The future of aircraft lies in highly intelligent vehicles which are able to adapt themselves to different missions and take-off and land anywhere. Tailsitters, aircraft capable of controlled transitions between horizontal flight (like a fixed-wing aircraft) and vertical flight (like a rotary-wing aircraft), are one such form of vehicle. The focus of this research stems from a collaboration between the Surrey Space Centre and QinetiQ involving a new class of VTOL tailsitter - the QinetiQ Eye-On™ UAV - which offers uniqueness from all other known tailsitters in its use of twin helicopter rotors, elevons and a rudderless flying-wing design. A core objective of this research is to develop a control and navigation architecture capa.ble of handling the transitional flight regime in tailsitters and to understand the mechanism by which a transition can be controlled. Very little past research has addressed either of these in detail, often including only cursory modelling and simulation, no regard to how transitions can be 'shaped', and with no consideration of optimisation of transitions or whether their control laws are even robust. Another shortcoming of past literature is the minimal amount of experimental work undertaken which mostly uses only generic, simple single-propeller aircraft and does not consider transitional flight. Furthermore, examination of real-world applications where a tailsitter can be used has also been barely considered in literature. The limitations are addressed in three research divisions: I, II, III. {I} Development of a novel six degree of freedom (6-DOF) non-linear model with custom-designed numerical fluid dynamics, has allowed. high-fidelity simulation of all flight regimes to be performed. The developed control and navigation architecture is the first all-encompassing control architecture for the class of twin rotor tailsitters; it uses rudimentary low-level controllers and is capable of performing three different transitions: vertical to horizontal (V to H) , H to V (altitude elevation) and H to V (altitude invariant). The last of these is a ground-breaking discovery; transitions from H to V can be performed with virtually no increase in altitude. One improvement from past literature is that transitioning is undertaken in a closed-loop manner by commanding the vehicle to follow velocity and pitch setpoints. A carefully selected set of parameters has been devised to allow transitions to be shaped by transition time period, flight speed, sample size and smoothness of the control setpoint command. For the first time optimisation is applied to obtain ideal parameters for the transitions and robustness simulations stochastically consider environmental disturbances and variation of vehicle mass. [II] A comprehensive experimental framework has been developed tha.t uses various advanced testbed configurations to validate the control architecture, requiring the fusion of both aeroplane and helicopter technologies. Initially, an indoor motion capture testbed uses a series of precursory vehicles (including both quadrotor and Chinook) to pioneer taiisitter technology. A thrust testbed was also developed to explore thrust curve relationships and obtain optimal thrust zones for differing flight regimes. The outdoor testbed required the development of a complete self-contained autopilot system, including telemetry and ground station, which was tested in a progressive fl ight campaign spanning four flight locations across the UK. The experimentation forms the first demonstration of &-DOF untethered flight for the class of twin rotor tailsitters in VTOL, manual transitional and semi-autonomous transitiona.l modes. [III] In terms of systems analysis, two distinct civil and military scenarios are evaluated: linear asset monitoring, and perch and stare (which includes an innovative miniaturisation analysis) . The first thorough and realistic consideration is also given to the use of a reusable tailsitter v.'ith a docking station for staged exploration in extra-terrestrial environments. Industrially, the research programme extensively develops the technology necessary for autonomous flight of the UAV and extends from Technology Readiness Level (TRL) 2 to 6. Academically, significant contributions have been made to the field including: tailsitter modelling, transitioning methodology, control architecture, optimisation, testbed design, flight experimentation, systems design.

The noise of a rocket engine is a complex and complicated phenomenon which has been studied for more than half a century [1]. There are many sources to this noise, but due to its great potential impact to the surrounding structures, including the vehicle itself, it is important to have a model to estimate the acoustic environment the engine produces. This estimation can be used for the design of a launch pad or a flame deflector. Such a model was developed and then tested, by measuring the noise levels with six microphones at Rocket Factory Augsburg´s Vertical Test Stand at Esrange Space Centre. Three out of six microphones yielded valuable data. A comparison between the estimated and measured noise was then conducted which showed similar trends. The peak frequency in the estimation was in the order of 1 kHz. A sensitivity study was made to investigate the difference in Sound Power Level (SPL) when the engine and test stand parameters were adjusted. The parameters with the greatest effect on the SPL are the Mach number, thrust, potential core length, and impingement distance. The difference in SPL between the estimation and measured noise is 0-20 dB with a lower difference at lower frequencies and a higher difference at higher frequencies. The difference was higher when comparing the estimation to the test with an overpowered engine, with differences of up to 20 dB higher than the estimation in the upper frequencies. Differences with nominal engine data was up to 15 dB higher than the estimation, constrained to lower frequencies. Above 30% of the peak frequency, the noise was consistently lower than the estimation. The estimation can be concluded to likely be conservative at higher frequencies, further testing or a new estimation is necessary with accurate engine data. / Ljudet från en raketmotor är ett komplext och komplicerat fenomen som har studerats i mer än ett halvt sekel [1].Det finns många källor till det ljudet, men på grund av risken att det skadar omgivande strukturer, inklusive raketen, är det viktigt att ha en modell för att estimera ljudmiljön motorn produceras. Estimeringen kan användas för att designa en uppskjutningsramp eller en flammdeflektor. En sådan modell var utvecklad och testad genom att göra ljudmätningar med sex mikrofoner på Rocket Factory Augsburg´s testanläggning på Esrange Space Centre. Tre av sex mikrofoner gav värdefull data. En jämförelse gjordes mellan det estimerade och uppmätta ljudet vilket visade liknande trender. Toppfrekvensen i estimeringen var i storleksordningen 1 kHz. En känslighetsstudie gjordes för att undersöka skillnaden i ljudnivån (SPL) när motorns och testanläggningens parametrar justerades. Parametrarna med störst påverkan på ljudnivån var Mach numret, drivkraft, längden av flamman och avståndet till deflektorn. Ljudskillnaden mellan det estimerade och uppmätta ljudet var mellan 0-20 dB med mindre skillnad på lägre frekvenser och större skillnad på högre frekvenser. Skillnaden var större vid jämförelse mellan estimering och testet med en kraftigare motor, med skillnader på upp till 20 dB över estimeringen på de högre frekvenserna. Skillnaderna för nominell motordata var upp till 15 dB högre än estimeringen, begränsat till lägre frekvenser. Över 30% av toppferkvensen var ljudet konsekvent lägre än estimeringen. Estimeringen kan sannolikt konstateras vara konservativ på högre frekvenser, ytterligare tester eller estimeringar behövs med exakt motordata.

The H.R. MacMillan Space Centre is a multi-faceted organization whose mission is to educate, inspire and evoke a sense of wonder about the universe, our planet and space exploration. As a popular, Vancouver science centre, it faces the same range of challenges and issues as other major attractions: how does the Space Centre maintain a healthy public attendance in an increasingly competitive market where visitors continue to be presented with an increasingly rich range of choices for their leisure spending and entertainment dollars?This front-end study investigated visitor attitudes, thoughts and preconceptions on the topic of space and astronomy. It also examined visitors’ motivations for coming to a space science centre. Useful insights were obtained which will be applied to improve future programme content and exhibit development.