saving ratio, were proposed. With the help of optimization algorithms, the global performance curves and loads of each component were obtained during flights in the range of Mach 3.2∼6. The recuperator heat duty and compressor inlet temperature were key design parameters that affected system performance. The compressor inlet temperature is known to alter the heat sink utilization by changing the pinch point location in the gas cooler. The recuperator heat duty impacted both the system weight and power generation. The dynamic performance of the system indicated that the minimum heat sink saving ratio was approximately 10% during the entire flight, implying that the volume of fuel carried by the hypersonic vehicle could be reduced to some extent, while sufficient electricity was generated. The proposed system is a novel solution for thermal protection of TBCC engines and aircraft power generation technology under limited cold-source conditions.

Relationship Between Lateral Single Leg Jump Kinetics And Pitcher Success Determined By Earned Run Average And Strikeouts Per Inning: A Pilot Study.

INTRODUCTION: Lower body force production is a fundamental component of the pitching motion and may be an important predictor of pitching success. An exercise that mimics lower body movement during pitching is the lateral single leg jump (LSLJ). Lateral force production and horizontal takeoff velocity calculated from the LSLJ may be associated with pitching success, however, the relationship between these parameters is currently unknown. Therefore, the purpose of this pilot study was to examine the correlation between horizontal takeoff velocity calculated from force production during the LSLJ with earned run average (ERA) and strikeouts per inning (SO/I). METHODS: Eight NCAA Division I baseball pitchers (age range = 18 to 22) who had pitched more than 8 innings during the 2019 - 2021 baseball seasons volunteered to participate. Subjects performed two LSLJ trials on a force platform as part of data collection for a larger study. The force plate signal was filtered, and acceleration was calculated according to Newton’s 2nd law. Acceleration was then integrated with respect to time to calculate horizontal takeoff velocity for each LSLJ. Pearson r correlation coefficients were calculated to determine the relationship between the average horizontal takeoff velocity from the two trials with ERA and SO/I. RESULTS: There were no significant (p < 0.05) correlations between the horizontal jump velocity and ERA (r = 0.235, p = 0.65) or SO/I (r = -0.353, p = 0.49). CONCLUSION: Horizontal takeoff velocity during the LSLJ does not appear to be related to pitching performance characterized by ERA and SO/I in this small sample size. Further research using larger samples of subjects are needed to gain a better understanding of the relationship between jump kinetics and pitching success.

Horizontal take-off of an insect-like FMAV based on stroke plane modulation

PurposeVertical take-off is commonly adopted in most insect-mimicking flapping-wing micro air vehicles (FMAV) while insects also adopt horizontal take-off from the ground. The purpose of this paper is to study how insects adjust their attitude in such a short time during horizontal take-off by means of designing and testing an FMAV based on stroke plane modulation.Design/methodology/approachAn FMAV prototype based on stroke plane rotating modulation is built to test the flight performance during horizontal take-off. Dynamic gain and decoupling mixer is added to compensate for the nonlinearity during the rotation angle of the stroke plane getting too large at the beginning of take-off. Force/torque test based on a six-axis sensor validates the change of aerodynamic force and torque at different rotation angles. High-speed camera and motion capture system test the flight performance of horizontal take-off.FindingsStroke plane modulation can provide a great initial pitch toque for FMAV to realize horizontal take-off. But the large range of rotation angles causes nonlinearity and coupling of roll and yaw. A dynamic gain and a mixer are added in the controller, and the FMAV successfully achieves horizontally taking off in less than 1 s.Originality/valueThe research in this paper shows stroke plane modulation is suitable for insect’s horizontal take-off

A novel simplified precooled airbreathing engine cycle: Thermodynamic performance and control law

