Project Report POWERPLANT

Transcription

1 University of applied science Project Report POWERPLANT A report for a new Fokker 70 engine design Jonathan Alvarez Joost Bruin Joey de Groot Raul Heijs Mitchel van Lokven Christiaan Middelkoop Date: Amsterdam, December 2011 Aviation Studies: Project Group 2A2F

2 Table of contents Summary... 4 Introduction Fokker 70 engine: RR Tay Thermodynamics Gas Laws Brayton cycle Thrust related components Inlet Combustion chamber Subsystems Accessory Gearbox Power supply Starting and ignition Thrust reversal Fuel System Full Authority Digital Engine Control Internal Air Ice Protection Fire Protection Lubrication Requirements EASA CS Noise requirements Emission requirements Client Demands Improvement Research Fuel efficiency Old Fokker 70 engine calculations Purpose New Fokker 70 engine calculations Solution possibilities Period 6 Project group F Class 2A2F Page 2 of 46

3 2.2 Thrust improvements Old F70 engine calculations Purpose New F70 engine calculations Solution possibilities Noise efficiency Noise old engine Improvements Solution overview Conclusion Engine design Engine Design Specifications Certification Certification aspects Certification process Maintenance new engine Conclusion Bibliography Appendix list Period 6 Project group F Class 2A2F Page 3 of 46

4 Summary Hogeschool van Amsterdam Aviation Studies Project Powerplant Project power plant started with the assignment of the Amsterdam Aircraft Engines of developing a new engine. The engine must replace the Rolls Royce Tay 620 engine of the Fokker 70 aircraft. The new engine, must have a lower fuel consumption, and capable of delivering a higher amount of thrust to take off at 9000 feet altitude. Furthermore, with the new engines, the Fokker 70 needs to achieve a range of 1500 NM while cruising at flight level 350. Project group 2A2F started this project by investigating the current RR Tay 620 engine. The setup of the trust related components were researched in detail; the inlet, the fan, the compressor stages, the combustion chambers, the turbine and the exhaust of the engine. These components together create the thrust of the engine. Also the subsystems were investigated; starting & ignition, gearbox, fuel system, power supply, internal air, fire protection, FADEC, lubrication, thrust reversal and ice protection. These subsystems will cause an effective functioning of the engine. Furthermore, the certification class where the old engine was certified is investigated. There are certain parts of Certification Specifications and EASA which this engine needs to meet. The old RR Tay 620 engine is subscribed in detail and the engine was calculated. There is a clearly view of efficiency s, temperature s, thrust, and other important specifications. This overview is made in an excel sheet. With this overview, there is a clearly view of what points and systems could be improved. With making this excel sheet, there is concluded that the take-off thrust of the Tay 620 engine at 9000 feet is 36376,81 N and the cruise thrust of the old engine is 16196,66 N at flight level 300. There is another excel sheet, with the value s that were given in the assignment. In this excel sheet, some adjustments are made at the bypass ratio, fan diameter, fan efficiency, to improve the specifications of the engine and to meet with the demands of the assignment. With these adjustments, a new engine is created. There is found, that with these adjustments, the take-off thrust of the new engine at 9000 feet becomes 45230,70 N, and the cruise thrust at flight level 300 of the old engine is 16849,35 N. In the report there is described which specific adjustments there must be made on the engine, to achieve this improvements. Adding an intermediate compressor in the engine for a higher pressure ratio, replacing the combustion chambers for an annular combustion for a better fuel efficiency. Furthermore, also a noise reduction was achieved. Both for noise which reaches the ground, as well as for the noise which reach the passengers in the aircraft. This is done by an increased bypass to isolate the noise, and a chevron exhaust of the engine. At last, increasing the fan for a higher amount of thrust at the take-off, and increasing the length of the engine, due to the added compressor, the annular combustion and the chevron exhaust, where done. When all the necessary adjustments where achieved, there was written a specification chapter, with all the specifications of the new engine. The design of the engine is described. The inside, with an extra compressor; the intermediate compressor, and an annular combustion. The outside of the engine, with an increased diameter and length was subscribed and displayed. The specifications of the performance of the new engine meets the clients requirements, which is reaching a range of 1662NM (1500NM is requested) at FL350 with Mach 0,77 and taking off at airports with a field elevation of 9000ft with the outside temperature of ISA+35ᵒC (or 45ᵒC). Furthermore, the certification process of the new engine will take around 2 3 years. Together with the expected build time, the JAE WW will execute its first operation in Period 6 Project group F Class 2A2F Page 4 of 46

5 Introduction Hogeschool van Amsterdam Aviation Studies Project Powerplant The University of applied Science Amsterdam commissioned project group 2A2F to analyze the Fokker 70 engine and design a new engine that fulfills the requirements to enrich the current knowledge about aviation with a project assignment. This project assignment is meant for the second study period in the second year, and will be closed with an presentation and oral exam. The main thread in this report is summarized in one main question, and at the end of this report this question is answered; How do we acquire a new Fokker 70 engine design for Amsterdam Aircraft Engines (AAE), that satisfies the minimum airport elevation height (9000ft.) in different weather conditions (ISA+35 C or not more than 45 C), realizing a minimum range of 1500nm with 320kts speed (Mach 0.77) at FL350, reducing the fuel consumption and gaseous emissions while meeting the EASA regulations? The report will consist of three chapters, following the design process by H.H. van den Kroonenberg. The engines mounted on the Fokker 70 are mentioned for propulsion. This is generated with five main components and supported with subsystems. The client requires a new designed engine for the current Fokker 70 that is more powerful, more efficient and meets the current noise requirements (1). Designing the new engine, the old engine is screened for improvements on thrust, fuel efficiency and noise reduction, whereby from all independent improvement possibilities the best improvement combination is chosen (2). With the new engine, the design, specifications and certification procedure are investigated to conclude whether the design is feasible or not (3). In this project report the most used sources are Rolls Royce; The Jet Engine and the Fokker 70 Aircraft maintenance manual. At the end of this report the Appendix list can be found, which includes the Project assignment (Appendix I), the process report (Appendix II) and the group contact information (Appendix XIII). Period 6 Project group F Class 2A2F Page 5 of 46

6 1. Fokker 70 engine: RR Tay The first chapter is about the main functions of the F70 engine. Every engine runs on a certain Thermodynamic process. The laws by which this process is explained and the process itself are explained because this is needed to be able to understand situations spoken of later on. Thermodynamic laws include the first and second main law of the thermodynamic laws. Furthermore the process of Brayton is a process which is common in engines (1.1). This engine is mounted at the tail section of the fuselage; the dimensions are 48.6 inches by 102 inches and creates a thrust of lbs. This available thrust is created by several components which main functions are to create thrust (1.2). Subsystems on the engine are the systems which are not directly related to the created thrust (1.3). With regard to the assignment given by AAE the demands are that the new engine will be of the same certification but also will improve on certain flight conditions (1.4). 1.1 Thermodynamics The Fokker 70 engines give propulsion using combustion. How this combustion and burning arises can be proved with the physicist thermodynamic gas laws (1.1.1). Using the common thermodynamic gas laws, energy cycles are created for propulsion. The energy cycle used in the Fokker 70 is the Brayton process. The different stages in this cycle are similar to the stages in the engine (1.1.2) Gas Laws The propulsion of the engine is based on the thermodynamic gas laws. The first thermodynamic law is based on energy conservation (1.1.1a), while the second thermodynamic law is based on the natural gas flow (1.1.1b) a First thermodynamic law Based on the energy conservation, all the energy changes, counted together, equals zero. While adding energy to an object, this energy can be used to increase the internal energy, or to exercise work. This energy ratio is composed into an equation (Equation 1.1). Equation Q = U + W Variables Q = Energy [J] U = Internal Energy [J] W = Labor [J] Equation 1.1: First thermodynamic law The amount of Energy (Q) in the equation is positive, if energy is added to the object. The equation is called the First thermodynamic law b Second thermodynamic law Naturally, gas always flows from a warm area to a cold area. For instance, one side of a room is 90ᵒC and the other side is 10 C. After an amount of time, both sides of the room will reach the same temperature height. However, with the firsts thermodynamic law, the revered situation is theoretically possible, but in practice it is impossible (without adding energy). Therefore, the second thermodynamic law is introduced: Heat transport from a cold to a warm area is only possible when energy is added Brayton cycle As told before the current engine of the Fokker 70, the Rolls Royce Tay engine, is a straight jet engine. In this type of engine the process that takes place is at first a compression of the air, then the combustion and after that the expansion. It is an open cycle process, which means that the air from Period 6 Project group F Class 2A2F Page 6 of 46

7 the intake of the gas turbine is not used again after at the end of the cycle and replaced for new air. For each process of the cycle there is a separate part in the engine fulfilling each function. The name of this whole process is the Joule or Brayton process and schematically the it can be given with the following graphs (Figure 1.1). The Brayton process is a circular process. The first stage, the compression, takes place adiabatically because of the high gas flows (1-2). This means that there is no heat exchange with the environment. Then, because the compression and combustion chambers are openly connected, the combustion of the air mixed with kerosene takes place isobaric (2-3) and after this the mixture is expanded adiabatically again to the initial volume (3-4). The last step is the outlet of the obtained heat. This is again an isobaric process (4-1). The first graph is a pressure-volume diagram (p-v) and by determining the surface of this graph the produced amount of work (W= p dv) can be found. In the second graph the temperature is plotted against the entropy (T-S) and here the surface gives the amount of heat, produced during the Brayton Process (Q= T ds). Entropy is the quantitative measure of disorder in a system, which in this system is the transfer of heat energy. Figure 1.1: Theoretical Brayton Process The process as told before would apply if the Brayton process would have been an ideal process, but unfortunately in reality it is not this ideal because several losses are provoked during the process. The diagrams of figure 1.1 will after all these losses look like figure 1.2, where blue represents the real process and the normal lines the ideal Brayton process. The losses can be explained by the pressure decrease during the combustion (2-3 ), which is necessary for the flow further on. Losses during the combustion result in a higher usage of the fuel mixture, kerosene and air. There are also small vortices and friction factors that create losses. These losses are made in the compressor (1,2 ) and the same effects also count for the expansion of the gas (3-4 ). During the expansion the vortices and friction cause an increase of the gas temperature, which results in a higher temperature after the turbine (3-4 ) than in the ideal cycle. After this the temperature decreases isentropic, which means that the entropy stays equal (4-1). Figure 1.2: Real Brayton process Period 6 Project group F Class 2A2F Page 7 of 46

8 1.2 Thrust related components Thrust related components only involve those components responsible for creating thrust. Thrust is created by the engines, but engines not only supply power in form of forward thrust also other power forms like electric power and hydraulic power. But in this chapter only the main functions of each component regarding the thrust are explained. The engine of a F70 aircraft is a general engine composed of five main components for thrust. The first step in creating compression and suction, is a fan duct composed out of an inlet (1.2.1) and the main fan (1.2.2), which are shown in figure 1.3. After the fan, the airflow is divided in two parts. The airflow goes through the bypass (1.2.3) and around the core engine. For the combustion, speed and pressure needs to be increased. This is done through a compressor (2) (1.2.4). When pressure is created the mixture of air and fuel will be ignited in the combustion part of the engine (1.2.5) shown in the middle of the engine with number 3. The turbine is a part which will create power by using other components needed for thrust (1.2.6). This component is partly situated at the end of the engine and partly connected with the forward part, shown in the figure with 4. Nozzle situated at the end of the engine, shown with number 5, has an increasing function for the airflow available through the engine (1.2.7) Legend: 1) Inlet & Fan 2) Compressor 3) Combustion 4) Turbine 5) Exhaust Figure 1.3: General Thrust related components overview Inlet The purpose of the inlet is to provide an airflow for the compressor with as little vortices as possible to perceive the adequate airflow speed for the compression. The operation of the engine will continue under all conditions available like starting, taxiing, take off, normal flight with cruising speed or during crosswinds. The size of the inlet will be determinate by the general conditions where the F70 operates in. Analysing the side view of the inlet, there is in all cases a diverging passage. If the aircraft flies in the air, the speed of the air that flows in the inlet is equal to the airspeed of the aircraft. That speed is higher than the desired axial airflow speed. The purpose of the diverging passage is to reduce the airflow speed. While the flow speed is being reduced, the static pressure and the temperature increase. This conversion is called: RAM-effect. The decrease in airflow speed can be proved by the continuity formula (figure 1.4). Legend: 1) ρ1/v1 2) A1 3) A2 4) ρ2/v2 ρ = Air density V = Velocity A = Surface Period 6 Project group F Class 2A2F Page 8 of 46 Figure 1.4: Continuation law

