Hawk Turbine AB tillverkar mindre jetmotorer som ofta används i små obemannade och radiostyrda flygplan. I flygplansmodellen Lockheed T-33 Shooting Star är motorn monterad inuti planet varför luften måste ledas ut till atmosfären. För bästa möjliga prestanda måste ejektorn och utblåsröret som leder luften dimensioneras efter motor och flyghastighet. En 3-dimensionell CAD modell av flygplanets installation skapades och därefter simulerats i en virtuell vindtunnel med hjälp av datorprogrammet SolidWorks Flow Simulation. Flera olika utblåsrör i varierande storlekar samt olika former har testats för att avgöra om ändringar kan förbättra prestandan ytterligare. Simulationsresultat visar att det går att förbättra nuvarande konfiguration med 5,99 % om diametern på utblåsröret minskas från 75 mm till 70 mm med en bibehållen form på utblåsröret. / Hawk Turbine AB is a company that manufactures small jet engines which are often used in smaller unmanned and radio-controlled aircrafts. In the Lockheed T-33 Shooting Star aircraft the engine is mounted in the center of the aircraft and therefore requires ducts to be used for directing the exhaust to the atmosphere. For optimum performance the ejector and the exhaust manifold must be designed for the engine and the flight velocity. A 3-dimentional CAD model of the aircrafts ducts was created. The model was then used in virtual wind tunnel testing using the software SolidWorks Flow Simulation. Different shapes and sizes of the manifolds were tested in the simulations to determine if modifications can further improve the performance. The simulations show that the performance of the current manifold can be improved by 5,99 % if the diameter of the manifold is reduced from 75 mm to 70 mm while keeping the shape of the manifold unaltered.

<p>The engine of JAS 39 Gripen, RM12, has recently been equipped with a new flameholder and a new engine inlet. This change has caused an increased noise level from the engine when the afterburner is in use. The noise level reaches its peak when the afterburner is partially used. The problem is thought to be unstable combustion in the regions around the flameholder. A solution to the problem has been proposed by Volvo Aero. The idea is to modify the software in the engine control unit (FADEC) that changes the airflows in the engine. This master thesis implements the proposed changes and analyzes the effects of this implementation. The analysis is done by simulations of a model of the engine that Volvo Aero has created and implemented in MatrixX/SystemBuild. Simulations showed that it is possible to achieve the desired result by the software changes. Further the simulations showed some problems with stability for the engine when controlled by the modified control unit. This was solved by implementing a filter in the FADEC software.</p>

The engine of JAS 39 Gripen, RM12, has recently been equipped with a new flameholder and a new engine inlet. This change has caused an increased noise level from the engine when the afterburner is in use. The noise level reaches its peak when the afterburner is partially used. The problem is thought to be unstable combustion in the regions around the flameholder. A solution to the problem has been proposed by Volvo Aero. The idea is to modify the software in the engine control unit (FADEC) that changes the airflows in the engine. This master thesis implements the proposed changes and analyzes the effects of this implementation. The analysis is done by simulations of a model of the engine that Volvo Aero has created and implemented in MatrixX/SystemBuild. Simulations showed that it is possible to achieve the desired result by the software changes. Further the simulations showed some problems with stability for the engine when controlled by the modified control unit. This was solved by implementing a filter in the FADEC software.

Aircraft Academy of Sweden är en flygteknisk utbildningsorganisation som utbildarflygmekaniker. Utbildningsorganisationen är certifierade enligt Easa Part-147 och utfärdar videxaminering ett Certificate of Recognition. Kravet från transportstyresen är att eleverna skautföra något som har benämningen styrd praktik under sin studietid. Styrd praktik är enpraktikform som utförs antingen internt på AAS alternativt på en externunderhållsorganisation. Målet var att kvalitetssäkra den styrda praktiken för jetmotorutbildningen genom att flyttaden till en extern underhållsorganisation. Det gjordes via aktiva fältstudier där man besökteunderhållsorganisationer som bedrev styrd praktik, dock var den styrda praktiken riktad mothelikopter utbildningen. Det gjordes för att få en högre förståelse för ämnet för att sedantillämpa det mot jetmotorutbildningen. Man läste även litterära studier gällande den styrdapraktiken samt Aircraft Academy of Swedens Maintenance Training Organization Exposition. Man såg även till att hela tiden förhålla sig till de krav som tilldelades från Transportstyrelsen.Resultatet som presenteras är att man har lyckats upprätta en extern styrd praktik motjetmotorutbildningen för utbildningen på Aircraft Academy of Sweden.

<p>The jetengines of today are growing in complexity. Reliability for aircraft engines are of extreme importance, mainly due to safety reasons but also economical ones. This master thesis deals with faultdiagnosis in the turbine section of RM12, the engine used in Saab/BAe's Gripen. Three different faults which can occur in the turbine section was studied. These faults are: clogged fuel nozzle, hole in outlet guide vane and sensor fault. An analysis of the behaviour of the engine with these faults present was made. Based on this analysis an existing simulation model of RM12 was modified, so that these faults could be simulated. For the purpose of fault diagnosis two models were developed for two different engine parameters, one linear state space model and a neural network. These two models are then used to isolate the faults. The linear state space model is used to estimate the temperature right behind the engine turbines. This is a state space model with two states. This model estimates the temperature well at higher throttle levels, but has a temperature discrepancy of almost 100 K at lower throttle levels, the temperature right behind the turbines varies between 300 and 1200 K. A neural network was estimated to detect a decrease in turbine efficiency which is a phenomena which occurs when one or several of the engine's eighteen fuel nozzles are clogged. The neural network was able to detect this fault at some points. The diagnosis algorithm developed, based on the models mentioned above, is able to detect faults at most operating points, but fails to isolate the present fault at some points.</p>

The jetengines of today are growing in complexity. Reliability for aircraft engines are of extreme importance, mainly due to safety reasons but also economical ones. This master thesis deals with faultdiagnosis in the turbine section of RM12, the engine used in Saab/BAe's Gripen. Three different faults which can occur in the turbine section was studied. These faults are: clogged fuel nozzle, hole in outlet guide vane and sensor fault. An analysis of the behaviour of the engine with these faults present was made. Based on this analysis an existing simulation model of RM12 was modified, so that these faults could be simulated. For the purpose of fault diagnosis two models were developed for two different engine parameters, one linear state space model and a neural network. These two models are then used to isolate the faults. The linear state space model is used to estimate the temperature right behind the engine turbines. This is a state space model with two states. This model estimates the temperature well at higher throttle levels, but has a temperature discrepancy of almost 100 K at lower throttle levels, the temperature right behind the turbines varies between 300 and 1200 K. A neural network was estimated to detect a decrease in turbine efficiency which is a phenomena which occurs when one or several of the engine's eighteen fuel nozzles are clogged. The neural network was able to detect this fault at some points. The diagnosis algorithm developed, based on the models mentioned above, is able to detect faults at most operating points, but fails to isolate the present fault at some points.