Aero Eng flight sim lab 2021 PDF

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Flight sim lab 2021...

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Flight Simulator Experience Aeronautical Engineering

Introduction Aerospace engineers should have at least a basic understanding of piloting in order to be better, more forward-thinking engineers. Having a basic familiarisation with piloting and the various instruments on-board a plane is important for aerospace engineers as this knowledge compliments the theory of simple flight dynamics, like that taught in Aeronautical Engineering. Engineers will better be able to relate to pilots, airport procedure, and have a respect for the potential complexity of the logistics of flying. This practical represents the first step in the introduction of aerospace students to flying, and its relevance to the theory taught in class.

Flight Simulators In the lead up to World War II, Edwin Link invented the first flight simulator which would later come to be known as the ‘Link Trainer’. It was patented in 1931 and soon became a popular military teaching tool for pilots around the world. The US ordered six “Blue Box” trainers in 1934 and supposedly taught over 500,000 pilots from 1941 to 1945 (Robinson Museum and Science Centre 2000). Adapted Link Trainers would later be used for the Apollo missions, proving the importance of flight simulators, in general and experimental aviation alike, as an invaluable learning tool for flying. As well as enabling pilots to get a feeling for flying without having to physically fly a plane, flight simulators are useful tools for teaching pilots how to prepare for contingencies that would otherwise be too dangerous to practice in real life. Pilots are also able to absorb crucial information in a relaxed environment and will walk away unharmed from any flying mishap that should occur during the learning process. Additionally, learning to fly with a combination of flight simulator and real-flight training reduces the learning timespan; a pilot’s learning need not stop due to weather restrictions and other limiting factors. One can also repeat scenarios and procedures until they become “second nature” (Simtrain n.d.). Learning to fly in a flight simulator is cheaper than actual flight and does not cause general wear-and-tear on an aircraft during practice. Flight simulators are designed to very accurately model the aircraft that a pilot would otherwise be flying. The University of Adelaide’s flight simulator is the RedBird FMX and is an FAA approved Advanced Aviation Training Device (AATD), featuring an electric motion platform. It can model a large number of cockpit configurations for a variety of aircrafts. The configuration used for this practical will be the Cessna 172. The Cessna 172 Skyhawk is one of the most popular general aviation aircraft, and has favourable flight characteristics for recreational flying. If you are particularly interested, a supplementary exercise to get acquainted with a Cessna 172 steam gauge cockpit is to download the open-platform, FREE, flight simulator at http://www.flightgear.org. Here, you can download scenery packages so you can take off at Adelaide Airport, and other types of aircraft (make sure to check your internet usage and decide for yourself whether you want the “download scenery on the fly” option ticked while you play).

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Aims • • •

To take control of the plane and get a feel for the controls, To become familiar with the cockpit, with knowledge of the common controls, and To record the readings of certain flight procedures (cruise, climb and glide) and to implement them in manual calculations

The calculation section is not large in this lab so take advantage of the opportunity to learn about the layout of a cockpit and how the flight instruments operate. Sadly, you will not emerge from the flight simulator as pilots after this lab, but you will have gained some familiarisation and understanding as engineering students!

Marking Allocation and Deadline After each student has had their turn on the flight simulator, the lab demonstrator will fly the Redbird FMX and a student assistant will write down the necessary data. Meanwhile, students will be watching the live simulator feed on the T.V. The data will then be shared with the whole of the lab class. The results section of the lab will be based upon these calculations. Unless otherwise stated by the lab demonstrator, the report will be due at 11:59 pm three weeks after the student’s practical session and should be uploaded onto “myuni”. The following is the mark breakdown:

Pre-lab Quiz – 10% Report – 90%

Quiz To prepare for the quiz, make sure you read the background information and understand the lab manual for this lab, including (and especially) the safety rules and instructions, and complete the online module on myuni before attending your lab session.