9 1.2.2 Fan After the inlet (figure 1.5), there is a rotating propeller, which is called the fan. The fan is driven by the low pressure turbine. The purpose of the fan is to suck the air into the engine and accelerate the airflow. After the fan, the airflow is divided into two separate airflows. The first airflow, called the cold stream, is the airflow that flows through the by-pass. The second airflow, called the hot stream, is the airflow that flows through the core engine. The ratio between the cold and hot airflow is called the By-pass ratio [BPR]. The other purpose of the fan is to increase the air pressure that comes from the inlet. The air pressure increase takes mostly place during cruise. The fan blades are the first stage in compressing the air. Legend: 1) Inlet 2) Fan Figure 1.5: Clean air propulsion section Bypass The second part of the engine is the bypass. The air that flows in the bypass part does not experience the stages like in the core engine. The air that flows through the by-pass is accelerated by the converging passage. The acceleration of the air in the bypass has as result a strong thrust for the aircraft. At the end of the bypass, the airflow which goes through the bypass will be mixed with the air of the core engine coming out from the exhaust Compression After the air leaves the inlet and the fan, it must be compressed before it reaches the combustion chamber (figure 1.6). In aviation, the centrifugal and the axial compressors are used. Because Fokker 70 uses the axial compressor, only the axial compressor will be analysed. The airflow on the axial compressor is parallel on the axes of the whole core engine. Each stage of the axial compressor consists out of two parts: 1. Rotor 2. Stator Ad 1. Rotor During the engine operation, the rotor turns at a high speed thanks to the turbine. The high speed rotation has as result that the air is constantly in gurgitation in the compressor. Which will be accelerated by the rotating rotors and then the rotors sent the airflow backwards to the stator. The airflow speed results in kinetic energy. This kinetic energy is converted in pressure by the stators by reducing the airflow speed thanks to the divergent passage of the stator. Ad 2. Stator The stator has also the purpose to give the airflow the angle that is adequate for a good combustion. The last row of stator vanes of the compressor, acts as airflow straighteners that has the purpose to Period 6 Project group F Class 2A2F Page 9 of 46

10 prevent swirl prior for the airflow enters the combustion chamber. A row of rotor vanes followed by a row of stator vanes is called a stage. The compressor is divided into two parts, known as the Low pressure compressor and the high pressure compressor. The Fokker 70 has a total of 3 low pressure compressors and 12 high pressure compressors. The low pressure compressor together with the fan is driven via an axle (N1) by three low pressure turbine while the high pressure compressor is driven via another axle (N2) with 2 high pressure turbines. But there are some things that must be correct for a good compression. One of the demands for a good compression is the adequate angle of the airflow compared to the compressor blades. The result speed of the airflow is given by a velocity triangle (Appendix III). If the result airflow speed is to low, the airflow releases from the blades and as a result turbulence is created, which causes the blades to stall. If the axial compression is too much, the angle of the airflow compared to the blades is to small and can be negative. As result, the airflow is pushed from the blades. This phenomenon is called choked which also can cause the effect of surging. Surging means a complete breakdown in compression, resulting in a reversal flow and a violent expulsion of previously compressed air out of the engines intake. Legend: 1) Rotor 2) Stator 3) Turning cylinder of the stator 4) Outside cylinder for the stator Period 6 Project group F Class 2A2F Page 10 of 46 Figure 1.6: axial compressor Combustion chamber After the airflow has been compressed, it will enter the combustion stage (figure 1.7). On the combustion stage, the fuel is converted in kinetic energy. The gas that comes out of the combustion chamber is a homogenous gas, with the adequate temperature. Because of the high temperature, the gas expands and the air pressure increases as well. Due to the expansion, the airflow speed increases drastically, and is used to supply the turbines of power. The combustion chamber consist out of two concentric hollow cylinders. The inner cylinder is called the flame tube and the outer cylinder the air casting. Only 20% of the total air (primary air), that comes from the compressor, flows via the snout or entrance and the swirl vanes into the combustion chamber. The purpose of placing the swirl vanes is to prevent turbulent airflow and decrease the axial airflow speed, that comes from the compressor, for a stable combustion. This is done by the diverging passage of the vanes. For the combustion, jet fuel is injected to the gas mixture with high pressure by the fuel spray nozzle. The rest of the air (80% of the total air), also called the secondary air, flows in the outer cylinder and is added via dilution

11 holes to the primary air. Adding this secondary air, causes a temperature decrease, which is necessary for the turbines. There are many sorts of combustion chambers. These are the Multiple chambers, the tube-annular chambers and the annular chamber. The RR Tay , that is used on the Fokker 70 has a multiple combustion chamber, consisting out of ten combustion chambers. Al these chambers are placed around the core engine. The delivered air from the compressor is directly injected into the individual chambers by ducts, to pass via the snout. All these individual chambers are interconnected which allows each individual chamber to operate at the same pressure. Also does the combustion allow the air to propagate around the flame tube during the engine start-up, with the help of a spark plug that produces sparks. Legend: 1) Snout 2) Swirl vanes 3) Fuel spray nozzle 4) Flame tube 5) Air casting 6) Dilution air holes 7) Interconnector Turbine Figure 1.7: Combustion chamber The turbine is very important for the engine operation, because the turbine will create the power needed for the general operation and enables the engines start-up. Furthermore, the turbine serves for creating the rotation of the fan blades and compressor. The kind of turbine is a turbo fan engine (figure 1.8) installed on the F70 (1.2.6a). The current operation is not deflecting from the general operation of a turbofan engine (1.2.6b). The propulsion of the engine will be magnified by the exhaust (1.2.6c) a differences in turbines The turbine type of the Fokker 70 is a twin shaft, axial flow, medium by-pass ratio turbo fan. This name includes the several main components of the engine. The most important part is the fact that it is made clear that this is a turbo fan engine. Other kinds are piston engine, turbo prop, jet engine and a ram jet. These will not be explained as thorough as the turbo fan because these are not used on the F70. Piston engine uses one or more pistons to drive the engine. Turbo prop works with a turbine but is designed for propulsion via the fan blades only and not via pressure build up in the turbine. Visa versa is this done with the jet engine where via pressure build-up in the turbine the main propulsion is created. A ram jet works with thermodynamic laws which enables the engine to not be engaged with the turbine during flight. This is done via slowing the airflow speed and raising the pressure. Although these engines are all used in the aviation the general working of these engines and their differences are now clear. Period 6 Project group F Class 2A2F Page 11 of 46

12 1.2.6b Operations of RR-Tay For operation of the engine airflow and pressure are essential. Right before the turbine, the pressure will be at its maximum and have the highest Revolutions Per Minute (RPM). High RPM is demanded because this is directly equal to the RPM of the fan blades. High RPM will also create the most power, not only in thrust but also in forms of hydraulic power. When in start-up, an alternate and temporary power source 1 will create air pressure. This will then be injected in the front part of the turbine, which will cause the turbine to spin due to the air pressure. This can also be done electrically by the gearbox. Because the turbine is separated in a high-, and low-pressure turbine these both separate components will spin both with separate other components (figure 1.8). The high-pressure turbine (1), with 2 stages, is directly attached with the high-pressure compressor (2), with 12 stages. The lowpressure turbine (3), with 3 stages, is connected with the low-pressure compressor which includes both the fan blades (4) and the low-pressure compressor (5) itself which consist out of 3 stages. The pressure ratio created by the compressor is approximately 16:1. The combustion in the combustion chamber (6) will cause the turbine to keep spinning. The blades of the turbines are attached to the disc using the fir tree arrangement this includes an attachment with lock plates and rings. For the possible modification this arrangement could be changed. Due to pressure from ignition the turbine will start to rotate. This is done evenly around the axel because the combustion chambers exist out of 10 chambers placed curricular around the axel so an even pressure is applied to the turbine. This will result in the rotation of the fan and so the compressor as well Legend: 1) High pressure turbine 2) High pressure compressor 3) Low pressure turbine 4) Fan blades 5) Low pressure compressor 6) Combustion chamber Figure 1.8: Turbine components 1.2.6c propulsion The turbine is driven by the pressure from the compressor as well as the pressure created by the combustion this will create the RPM for the fan blades as well as the compressor. The fan will create propulsion by airflow through the bypass. The compressor will create more pressure for the rotation of the fan and for the forward propulsion due to pressure rise by the nozzle Exhaust The exhaust is placed at the end of the engine (figure 1.9). The exhaust exists out of two parts; the mixer (1) and the nozzle (2). The exhaust exists out of two (imaginary) converging cylinders, which are placed over each other. The outer cylinder is in contact with the by-pass airflow but where the inner is contact with the compressed airflow. To flow of the by-pass airflow will mix with the air from the turbine and by doing so aerodynamic performance can be effected by the mixer due to; cylinder diameter, converging ratio of the cylinder, structural from and the mixing tube differences. The function of the nozzle is creating extra thrust by accelerating all the possible air available from out the compressor as much as much as preferable. Preferable is to get the airflow speed as close as 1 Alternate power source during start-up can be an Ground Power Unit (GPU) or an Aircraft Power Unit (APU) Period 6 Project group F Class 2A2F Page 12 of 46

13 possible to the local speed of sound. This is because in this stage the engine will produce the most forward propulsion in this stage. The engine has a converging nozzle this will cause the air to increase in pressure and speed. This is done until the value of a chocked nozzle is achieved (local speed of sound). The chocked effect is wanted cause is creates the most thrust because of the most volume is accelerated. An engine itself will make a lot of noise without proper protection. 1 2 Legend: 1) Mixer 2) Nozzle Figure 1.9: Mixer, a part of the Exhaust 1.3 Subsystems Subsystems of a gas turbine are important for the functionality of the engine. A gearbox is needed to convert different rotations (1.3.1), which is connected to the power supply (1.3.2) that delivers electrical power to the cabin. A start and ignition system is needed to start up the engine (1.3.3) and trust reversal is needed to slow an aircraft down (1.3.4). A fuel system is created to manage the fuel flows (1.3.5) and the Full Authority Digital Engine Control system is a system which manages all the engine information (1.3.6). In the engine there is an internal air system which disposes the air at some point for use at other places in the engine (1.3.7). An ice protection system is developed to prevent ice-forming on the engine, which can cause damage (1.3.8). Also to prevent damage due to a fire, a fire protection system is installed (1.3.9). At last, for a good functioning of the engine and to dispose heat, a lubrication system is installed (1.3.10) Accessory Gearbox Most components in an aircraft obtain energy from the engine. Electrical systems are provided by a generator that converts motion into electrical energy. Each engine had a generator that is driven by the core engine. Because the RPM of the core engine is variable and the generator works on one RPM a system that converts the motion into the right amount of RPM is needed. This system contain multiple accessory gearboxes to transfer the motion from the core engine to the generator located outside the engine (Figure. 1.10) Legend: 1) Internal gearbox 2) Radial driveshaft 3) External gearbox 4) Intermediate gearbox 3. Figure 1.10: Accessory Gearboxes Period 6 Project group F Class 2A2F Page 13 of 46

14 The internal gearbox (1) is placed in the core engine and extracts the movement from the shaft of the engine. This movement is transmitted through a radial driveshaft(2) to the external gearbox (3). This radial driveshaft contains an intermediate gearbox (4) that changes the direction so it is possible to connect to the external gearbox. The external gearbox contains many accessory drives for various systems, an aircraft electrical generator and the function to manually rotate the engine (Appendix IV). The external gearbox is elongated and curved along with the bottom of the engine. The motion enters the external gearbox by a radial driveshaft. Here the starter/driven gearshaft is attached and this allows to form two groups of accessory drives. One for high and one for low power accessories. All accessories are connected through a shear-neck shaft. This ensures that the shaft breaks when an accessory gear fails so it has no consequences for the other gears Power supply Because an aircraft needs to be supplied with electricity during the flight there is a power supply system in the engines of the aircraft. In the RR Tay 620 engines, there is a generator attached to the axle of the turbine at the backside of the engine. This turbine is rotating with a very high velocity because of the gas flow which flows through it. With this high RPM, the generator can generate a large amount of electricity which can be used in the cabin of the aircraft. When the engines are not running and the aircraft is standing on the ground, the Auxiliary power unit [APU] can be used to deliver the electricity needed in the cabin Starting and ignition To let an engine run, it needs to be started with another system, cause it cannot be done with the engines itself. Therefore there is a starter engine to let the engine start spinning (1.3.3a). Besides that there is an ignition system to start the combustion in the engine (1.3.3b) a Starter engine Because the RR Tay 620 engine is not capable of starting itself, it is equipped with an engine starter (figure 1.11). This engine starter is a small air powered engine which is placed on the downside of the aircraft engine. The air power which drives the starter engine is supplied from the pneumatic system of the aircraft. The air in this system is supplied from the aircraft engine itself. This starter engine converts the air under high pressure into a high force momentum. How this starter engine works in detail, is shown in appendix V. This starter engine is on the other side connected to the gearbox, which is told in paragraph Between the starter engine and the gearbox, there is a free running clutch. Which is shown in figure 1.8. The axle in the middle (1) is connected to the starter engine Legend: 1) Starter engine axle 2) Gearbox axle 3) Spring-loaded pawls in attached position 4) Spring-loaded pawls in outside forced position Figure 1.11: Free running Clutch Period 6 Project group F Class 2A2F Page 14 of 46

