Technological challenges must be objectively and rigorously studied through simulation and modeling with the transition to more advanced air transportation systems. This dissertation addresses two relevant problems in air transportation: airport runway infrastructure evaluation and the prediction of worldwide demand for future supersonic aircraft. Both topics aim to improve air transportation mobility, which benefits society and contributes to economic growth. The Federal Aviation Administration (FAA) Advisory Circular (AC) 150/5325-4B contains the current method of estimating runway length requirements at small airports. With the introduction and significant growth of new-generation aircraft operations, the aircraft group approach and the oversimplification of several design variables described in the AC are problematic. This dissertation developed a series of modules to address these problems. These modules are integrated into the Small Aircraft Runway Length Analysis Tool (SARLAT), a stand-alone computer program used by airport designers. The latest version of SARLAT incorporates 67 individual aircraft performance characteristics based on a robust data processing, consolidation, and validation workflow. A conservative regression-based model has been developed to account for non-zero runway gradients and different runway surface conditions. A comparison between the FAA AC and SARLAT indicates that the current design methods are conservative for new-generation corporate jets but fall short for modern piston and turboprop aircraft. The models developed include aircraft stage length and payload-range analysis to assist airport designers and improve decision-making. The stage length analysis model uses Traffic Flow Management System (TFMS) data to estimate the cumulative distribution distances flown by individual aircraft. Using a time-step numerical simulation, the payload-range analysis developed a series of MATLAB functions to quantify the trade-offs between the aircraft's useful load and mission range. Another model developed in the dissertation and integrated into SARLAT determines the critical aircraft operating at the airport. All federally-funded projects require this process as part of the Airport Improvement Program (AIP). The models developed in the dissertation lead to more accurate and cost-effective estimates of runway length designs. The desire for supersonic transport was revived recently with advancements in aeronautical technologies and worldwide economic growth. Recent studies have developed various open-loop systems to assess worldwide demand and fleet size of future supersonic aircraft designs, assuming a fixed percentage of business passengers willing to switch to supersonic travel (i.e., switch rate). However, these studies overlooked the strong causality between supersonic transport airfare, the cost of the aircraft, and the market size for an assumed switch rate. To address this important causal gap, this dissertation develops a four-discipline coupled system, the Low Boom Systems Analysis Model Version 2 (LBSAM2). This system captures the dynamics between passenger preferences, fleet assignment, aircraft development cost, and aircraft operational economics to reach an equilibrium point. The passenger preference model quantifies the differences between supersonic and subsonic travel by introducing a "Value of Comfort" (VOC) concept to account for comfort loss due to seat pitch reductions. The fleet assignment model finds the minimum number of aircraft required to satisfy worldwide supersonic demand, which is subject to several constraints, including aircraft routes, airport curfews, aircraft utilization, and aircraft maintenance requirements. The aircraft development and life cycle cost models consider total aircraft production, technical specifications, and various operating and maintenance costs to derive a Cost per Passenger Nautical Mile (CPM) for each concept of supersonic aircraft. The integrated LBSAM2 shows that low-boom aircraft designs could attract 28% more business travelers worldwide than Mach cut-off designs (i.e., supersonic aircraft must slow down while flying overland to avoid excessive sonic booms over populated areas). Higher passenger demand for low-boom aircraft increases aircraft production leading to lower unit airframe cost, which achieves parity with the Mach cut-off design. This dissertation conducted a sensitivity analysis to investigate the effect of jet fuel prices on the market potential based on realistic and optimistic assumptions for airport emissions, noise, and landing fees. The estimated number of aircraft required and annual passengers are sensitive to fuel prices and operational factors. The potential market for a 50-passenger low-boom supersonic design ranges between 315 and 719 in 2040, depending on assumptions and jet fuel price. Based on a forecast of $5/gallon Sustainable Aviation Fuel (SAF) fuel price in 2040, LBSAM2 indicates that the low-boom design is not economically viable with only a worldwide projected demand of 1.24 million passengers. The models developed in this dissertation advance the state of knowledge in air transportation engineering. First, the dissertation develops an integrated method to predict runway length requirements at small airports. The models developed include detailed aircraft performance models for 67 individual aircraft with correction factors for runway grade and runway surfaces. Other models developed estimate