Safety In order to participate in the lab, students must have read the occupational health and safety information and filled out the safety sign-off sheet provided by the School of Mechanical Engineering. The safety sign-off sheets must be completed and uploaded to myuni before attending the lab session. Closed-toe shoes must be worn and loose-fitting clothes and hair tied back (anyone not meeting these requirements will have to participate in the lab another day). The room is set up such that the Redbird FMX space occupies two thirds of the room. A room divider is used to separate the simulator space and the waiting space that students will enter into on entering the room. A LASER curtain lies just beyond the room divider, such that anyone crossing the room divider after the flight simulator is switched ON will trigger an automatic shutdown of the motion platform. Crossing the room divider while the flight simulator is in operation, or against the supervisor’s instruction, is strictly prohibited. Only one student and the supervisor are allowed in the flight simulator at any one time. All other students are to wait on the other side of the room divider, reading the posters, watching their fellow students on the real-time TV monitor or taking notes. Anyone needing to exit the room should wait until student changeover to notify the supervisor. At each student changeover, the motion platform will need to re-calibrate. Only the supervisor is permitted to turn the motion platform ON. During this time the flight simulator will move sharply to the right (from student perspective). Common sense dictates to stay clear of the

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moving flight simulator and wait until the supervisor has said it is safe before climbing into the cockpit (this will be when the yellow light has finished flashing). In case of an emergency there is a red shutdown button outside the flight simulator, and for the student inside, there is a big red emergency button to the bottom left of the cockpit. Students who feel they may suffer from motion sickness (or anything else that might hinder their experience) should voice concerns to the supervisor at the beginning of the session so that appropriate adjustments to the procedure can be made. A safety briefing will be given at the start of the session. Students can also refer to the Risk Assessment and Safe Operating Procedure of the flight simulator available in the lab. COVID safety Everyone is required to use the provided hand sanitisers and wipe clean the commonly touched surfaces after their turn in the flight simulator.

Background The cockpit that will be used for this practical is the traditional “Steam Gauge” cockpit of the Cessna 172. The Primary Flight Instruments consist of the six gauges presented above the yoke, otherwise known as the “Six Pack”. The Six Pack is what we will be focusing on in this practical. Some of these important flight instruments/gauges are labelled in the figure below. Course Deviation Indicator, CDI uses Very high frequency (VHF) Omnidirectional Radio Range, VOR 1

Outside Air Temperature, OAT /Timer

CDI/VOR 2

Automatic Direction Finder, ADF Fuel Gauge (Left and Right tanks) …is a part of the Engine Cluster Tachometer, RPM Figure 1: Aviation Six Pack – Instrument 6 Pack (McKay, G 2010) 1. 2. 3. 4. 5. 6.

Airspeed Indicator (in knots, ASI) Attitude Indicator (AI) Altimeter (ALT) Vertical Speed Indicator (VSI) Heading Indicator (HI) - also known as the Directional Gyro. Turn Coordinator (TC)

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Information gained from the pitot static tube contributes to the readouts for the Airspeed Indicator, the Altimeter and the Vertical Speed Indicator. Information gained from the gyroscopic sensor contributes to the readout for the Attitude Indicator, the Heading Indicator and the Turn Coordinator. In order to be in total control of the plane, pilots scan these instruments often to make sure each gauge is showing the desired value. The basic flight instruments are arranged in a “T” shape and include the ASI, AI, ALT and HI gauges. These are great sites to learn about the inner mechanisms which govern the traditional steam gauge cockpit outputs: • •

http://learntofly.ca/six-pack-primary-flight-instruments/ http://nashvillecfi.com/instrument/instruments.html

The Engine Cluster As can be seen in the figure alongside, the Fuel Quantity gauge, present in the top left-hand side, for the left and right fuel tanks, is measured in gallons. It is common practice in routine flights that the Fuel Selector Valve (present below the dashboard) is set to BOTH such that fuel is drawn from both tanks simultaneously, for balancing purposes.

Figure 2: Cessna Style Engine Cluster (Aviation Megastore 2015)

In the top right-hand corner, the Exhaust Gas Temperature (EGT) and Fuel Flow (FFLOW) are measured in Fahrenheit and gallons/hour respectively. The Cessna 172S does not give a Cylinder Head Temperature (CHT) in the steam gauge cockpit. Although a mixture can be correctly leaned using EGT, CHT is a very important engine parameter that all pilots need to consider when leaning the fuel-air mixture. EGT indicators for a C172S read between 1250F and 1650F. Maximum CHT is from 460F to 500F (260C) but should be kept below 400F.