15 The axle on the outside (2) is connected to the gear box. This gearbox is attached to the fan of the aircraft engine, and will let the fan start rotating if the starter engine is running. On the outside axle are spring-loaded pawls attached, which connects the outside axle with the inside axle(3). However, when the aircraft engine is starting to run, and the ignition has lighten up, the aircraft engine will rotate with a much higher RPM as the starter engine will do. When the outside axle which is connected to the aircraft engine, would stay connected to the start-up engine, the start-up engine would be damaged. Because of the centrifugal force which is created by running the aircraft engine on a high RPM, the spring-loaded pawls are forced to the outside (4) so the outside axle is no longer attached to the inside axle. The aircraft engine itself will take over the start-up process until idle RPM is reached b Ignition system The gearbox which is attached to the starter engine, is also attached to the fuel pumps. So when the gearbox starts running, the fuel pumps are beginning to pump the fuel under pressure. When a limit pressure is reached, the nozzle will start to spray in the combustion chamber. At the same moment, the ignition system starts to run. On the outside of the engine (Figure 1.12), two exciter boxes are attached (1). 1 Legend: 1) Exciter boxes Figure 1.12: Exciter boxes These exciter boxes are devices which are capable of delivering a very high Amperage, under a very high Voltage. these exciter boxes are connected with very strong and isolated electricity cables with the two igniters. These igniters are placed in the combustion chamber. These igniters create a massive sparkle to ignite the fuel nozzle which is sprayed in the combustion chamber. As shown in figure 1.13, the igniters are placed at the special kind of way (1), that they aren t constantly exposed to the combusting nozzle (2). When the ignition has started, the cabin crew will receive the signal: light up, and at that moment the start engine and the ignition system can be shut off. The engine will continue on its own power till it reached the idle RPM. 1 2 Legend: 1) Igniter 2) Fuel nozzle Figure 1.13: Combustion chamber Period 6 Project group F Class 2A2F Page 15 of 46

16 1.3.4 Thrust reversal Both engines are equipped with thrust reversers (Figure 1.14). Thrust reversers are placed at the end of the nozzle and are able to change the thrust direction from aft to forward. This is used when the aircraft lands and allows less braking distance. The Thrust reverser consists of an upper (1) and lower door (2) that can rotate in front of the airflow produced by the engine. This causes the airflow to bend in the forward direction of the aircraft and so produces deceleration. 1. Legenda: 1) Upper door 2) Lower door 2. Figure 1.14: Thrust Reversal The thrust reversers are linked to the air/ground sensor so they can only be used after touchdown. Another requirement to use the thrust reversal is an idle setting of the thrust lever. This is because there can occur unintentional airflows and forces when there is a thrust when moving the doors in front of the nozzle. This may provoke damage to the doors and engine. After the doors are in placement, the engine can produce thrust so the thrust reversal takes into effect. Thrust reversal can also be used to move the aircraft backwards. This is uncommon but can be used when leaving a gate backwards. This is called a powerback. Period 6 Project group F Class 2A2F Page 16 of 46

17 Legend: 1) Full down 2) Reverse idle 3) Normal maximum 4) Emergency maximum Figure 1.15: Reverse thrust lever The Thrust reversers are set by the reverse thrust levers (Figure 1.15). One for each engine. When the thrust reversers are not used and stowed the lever is set on full down (1). When setting the lever in reverse idle position (2) the doors are placed in extended position but they do not produce reverse thrust. For producing reverse thrust the lever must be set in normal maximum (3) for normal reverse thrust and in emergency maximum (4) for maximum reverse thrust only in emergency Fuel System The fuel system of the RR Tay 620 consist out a lot of different components which have all their own function. It starts with the aircraft fuel storage and system which is connected to the engine fuel pump. The engine fuel pump is actually a name for a small system. (Figure 1.16) first, the fuel will flow through a impeller pump (1) which pumps the fuel under a pressure of pounds per square inch(psi). After the simple impeller pump, the fuel goes through a small filter (2), to filter irregularities out of the fuel, because it can damage the next pump. The next pump is a gear pump(3). A simple pump which works with two gears which pumps the fuel up to a pressure of psi. After the fuel pump, the fuel goes through a heat exchanger (4). This is a device where the very cold fuel and the very hot oil of the engine flow very close the each other. At this way, the oil cools down, and the fuel heats up, so there is no possibility of ice pieces in the fuel, which could occur problems for the next device, the fuel filter(5). The fuel filter makes sure that nothing but only clean fuel goes to the engine. This filter has a very high density, which makes it very hard for dirt to come through. Parallel to the fuel filter, there is a bypass (6). In the case the fuel filter is blocked, the fuel can still flow through the bypass, so the engines can still run. When the fuel has been through the fuel filter or bypass, it needs to pass the fuel shutter valve. This valve can be opened and closed from the cockpit and controls the fuel flow. When the fuel has passed this valve, it flows through pipelines to the fuel nozzles in the combustion chambers. Period 6 Project group F Class 2A2F Page 17 of 46

18 Legend: 1) Impeller pump 2) Small filter 3) Gear pump 4) Fuel/oil heat exchanger 5) Fuel Filter 6) Fuel bypass Period 6 Project group F Class 2A2F Page 18 of 46 Figure 1.16: Fuel pump system Full Authority Digital Engine Control The Full Authority Digital Engine Control [FADEC] System monitors and regulates the engines. This is done by an Electric Control Unit [ECU] that provides data of the engine. The ECU is connected to sensors that measure temperatures and pressures on different stages of the engine. The FADEC system also receives inputs of the outside air pressure and temperature, the throttle positions and the input of the pilots on the Flight Management System. The FADEC system regulates the engine by comparing all these data. This ensures a maximum efficiency that creates a longer durability and less fuel consumption. Because of the FADEC system, the pilots do not need any equipment for measuring this engine data and controlling these settings. But when the FADEC system fails the whole engine will not work properly. Therefore the system needs a redundancy. All sensors are double placed and an extra ECU works as back-up. The Hydro Mechanical Unit [HMU] will provide the right amount of fuel in case of a FADEC failure Internal Air In an aircraft engine, there are a lot of different airflows, most of them are used for the propulsion of the engine, but some are for other purposes. At some places in the engine, airflow is drained at different places under different circumstances, to use for other functions. At the fifth and the seventh stage of the high pressure compressor, hot air is drained to use for the pneumatic system of the aircraft. Besides the pneumatic system, this hot air under pressure is also used for the anti-ice system of the inlet duct of the engine, and the low pressure compressor. The hot air is also directly guided to the starter engine, which is the driving power for this engine. To the thrust reversers of this engine, this hot airflow is also guided. The thrust reversers use the air pressure to put the system into work. Besides hot air out of the compressors, cold air is drained out of the fan at the front side of the engine. This cold air is used to cool some parts of the engine which become very hot during the combustion process. This cold air is also used to cool some parts of the hot air which is drained in the compressors, making it capable of using it inside the cabin of the aircraft. When the aircraft is standing on the ground and the pneumatic system is not under pressure, the aircraft can make use of the Ground Power Unit (GPU) to support its engines. The GPU is a large air

19 generator which provide air under pressure to the engine. The Fokker 70 also has its own power unit on board, the Auxiliary Power Unit (APU). This APU can also provide power to the pneumatic system and the engine s if necessary Ice Protection Ice on the inlet can restrict the airflow through the engine, and so decrease the performance. Ice can be dangerous and can damage the engine when ice breaks of the inlet and gets dragged into the engine. The ice protection system not only needs to prevent icing of the inlet but many more ice vulnerable parts. The system consists of hot air flowing through tubes and electrical warming (figure 1.17). The Hot air is taken from the high pressure compressor and pumped through a system by pressure regulating valves. These valves control the amount of hot air flowing through the system. This prevents loss in pressure and temperature, thus performance, while the taken hot air is not necessary.the hot air ice protection systems includes the nose cone, bypass fan (1), oil cooler (2) and the stator blades (3) of the compressor. The rotor blades are not necessary to warm cause of their centrifugal force that prevents ice forming Legend: 1) Fan 2) Oil cooler 3) Stator blades 4) Nose cowl 2. Figure 1.17: Ice protection system The nose cowl (4) can be warmed electrically by a generator. The benefit is that this can be used when there is no hot air produced by the compressor. This electrical warming is done by placing electrical elements under a layer of neoprene Fire Protection To Prevent fire in the engines all flammable parts and fluids are isolated with not flammable material and are located in safe cool zones. These cool zones are surrounded with ventilated air and closed by fireproof bulkheads. All flammable fluid pipes that cannot be located in a cool zone are made of fire resistant material. When a fire occurs the pilots must be informed immediately. Therefore a fire detection system containing multiple allocated detector units is placed. These detectors are placed in two loop circuits containing the same placement. The detector units consist of two metal pieces separated with a small distance. When the temperature rises the metal will expand and the pieces will come in contact and will give of a signal. When both loop circuits give off a signal, the fire signal will be transmitted to the cockpit and the fire extinguishing system. Period 6 Project group F Class 2A2F Page 19 of 46

20 Legend: 1. Fire extinguishing bottles 2. Fire control handle 3. Fireproof bulkhead 4. Discharge nozzle Figure 1.18: Fire extinguisher system The Fire extinguishing system include a system that shuts off al flows of flammable fluids through the danger zone and a system for extinguishing the fire (Figure. 1.18). The system for extinguishing the fire contains two fire extinguishing bottles (1) outside the fire risk zone that can be used for both engines. These fire extinguishing bottles are separately pressurized and contain halon. The Bottles can be fired by the fire control handle (2). Both bottles can be fired separately by turning clockwise and anticlockwise. When a bottle is fired the pressurized halon flows through the fireproof bulkheads (3) and gets spread by the discharge nozzles (4) Lubrication The lubrication is important for the functioning of the aircraft engine. The most important task of the oil in the lubrication system is to absorb the heat which is created in the bearings because of the high velocity rotations in the engine. After absorbing the heat, the oil needs to dispose the heat, and new cool oil will flow through the bearings. Especially the bearings in the turbine section need extra attention, because they become very hot, this is the hottest section of the engine. The gas turbine such as the RR Tay 620 has about fifteen liters of oil in its lubrication system. this quantity of oil is pumped through the engine several times a minute. This is necessary to dispose the huge quantity of thermal energy out of the bearings. De oil in the lubrication system has nothing to do with the combustion process, as it does in a piston engine, in a car. That is why the oil consumption of a gas turbine is relative low. The oil viscosity in the lubrication system is very low, it needs to stay thin in a lot of different circumstances. This because thick oil is way harder to pump than thin ones. Furthermore, the oil needs to have a high flashpoint, it may not be easy flammable. But on the other hand, it also has a good resistance against ice forming. The oil needs to stay liquid, so it could easily be pumped to the bearings. 1.4 Requirements In the future engine design, multiple aspects must be taken into account. This new design has to meet up with the standards of today for aircraft power plants and all the requirements that go with it. These regulations for all aircraft are stated by the European Aviation Safety Association [EASA] and of all of their documents, Certification Specification 25 [CS-25] is meant for larger aircraft, like the Fokker 70 (1.4.1). Furthermore, there are also some other aspects where the new engine design has to comply to. So the engine must be a more silence design and the emission and fuel consumption must be decreased, compared to the old engine. For noise the requirements are stated in EASA CS-36 (1.4.2) and for emission the new engine design has to reckon with EASA CS-34 (1.4.3). Eventually the design must also meet up with our clients demands (1.4.4). Period 6 Project group F Class 2A2F Page 20 of 46