aircraft payload-range diagrams, historical stage length analysis, and an automated critical aircraft determination to obtain a final recommended runway length. These functions have been integrated into the SARLAT tool - a stand-alone and user-friendly computer program. SARLAT provides information for airport designers and planners to streamline runway length design and improve the decision-making process in evaluating runway extension projects. This dissertation developed passenger preference and optimization network fleet analysis modules to predict supersonic aircraft demand. The passenger preference model quantifies time-saving benefits and comfort loss between the subsonic and supersonic flights. A fleet assignment model has been developed to minimize the number of aircraft under aircraft routes, airport curfews, maximum daily aircraft utilization, and passenger demand constraints. Considering realistic operational constraints, LABSAM2 enables a quantitative comparison for system-level trade-off studies between aircraft weight, range, and ground noise from the sonic boom. Passenger mobility is a central focus of this dissertation. Enhancing passenger mobility not only meets the needs of air travelers but also stimulates economic growth by generating additional job opportunities. The development of SARLAT offers an accurate and cost-effective solution for determining runway length requirements at small airports, thereby improving their accessibility. Enhanced airport accessibility brings socio-economic benefits to surrounding communities. In addition, the dissertation developed a set of modules to predict worldwide supersonic passenger demand. Advancing passenger mobility through supersonic designs could foster socio-economic benefits by significantly reducing intercontinental travel time and expanding business opportunities for companies worldwide. / Doctor of Philosophy / The scope of this dissertation includes airport runway infrastructure evaluation and the worldwide demand for future supersonic aircraft. Both topics aim to improve air transportation mobility, which benefits society and contributes to economic growth. The existing method of determining runway length requirements categorizes aircraft into different groups and simplifies several design variables. However, the current group design approach and simplification are problematic for new-generation aircraft. This dissertation has developed a series of models to address these problems and then integrated these models into the Small Aircraft Runway Length Analysis Tool (SARLAT), a stand-alone computer program used by airport designers. The latest version of SARLAT incorporates 67 individual aircraft takeoff and landing distances with conservative correction factors for runway grade and different runway surfaces. Other models developed include aircraft payload-range diagrams and historical distances flown to assist airport designers in the decision-making process. The models developed in the dissertation lead to more accurate and cost-effective estimates of runway length designs. Recent studies have developed various methodologies to assess worldwide demand and fleet size of future supersonic aircraft designs, assuming a fixed percentage of business passengers willing to switch to supersonic travel (i.e., switch rate). However, these studies overlooked the strong causality between supersonic transport airfare, the cost of the aircraft, and the market size for an assumed switch rate. To address this important causal gap, the Low Boom Systems Analysis Model version 2 (LBSAM2) has been developed. The passenger preference model quantifies the differences between supersonic and subsonic travel by introducing a "Value of Comfort" (VOC) concept to account for comfort loss due to seat pitch reductions. The fleet assignment model finds the minimum number of aircraft required to satisfy worldwide supersonic demand, which is subject to several constraints, including aircraft routes, airport curfews, aircraft utilization, and aircraft maintenance requirements. The estimated number of aircraft required and annual passengers are sensitive to fuel prices and operational factors. The potential market for a 50-passenger low-boom supersonic design ranges between 315 and 719 in 2040. Based on a forecast of $5/gallon Sustainable Aviation Fuel (SAF) fuel price in 2040, LBSAM2 indicates that the low-boom design is not economically viable with only a worldwide projected demand of 1.24 million passengers. Considering realistic operational constraints, LABSAM2 enables a quantitative comparison for system-level trade-off studies between aircraft weight, range, and ground noise from the sonic boom. Passenger mobility is a central focus of this dissertation. Enhancing passenger mobility not only meets the needs of air travelers but also stimulates economic growth by generating additional job opportunities. The development of SARLAT offers an accurate and cost-effective solution for determining runway length requirements at small airports, thereby improving their accessibility. Enhanced airport accessibility brings socio-economic benefits to surrounding communities. In addition, the dissertation developed a set of modules to predict worldwide supersonic passenger demand. Advancing passenger mobility through supersonic designs could foster socio-economic benefits by significantly reducing intercontinental travel time and expanding business opportunities for companies worldwide.