The precooled airbreathing engine is a promising propulsion concept for horizontal takeoff and landing hypersonic aircraft. The helium closed cycle has been introduced in the precooled airbreathing engine such as the Synergetic Air-Breathing Rocket Engine to enhance safety and thermal efficiency of the engine, whereas increasing the system complexity inevitably. To achieve a better compromise between the specific impulse and system complexity, a novel thermodynamic cycle layout was proposed in this paper. The air was moderately precooled in the precooler at high flight Mach number, and a relatively simple two branches splitting-cooling-recompression scheme was adopted in the helium closed cycle, as well as a bypass engine path with small bypass ratio was introduced to burn the excess hydrogen. Firstly, the parametric analysis of key design variables and performance optimization were carried out at the Mach 5.0 design point, and the specific impulse could reach a value of up to 3282 s. The engine was controlled by adjusting the air & fuel path and the helium closed cycle simultaneously. As for the air & fuel path, the amount of liquid hydrogen used for cooling and combustion could be equilibrium by adjusting the equivalence ratio in the bypass combustor and the area of bypass nozzle throat concurrently. In the helium closed cycle, the charge control and bypass control methods were adopted separately. The engine thrust could be effectively regulated over a wider range as well as all the main components work stably under the charge control. The results show that the bypass control is easier to implement but the regulation range of thrust is limited. The overall engine performance calculated along a typical flight trajectory shows that this simplified precooled airbreathing engine cycle has comparatively high specific impulse from take-off to Mach 5.0. As the helium closed cycle layout is relatively simple, it is maybe easier to achieve engineering realization.

Predefined-time control for a horizontal takeoff and horizontal landing reusable launch vehicle

PurposeThis paper aims to investigate the problem of attitude control for a horizontal takeoff and horizontal landing reusable launch vehicle.Design/methodology/approachIn this paper, a predefined-time attitude tracking controller is presented for a horizontal takeoff and horizontal landing reusable launch vehicle (HTHLRLV). Firstly, the attitude tracking error dynamics model of the HTHLRLV is developed. Subsequently, a novel sliding mode surface is designed with predefined-time stability. Furthermore, by using the proposed sliding mode surface, a predefined-time controller is derived. To compensate the external disturbances or model uncertainties, a fixed-time disturbance observer is developed, and its convergence time can be defined as a prior control parameter. Finally, the stability of the proposed sliding mode surface and the controller can be proved by the Lyapunov theory.FindingsIn contrast to other fixed-time methods, this controller only requires three control parameters, and the convergence time can be predefined instead of being estimated. The simulation results also demonstrate the effectiveness of the proposed controller.Originality/valueA novel predefined-time attitude tracking controller is developed based on the predefined-time sliding mode surface (SMS) and fixed-time disturbance observer (FxTDO). The convergence time of the system can be selected as a prior control parameter for SMS and FxTDO.

The Influence of Biological Maturity on Sprint Speed, Standing Long Jump, and Vaulting Performance in Young Female Gymnasts.

To quantify speed, peak momentum, standing long jump (SLJ), and the ratio of vertical to horizontal take-off velocity (Ratiovert-hori TOV) in young female gymnasts of different maturity status and their influence on vaulting vertical TOV. One hundred twenty gymnasts age 5-14years were subdivided into maturity groupings using percentage of predicted adult height. Participants performed three 20-m sprints, SLJ, and straight jump vaults that were recorded using 2-dimensional video and analyzed using digitizing software. All speed intervals, peak speed, peak momentum, SLJ distance, vault height, and vertical TOV increased between the early prepubertal and late prepubertal (P < .001; d = 0.65-1.10) and early prepubertal and pubertal (P < .001; d = 0.75-1.00) groups. No differences between these metrics were observed between the 2 most mature groups (d = 0.01-0.55). Multiple regression analyses revealed peak speed had the strongest association with vertical TOV (R2 = 59%) and also identified the Ratiovert-hori as a secondary determinant (R2 = 12%). A separate regression model indicated that maturity status (percentage of predicted adult height) moderately influences vertical TOV during vaulting (R2 = 41%). Speed and SLJ performance increase between the early prepubertal and late prepubertal years in young female gymnasts. However, given that peak speed and Ratiovert-hori combined to explain 71% of the total variance in vaulting vertical TOV, in order to increase aerial time for more advanced vaulting, practitioners should attempt to enhance peak speed alongside takeoff technique to develop gymnasts' ability to transfer linear speed to vertical TOV.