21 1.4.1 EASA CS-25 In EASA CS-25 all the rules and regulations that are related to aircraft power plants can be found in EASA subpart E, which is subdivided in smaller paragraphs. For an aircraft engine in general there are multiple regulations to which it has to comply for guaranteeing safe operations (1.4.1a) and not only there are regulations for the engine itself, but also for the separate parts and functions of the engine. For fuel supply each aircraft has separate fuel systems, which provide the fuel for the combustion phase in the engine (1.4.1b) and also the oil system is bound to the regulations stated in EASA CS-25 (1.4.1c). Besides those two systems, in an aircraft there must be means for cooling the engine to avoid excessive high engine temperatures (1.4.1d). Next are the regulations for the air-intake system (1.4.1e) and the exhaust system (1.4.1f). The controls, that can be used for controlling the aircraft its engines, are bound to the regulations of EASA (1.4.1g) and precautions in the engine and it s systems should prevent the engines of hazardous fires (1.4.1h) a General EASA states for power plants that all components of the installation must be constructed, arranged and installed so, that a continued safe operation between normal inspections or overhauls can be ensured and that the installation must be accessible for maintenance and necessary inspections. Furthermore the engines must be arranged and isolated from each other on an aircraft. This is done so that if one of the engines or engine systems fails or malfunctions, a safe operation of the remaining engine(s) is still possible and no immediate action by any crew member is needed. Also in flight there must be abilities to stop each engine from rotating in flight, when a continued rotations could jeopardise the aircrafts safe operation. This also means that a restart of each engine during flight must be possible. For the thrust reversing systems of the aircraft it must be proved, because the system is only for ground operation, that a continued safe flight and landing after an in-flight trust reversal is possible or that in-flight thrust reversal is most likely impossible to happen, not even as a result form any failure or malfunction in the system. Also not more than idle thrust may be produced when a failure in the thrust reversal system occurs. The thrust reversers must meet the requirements of CS-E 890. At last no vibration harmful to the engine may be produced by the air inlet system b Fuel system For the fuel system applies that it must be constructed so that fuel flows at a rate and pressure, which is needed for a good functioning of the engine, under every condition and any certified movement during the operation. The air that comes in the system may not result into a flameout and the system must be designed that ignition of fuel vapour within is prevented. There may be any ignition sources near the fuel tanks or parts of the fuel system where a catastrophic failure could happen. Each fuel system must provide a hundred percent of the required fuel flow under every certified condition and movement and also in hot weather conditions the fuel system must perform properly during the operation. For interconnected tanks applies that fuel is able to be pumped between the fuel tanks and overfilling the tanks should not cause any structural damage. The design of the fuel tanks must be designed so that no fuel can be released in or near the fuselage in quantities that could cause a serious fire. The limits for fuel tanks are a pressure of 24 kpa, 125 percent of the maximum air pressure developed in the tank from ram effect, all developed pressures of aircrafts accelerations and of the most adverse combinations of aircraft roll and fuel load. The expansion space cannot be less than two percent of the fuel capacity. From the top part of the fuel tank, each tank must have the ability to be vented, and strainers in the fuel system should prevent the passage of all objects that could damage the system or restrict the fuel flow. An escape of dangerous fuel quantities must be prevented. An emergency fuel pump must Period 6 Project group F Class 2A2F Page 21 of 46

22 be instantly available to feed each engine when a failure in the main pumps occur and on every aircraft there must be a fuel jettisoning system. All of the systems fuel lines within the fuselage must have a reasonable degree of deformation an stretching, without causing any leakage c Oil system According to EASA CS-25 each engine must have an independent oil system, which is able to supply the engine of the appropriate quantities of oil at a temperature, save for the continuous operation. For the oil there must be some expansion space, which may not be less than ten percent of the tank capacity and the reserve oil tank, not directly connected to any engine, not less than two percent of the tank capacity. Also it must be impossible to fill this expansion space inadvertently and the oil tanks must have the ability to be vented. The oil of the oil system may not come into the tank, the tank outlet or any other object that could obstruct the oil flow and therefore should be preventing this. Unless the external portion of the oil system is fireproof, there must be a shut-off valve at each oil tank outlet. Furthermore, each oil tank and also each fuel tank must be designed so that it can withstand any vibration, inertia forces and load forces during normal operations, without any failures. This also counts for the oil radiators. At last a drain must be installed so that the oil system can safely be drained when needed and the oil system must have special strainers or filters to ensure a safe operation d Cooling With the cooling provisions of an aircraft power plant the temperatures of the power plant components and engine fluids must be maintained within the temperature limits, that stand for these parts in all conditions and after the normal shutdown of the engine. Tests for the cooling system have to be done within the ICAO standards and for each stage of flight must be continued until a component or fluid temperature is stabilised, the operation stage is completed or the limits for the operation are reached. A temperature is considered stable when the rate of change is less than 1 C e Air intake system The air intake system must be capable of supplying the required air for every engine, under all conditions for which certification is requested and be able to fulfil proper fuel metering and mixture distribution with the air intake system valves in any position. Dangerous quantities of fuel leakage or overflow from drains, vents or other components should be prevented from entering the air intake system. Also hazardous quantities of water or slush from the pavement where the aircraft is manoeuvring on, must be prevented to be directed into the engine. The air intake ducts must be protected to minimize the damage of foreign objects, during ground manoeuvring. Tests should prove that parts of the air intake system that could be damaged are able to withstand the impact of possible foreign objects. The engines must always be able to operate throughout the flight power range without the accumulation of ice, which would affect the engine operation and causing serious loss of power. The air intake system must be able to handle the forces from engine surging for the bleed air system no dangerous conditions may occur when a duct rupture or failure happens at any point between the engine port and aircraft unit served by bleed air f Exhaust system Of each exhaust system is required that exhaust gasses are emitted safe without fire hazard or carbon monoxide contamination in any personnel compartment. When there are parts of the exhaust system with a surface hot enough to ignite flammable fluids, these must be located or shielded so that a leakage with flammable fluids will not result in a fire. Also no exhaust gasses may Period 6 Project group F Class 2A2F Page 22 of 46

23 discharge in such way, that they cause a glare which seriously affects the pilots vision at night and all exhaust system components must be ventilated, preventing points of extreme high temperature. Heat, corrosion, expansion by operating temperatures, vibrations and inertia loads in the operation may not inflict the exhaust piping and piping connected to components between which relative motion could exist must have means of flexibility g Power plant controls and accessories All power plant controls must be located so that no one can accidentally operate them, when moving in the cockpit. They also must have sufficient strength to withstand operation loads without any movement from position or failure and always maintain the position to which it was set. Inadvertent movements may not take place and for this reason there must be stops or locks for in the idle position. There must be a separate power or thrust control for each engine, for the separate control of each engine, but also the simultaneous control for both engines. Furthermore must the engines immediate respond to the controls. The ignition switches must control each engine ignition circuit on each engine and there have to be means for quickly shutting off all ignition and these controls may not operate inadvertent. In an aircraft there must be an automatically available alternate energy source for each battery ignition system by a generator if any battery becomes empty. The capacity of these batteries and generators must be big enough for providing the simultaneous needs of the engine ignition system and the greatest demands of any electrical system components of the same source. The ignition system must be independent of any other electrical circuit, which is not used for assisting, controlling or analysing the operation of that system and there must be ways to warn the flight-crew members when a failure or malfunction happens in any part of the electrical system. For accessory gearboxes possible misalignments and torsional loading of the gearbox, transmission and shaft system must be evaluated under normal operation conditions and kept as low as possible h Fire protection The engines of an aircraft count multiple designated fire zones. These can be divided in the engine power section, the engine accessory section, the compressor, the lines and components that carry flammable fluids, the power plant compartments without isolation between the engine power section and the engine accessory section and any fuel-burning heaters. To minimize the fire hazards resulting from failures, most parts must be fire protected. This means that every part of the aircraft power plant, that contains flammable fluids, must be made fire resistant. Also each designated fire zone must be vented. In the engine system there must be means to shut-off each fire zones, to prevent hazardous quantities of flammable fluids flowing into the fire zones. Closing the fuel flow for one engine may not stop the fuel flow for the remaining engines. With firewalls, shrouds or equivalent means all combustion equipment must be separated from the rest of the aircraft. Furthermore, for each designated fire zone there must be a fire extinguisher system available. Fire-detector systems must provide the fast and specific detection of any fires within the fire zones. Full scaled fire tests should show the compliance with the requirements Noise requirements While designing a new engine for the Fokker 70, the law requirements stated in EASA CS-36 must be met. Referenced to ICAO Annex 16 - volume I, the new engine must meet the new noise requirements (chapter 4, subsonic jet aeroplanes type certificate after 1 January 2006) instead of the current noise requirements for the current Fokker 70 engine (chapter 3, subsonic jet areoplanes type certificate on or after 6 October 1977 and before 1 January 2006). The following noise requirements must be met: Period 6 Project group F Class 2A2F Page 23 of 46

24 At the lateral full-power reference noise measurement point the noise shall not exceed 103 EPNdB with the maximum certified take-off mass of kg decreasing linearly of the logarithm to 94 EPNB at kg. At the flyover reference noise measurement point the noise shall not exceed 101 EPNdB with the maximum certified take-off mass for airplanes with two or less engines, of kg decreasing linear of the logarithm with 4 EPNdB for halving the aircraft mass to 89 EPNdB. At the approach reference noise measurement point the noise shall not exceed 105 EPNdB with the maximum certified take-off mass of kg or above, decreasing the mass linear with the logarithm to 98 EPNdB at kg. If the noise levels are exceeded at two or less measurement points, the following requirements are stated: The sum of all excesses shall not be higher than 3 EPNdB. The excess at one single measuring point shall not be higher than 2 EPNdB, and; The excesses shall be offset by a noise reduction at the other measuring points Emission requirements As stated in EASA CS-34, the emission requirements are according to ICAO Annex 16 Volume II. The applicable emission requirements are stated in chapter 2 of volume II for turbojet and turbofan engines only at subsonic speeds. At predetermined testing value s (1.4.3a), the smoke (1.4.3b) and gaseous emission (1.4.3c) are tested for certification a Predetermined testing value s For the emission requirements, all the certification tests are tested in predetermined value s and conditions. The following settings are predetermined: The atmospheric conditions shall be ISA, at main sea level, with water/kg dry air. The engine shall be tested at different thrust settings as following: o Take-off: 100% Thrust o Climb: 85% Thrust o Approach: 30% Thrust o Taxi/ground idle: 7% Thrust The fuel specifications shall met the prescribed value s used in turbine engines for testing (Appendix VI) b Smoke The produced smoke at any of the four thrust settings, shall not exceed the determined smoke level from the following equation: Regulatory Smoke Number = 83.6 (thrust level) or 50 as value, (whichever is lower) c Gaseous emission The gaseous emission level is measured for Hydrocarbons (HC), Carbon monoxide (CO) and Nitrogen oxides (NOx). The following equations are used for the emission level determination: Hydrocarbons (HC): Dp/Fo = 19.6 Carbon monoxide (CO): Dp/Fo = 118 Nitrogen oxides (NOx): o For engines with a pressure ratio of 30 or less, and maximum thrust more than 89.0kN: Dp/Fo = ( π) Period 6 Project group F Class 2A2F Page 24 of 46

25 o o o o For engines with a pressure ratio of 30 or less, and with maximum thrust more than 26.7kN but not more than 89.0kN: Dp/Fo = ( x π)-( x Fo) ( x π x Fo). For engines with a pressure ratio more than 30, but less than 82.6 and with maximum thrust more than 89.0kN: Dp/Fo = (2.0 x π) For engines with a pressure ratio more than 30, but less than 82.6 and with maximum thrust more than 26.7kN but less than 89.0kN: Dp/Fo = ( x π) ( x Fo) + ( x π x Fo) For engines with a pressure ratio of 82.6 or more: Dp/Fo = 32 + (1.6 x π) Where Dp stands for the mass of the emitted gaseous pollutant during the reference emissions of landing and take-off, Fo is the rated thrust (expressed in Newton), and π stands for the compression pressure ratio with take-off engine thrust at ISA mean sea level conditions Client Demands AAE wants a new gas turbine engines for the Fokker 70, which fulfils the standards of today. Therefore AAE has summed up the following demands for their new Fokker 70 gas turbine engines: The new engines need to be powerful and fuel efficient. The new engines must be suitable for the propulsion of the Fokker 70. The engine design must meet the current environmental requirements (for new engines) and meet the aircraft performance characteristics. The new engines must provide the needed aircraft thrust to land and take-off at the clients current airport network during different weather conditions. o The elevation of the highest airport is 9000ft. o The required temperature for take-off is ISA+35ᵒC or 45ᵒC at max. The minimum range of the aircraft with the new engines must be at least 1500nm with an airspeed of 320kts (Mach 0.77) on FL350. The design of the new engine for the Fokker 70 should at least meet these client demands, but may increase if it is feasible. Period 6 Project group F Class 2A2F Page 25 of 46