Other important gauges present in the Engine Cluster are the engine oil temperature and pressure, and the ammeter and vacuum indicators. A 28V battery supplies electricity to all electrical systems. The Master Switch (BAT & ALT) engages the battery to the Primary Bus Bar and allows connection to the electrical devices (Pilot Friend n.d.). The Alternator recharges the battery after start up and provides continuous electricity to the instrument and avionics system. The Master Avionics Switch connects the secondary bus to the Primary Bus, which is turned on after engine start. The amperage of the aircraft electronics panel is checked before flight, such that the dial is showing a zero or positive change in amps. Voltage will be between 27 to 29 V for normal operation. After approximately 30mins of cruise, the ammeter should display approximately 5 amps or below. This is to prevent the battery electrolyte from overheating and evaporating (as per the Cessna 172S POH). Some of the most draining instruments in terms of amperage are the wing flaps, landing light and pitot tube heater. The vacuum readout/suction gauge is measured in inches of mercury, and refers to the degree of suction with which cabin air is being drawn into the gyro-driven instrument cases – the HI and AI (the TC still runs on a Gyro, but the precision of spin is electrically controlled and not spun by air flow). Fast gyroscopic spin rates can lead to inaccurate readings and slow spin rates cause overactive instrument readings (Pilot Friend n.d). A problem with the vacuum system may indicate unreliable readings from the HI and AI gauges.

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Switch Panel The switch and circuit breaker panel is located underneath the primary flight instruments and contains the controls that ultimately enable the pilot to dictate the configuration of the engine and power output. This panel also contains the flaps switch and extra controls such as taxiing/landing lights, the Alternate Static Air Source Selector Valve, carburettor heat (typically located to the left of the throttle), trim tab and landing gear (if applicable). The figure below contains a “Glass Cockpit” display – for reference only – with the Primary Flight Display (PFD) on the left and the Multi-Function Display (MFD) on the right. Combined, these make up the Electronic Instrument System (EIS). Notice how the ASI, AI and ALT gauges are still present in their traditional form.

Master Alternator and Battery, and Master Avionics Switch

Dimming Panel and Electrical Switches

Ignition

Electrical and Avionics Circuit Breakers

Rudder Pedals – Dynamic Breaking

Throttle

Fuel Mixture Control

Wing Flap Switch

Figure 3: Glass Cockpit of Cessna 172 (Michigan Flyers 2014)

Dynamic Braking The rudder pedals combine control of the yaw motion in flight, and a proportional brake system while on the ground. To control the yaw, a pilot must move the bottom of the pedals forwards or backwards. For example, yawing the plane to the right requires the right pedal to be pushed away from the pilot, while the left pedal will automatically shift forward, and vice versa. Should the pilot wish to employ the brakes whilst on the ground, the pilot should use their whole foot to press the front of the pedal down into the floor of the plane. This enables the pilot to break the left and right brakes separately. Although the pedals control both braking and yaw, it is difficult for a pilot to confuse the desired command as each operation acts with a distinct difference in motion of the pedal.

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Pro-Tips There is a lot to learn before becoming a certified pilot. However, there are some simple techniques for this practical that may prove useful when handling the plane. While in the air, aim to keep the speed of the airplane above the stall speed (around 53 KIAS for this Cessna). The instruments that alter movement in each of the three degrees of flight (yaw, pitch and roll) are very sensitive, so it is a good idea to handle the yoke and rudder pedals delicately. Additionally, it is also general practice to wait until the plane responds to one command, before giving it another. This makes for the controlling of the plane to be less erratic. Chapters from the lecture notes that may prove useful are Atmospheric Properties and Requirements for Flight Segments (climb). This practical requires students to be able to calculate the Calibrated and True airspeeds from a reading of Indicated airspeed at a given altitude.

Procedure This practical will be split into several parts which students are expected to complete: (1) (2) (3) (4)

Familiarisation Cruise Climb Glide

Part (1) is all about familiarising oneself with the cockpit controls and with the motion of the flight simulator. Students will get a chance to fly the simulator in Part (1). Part (2) will be based upon the data collected for the Cruise section. The data collected in the Climb section will enable students to manually calculate the ‘feet per minute’ of ascent for Part (3). For Part (4), students will need to calculate the sink rate of the aircraft from data collected from the Glide section and compare the theoretical values with the information from the indicator.