Conceptual Design Study of a Vertical Takeoff and Landing Airbreather

In this paper, the authors investigate whether airbreathing engines have useful application to vertical takeoff and vertical landing systems, which currently represent the mainstream for reusable launch vehicles. A theoretical analysis has been performed to determine the net impact of the specific impulse benefits and weight penalties of a vertical takeoff reusable launch vehicle fitted with an airbreathing propulsion system. To maximize the thrust-to-weight ratio of an airbreathing engine, the authors propose using a conventional fan driven by a separate gas generator in lieu of a conventional core airbreathing combustor, as well as combined rocket–airbreathing operation to reduce engine size. The proposed engine system and its propulsive performance are described herein. Furthermore, a new sounding rocket is described as a practical application for the proposed vertical takeoff and vertical landing airbreathing engine. Conventional horizontal takeoff and horizontal landing airbreathing engine concepts tend to focus on maximizing specific impulse and airspeed, which necessitates further development, specifically in the areas of heat-resistant materials and structural technology. By proposing a vertical takeoff and vertical landing airbreather in this study, a different approach is taken and the potential to significantly improve launch capability and reliability is demonstrated in comparison to the current technology level for reusable launch vehicles.

Accelerated Landweber iteration based control allocation for fault tolerant control of reusable launch vehicle

This paper presents a novel Fault Tolerant Control (FTC) scheme based on accelerated Landweber iteration and redistribution mechanism for a horizontal takeoff horizontal landing reusable launch vehicle (RLV). First, an adaptive law based on fixed-time non-singular fast terminal sliding mode control (NFTSMC), which focuses on the attitude tracking controller design for RLV in the presence of model couplings, parameter uncertainties and external disturbances, is proposed to produce virtual control command. On this basis, a novel Control Allocation (CA) based on accelerated Landwber iteration is presented to realize proportional allocation of virtual control command among the actuators according to the effective gain as well as the distance from the current position of actuator to corresponding saturation limit. Meanwhile a novel redistribution mechanism is introduced to redistribute oversaturated command among healthy actuators (non-faulty or redundant). The proposed method can be applied to a real-time FTC system so that the controller reconfiguring is not required in case of actuator faults. Finally, the effectiveness of the proposed method is demonstrated by numerical simulations.

Differences in the key parameters of the individual versus relay swimming starts

ABSTRACT The purpose of the present study was twofold: (i) to compare the kinematic characteristics of individual and relay swimming starts; and (ii) to relate the kinematic variables to 5 m performance for both starts. Twelve elite-level swimmers performed 2 × 25 m at maximal effort (one with an individual and one with a relay start randomly). Two-dimensional direct linear transformation algorithms were used to calculate swimmers’ centre of mass (CM) kinematics during each subphase. The results indicated moderate to much faster 5 m, 10 m 15 and 15 m times (29.4, 10.7 and 6.5%) for relay than individual starts as well as the differences at specific parameters, but no differences in take-off horizontal velocity between start techniques. Large correlations to performance times were found in block time, horizontal take-off velocity, take-off velocity and entry angle (r = 0.77 to 0.83) 20 for individual start, but in changeover time, take-off height and entry distance (r = 0.69 to 0.90) for relay start. Differences on swim start regulations between individual and relay events were in line with different key parameters related to start performances in each event. This should be considered by swimmers and coaches when addressing the starting improvement.