26 2. Improvement Research Possible solutions are to improve the research done by the most important factors available for the best outcome of the new engine. Given by the project manager the fuel consumption (2.1) needed to be improved for a bigger range furthermore the available thrust (2.2) creating a available climb rate must be increased. All this must be realized without interfering with the new noise requirements (2.3). All the possible modification for the individual part will be combined to get the most efficient engine. The result of the best combination which will create the new engine will be shown in the parts list (2.4). Afterwards the new engine will be explained and the chosen components of individual stages are explained in the conclusion (2.5). All variables used in this paragraph are calculated with the excel sheet and the equations in the excel sheet are summed up in Appendix VII. 2.1 Fuel efficiency The client requirements for the new engine are a fuel efficient engine, meeting the environmental requirements with a minimum range of 1500NM at FL350 with Mach 0,77. For a proper engine design, the old Fokker 70 engine is calculated (2.1.1) for the shortcomings. With the purpose the client wants to achieve (2.1.2), the new engine calculations are composed (2.1.3). To achieve these new calculations, possible solutions (2.1.4) regarding the fuel efficiency are setup for the new engine Old Fokker 70 engine calculations Using the excel sheet for the current Fokker 70 engine (Rolls Royce Tay ) at FL300 and Mach 0,73, the thrust specific fuel consumption (TSFC) is 0,982 kg/dn.h. TSFC is the required fuel (in kg) required to deliver 1 Newton of thrust for 1 hour. The current range and endurance for the current Fokker 70 are representative 1259,62 NM and 3,2 hour Purpose The purpose for the new engine is to decrease the efficiency and the gaseous emissions for better range, endurance and environmental pollution, while cruising at FL350 with Mach 0,77 to reach a new range with a minimum of 1500 NM, which is a range increase of 157,66 NM New Fokker 70 engine calculations Achieving an engine that is more fuel efficient, the following specification can be changed for a range increase and fuel decrease: 1. Fan Pressure Ratio 2. By-pass Ratio 3. Fan efficiency 4. Overall pressure ratio Ad 1. Fan Pressure Ratio The FPR of the old engine is 1,4:1 and to reach the 1500 NM of range the FPR needs to be increased with 25% to 1,75:1. As seen in the graph, when further increasing the ratio, the positive effect on the range will get less (Figure 2.1). Increasing the FPR even more does not always improve the range. When exceeding a certain ratio, the range will be decreased exponentially. This will be around a ratio of 2,5:1 depending on the other specifications. Period 6 Project group F Class 2A2F Page 26 of 46

27 Range (NM) Range (NM) Hogeschool van Amsterdam Aviation Studies Project Powerplant 1800, , , , ,00 800,00 600,00 400,00 200,00 0,00 0 0,5 1 1,5 2 2,5 3 3,5 4 4,5 5 Fan Pressure Ratio Figure 2.1: Range/FPR graph Ad 2. By-pass Ratio The current BPR is 3,04:1. For improving the range to 1500 NM the BPR needs to be at least 5,1:1. This must be achievable assuming that the new Rolls Royce engines can have BPR s of 10:1. Ad 3. Fan efficiency The efficiency of the fan on the current engine is 0,90. Because the maximum of the efficiency is 1,0, the range of 1500 NM cannot be achieved by only improving this efficiency. When assuming that the efficiency can be improved by 0,05 to 0,95, the range will be increased by about 46,97 NM. The exact improvement will depend on the other specification improvements. Ad 4. Overall pressure ratio The overall pressure ratio of the nowadays Fokker 70 engine is 16:1. The graph of the relation of the range with the pressure ratio results in a parabolic line (Figure 2.2). This means that increasing the pressure ratio will exponentially have less influence on the improvement of the range. New Rolls Royce engines got overall pressure ratios of 52:1. but even when this could be further increased, the 1500 NM of range cannot be achieved. By assuming the new engine can be improved to an overall pressure ratio of 40, the range will be improved with around 71,12 NM to a total of 1413,46 NM. 1600, , , ,00 800,00 600,00 400,00 200,00 0, Overall compression ratio Figure 2.2: Range/compression graph Period 6 Project group F Class 2A2F Page 27 of 46

28 2.1.4 Solution possibilities To realize the new engine calculations, the materials, dimensions and/or the mechanical aspects of the engine should be changed. Note that the old Fokker 70 engine is used and mechanics are compared for the design of the new engine. The following parts will increase the fuel efficiency: 1. Increasing the fan 2. Increasing the cold airflow 3. Other fan blade material type for less creep 4. The compressor rotating speed increase 5. Annular combustion Ad1. Increasing the fan By increasing the fan in the engine, the total mass flow will increase. By keeping the mass flow through the core engine the same, the amount of combusted air by the fan is increased without an increase of the TSFC. The disadvantage is a bigger fan with a bigger cowling. Ad2. Increasing the cold airflow By increasing the amount of air flowing through the bypass and decreasing the airflow through the core engine, the consumed fuel is decreased. This is realized by decreasing the flow surface for the core engine, and increasing the flow surface for the by-pass. The thrust however, is also decreased. Ad3. Other fan blade material type for less creep Changing the material type for the fan blades, a decrease of creep can be realized. When the fan has less creep the space between the fan tips and the cowling can be decreased, which results in less pressure loss and a fan efficiency increase. Ad4. Compressor rotating speed increase When the rotating speed of the compressor is increased, the overall pressure through the core engine is increased and results in an improved combustion. Improving the combustion efficiency means that the same thrust level is reached with less fuel. Ad5. Annular combustion By using an annular combustion instead of multiple combustion chambers, the impact on the turbine is more even divided over the turbine blades. Due to more even divided impact, the turbine will intercept more energy out of the combusted gas and rotates with the same speed when less fuel added just before the combustion. 2.2 Thrust improvements One of the requirements of the new engine, is that the engine can provide enough thrust to take off the Fokker 70 at 9000 feet. First the take-off thrust of the old F70 engine is calculated (2.2.1). Taking into account with the purpose (2.2.2) that is adequate with the client demand, take-off thrust calculation of the new F70 engine is made (2.2.3). Using the calculated trust value of the new engine, solution possibilities of the design is made(2.2.4) Old F70 engine calculations. Using the excel sheet, the delivered take-off thrust of the RR Tay 620 engine on 9000 feet is 36376,81 N. This amount of thrust needs to be improved to let the Fokker 70 make a smooth and shorter takeoff at 9000 feet. Period 6 Project group F Class 2A2F Page 28 of 46

29 2.2.2 Purpose The purpose is to make the right engine design adjustments to create new engine properties that are able to make the F70 take-off at an airfield with an elevation of 9000 ft. Therefore it needs to be able to providing a higher take-off thrust New F70 engine calculations As told in the purpose, the delivered take-off thrust of the RR Tay-620 engine at 9000 feet, is 36376,81 N. To create an engine that has a higher amount of take-off thrust than the old engine has, the following specifications can be changed for this thrust improvement: 1. Fan Pressure Ratio 2. Fan efficiency 3. Inlet diameter 4. By-pass ratio ad 1. Fan Pressure Ratio according to the excel sheet, the fan pressure ratio in the engine could be raised, to improve the take-off thrust for the Fokker 70. It is achievable by assuming to raise the FPR to 1,8. This will cause a higher pressure difference in the engine. According to the excel sheet, when a FPR of 1,8 is achieved, the take-off thrust on 9000 feet than will be 39890,66 N. this is an improvement of 3531,85 N. This is a significant improvement and therefore a good option for thrust improvement. ad 2. Fan efficiency for thrust improvement, the efficiency of the fan could be improved, this will result in a higher thrust. However, the fan efficiency is already 90%. With redefining the this efficiency, there is assumed that it could be achievable to create a fan efficiency of 97%. According to the excel sheet, with this new efficiency, the take-off thrust on 9000 feet will be 37420,56 N. this is an improvement of 1043,76 N. This is a small improvement, and therefore could be considered if it would be efficient. ad 3. Inlet diameter Increasing the inlet diameter of the Fokker 70 engine is a possible option for thrust improvement. This kind of adjustment is has an enormous effect on the take-off thrust. There is assumed that the inlet diameter can be increased from 1,11 meters to 1,2 meters, for a take-off thrust of 42790,26 N. this is an improvement of 6413,45 N. a good option for thrust improvement, because this improvement is of a significant value. ad 4. By-pass ratio The bypass ratio should be decreased to improve the thrust. To achieve a significant take-off thrust improvement at 9000 feet. Assumed is, that the bypass ratio could be decreased from 3,04 to 2,2. When the bypass ratio is decreased to 2,2, the take-off thrust at 9000 feet will be 41738,89 N. This is a take-off thrust improvement of 5362,08 N, and thereby a really significant one. ad 5. Combined adjustments. When all these adjustments are applied at the same time, according to the adjustments described above, all the extra thrust will which is created, will cause in a final thrust of 52727,95 N. However, there is been calculated in the excel sheet, that the delivered thrust by take-off at 9000 feet in this configuration is 54775,11 N. this is a higher amount of thrust because all the adjustments are also slightly depending on each other. Therefore the Total thrust with all these adjustments together deliver a higher thrust. compared with the take-off thrust of RR Tay-620 engine on 9000 feet, this is an improvement of 18398,3 N during the take-off. Thereby providing enough thrust for a smooth and short take-off. Period 6 Project group F Class 2A2F Page 29 of 46

30 2.3.4 Solution possibilities In the previous sub-paragraph, many value changes are mentioned to improve the thrust. The values that can be changed for improving the thrust are the fan pressure ratio, fan efficiency, inlet diameter and the bypass ratio. To realize the changes of these components, three possible solutions can be done. These solutions are: 1. The increase of the fan diameter 2. The increase the angle between the fan blades 3. The increase of the diameter of the core engine 4. Intermediate pressure compressor Ad1. The increase of the fan diameter By increasing the inlet diameter, the engine is able to support more airflow by increasing the inlet diameter, the diameter of the fan also must be increased. The increase of the fan diameter has as advantage that the increased airflow can be compressed by the fan for a better thrust. But, the increase of the inlet and the fan may not be too much, because if the inlet and the fan diameter increase to much, the bypass ratio will increase to much and the bypass ratio must by decreased for a better thrust. Ad2. The increase of the fan diameter Another solution is to increase the angle of the fan blades. Increasing the angle of the fan blades will increase the passages between the blades, the fan pressure ratio and the fan efficiency will increase as well. Ad3. The increase of the diameter of the core engine The manner to decrease the by-pass ratio if the fan diameter is increased is to increase the core engine diameter. The increase of the core engine diameter has the advantage that the compressor diameter must be increased and increasing the diameter of the compressor, makes the compressors be able the handle more airflow mass. More airflow mass means more air can be compressed for a better thrust. An increasing the core engine diameter will decrease the bypass ratio for a better thrust. Ad4. Intermediate pressure compressor For extra thrust an intermediate pressure compressor can be added in the compressor for increased thrust. The advantage of adding an intermediate pressure compressor is that the pressure ratio of the whole engine increases. More pressure increase means a better thrust of the engine. 2.3 Noise efficiency Our client demands that also the noise of the Fokker 70 engine is reduced in a new engine design. In aviation noise has always been a problem and because generally in aviation there is always a demand for more aircrafts flying from and to every airport, the noise zones around an airport getting too full. A way to solve this problem is by reducing the generated engine noise of the aircrafts flying within these zones, which is responsible for the main part of the aircraft noise production. The more quiet all aircraft together get, the longer it takes until the noise zones around an airport overflow and the more aircraft can fly within these zones. As the number of aircraft flying increases, the local population around airports complain more and this leads to demands for stricter regulation of aircraft noise. This results in the fact that aircraft designers are constrained to be constantly searching for ways to make aircrafts more quiet. So, a more quite aircraft is attractive for airports and so is it for airlines. Also can certification be a factor which influences the noise demands. This certifications (ICAO Annex 16, Vol.1) has been changed since the first development of the Rolls Royce Tay engine, which Period 6 Project group F Class 2A2F Page 30 of 46

31 was certified on the 24 th of June Nowadays the new certification requirements of 2006 must be taken into account. Because of this difference in noise certification, first it must be researched for what properties the current engine is certified. To eventually design an engine with a lower noise emission, it is important to know which parts are responsible for noise production. Mainly the noise is produced by the rotating fan and the mixing of the exhaust gasses with uncelebrated air (2.3.1). After researching the old engine, there can be found out what should be changed to meet up with the current certification requirements and what the options are for reducing the noise in a future engine design. These values can eventually be reduced to the possible solutions for the noise problem (2.3.2) Noise old engine The noise of an aircraft is given with the value EPNdB, which stands for the Effective Perceived Noise level in Decibels. The maximum permitted EPNdB can be found in chapter four of ICAO Annex 16 (used from 2006). Here a distinction is made between three measurement points, knowing the lateral full-power reference noise measurement point, the flyover reference noise measurement point and the approach reference noise measurement point. According to ICAO for these points the following can be said (Figure 2.3): Figure 2.3: Reference noise measurement points The maximum values for these points are mass dependent (Appendix VIII) and for the current Fokker 70, which has a Maximum Take-Off Mass [MTOM] of kg, in succession 94,7 EPNdB, 89,0 EPNdB and 89,6 EPNdB. In chapter four the same calculations as in chapter three (valid for aircraft between 1977 and 2006) are used, but because the requirements since 2006 are stricter, an extra -10 EPNdB must be taken into account (Appendix IX). Cumulative the maximum noise of the Fokker 70 becomes 272,2 EPNdB. The noise that is now produced by the Fokker 70 is for the lateral measurement point 89,5 EPNdB, for the flyover measurement point 80,1 EPNdB and for the approach measurement point 88.3 EPNdB. Cumulative this is 257,9 and this means that the current Fokker 70 engine does already meet up with the required noise regulations. An overview of these values can be found in figure 2.4. Period 6 Project group F Class 2A2F Page 31 of 46

