Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 146 for “"takeoff"”.
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Comparing Time and Accuracy of Building Information Modeling to On-Screen Takeoff for a Quantity Takeoff of a Conceptual Estimate
… tedious component of an estimate is the quantity takeoff. Different tools are available to improve an estimator's productivity for a quantity takeoff. Faster quantity takeoffs enable estimator to bid more jobs. This study analyzed the time and accuracy of performing quantity takeoffs when using …
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Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft
… efficient, especially during the takeoff phase. In the past, naval architects have implemented ways to make boats, yachts, and large ships more efficient; one of them being the addition of chine strips and spray rails on the hull. This thesis study explores the possibility of …
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Hybrid Electric Distributed Propulsion for Vertical Takeoff and Landing Aircraft
… system (HEPS) design and control for vertical takeoff and landing (VTOL) aircraft applications. Specifically, this research focuses on embedded distributed electric propulsion systems, for which the aerodynamic forces and moments are inextricably linked to power input.</p> <p>This effort begins …
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Performance, Stability and Control of Electric Short Takeoff and Landing Aircraft
… of a new class of electric super-short takeoff and landing (eSTOL) aircraft, which are fixed wing aircraft designed for sufficiently short runways to make them competitive with vertical flight aircraft. The objectives of this thesis is to examine where in the design space of potential …
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Multidisciplinary optimization of aircraft design and takeoff operations for low noise
Aircraft planform design, takeoff operations, and airfoil design are examined as a complete system in order to quantify tradeoffs that can result in a quiet aircraft. An aircraft design model was developed to generate blended-wing-body-type designs using simple-physics models and empirical scaling …
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Landing Asymmetry in Back Tucked Saltos and the Effect of Takeoff Asymmetry
… injury risk factor that may have antecedents at takeoff. The goals of this study were to (1) characterize normal takeoff and landing asymmetry and (2) examine how landing asymmetry is related to takeoff asymmetry for both force and kinematic variables during a back tucked salto. Since a takeoff …
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A Simulation of the Impacts of Climate Change on Civil Aircraft Takeoff Performance
… and headwind speed are major determinants of takeoff performance, and their sensitivity to global warming carries potential operational and economic implications for the commercial air transport industry. Previous archival and prospective research observed a weakening in headwind strength and …
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3-D flow calculations of a bifurcated 2D supersonic engine inlet at takeoff
… 2D high speed civil transport engine inlet at takeoff. The objective of the study was to obtain the causes of flow distortion at the inlet fan face. The inlet was modeled with the centerbody in the fully collapsed takeoff position. A single block, 14Ox40x40 Polar grid topology of a 1/4 symmetry …
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Aircraft Greenhouse Gas Emissions during the Landing and Takeoff Cycle at Bay Area Airports
<p>The aviation industry is a growing industry and has global environmental impacts. Throughout all phases of air transit, pollutant emissions, including greenhouse gases (GHGs), are released. The goal of this study is to quantify and characterize these emissions produced from aircraft in the LTO …
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Knee Joint Forces During the Takeoff and Landing Phases of Different Types of Vertical Jumps
… and patello-femoral contact forces during the takeoff and landing phases of eight different types of vertical jumps (squat, countermovement, hop approach and drop jumps each with and without the use of arms) using musculoskeletal modeling techniques and (b) to determine whether there are …
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DESIGN OF AVIONICS AND CONTROLLERS FOR AUTONOMOUS TAKEOFF, HOVER AND LANDING OF A MINI-TANDEM HELICOPTER
… lot of research has been carried out on Vertical Takeoff and Landing (VTOL) vehicles especially single rotor small scale helicopters. This thesis focuses on a small scale twin rotor helicopter. These helicopters are more useful because of their power efficiency, scalability, long range of center …
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Comparative Evaluation of Propulsive Power Transmission Technologies for High-Speed Vertical Takeoff and Landing (HSVTOL) Cargo Aircraft
<p>Designing High-Speed Vertical Takeoff and Landing (HSVTOL) cargo aircraft capable of both low downwash velocity hovering and high subsonic speed cruising presents a significant engineering challenge. This challenge, stemming from conflicting design requirements, has been substantially influenced …
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Performance Analysis and Tank Test Validation of a Hybrid Wave-Current Energy Converter with a Single Power Takeoff
… from current and wave with one single power takeoff (PTO) is designed.The wave energy is extracted through relative heaving motion between a floating buoy and a submerged second body, while the current energy is extracted using a marine current turbine (MCT). Energy from both sources are …
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A Framework of a Power Management System for a Hybrid Electric VTOL Aircraft using Optimal Control
The operation of a hybrid fixed-wing vertical takeoff and landing unmanned aerial vehicle (VTOL UAV) is assessed using an optimal control framework for the most energy-efficient and time-efficient trajectories. The UAV is equipped with a modular hybrid propulsion system (MHPS) where the electrical …
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A comparative analysis of the Army MQ-8B Fire Scout Vertical Takeoff Unmanned Aerial Vehicle (VTUAV) AND Navy MQ-8B manpower and training requirements
The recent increased urgency to combat terrorism and asymmetric threats, combined with the environment in which field troops are forced to operate has created a unique demand for non-standard war fighting capabilities. Beginning in 2004, the U.S. Navy, in a joint effort with the U.S. Army, began …
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A tilt rotor UAV for long endurance operations in remote environments
… long endurance operation by combining autonomous takeoff and landing capabilities with a solar energy harvesting system. Mass and power models are developed for the proposed vehicle configuration to provide mission performance and sizing analysis. Results indicate that a feasible design exists …
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Evaluation of primary flight display enhancements for improving general aviation safety
… of general aviation accident causes identified takeoff and climbout, stall, and spatial disorientation as potential root causes that could be addressed with enhancements to the Primary Flight Display of an integrated general aviation cockpit. To address these accident causes, four prototype …
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Comparative System Analysis of Reusable Rocket and Air-Breathing Launch Vehicles
… inlet geometries and horizontal and vertical takeoff modes utilizing rocket or turbine engines. The baseline payload requirement was 20,000 lb to low-Earth orbit. The vehicles were evaluated utilizing several figures of merit including empty weight, wetted area, and maintenance hours. A …
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Preliminary design capability enhancement via development of rotorcraft operating economics model
… cost. The analysis shows that the maximum takeoff gross weight of the rotorcraft design is strongly correlated with direct operating costs. Specifically, a simple regression model using the square root of maximum takeoff gross weight as the only explanatory variable can be used to account …
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Performance scaling of a novel Modular Hybrid Propulsion System for aircraft flight performance flexibility and enhancement
… for the MHPS concept for a conventional takeoff and landing (CTOL) aircraft. Takeoff, climb, cruise, and payload performance metrics are formulated in terms of hybridity (proportion of electric power output and energy storage) and modularity levels (proportion of total aircraft mass that …
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