On-block mechanistic determinants of start performance in high performance swimmers

ABSTRACT This study aimed to 1) identify what starting block outcome kinetics have the greatest relationship to 15 m start time; 2) investigate key mechanistic determinants of the block phase and how these forces are sequenced. One hundred and fifty-two high-level competitive swimmers were included in the study. Linear mixed modelling identified four on-block outcome kinetic variables (work, average power, horizontal take-off velocity (HTOV), and average acceleration) as having a very large relationship (R2 = 0.79–0.83) to 15 m start time, with average power having the most substantial impact. On-block force sequencing started with the rear leg, followed by upper limb grab forces and the front leg. Further exploration of underlying determinants was performed for average power and HTOV of the centre of mass. Multiple linear regression identified grab resultant peak force, rear resultant average force, front horizontal peak force, and resultant peak force as significant predictors of average power (R2 = 0.88). HTOV was predicted using the same variables, apart from the inclusion of rear horizontal peak force instead of rear resultant average force (R2 = 0.73). These findings may influence how strength and conditioning and skill acquisition interventions are designed to improve swim start performance.

Spring-loaded body mass equivalent horizontal reactive countermovement jump ground contact and flight times, but not peak forces, are comparable to vertical jumping

Horizontal (cylinder-based) sledge jumping has been shown to ameliorate multi-system deconditioning induced by long-term bed-rest. However, biomechanics differ from 1 g vertical jumping, in particular prolongation of ground contact times (GCT), reduction of peak force, rate of force development (RFD) (and presumably stretch shortening cycle [SSC] efficacy) and stiffness, whilst also requiring relatively complex equipment. Thus, we sought to determine if horizontal spring-loaded countermovement jumps were more analogous to vertical jumping.9 healthy (5 female) subjects (27 ± 7yrs; 169.0 ± 5.3 cm; 63.6 ± 2.6 kg) performed 10 reactive countermovement jumps vertically, and horizontally (randomized) when lay on a spring-loaded carriage performed against loading (at lift-off) equivalent (±6%) to their body weight. Jump kinetics, kinematics and lower limb/trunk electromyographic activity were compared between conditions (paired t-tests).Mean flight and GCTs did not differ, however, peak jump height (p = 0.003; d = −0.961) was greater when jumping horizontally. In contrast, ground reaction forces (zGRF) during take-off (p < 0.001; d = 1.645) and landing (p = 0.002; d = 1.309), peak acceleration (p = 0.001; d = 1.988), leg stiffness (p = 0.001; d = 2.371) and RFD (p = 0.023; d = 1.255) were lower horizontally. Mean rectus femoris activity was lower during landing (p = 0.033; d = 0.691) when horizontal, but did not differ during either take-off or land-lift. Mean medial gastrocnemius activity was significantly (p = 0.018; d = 0.317) lower during horizontal take-off.Spring-loading (1 g at take-off) maintained short GCTs and flight times presumably maintaining muscle SSC efficacy in a manner that appears intuitive (in young active subjects), simple, robust and potentially compatible with spaceflight. Whether appropriate jump characteristics can be achieved in older subjects and in μg/hypogravity needs to be determined. However, greater jump height, lower peak zGRF, RFD and leg stiffness along with reduced lower limb and trunk muscle activity suggests that 1 g at take-off is insufficient to replicate vertical jump biomechanics. Thus, further investigation is warranted to optimize, and evaluate spring-loaded jumping as a gravity-independent multi-systems countermeasure on Earth, and in Space.

A Kinematics Comparison of Different Swimming Relay Start Techniques

ABSTRACT In swimming relay races, various start techniques are performed by swimmers, but it remains unclear which technique leads to a better start performance. Therefore, the purpose of the present study was to compare the kinematic characteristics of different relay start techniques with the new starting block Omega OSB11. Eleven international youth swimmers were filmed during 1) no step with parallel feet, 2) no step with separated feet and 3) one-step starts and their centre of mass kinematics calculated with 2D-DLT algorithms. Results indicate that differences between techniques were detected in the spatiotemporal parameters of the block and aerial start phases (e.g., initial and take-off positions, entry height, preparation and changeover times) and in selected parameters of the underwater phase (e.g., emersion time and distance, underwater time and distance). However, no statistical effects were found in 5 m, 10 m and 15 m start times, nor in horizontal take-off velocity, despite an observed trend for the one-step start to be superior to the non-step techniques. These results suggest that differences between relay techniques could rely more on the swimmer’s body posture (angular kinematics) on the block, flight and underwater phases than on the centre of mass linear kinematics.