32 Figure 2.4: Noise levels Fokker 70. Although the aircraft already measures up with the current noise regulations (those of 2006), our project group still decided to try to decrease the noise level of the Fokker 70 engines, also because this was one of our clients demands. The noise of an aircraft is normally divided into two main sources. One is the noise generated by the airframe itself and the other one is the noise generated by the aircraft engine. In the engine noise is generated by multiple parts of the engine (Figure 2.5). This means that there is not just one factor that can be eliminated for decreasing the noise. The main factors in turbo-fan engines that are responsible for the generation of noise, are the rotating fan (to the front) and the mixing of the exhaust gasses with the un-accelerated air stream (from the rear of the engine). This last effect causes a low frequency noise by the turbulent mixture of the high airspeed exhaust and the ambient air. The fan noise is created because of the tip speed and the intensity of the tip vortices. Noise here would also have been higher, when the fan would not have been ducted. Moreover, a bigger fan helps increasing the thrust, but does also contribute to a higher production of noise. Also the compressor, combustor and turbine are responsible for creating a certain amount of noise, but this noise is significantly lower than the noise of the fan and the exhaust. In general can be said that a compression of the air within the engine increases the engine noise, by making the air stream more turbulent. Lowering the turbulence within and after the engine would be a solution for decreasing the noise. Period 6 Project group F Class 2A2F Page 32 of 46

33 Figure 2.5: Noise production of an engine Improvements The old engine has several downsides regarding noise, which can be improved with the application of several components. These components can be either modified components or new components. The regulations for the new engine are set by ICAO and here the new certification of the engine is different from the old engine, because of the raise of flight demands. Due to the higher amount of flights taking place nowadays, the amount of noise per aircraft should be lower. The values were these new modification should comply with are set by different demands in ICAO (2.3.2a). The actual modification, which should improve the engine with noise, consist of several single acting components (2.3.2b) a Certification New certification is set to demand the improvements for the current engine. Therefore the new demands of ICAO certification need to be set. This will result in stricter regulations to guarantee the demanded improvement. The maximum noise levels will decrease. In figure 2.4 a table is shown which shows the maximum amount of noise allowed, the amount of produced noise and the margin by which the engine complies with the certification. Old certification New certification = % = 3.67% certification being more strict compared to the old certification. New EPNdB Old EPNdB Old EPNdB = % = 41.2% decrease in succes rate Figure 2.6: Certification tightening Shown with the equations is without new protection the old engine will still comply with the new regulations. The figures shown above in figure 2.6 are constructed out of figures shown in the table in figure 2.4. Although the EPNdB is a logarithmic per cents shown will show the decrease of allowed noise and the decrease of the margin from the old engine. The old engine loses 41.2% of the margin for noise production with the increase of stricter regulations by 3.67%. Important to notice is that with under current conditions and the demand for flights growing, the maximum noise production will most likely be decreased in the future. Therefore the noise production must to be held in place or favourably be decrease. Period 6 Project group F Class 2A2F Page 33 of 46

34 2.3.2b Possibilities The noise reduction of the old Rolls Royce Tay 620 engine can be done with several components. In some cases these intentional single acting modification of certain components can be combined with other available solutions. It is also possible to combine two or more of these solutions or even combining them with other solution possibilities. Such combination is called a hush kit. For decreasing the noise, four possibilities where found: 1. Chevron exhaust 2. By-pass ratio 3. Acoustic fan liner 4. Swept fan rotor Ad.1 Chevron exhaust Damping the noise can be done by creating a chevron pattern on the outer surface of the nozzle or by-pass. It decreases the noise by causing a gradual pressure build-up along the body of the engine (Figure 2.7). These segments will cause the airflow, which wants to go out of the engine, to blow around the tips of the chevron pattern (1). This causes an even distribution of the airflow coming out of the engine. Along the back piece a crenate 2 schematic is made for a sooner release of built up pressure. This results in a less sudden pressure change and also less noise production. Although the positive effects are fairly straight forward, the negatives are a common problem in aviation. Metal wear will cause the tips to wear under the pressure of the airflow. Furthermore the engines body could be damaged sooner with this application. Maintenance on the engines will be needed to be done more often. Legend: 1) Chevron pattern peace 2) Outside view engine (1) (2) Figure 2.7: Chevron exhaust Ad. 2 By-pass ratio The influence of the by-pass ratio is not only noticed with the fuel consumption and efficiency, but also the noise production can be influenced by it. The difference between the amount of air streaming through the by-pass and through the core of the engine is called the by-pass ratio. This ratio is in proportion to the dimensions of the by-pass and core engine and more specific the airflow going through those engine parts. The more by-pass air is going through the engine to more it will mix with the hot air, which comes from the engines core. The cold air will act as a damper when it comes into contact with the relative warm air from the core engine. By modifying the by-pass ratio almost certainly the outside dimensions of the engine will change. This depends on the specific modification. BPR is not a number based on dimensions but on volume air there for dimensions don t need to be changed if the dimension of the core engines changes. Overall this will affect the handling of the aircraft considerably. Also will the noise produced by the fan slightly increase with the by-pass ratio change, because in most cases of a BPR change the fan must be made bigger (Figure 2.8). 2 Crenate is a shark tooth pattern at the end of the bypass and nozzle. Period 6 Project group F Class 2A2F Page 34 of 46

35 Figure 2.8: By-pass ratio vs. noise Ad.3 Acoustic fan liner With acoustic fan liners the airflow around the fan blades is prevented to move around the fan blades freely and therefore preventing movement of the airflow in the wrong direction. These acoustic strips are shown in figure 2.9 and function as an airtight seal between the fan blades and the inlet. The fan blades efficiency increases and the vortices, coming from the tips of the fan and responsible for the generation of noise, are reduced. Figure 2.9: Acoustic fan liner Ad. 4 Swept fan rotor A sweep in the fan blades is a simple modification to the engine by replacing the normal fan blades for blades which are more curved in the middle. These blades have a wider centre width and a bigger core. Airflow will not cause movement in the surrounding air when there are no changes in direction. When a converging or diverging process is in effect this could cause the airflow to separate from each other. This movement of the air in different direction than the airflow velocity direction, causes pressure differences. These differences can, when you take them cumulative, raise to high values. A sweep in the fan blades (Figure 2.10) intentionally produces a certain airflow direction. Therefore the airflow can be directed in the way with the least deflection. The production of straight air through the engines will minimize the noise. Figure 2.10: Swept fan rotor Period 6 Project group F Class 2A2F Page 35 of 46

36 2.4 Solution overview. Now that multiple solutions for all our clients project problems are found, the only thing that is left to do is making an adequate choice for the solutions that will be used in the new Fokker 70 engine. An overview of all possible solutions is given in Appendix X. In this table all solutions, handled in the previous paragraphs, are clearly summarized. Noticeable is that for every improvement factor almost the same solutions can be used. In the solution overview the red line gives al the solutions that will be used in the future engine. After some research with the excel sheet and combining multiple solution options in the new Fokker 70 engine design should be as follows. The by-pass ratio of the engine should be increased with 29 percent of the current value to meet up with the clients demands and accomplish a maximum ratio between the TSFC decrease and the thrust improvement. Unfortunately it was not possible to increase the BPR much further, because the increase in the BPR has a negative effect on the thrust and would also increase the engine size too much. The new BPR should now be 3,9. For the increase of the BPR also the fan diameter has to be increased and therefore this part will be increased with 10 centimetres to 1.22 metres, which is an increase of 10 percent. The rest of the improvement in BPR is realised by a decrease of the engine core size. Because an increase of the BPR has a negative effect on the thrust, the BPR is only moderately increased, aiming for the demanded amount of the thrust. Changes in the overall pressure ratio will be realized in the new engine by installing a new compressor stage between the high pressure compressor and the low pressure compressor. With this intermediate pressure compressor stage, the overall pressure ratio will raise to 17 and a small but positive effect on the thrust is realized. The FPR is improved with 25 percent to 1,75 by a change in the fan blade angle. For a bigger improvement in the fuel efficiency, besides the already given solutions, the fan efficiency will be improved by using another fan material type. For the new engine there has been chosen for a single crystal type titanium alloy, which is more resistant to creep, instead of the current directional solidified type. With this change in material the fan efficiency should be increased to 95 percent. For an extra improvement in the fuel efficiency, besides the already summarized solutions, also annular combustion is an option that will be used in the new Fokker 70 engine. The noise of the Rolls Royce Tay can be reduced with the chevron type exhaust and the acoustic fan liner. The by-pass ratio increase was not intentionally be chosen, but was a positive side effect of the improvements in fuel efficiency. The acoustic fan liner and the chevron type exhaust are chosen because these where only small adjustments to the current engine. In contrast to this, changing the fan type is a far bigger adjustment and therefore not chosen for the future engine. These noise adjustments together should be able to provide a noise decrease of around 10 percent. Eventually the new Fokker 70 engine will, with all these adjustments, have a flying range of 1540 NM at a cruising speed of M0,77 on FL350. The provoked amount of thrust will be 15 kn and a TSFC of 0,88. The minimum altitude where the aircraft will still be able to fly with cruising speed, ensuring a range of at least 1500NM is feet. 2.5 Conclusion The design for the new Fokker 70 engine is based on three aspects; noise efficiency, fuel efficiency and thrust improvement. For each aspects, the improvement possibilities are overviewed, where after the improvements are picked, based on the overall performance, for the final design. For the noise, the following improvements possibilities are composed: Chevron exhaust Increased by-pass ratio Acoustic fan liner Period 6 Project group F Class 2A2F Page 36 of 46

37 Swept fan rotor Since the current Fokker 70 engine already satisfies the current law requirements for new engines, decreasing the noise will not have direct influence. But if the noise level is reduced for the new engines, they will be applicable for future aircrafts, and is more beneficial for airport charges. To decrease the TSFC, which is the amount of fuel used for one Newton of propulsion, the following possibilities are composed: Fan increase By-pass ratio increase Fan blade material for less creep Increased compressor rotating speed Annular combustion While noise reduction and less fuel usages are granted, the client also requested a thrust increase. The next findings results in a thrust improvement: Fan pressure Ratio increase By-pass ratio increase Increased fan efficiency Fan increase Combining all the advantages and disadvantages the solutions offers, the best part combination for the new engine design achieves the following: Diameter fan increased with 10% to 1,22 meters. By-pass ratio increased with 25% to 3,9. FPR is increased with 25% to 1,75, due to increase the set angle of the fan blades. Overall pressure (π) is increased with 6,25% to 17, due to adding an intermediate compressor stage. Fan efficiency increased from 90% up to 95% due to titanium with increased creep resistance by using single crystal type titanium alloy. Multiple combustion chambers replaced for annular combustion. Acoustic fan liners applied. Chevron exhaust applied. With the current composed engine parts, the final design for the engine is created, the engine specifications are set-up and the certification and testing are clarified (chapter 3). Period 6 Project group F Class 2A2F Page 37 of 46

38 3. Engine design The last phase in the design process of the new engine, is the phase where the new engine is put together. From now on, this new engine design is called the JAE WW further on in this report. The new engine and its improvements must now be completely analysed and all the parts must work well together, when installed in the JAE WW (3.1). By using the excel sheet, all the specifications of the new engine can be found, which will reviewed carefully (3.2). The JAE WW cannot be taken in use instantly after manufacturing. Before that, the engine must be certified, because the JAE WW is a new engine design and all new engines always must be tested and certified before use in aviation (3.3). Eventually will in the conclusion the answers on the main question of this project be answered (3.4). 3.1 Engine Design When applying all the engine improvements found in chapter two, the new engine will have a new design (figure 3.1). This schematic overview shows how all the engine improvements can be combined in a well functioning system. In Appendix XI, the engine is enlarged for a better view. The adjusted parts, compared to the current Rolls Royce Tay , are further described: 1. Inlet diameter 2. Fan 3. Acoustic fan liners 4. Intermediate Pressure Compressor 5. Annular combustion chamber 6. Chevron exhaust Ad 1. Inlet diameter The inlet diameter is increased with 10% to 1,22m. This will result in more weight because of the increased perimeter. This is not only caused by the extra skin material but also by extension of the internal systems like the de-icing system. Ad 2. Fan The fan is adjusted in two aspects. First, the diameter of the fan is increased along with the inlet. And second, the material of the fan is changed to a single crystal type titanium that is more resistant to creep. Both have a negative influence on the weight of the engine. Ad 3. Acoustic fan liners Acoustic fan liners are placed around the fan on the inside of the engine. This will help reducing the noise of the fan. Because of the minimum interspace around the fan, the inlet diameter increase must be more than the fan increase to create space for placing the acoustic fan liners. Ad 4. Intermediate Pressure Compressor The Intermediate pressure compressor is placed between the low and high pressure compressors. It consists out of one line of stator and one line of rotor blades. For placing the I.P compressor, space is needed. Therefore the engine will be 15cm longer than the current engine. Ad 5. Annular combustion chamber The combustion chamber is replaced by an entirely different chamber. The annular combustion chamber is a single chamber that replaces the multiple minor chambers. The annular combustion chamber contains less parts and therefore weigh less and take less space. Period 6 Project group F Class 2A2F Page 38 of 46