This dissertation investigates the advantages of using curvilinear spars and ribs, termed SpaRibs, to design supersonic aircraft wing-box in comparison to the use of classic design concepts that employ straight spars and ribs. The intent is to achieve a more efficient load-bearing mechanism and to passively control aeorelastic behavior of the structure under the flight loads. The use of SpaRibs broadens the design space and allows for the natural frequencies and natural mode shape tailoring. The SpaRibs concept is implemented in a new MATLAB-based optimization framework referred to as EBF3SSWingOpt. This framework interfaces different analysis software to perform the tasks required. VisualDOC is used as optimizer; the generation of the SpaRibs geometry and of the structure Finite Element Model (FEM) is performed by MD.PATRAN; MD.NASTRAN is utilized to compute the weight of the structure, the linear static stress analysis and the linear buckling analysis required for the calculation of the response functions. EBF3SSWingOpt optimization scheme performs both the sizing and the shaping of the internal structural elements. Two methods are compared while optimizing the wing-box; a One-Step method in which sizing and topology optimization are carried out simultaneously and a Two-Step method, in which the sizing and topology optimization are carried out separately but in an iterative way. The optimization problem statements for the One-Step and the Two-Step methodologies are presented. Three methods to define the shape of the SpaRibs parametrically are described: (1) the Bounding Box and Base Curves method defines the shape of the SpaRibs based on the shape of two curves called Base Curves which are positioned into the Bounding Box, a rectangular region defined on the plane z=0 and containing the projection of the wing plan-form onto the same plane; (2) the Linked Shape method defines the shape of a set of SpaRibs in a one by one square domain of the natural space. The set of curves is subsequently transformed in the physical space for creating the wing structure geometry layout. The shape of each curve of each set is unique however, mathematical relations link their curvature in an effort to reduce the number of design variables; and (3) the Independent Shape parameterization is similar to the Linked Shape parameterization however, the shape of each curve is unique. The framework and parameterization methods described are applied to optimize different types of wing structures. Following results are presented and discussed: (1) a rectangular wing-box subjected to a chord-wise linearly varying load, optimized using SpaRibs parameterized with Bounding-Box and Base Curves method; (2) a rectangular wing-box subjected to a chord-wise linearly varying load, optimized using SpaRibs parameterized with Linked Shape method; (3) a generic fighter wing subjected to uniform distributed pressure load, optimized using SpaRibs parameterized with Bounding-Box and Base Curves method; (4) a general business jet wing subjected to pull-up maneuver loads computed using ZESt (ZONA Technology Inc. Steady Euler equations solver), optimized using SpaRibs parameterized with Independent Shape method; (5) a preliminary application of the Linked Shape parameterization to place SpaRibs into a high speed commercial transport aircraft wing-box characterized by high geometry layout complexity; and (6) an optimization of panels subjected to axial and shear loads using curvilinear stiffeners and grids of curvilinear stiffeners. The results for the optimization of the rectangular wing-box show 36.8% weight reduction from the baseline, when the Bounding Box and Base Curves parameterization is applied and the Two-Step framework is implemented. For the same structure the weight reduction amounts to 46.7% when the Linked Shape parameterization and the Two-Step framework are used. Similar results are obtained for the generic fighter wing-box structure. In this case, the weight saving is about 20%. Bounding Box and Base Curves parameterization and Two-Step framework are used. Finally, the weight reduction for the general business jet wing-box structure amounts to 17% of the baseline weight. In this case, the computation is carried out using the Independent Shape parameterization and the Two-Step framework. In general, the Two-Step optimization framework finds better optimal structure configurations as compared to the One-Step optimization framework. However, the computational time required to find to optimum with the Two-Step optimization is larger when a small number of particles are used in the particle swarm optimization method. For larger number of particles, the computational time for the two methods is comparable. Finally for very large number of particles the Two-Step optimization requires less computational time. It is also important to notice how the Two-Step framework consistently leads to a better optimum than the One-Step framework, for the same number of particles. / Ph. D.

