The thesis is a preliminary mission analysis and design of a small satellite swarm. The concept of the mission is to probe altitudes between 200 km and 6000 km to study the structures and dynamics of the magnetic field aligned currents. The mission lifetime is about 3 months. Aerodynamic drag at low altitudes is used for orbit and formation control. During the perigee passage, the satellite would decelerate due to drag, therefore, reducing its apogee. In addition, the attitude control of the spacecraft during the perigee passage could be used for formation control by changing its cross-sectional area. The simulations indicated that an appropriate insertion orbit should be at the perigee of 168 km and an apogee of 6000km. Moreover, from the orbital decay simulations, it was found that by maintaining a constant ram-facing area of 0.1 m2, it is possible for the satellite to decay in 90 days. The attitude simulations show that for at least one perigee passage at a perigee altitude of 168 km, the satellite is able to maintain its attitude and not tumble throughout the trajectory. In addition, investigation of the leader-follower satellite formation yielded that the relative translation of a circular orbit oscillates in all relative directions whereas in an elliptical orbit it only oscillates in the cross-track direction. Furthermore, the simulation has also shown that the relative translation of a leader-follower formation with a elliptical reference orbit, would spiral out of the radial-cross-track plane.

Equipment planned to be part of space missions is put through a substantial series of tests inorder to ensure a very high degree of reliability. This also applies to the HPGP thrusters manufactured by ECAPS AB. While conducting live fire tests the temperature is monitored using two separate systems, one pyrometer and one Infrared camera. The two systems show a difference in temperature for the same spot on the thruster. This is believed to be due to changes in the emissivity. An experimental setup is designed in order to measure the behavior of the emissivity of this material to decrease measurement errors. The emissivity of the main construction, an aerospace alloy called TZM, is proven to change as function of temperature and surface state, thus giving rise to large inaccuracies in temperature when conducting measurements using an infrared camera.The acquired emissivity data are presented together with a suggested method to implement the results back into the system.

This paper deals with the adaptation of a flight-test tool on A350 simulators in order to support a flight profile. This adaptation has been performed by doing first, an anal- ysis of the current situation of the existing tool on old programs like the A320 or the A330. Then, several modifications on the tool have been performed in order to adapt this tool on simulators. Finally, the validation of this tool has been done by performing several tests on A350 simulators. The difficulty of this adaptation was due to the appari- tion of new state-of-the-art technologies. The main improvement concerned the signals technology that appeared from the A380. Therefore, a modification on the parameters acquisition process has been done to take into account these improvements. Finally, the implementation of this mock-up on A350 simulators consists in a feasibility study that enables simulator test engineers to automate the tests performed on simulators and to do a traceability of these tests. The realisation of this mock-up is necessary because the simulator test engineers need this tool for the end of 2012 in order to develop the A350 whereas the real evolution of this tool will be done when the real aircraft A350 will be produced in 2014.

No description available.

No description available.

The aerodynamic sub-discipline of flow control has for many years been, and still is today, a very prominent subject of research. This field encompasses devices that produce a beneficial change in wall-bounded or free shear flows that may lead to, among many possibilities, reduced drag of ground vehicles and airplanes. The end result could have a substantial improved impact on fuel economy and also introduce new possible design options. Creo Dynamics AB recently started to venture into the field of active flow control with huge interest for the technology and its possible applications. One such application includes a system that reduces drag on ground vehicles via the use of active flow control. The system is composed of three components: actuators, controller and sensors. The work carried out in this thesis deals with a study into the sensory placement and control approach related to the system on a very conceptual level. According to Creo’s vision of the project the sensor shall record the pressure distribution and characteristics up-stream of the actuators. In turn the algorithm shall be capable of translating and correlating this data to the flow state downstream and in the wake. This data is then to be relayed to a control system producing the correct actuation response to achieve desired flow characteristics. For this system to work knowledge about the coupling between wake behavior and pressure distribution on surfaces upstream of the separated flow is necessary. This thesis is an initial investigation into the possible couplings that can be found. The scope also includes investigation of the coupling during cross-winds and gusts. Simulations of a simplified car geometry were carried out using the CFD package OpenFOAM and the DDES turbulence model. The initial investigation yielded promising results, showing that a link between the wake behavior and pressure distribution up-stream exists. But further work has to be carried out, as is discussed in the last chapter, before the algorithm according to Creo’s specifications can be constructed.