39 Ad 6. Chevron exhaust The chevron exhaust type is installed on the exhaust duct and the nozzle. This will decrease the produced noise at the aft of the engine. Because of the notches, the length of the engine is increased Legend: 1. Inlet diameter 2 Fan 3. Acoustic fan liner 4. IP Compressor 5. Annular Combustion chamber 6. Chevron exhaust Figure 3.1: Engine Design 3.2 Specifications The specifications of the new engine are the standard specifications during operation. The current Fokker 70 Rolls Royce Tay engine is compared with the new designed JAE WW engine to clarify the improvements of the design. Rolls Royce Tay JAE WW Take-off (ISA 9000ft.) Thrust ,89N ,40N Bypass ratio 3,04 3,9 Pressure ratio Mass flow 118,990kg/s 144,852kg/s TSFC 0,694kg/DN.h 0,546kg/DN.h Climb Maximum thrust ,89N ,40N Cruise Altitude ft ft. Mach number 0,73 0,77 Thrust ,66N ,35N TSFC 0,982kg/DN.h 0,799kg/DN.h Dimensions Length 2,40m 2,55m Fan diameter 1,11m 1,22m Basic engine weight 1170,11kg 1228,2kg-1251,9kg Layout Number of shafts 2 3 Compressor 1+3LP+12HP 1+3LP+1IP+12HP Period 6 Project group F Class 2A2F Page 39 of 46

40 Altitude (ft.) Hogeschool van Amsterdam Aviation Studies Project Powerplant Aircraft Fokker 70 Fokker 70 Service date April Engine costs 1,84M 1,97M During take-off and cruise, the thrust and TSFC are improved with the new engine. The expected basic engine weight increase is approximately 5%-7% to 1228,2kg-1251,9kg due to fan and cowling increase. The engine costs are increased slightly due to added fan blade material (increased diameter), intermediate compressor grade and annular combustion chamber. The range of the JAE WW is compared with the old engine with range graphs on different flight levels. Graph 3.1 displays the range of the old engine and the JAE WW New engine Old engine Range (NM) Graph 3.1: Aircraft Range The aircraft range with the new engine will increase with 153NM, but with increased cruise altitude of ft. the total range increase rises to 325NM to a total of 1662NM. At fight level ft. the aircraft will already achieve the minimum stated range of 1500NM. 3.3 Certification The new engine which is designed needs to comply with the new engine. Therefore the engine modification needs to comply to the up-to-date regulations. Because the old engine did comply with the regulations, only the topics which are changed will be discussed in certification. As stated in chapter two, the changes where done in the topics of fuel, thrust and noise. These topics are all reviewed in the paragraph of certification aspects (3.3.1). The time the process takes and the steps taken are part of the process of certification (3.3.2). After the engine will be certified the regular maintenance will keep the airworthiness up to date (3.3.3) Certification aspects For the certification process, it is needed to know on which aspects adjustments are made, so these can be certified. For the improvement of the thrust of the engine, adjustments are made which need to be certified (3.3.1a). Furthermore, the fuel consumption is improved, and the adjustments which Period 6 Project group F Class 2A2F Page 40 of 46

41 are made also have some certification regulations (3.3.1b). at last, the noise of the new engine needs to meet the noise regulations of nowadays (3.3.1c) a Thrust regulations With the adjustments that are made on the engine, the thrust of the engine will change. This might lead to changes in the certification of this new engine for the f70. An adjustment is made, by increasing the FPR in the engine. The operating pressure in the engine will increase. According to CS- E, there are some regulations before the adjustments may be achieved. With the new FPR, within the timeslot of a minute, the following rules must be achieved: The pressure may not rise beyond serviceable limits, and no permanent damage may occur when the engine is running this full minute, with the new FPR. During this minute, no exhibit leakage may occur, which could result in a tremendous engine effect when it is exposed to a minimum of the following pressures: o 115% of the maximum possible working pressure in the engine. o 150% of the maximum working pressure in the engine. o 35 kpa above the maximum possible working pressure in the engine. To improve the trust, also an adjustment is made in the fan efficiency. The fan efficiency is improved to 97%. This means that the fan should probably be redesigned with other blades or a different RPM. Besides the efficiency, another adjustment will be made to the fan. The diameter of the fan will be increased. CS-E state, that adjustments on the fan must be done according to the following points: It must be demonstrated that Failures of the new fan systems will not result in hazardous engine effects. It must be established that the shaft systems are designed so that failures are predicted to occur at a rate not in excess of that defined as remote b Fuel regulations For the improvement of the fuel efficiency the new engine is modified on several aspects which will improve the fuel efficiency. How the efficiency is maintained is explained in chapter two. The performed modifications needs to comply with the current regulations. Fuel efficiency will be improved on several ways. One of them is an increase of the fan. The increasing of the fan is not only positive for the improvement of fuel efficiency, also the thrust modifications provide from the increasing of the fan. For regulations about the increase of the fan, review 3.3.1a thrust regulations. Fuel efficiency is also been improved by the decrease of the flow through the core engine that increases the volume of air passing through the by-pass. The core engine can only be changed when the new design complies with the regulations and the same regarding thrust. The fuel efficiency is improved by using an annual combustion, and this system bust be tested. Therefore the engines combustion chamber needs to comply with the following rules. Combustion will be tested with the conditions same as when the aircraft will be generally used in or minimum requirements. The general operation must be tested with full combustion use during the whole test for at least 1000hours in the appropriate conditions. Alternate testing can be done on a rig that is able to cope the testing forces. To certify the engines endurance, a ten hour test is performed on similar conditions to the operating conditions. The fuel efficiency can be increased with one method. Changing the materials will cause more efficient use of the fuel. The following guidelines are put in place for the use of new materials: The materials used needs to be tested for durability as well as suitability for the engine. The specific properties must comply with the minimum properties stated in the materials specifications. Period 6 Project group F Class 2A2F Page 41 of 46

42 Under normal operation conditions, the design which consists out of the new materials must always retain the minimum mechanical properties needed. Cooling air must be supplied so that the fan can run on maximum thrust without damaging the materials of the fan blades or changing its characteristics c Noise regulations The noise which was produced by the old f70 engine, had to meet the old regulations which were in effect at the moment the old engine was produced. The new engine which is designed right now, needs to meet the regulations according to noise, nowadays. In paragraph 2.3 is described what these adjustments are, that are approved to the engine, and what the noise production is of the new engine. There is concluded that the new engine will meet with the new noise regulations Certification process To get the engine through the certification, and bring it into service, it must meet all the requirements and guidelines as told in therefore this must be achieved on the new engine, making it operate as it should be according to Certification Specifications. This process will take a while. Because there are certain adjustments and improvements compared to the old f70 engine, the certification of the new engine must be considered as an totally new engine. Especially the new parts must be tested. The working of the whole engine in general must be tested and examined in detail. This is a time taking process. According to this certification process, the total time for the certification of the new engine will be between two and three years, depending on the circumstances of the certification and government maintenance new engine When the new engine for the f70 is in service, it needs adjusted maintenance and engine check s. There are a lot of different check s which are necessary for the new engine, to maintain the performance of the engine. Fan efficiency is raised and therefore the fatigue on parts will increase. The roll bearings, lubrication system and inlet are involved with the forces created by the fan. These forces are being increased due to the friction between surfaces. After modification, these parts needs to be checked more though. The FPR is raised which will increase reacting forces on the fan blades. Therefore the fan blades are operating closer to the limits. Fan blades should be checked more often for fatigue. The general maintenance and checks are described in Appendix XII. Difference in checks in these appendices are shown with red. 3.4 Conclusion At the beginning of this project Amsterdam Aircraft Engines gave project group 2A2F the assignment to make a conceptual design of a new propulsion power plant for the Fokker 70. For making this design first the current Fokker 70 engine, the Rolls Royce Tay , was analysed, after which research was done for the main parts that should be improved in a new engine to meet up with the clients demands. AAE demanded that with the new engines, the Fokker 70 should gain the possibilities to fly for at 1500 nautical miles at flight level 350, with an airspeed of 320 knots (or Mach 0,77), in different weather conditions (ISA+35ᵒC or not more than 45ᵒC). Furthermore the aircraft should have gained the ability to take-off and land at airports with a field elevation of at least 9000 feet and the fuel consumption, gaseous emissions and engine noise should had to be reduced, meeting the EASA regulations. Now, after several weeks of research, it can be concluded that designing a new engine with all these demands is possible. Our project group came up the JAE WW. To increase the amount of thrust, in the new engine design an intermediate pressure compressor added and the fan diameter was increased, which also caused a positive effect on the fuel efficiency. Period 6 Project group F Class 2A2F Page 42 of 46

43 By increasing the cold airflow and adding an annular combustion chamber, instead of the multi chamber combustion the current engine had, the improvement in fuel efficiency was obtained. Using a more expensive type fan material, a single crystal type titanium fan, there was strived for a higher fan efficiency, which also positively effects the fuel efficiency. With a higher fuel efficiency the fuel consumption and gaseous emission was decreased. At last, by using a chevron exhaust and acoustic fan liners, the noise was decreased, compared to the current Fokker engine and was the noise production of JAE WW kept limited by the earlier explained by-pass ratio increase. Eventually the Fokker 70 should, with these new engine options, obtain a flying range of 1662 NM at flight level 350, with the demanded airspeed and weather conditions and is the noise decreased with around 10 percent. Also will the aircraft with the JAE WW engines be able to already reach a flying range of 1500 NM at FL300. The new engine design does now already meet up with the noise regulations (ICAO Annex 16), but still has to be certified, before replacing all current Fokker 70 engines. This will take around 3 years and so the objective will be to that this new engine, the JAE WW, could be taken into use at the end of Period 6 Project group F Class 2A2F Page 43 of 46

44 Bibliography Hogeschool van Amsterdam Aviation Studies Project Powerplant Books: Kooijman, H.S. Gasturbines Algemeen Rolls Royce The Jet Engine 5th edition Pietersz, Frenchez Projectboek Power Plant Fokker 70 Amsterdam, Oktobre 2011 Hogeschool van Amsterdam, Domein Techniek Wentzel, Tilly Opbouw projectverslag Amsterdam, 2010 Hogeschool van Amsterdam, Domein Techniek ICAO Annex 16 Volume 1 (5th edition - July 2008) ICAO Annex 16 Volume 2 (3th edition - July 2008) Scholder, R.H.G. Vliegtuiggasturbines Van Dijk, B.H. Prestatieleer April 2009 Scholder, R.H.G., Van Dijk, B.H. Thermodynamica April 2007 Fokker Fokker 70 Aircraft maintenance manual part 73-Power plant Period 6 Project group F Class 2A2F Page 44 of 46

45 Webpages: Easa Fokker certification URL: A.037_Fokker_F pdf Airliners Fokker 70 data URL: Fokker-aircraft Tay engine information URL: Aviation today Green engine adjustements URL: Rolls Royce Tay 620 information URL: Smart cockpit Powerplant Fokker 70 URL: Fly Fokker Noise and emission URL: Stanford Noise URL: Period 6 Project group F Class 2A2F Page 45 of 46

46 Appendix list Appendix I: Formulation of the assignment... 1 Appendix II: Process report... 2 Appendix III: Velocity triangle... 4 Appendix IV: External gearbox... 5 Appendix V: Starter engine... 6 Appendix VI: Emission requirements... 7 Appendix VII: Explanation excel sheet calculations... 8 Appendix VIII: Maximum Noise levels Appendix IX: Noise Calculations Appendix X: Solution overview Appendix XI: The JAE WW Appendix XII: Engines checks Appendix XIII: Chairman / secretary schedule & group info Period 6 Project group F Class 2A2F Page 46 of 46