abstract: The objective of this study is to understand how to integrate conical spike external compression inlets with high bypass turbofan engines for application on future supersonic airliners. Many performance problems arise when inlets are matched with engines as inlets come with a plethora of limitations and losses that greatly affect an engine’s ability to operate. These limitations and losses include drag due to inlet spillage, bleed ducts, and bypass doors, as well as the maximum and minimum values of mass flow ratio at each Mach number that define when an engine can no longer function. A collection of tools was developed that allow one to calculate the raw propulsion data of an engine, match the propulsion data with an inlet, calculate the aerodynamic data of an aircraft, and combine the propulsion and aerodynamic data to calculate the installed performance of the entire propulsion system. Several trade studies were performed that tested how changing specific design parameters of the engine affected propulsion performance. These engine trade studies proved that high bypass turbofan engines could be developed with external compression inlets and retain effective supersonic performance. Several engines of efficient fuel consumption and differing bypass ratios were developed through the engine trade studies and used with the aerodynamic data of the Concorde to test the aircraft performance of a supersonic airliner using these engines. It was found that none of the engines that were tested came close to matching the supersonic performance that the Concorde could achieve with its own turbojet engines. It is possible to speculate from the results several different reasons why these turbofan engines were unable to function effectively with the Concorde. These speculations show that more tests and trade studies need to be performed in order to determine if high bypass turbofan engines can be developed for effective usage with supersonic airliners in any possible way. / Dissertation/Thesis / Run file and text files from the propulsion simulations performed in NPSS. / Input and output file used in EDET to generate aerodynamic data of Concorde. / Five column propulsion data of tested engines after inlet matching. / Masters Thesis Aerospace Engineering 2018

<p dir="ltr">Supersonic transport has been an active field of aviation research since the 1950s, and its commercialization culminated in the Anglo-French airliner, the Concorde. Due to unsustainable operation costs and the sonic booms emanating along the path, supersonic transports have retreated from the forefront of research since the Concorde’s decommission. The annoyance caused by sonic booms further prompted the FAA to prohibit all overland civil flights over Mach 1. However, recent resurgence in SST projects such as NASA’s QueSST project and its experimental aircraft X-59 is set to employ a boom-minimization configuration and to re-evaluate the prospects of overland supersonic flights. In light of this advancement, a trajectory optimization framework that minimizes perceived boom along the path, tailored to supersonic in-land flights, is developed. An optimal control problem combining a sonic boom propagation model, the population distribution of the continental U.S., and a noise measure based on Perceived Level decibels is formulated and solved numerically via GPOPS-II. Two trajectories over the continental U.S. based on this framework are illustrated and aim to provide insights into future supersonic transport design, regulations, as well as air-traffic management.</p>

Tato práce se zabývá problematikou zavedení a provozu nadzvukových business jetů. V dnešní době se v civilní letecké přepravě, po ukončení provozu Concordu, žádná nadzvuková letadla nevyskytují. V dnešní době existuje mnoho projektů a organizací, které se zabývají znovuzavedením nadzvukových letounů do civilního letectví a soustředí se převážně na business jety. Hlavní otázkou je, zda je vůbec vhodné, či rozumné se k tomu typu dopravy znovu vracet. Existuje hodně problémů, které toto komplikují. Tyto letouny způsobují příliš velký hluk, mají obrovskou spotřebu paliva a musí řešit nadměrné emise, létají ve vysokých výškách ve kterých může docházet k problémům s přetlakováním kabiny, navigací, radioaktivním zářením apod. Navíc zákaz supersonických letů nad pevninou letové cesty omezuje a prodlužuje. Současně vznikající projekty navíc nedosahují tak velkého doletu jako klasické moderní bussjety, což způsobuje, že se nadzvukové business jety se na delších tratích stávají neefektivní. I přes tyto problémy, je víceméně jisté, že k zavedení nadzvukových business jetů dojde během následujících 10 - 15 let, i kdyby to měla být jen otázka jisté prestiže velmi bohatých lidí.