The interest for Flapping Wing Micro Air Vehicles (FWMAV) is growing. With this comes a need for future users to test and evaluate these vehicles with simulations. This study presents a first iteration of an implementation of a FWMAV in FLAMES Simulation Framework. An aerodynamic model based on the widely used quasi-steady blade element approach is presented and a first linearised version is implemented in FLAMES. The simulation model is capable of both manual and autonomous flight. With the first person view a pilot can investigate buildings and objects. The study gives an idea of how FLAMES can be used for this type of simulations. FLAMES provides a good environment for testing the vehicle both individually and in a context with other units.

The use of military UAV’s has become increasingly popular amongst the military powers of the world. But most of these UAV’s lack the vertical take-off and landing (VTOL) ability. This report investigates the quadrotor which is an excellent VTOL platform. The main disadvantage that the quadrotor platform possesses is that it suffers from poor performance if compared to airplanes. Quadrotors lack the endurance and the capability to carry heavy payloads. An effort is to be done to investigate the possible application area of use for the quadrotor platform from a military point of view. In order to solve these problems, two COTS (Commercial off the Shelf) quadrotors has been bought and a number of test flights have been performed with them. The results from these tests have been evaluated in MATLAB and a number of simulation models have been created in order to get a clear picture of the quadrotors potential. Rotorcraft such as the quadrotor is affected by the aerodynamic phenomena of induced power, this phenomena is important to understand when designing a control system for the quadrotor and when optimizing its endurance. A number of suggestions for how to improve the quadrotor platform have been proposed such as using ducted propellers, hybrid fuel systems, gyroscopes, and micro technology. A simulation model has been created that predicts the time that a quadrotor of a given size carrying different payloads could maintain itself in hover, this model show that battery based quadrotors are limited in how big they can be made. Much work has been dedicated to the extended sight concept where the quadrotor is intended to be powered by a cable and serve as a pair of extra eyes to an army vehicle such as a tank in an urban environment. Most of the technical difficulties for this concept has been defined and solved, these are mainly electrical difficulties and work on a demonstrator for this concept has been started. All these investigations points towards that the military would benefit from having quadrotors in their arsenal, they could be used for reconnaissance, placing out surveillance equipment and resupplying soldiers behind enemy lines.

Air intake related aerodynamic aspects of an air breathing cruise missile are analyzed. A method for thrust and drag accounting is established, and, based on that, a partial simulation model for the thrust and intake spillage drag force of the missile is developed. The model combines wind tunnel data with analytical data. The intake spillage force has two components, pre entry force and cowl force. The pre entry force can be computed relatively easily, while the cowl force depends strongly upon actual intake geometry and no general method exists. An approximate cowl force is computed based on available data. The accuracy of the cowl drag results is difficult to predict, as no complete theoretical model is available, and the partial models published cite no accuracy limits. The cowl drag results need further verification through wind tunnel tests or CFD analysis. However, spillage force results are produced that are in the magnitude of 30% of total drag, which is expected. Also, dependencies on known variables and trends are as expected. Finally, flight test profiles in order to validate the model are suggested.

The objective of this study was to evaluate the 　ying qualities of a light unmanned aerial vehicle (UAV) developed by the Thai company AVIA Satcom Co., Ltd. Based on the study changes in design was to be suggested to meet stability requirements and recommendations from European Aviation Safety was based on two dierent analyses. First, the stability characteristics in terms of stability modes were examined by creating a flight dynamics model of the studied airplane. Secondly the controllability of the vehicle was investigated by examining the control surfaces. It was found that the original design of the UAV was dynamically unstable and that the control surfaces were too large making the airplane di-cult to 　y in trim condition. By studying the stability characteristics of the simulated airplane it could be concluded that the UAV was dynamically stable for the improved design and thereby meet the requirements and recommendations.