47 Appendix I: Formulation of the assignment Team 2A2F team was awarded by Amsterdam Aircraft Engine to create a new engine design for the Fokker 70. The project assignment is given below: Baseline Amsterdam Aircraft Engines awarded an assignment to make a conceptual design of a propulsion plant, with which the current Fokker 70 (20 years of operational life remaining) fleet can be outfitted. The current engines (Rolls Royce Tay) have relatively high fuel consumption and gaseous emissions. The engine manufacturer AAE, has target group of airlines that primarily operate in Europe and South-America. The current engines won t allow operations on high altitudes, thus a new engine is needed to provide the thrust required. Formulation of the assignment As the project team of Aviation Studies of the Amsterdam University of Applied Sciences, you are going to make a conceptual design for the new engine. The new engine must provide the needed thrust, for the customers to land and take-off, within their current net-work of airports, under different weather conditions, such as hot day conditions. The elevation of the airports is at the most 9000 ft. In addition the specific fuel consumption, thus the efficiency must be at least adequate to provide a range of more than 1500 nm (without refueling), at a Vmo = 320 kts/mmo = M 0.77 and 35000ft. Also the thrust, needed on MSL on standard day conditions to achieve the previous requirements needs to be calculated, the static thrust T/O, N-1 and 2.4% climb gradient T/O performance. The temperature requirements OAT limitations are T/O = OAT max ISA+35ºC or 45ºC, take-off thrust is the flat rated thrust principle. Also the EASA requires that all major changes may not deteriorate the airworthiness certificate of the airplane, thus requiring an additional certification of the airplane. Describe/analyse the certification process of a gas turbine engine and determine the influence on the certification of the airplane. Additionally to make the new engine a commercial success, at least the field height must be fulfilled and competitive in the current market. Period 6 Project group F Class 2A2F Page 1 of 18

48 Appendix II: Process report Project group 2F consists out of 6 group members (John Alvarez, Joost Bruin, Joey de Groot, Raul Heijs, Mitchel van Lokven and Christiaan Middelkoop). We got the assignment to design a new engine for the Fokker 70. The cooperation process is described in this appendix to overview the good points as well as the bottlenecks, to improve future cooperation. We started this project with only six men, due to two unexpected dropouts as result of poor school administration. This administrative error was presented to the project teacher with the question if it was possible to provide two extra group members. Unfortunately this was not possible. In the first two weeks the Plan of approach was setup without problems and after the feedback the plan of approach was approved and we moved on to the report. The first chapter was made in two weeks, but the final form of chapter one was completed three weeks later (5 th week of the project) due to repeatable adjustments in 1.2. Chapter two had a difficult start due to different opinions about the excel sheet. Eventually two persons started with the excel sheet, and have put allot of time into constructing the excel sheet. At the project meeting, Joey, Raul and Mitchel had notified that the workload was unfairly distributed. During the discussion it became clear other project members should do more work later, to compensate for the time that was put into the excel sheet by the other members. At the end of chapter two, paragraph 2.2 Thrust, needed allot of changes due to the large overlap with 2.1 Fuel. At the end, the deadline of chapter two was moved backwards by almost a week. And the final version of chapter two released more than one and a half week after the backward pushed deadline. With only one and a half week remaining, chapter three and the final report had to be made before the deadline. For chapter three the required time to produce the paragraphs was around three days less than the assumed time. One day before the actual deadline we received some demotivating feedback about chapter three and the overall report. Work division Paragraph Writer(s) Chapter Thermodynamics Raul + Mitchel 1.2 Thrust related components John + Joost 1.3 Subsystems Joey + Christiaan 1.4 Requirements Raul + Mitchel Chapter Fuel efficiency Raul + Joey 2.2 Thrust improvement John + Christiaan 2.3 Noise efficiency Joost + Mitchel 2.4 Solution overview Mitchel 2.5 Conclusion Raul Chapter Improved engine design Joey + Mitchel 3.2 Specifications Raul + John 3.3 Certification Christiaan + Joost 3.4 Conclusion Mitchel Period 6 Project group F Class 2A2F Page 2 of 18

49 Other threads Excel sheet +calculations old engine Excel sheet + calculations new engine Introduction Summary Appendices Bibliography Process report Joey + Raul Joey + Raul Raul Christiaan John Joey Together Period 6 Project group F Class 2A2F Page 3 of 18

50 Appendix III: Velocity triangle The velocity triangle is mostly used for a speed that has not a straight direction. The velocity triangle is given by the Axial airflow speed and the vertical airflow speed component. To low Axial airflow speed has as result that the compressor blade stalls. To high axial airflow speed has as result that the compressor blade chokes. Stall of a compressor blade given in the velocity triangle Choked compressor blade given in the velocity triangle Period 6 Project group F Class 2A2F Page 4 of 18

51 Appendix IV: External gearbox Period 6 Project group F Class 2A2F Page 5 of 18

52 Appendix V: Starter engine The starter engine of the aircraft engine is functioning on the power of air pressure. In the figure below the air driven starter is shown. At front side, air under pressure from the pneumatic system will flow in the engine (1). First, the air flows through the stator blades, which aim and speed up the air flow (2). After the stator, the air will flow under high pressure through the rotor (3) which is going to rotate under a very high velocity such as revolutions per minute (RPM). The axle of the rotor turbine will drive a gear train (4). In this gear train, the high RPM will be converted to a lower RPM, such as 2500, but a very high force momentum. the output shaft of the starter engine goes to the free running clutch (5) and the gearbox, as told in 1.3.5a Legend: 1. air input 2. stator 3. rotor 4. gear train 5. free running clutch 3 2 Period 6 Project group F Class 2A2F Page 6 of 18

53 Appendix VI: Emission requirements Designing a new engine, the emission requirements must be taken into account. The new engine may not exceed the maximum values of gas emission that are given in the EASA regulations. This appendix gives the maximum gas emission values. Period 6 Project group F Class 2A2F Page 7 of 18

54 Appendix VII: Explanation excel sheet calculations All the used formulas for the excel sheet are summed up to follow the calculated steps. The excel sheet is divided into two sections. The first section is the engine calculations (VII.1). The second section are the performance calculations (VII.2). VII.1 Engine calculations All the formulas used for the engine calculations belonging to the airspeed(vii.1.1), inlet (VII.1.2), fan (VII.1.3), by-pass (VII.1.4), compressor (VII.1.5), combustion (VII.1.6), and exhaust (VII.1.7) are divided into their own separate calculation section. The final thrust of the engine is calculated with the previous achieved values (VII.1.8). VII.1.1 Airspeed VII.1.2 Inlet VII.1.3 Fan Period 6 Project group F Class 2A2F Page 8 of 18

55 VII.1.4 Bypass VII.1.5 compressor VII.1.6 Combustion Period 6 Project group F Class 2A2F Page 9 of 18

56 VII.1.7 Exhaust VII.1.8 Thrust VII.2: Performance calculations For performance all used equations can be divided into 4 subparts. These three parts are the Lift and drag (VII.2.1), the range and endurance (VII.2.2), the required thrust at cruise (VII.2.3) and the limitation calculations (VII.2.4). VII.2.1 Lift and drag Period 6 Project group F Class 2A2F Page 10 of 18

57 VII.2.2 Range and endurance VII.2.3 Required thrust at cruise Required Thrust = VII.2.4 limitation calculation Other formulas which are used to calculate the limitation speed, such as formulas for sound speed, air temperature and air density are already explained at engine calculations. However, for calculating the limitation speed at height, the Mach number or the V mo, another formula is needed: True- and indicated airspeed: Period 6 Project group F Class 2A2F Page 11 of 18

58 Appendix VIII: Maximum Noise levels Designing a new engine, the noise values must be taken into account. To prevent too high noise on the community around the airport, maximum allowed sound level are given in the EASA. This appendix gives the maximum allowed noise levels and the calculations. Period 6 Project group F Class 2A2F Page 12 of 18

59 Appendix IX: Noise Calculations. Noise calculations for the current engine Noise calculations for the new engine Period 6 Project group F Class 2A2F Page 13 of 18

60 Appendix X: Solution overview Period 6 Project group F Class 2A2F Page 14 of 18

61 Appendix XI: The JAE WW Period 6 Project group F Class 2A2F Page 15 of 18

62 Appendix XII: Engines checks Normal engine check The minimum necessary checks which need to be performed to keep the engine in a well state of serviceability. These specific checks are done without any occurs with checks involved. When the engine complies and successfully fulfils these checks the engine is well enough to fly with. Checks are performed in two measures. In time intervals or with an interval in flight cycles. Small checks will be performed to most and so with the most small time interval. More detailed checks are performed less often. Normal checks will be explained in the time interval which will increase. With checks becoming more detailed and more advanced systems will be checked. For example with the 250 hours check the stage three blades of the low pressure turbine will be visually checked. But the 600 hours contains the mountings of the components and the 2000 hours will be on a full condition simulation for each component. Kind of check Daily check Description Consists of inspecting the oil filter blockage ( pop-up ) indicator and replenishing the engine oil as required. 250 Hour Check Consists of inspecting the two master magnetic chip detectors and a visual inspection of the stage 3 blades of the low pressure turbine (LPT). 500 Hour Check Consists of inspecting the LPT bearing support spokes, 12 lobed mixer, exhaust cone and exhaust case fairings. Check bearings turbine and fan. 500 Cycle Check Consists of inspecting the nose spinner, fairing and dynamic ice shedder, the LP1 (fan) compressor blades, the LP compressor case and linings and checking the oil level in the LP air starter motor. The new installed acoustic fan liner should be checked for tight seal. This can be prevented with filling. 600 Hour Check Consists of changing the fuel filter element Hour Check Consists of inspecting the mountings for the right hand gearbox and engine mounted accessories, the engine front link mounting lugs, the visible areas of the by-pass ducts, the EPR manifold drain plug and all fuel pipes and associated fittings Cycle Check Consists of inspecting the oil pipes, oil tank and associated fittings. Acoustic fan liner will be checked for efficiency and with a full operation test in similar conditions Cycle Check Consists of changing the oil in the LP air starter motor. As well as the above Routine Inspections, the following components are subject to on condition monitoring : Low pressure compressor (fan) outlet guide vanes (LPC OGV s), intermediate pressure compressor (IPC) and casing, IPC OGV s, high pressure compressor inlet guide vane (HPC IGV) mechanism, HPC 7th stage manifold, HPC, fuel spray nozzles, combustion liners and discharge nozzles, combustion casing, LP cooling air outlet, HP turbine, LP turbine, engine rear mounting points, right hand gearbox casings, airflow control regulator, T26 phial, HP rpm signal transmitter, fuel flow regulator, HP fuel pump, oil pump and cooler, LP air starter motor. Remedial action should be taken should any of the inspections reveal components in a condition that are outside the limits specified in the Rolls- Royce manuals. Period 6 Project group F Class 2A2F Page 16 of 18

63 Non normal engine check Non-normal checks being performed when aircraft is involved with problems or situation which may affect the aircrafts operation. Follow table describes checks which need to be done after certain situations. With red, deviations are shown which are created due to the new design. Non normal behavior After Engine Surge After Engine Shock Loading (This can be caused by incorrect service handling, damage during transportation or crash damage.) After Lightning Strike After Bird Strike Checks needed to perform 1. Examination of all compressors and L.P. turbines using borescope equipment. Examination of exhaust mixer. 2. Rotation of L.P. and H.P. rotor and listening for unusual noises. and the new I.P. check for noises. 3. Examination of M.C.D s. 4. Ground running the engine. 5. Examination of M.C.D s. 1. Checking the entire engine and mountings for damage. 2. Rotation of L.P. and H.P. rotors and listening for unusual noises. 3. Checking the mechanical controls for damage and freedom of movement. With detail to possible fatigue signs shown on the parts. 4. Checking the oil filter and M.C.D s. 5. Ground running the engine. 6. checking the oil filter and M.C.D S. 1. Checking the engine for damage. 2. checking the scavenge strainers and M.C.D s (This is repeated every 25 hrs for the next 100 hrs of operation). 1. Examine inlet nose cowling & nose cone fairing for damage. 2. Clean and examine the L,P. compressor blades and casing. 3. Rotate the L.P. rotor and listen for unusual noises. 4. Examine the L.P. OGV s, I.?. IGV s and I.?. 1 & 3 and H.P.1 compressor rotors. 5. Examine and, if necessary, clean the H.P. compressor rotors. Period 6 Project group F Class 2A2F Page 17 of 18

64 Appendix XIII: Chairman / secretary schedule & group info Wie Weekplanning Persoonsgegevens Naam Voorzitter Notulist Tel. HVA adres Woonplaats Alvarez, John Week 45,51 Week John.Alvarez@hva.nl Jonyboy-7@hotmail.com Diemen Bruin, Joost Week 46 Week 45, Joost.Bruin@hva.nl Joost_bruin@hotmail.com Amstelveen Groot, Joey de Week 47 Week Joey.de.Groot@hva.nl Joey@joeydegroot.nl Heemskerk Heijs, Raul Week 48 Week Raul.Heijs@hva.nl Raulheijs@hotmail.com Rucphen Lokven, Mitchel van Week 49 Week Mitchel.van.Lokven@hva.nl Mitchelvanlokven@hotmail.com Sint-Michielsgestel Middelkoop, Christiaan Week 50 Week Christiaan.Middelkoop@hva.nl Chrizzz13@live.nl Nijkerk John Alvarez Raul Heijs Christiaan Middelkoop Joey de Groot Mitchel van Lokven Joost Bruin Period 6 Project group F class 2A2F Page 18 of 18