Data collection For valid results, the data collection for this practical can be a little tricky. So, for an accurate comparison between cockpit readouts and the physical parameters tested within the program, the lab demonstrator will be flying for the data collection in Parts (2-4). One student will be chosen to accompany the lab demonstrator to help record the data. Outside of the simulator, students will be watching the live feed on the TV or practicing calculations for the practical.

Part (1) - Familiarisation Students will then take it in turns to have a fly in the simulator. Any student who is not currently engaging in their turn MUST be waiting behind the yellow and black barrier. As there is a limited flight time of 5 minutes for each student in the flight simulator, students will spend this time getting to know the cockpit and familiarising themselves with the controls of the plane. Students will begin a mission at 3500ft heading to Adelaide Airport (YPAD). They will not be asked to land, but will be encouraged to perform some manoeuvres in order to take advantage of the flight simulator experience.

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Exercises the supervisor may ask you to do: • Yaw the plane first left, then right • Do a barrel roll • Lower the flaps in mid flight • Roll at more than 60 degree angle either left or right Note: if you do not feel comfortable performing a particular task, let the lab demonstrator know. Don’t be afraid to communicate what is going on with the instrument panel to the supervisor, as good communication and cooperation is what makes a piloting team successful! Make a mental note of how the certain manoeuvres felt from a piloting perspective, and make sure to write them down on paper before you leave the lab class. Also think about the way the plane is simulated to move and respond to your commands.

Part (2) – Cruise How can we verify that the speed shown on the gauges is actually the speed at which the plane is flying? One way is to measure the distance travelled by the plane in a certain amount of time. However, aircraft cockpits commonly do not display accumulative distances in varying directions, but rather distances between VOR beacons and airports. Therefore, the supervisor will create a “Direct-to” route to either Parafield or Adelaide Airport. A magenta line will appear on the Navigation screen. Once the plane is flying along the magenta line, the distance countdown displayed on the navigation screen represents the remaining distance along the line the plane must travel before reaching the airport. The timer will be started and the starting distance, altitude and velocity will by recorded. For steady-level flight, the velocity must stay approximately the same, and so must the altitude. However, a degree of speed variation and altitude change is inevitable. The GPS velocity will also be recorded in the tables below for comparison reasons. In order to do the calculations for Part (1), the altitude should be averaged. Two runs will be completed in the tables below. CRUISE #1 Time (s): insert time Measurement:

Start:

Finish:

Distance (nm) Altitude (ft) KIAS (kts) CRUISE #2 Time (s): insert time Measurement:

Start:

Finish:

Distance (nm) Altitude (ft) KIAS (kts) CRUISE #3

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Time (s): insert time Measurement:

Start:

Finish:

Distance (nm) Altitude (ft) KIAS (kts)

Calculations: Calculate the calibrated and true airspeed for each run. 𝑉𝐼𝐴𝑆 = 𝑉𝐶𝐴𝑆 = 𝑉𝐸𝐴𝑆

𝑉𝑇𝐴𝑆 = 𝑉𝐸𝐴𝑆 × √

𝜌𝑆𝑆𝐿 𝜌∞

From the Cruise data, also calculate the speed of the airplane based on time and distance travelled for both of the runs. Report the data collected from all three runs. Conduct an error analysis for the three runs and discuss the errors and limitations of the data collection.

Part (3) - Climb When the plane is flying steady and level, the instructor will gently angle the plane upwards at a horizontal attitude of approximately 5. With adjustment of the throttle, the supervisor will then attempt to fly the plane with a consistent climb angle and speed. The crucial aspect of this experiment is to keep the needle on the VSI gauge between two of the white dashes and as still as possible. Maintaining steady climb for 30s will be sufficient. The student assisting the supervisor in recording the data will be asked to fill in the table below: CLIMB #1 Time (s): insert time Measurement:

Start:

Finish:

Altitude (ft) KIAS (kts) Vv from gauge (fpm) CLIMB #2 Time (s): insert time Measurement:

Start: