A basic flight simulator tutorial



Foreword
Hardware
Software

The basic catastrophe: flying straight
Basic turning
Turning on the ground
So, two methods exist to turn in the air?

Engine control
Wings and speed
The flaps
The stall
The trim
What direction am I flying?

A realistic take off
Landing

How to fly when there is wind
How to take off when there is wind
How to land when there is wind
How to taxi when there is wind

The autopilot

Security

How to land the Cherokee Warrior II
How to take off and land the Piper J3 Cub
How to take off and land a jet
How to take off and land the P-51D Mustang
How to take off and land the B-52 Stratofortress

What then?
What is a flight simulator worth to learn flying?





Foreword


Aviation is about extremes:

This tutorial is based on the Cessna 172p, which is the default airplane on lots of flight simulators and a great airplane:





Possibly take a quick look at the following articles. You may feel the need to come back to them later. They contain answers to questions that can arise while reading this tutorial. The first ones show the airplane's main parts and controls:

I did my best not to tell too much nonsense. I apologize for the bad habits or reflexes you may get due to this tutorial. It contains for sure some ugly mistakes. Maybe come back in some time, as I make changes once in a while to better it.




Hardware


I assume you are using the regular mouse and keyboard of your computer. You need no joystick nor plastic pedals or control yoke to use the flight simulator. Such hardware would be more realistic (especially with force feedback). Yet I don't own any myself and I suppose most flight simulation candidates don't.

You need a "3D-accelerated graphics card" inside your computer and its proper drivers installed. Don't bother if you don't know what this is. Today most computers are sold with such a graphics card. Simply install the flight simulator software and start it to check you get a fluent display. If not, either an 3D-accelerated graphics card isn't installed or its drivers aren't properly installed. Get help.

Sound is not mandatory but it really helps. For example when landing you need to hear the wheels touch the runway. Sound is one of the direct neural connections that allow a pilot to become the airplane's brain.




Software


I assume you are using the flight simulator FlightGear. It's free! FlightGear can be installed under Windows, Linux, Mac OS X, SGI Irix, Solaris and FreeBSD systems. Probably also on other Unix-like systems. Go to the Web site http://www.flightgear.org to get the FlightGear installation file(s) adequate for your system. You will find there all kinds of great downloads and documentation.  (Some Linux releases include FlightGear on their installation CD's or DVD, or on one of their online repositories. You just have to pick FlightGear out in the list of available software.)

I assume you know how to download, install and start a standard software on your particular computer (or you know a person who can do that for you). This page can help: http://www.flightgear.org/Docs/InstallGuide/getstartch4.html#x9-33004.4




Most airplane airports should fit but in this tutorial I assume you are using FlightGear's traditional airport of San Francisco (KSFO):





In the final dialog maybe best cancel all display options. Ask for a flight at noon (your choice, but best a moment with the Sun still up). (The first time you use FlightGear, pick "noon" in the drop list, even if it is already selected.) Best start with a little display window of 800x600. Later on you can try to add options and ask for a wider window. Press the Run button and the flight simulator window should start:





(If you get problems when you run version 0.9.9 of FlightGear on your Windows system, try installing version 0.9.8. It is available inside the FTP mirrors mentioned at the top of the FlightGear download page.)
(By a parallel way, volunteers are needed to compile future source code pre-versions of FlightGear and test them on their computer. See http://www.flightgear.org/Docs/Tutorials/fg_cygwin/fgfs_cygwin.pdf and http://www.flightgear.org/docs.html for documentation.)

(If you get problems under Windows Me; the flight simulator suddenly stuttering, too few images per second... try killing all tasks except Explorer and Systray before you launch FlightGear. (If one of the tasks you kill is an antivirus or such protection software, this is a security risk.) Also, on one Windows Me machine, a FlightGear window of 800x600 yielded good results, while a lower resolution of 640x480 triggered awful FPS drops and stutters (Frames Per Second).)
If you don't use the  --timeofday=noon  option, it often happens that FlightGear starts in a night environment. To get a daytime environment, use the Weather menu. Choose Time of day. In the dialog box ask for say Noon. Then click Dismiss:




(If FlightGear is available in your KDE or Gnome menu, you can edit the FlightGear launch icon properties and change the simple  fgfs  command to something like  fgfs --geometry=1024x768 --timeofday=noon  or whatever command options you require. You can use any other resolution you want instead of 1024x768. (I try to keep a 4x3 ratio.))

Depending on your operating system and the way you get FlightGear, you will get different sets of airplanes and runways. To get more airplanes and sceneries (that contain runways) you have to download the appropriate files from the http://www.flightgear.org site, uncompress them and put the result in the adequate place inside your computer. See:



The basic catastrophe: flying straight


Once FlightGear is started you see this window content and you hear the sound of an engine:





The airplane engine is on, at low power. The airplane trembles a little, yet it doesn't move.

About the keyboard:




Type key v to see the aircraft from the outside. Type v several times, till you get back inside the aircraft. (Typing V makes you cycle backwards through the views.):





! Each time before you step inside a real airplane, you have to inspect the airplane all around to check every part of it. You make sure nothing is hampering the moving parts, nothing obstructing the instrument openings...

Hold the Page Up key down for eight or so lengthy seconds. You hear the engine sound rise.

The airplane starts moving. It drifts to the left, accelerates, rises in the air, banks to the left, falls to the ground, hits it, rises again and crashes.

Maybe you wish to see a replay of this crash: use the View menu, choose Instant Replay, then click the Replay button at the bottom of the dialog window. (Use v and V to see the airplane from the outside.) The picture below shows the end part of the flight. (Type key F3 to make a snapshot. Key F10 to remove the menu bar.)





Close the FlightGear window and start a new FlightGear window.

In order to fly straight you need the airplane's control yoke:





Move the yoke by moving the mouse. For this you need to be in mouse yoke mode. Get in that mode by clicking the right mouse button. The mouse cursor becomes a + sign. Move the mouse and see the yoke moving accordingly. Type v to see the plane from the outside. Again move the mouse and see the tail elevator moving and the ailerons at both wings ends. (Type x a few times to see the airplane from a closer point of view and better see the ailerons moving up and down. Type X to zoom back out. Ctrl-x for default zoom. Type V to get back inside the plane.)

! Each time you start flying a real airplane, you have to visually check that moving the control yoke makes the ailerons and elevator move.

One more click on the right mouse button gets you in mouse view mode. The mouse cursor becomes a <-|-> sign. This allows you to move your virtual head all around. Click the left mouse button to center the view back in. A third right-click will bring you again in standard mouse pointer mode.

The right mouse button cycles the mouse through three modes:
Restart the flight simulator, right-click to put the mouse in control yoke mode (+ pointer shape) and put the engine throttle on maximum by holding Page Up down. Do not try to keep the airplane rolling straight on the runway using the mouse/yoke. Let it drift leftwards. Wait till it rises in the air. Then use the mouse to try and get the airplane to fly straight. (If you want to control the airplane on the ground see chapter Turning on the ground.)

You have to prevent the airplane from banking to the left:





Prevent it from banking to the right:





Prevent it from plunging to the ground:





Prevent it from raising its nose in the air (and the stall warning siren from yelling):





Try to fly more or less straight, with the horizon stable above the airplane nose:





Whatever your skills at video games or maybe even air combat simulators, you won't succeed. The airplane will crash, probably even faster than when you didn't try to control it. This is the moment where most candidates get desperate and abandon trying to fly a simulator or a real aircraft. Just hold tight. Keep trying. Five minutes every day. And read the technical explanations below:

Most awful is this error: when the airplane plunges to the ground, you move the mouse forwards (push the yoke). Because you want to move the airplane's nose upwards. Actually you have to do the opposite: move the mouse backwards (pull the yoke).

Reciprocally, when you want the airplane's nose to dive, you must move the mouse forwards. This can seem odd, but all airplane control yokes are designed that way. You have to get used to it. (Little mouse moves have strong effects on the airplane. Maybe decrease the mouse speed for your first virtual flight attempts.)

A visualization may help: imagine a soccer ball is on your desk and you "glue" your hand on top of it. If you move your hand forwards the ball will roll and your hand will plunge to the desk. If you move your hand backwards the ball will roll back and your hand will now be directed to the ceiling. Your hand is the airplane:





A second error is when you assume the control yoke bank imposes the airplane bank. In other words, you believe if the control yoke is level, the airplane will fly level. This is false. Actually the yoke bank imposes the speed at which the airplane banks. If the airplane is banked 20° to the left and the control yoke is level, the airplane will stay banked at 20° left forever (roughly speaking). If you want the airplane to bank back to level, you have to turn the control yoke slightly to the right (move the mouse slightly rightwards) and keep it slightly to the right for a while. The airplane will turn slowly rightwards. Once it is level with the horizon, put the control yoke level too. Then the airplane will keep level (for a short while).

A third error is: you try to find "the right position" for the yoke/mouse. You try to find the fine tuning that will leave the airplane fly straight. Actually there exists no such ideal yoke position. The airplane is unstable. You constantly have to move the mouse a little bit to correct the airplane's attitude and keep it flying straight. This may seem a stressing nightmare but you will become used to it. Just like with driving a car. After a few months you will even no longer notice you are guiding the airplane to fly straight. (You can use the autopilot to keep the airplane level during long flights.)

An important hint: don't keep your eyes on the airplane instrument panel or on the control yoke drawing. Keep your eyes on the outside scenery and especially the horizon. Check the angle of the horizon and its height above the airplane's white nose. The horizon line and the white airplane engine cover are your main flight instruments. Look at the instrument panel only once in a while.

(While the mouse is in yoke control mode (+ pointer shape), don't move it close to the FlightGear window edges. It's useless and awful things can happen. If you want to get the mouse outside of the window, first go back to standard mouse mode by clicking two times on the right mouse button.)

You can also control the yoke using the four keyboard arrow keys or the keypad 8, 2, 4 and 6 keys.

You may hear beeping sounds while flying around the airport. Those are landing aid signals. Don't pay attention to them, they don't warn for a danger.

You master the thing if, while you are flying straight, the airplane very steadily climbs in the air. Next step is to keep the airplane at more or less constant altitude or make it descend slowly then rise again slowly.

The altimeter instrument is at the middle top of the instrument panel. The long needle shows hundreds of feet, the short needle shows thousands of feet. Hence the altimeter below shows an altitude of 300 feet. That makes roughly 100 meters.





Beware: an altimeter does not automatically show the absolute altitude above sea level. You have to tune that in. See the little black knob on the lower left side of the altimeter. Start FlightGear and stay on the ground. Click (in normal mouse mode) inside the black knob. A click on the left half makes the altimeter turn back. On the right half the altimeter turns higher. Use that little knob to tune in the altitude. The principle is you use the knob when you are sure about the altitude. If you know you are at 1,100 feet altitude, tune in 1,100 feet on the altimeter... (Clicking with the middle mouse button makes the knob turn faster. Type Ctrl-c to see the two button halves highlighted.)





Also keep in mind the difference between "altitude above sea level" and "altitude above the ground". If you fly above Mount Everest at an altitude of 24,000 feet above sea level, then you are at 0 feet above the ground. (That's why the HUD displays two altitudes.)

By the way: it may be that you get seasick while piloting on the simulator. I always got a little seasick after lengthy flights or acrobatics. The solution was the Cube video game and its successor Sauerbraten. I got *really* seasick while playing Cube: a very strong nausea and vertigo. It was painful but Cube is such a nice game that I didn't notice the pain until a level was finished. Then I had to lay down and wait a few minutes to recover. After a few hundred times playing I got used to it. Now I no more experience seasickness when playing Cube, except maybe a little bit when I stopped playing for a long time. The result is I get no more seasick either while using the flight simulator, even after awesome acrobatics.

Basic turning


Once you are able to fly straight, even just approximately, you can begin to learn to turn. The principle is simple: Don't overbank. 20° is a good bank to get a steady and reliable turn. This it what the turn coordinator is used for. On the picture below the indicator shows the airplane is banked 20° to the right. This is just fine to turn to the right:





Try this out: keep the airplane banked around those 20° for a few minutes and look at the outside. You will see the same ground features appear again and again, every 120 seconds. This shows you need 120 seconds to make a 360° turn (or 60 seconds for a 180° turn). (This is utterly important when navigating: whatever speed the airplane is flying, if you bank at 20° you always need 60 seconds to make a 180° turn. Whatever the speed or altitude. The bank indicator and the clock are essential navigation instruments.) (Note there seems to be a small error on FlightGear: a 180° takes only 50 seconds instead of 60.)

So, by banking the airplane to the left or to the right, you make it turn to the left or to the right. Keeping the airplane level with the horizon keeps it flying straight.

(The little purple ball in the bottom of the turn indicator shows the sideways forces. If you turn neatly (using the rudder a little bit (see below)), the ball will remain centered. If the ball is pushed say rightwards, this means you the pilot too are pushed rightwards. Like in a car turning to the left. During a neat turn in an airplane, even a strong turn, the passengers never endure a sideways force. They are only pushed a little harder on their seats.)

By experimenting you will notice you easily get fast and spectacular turns by banking the airplane to strong angles and pulling on the yoke. It would be mad to do this with a real airplane if you are a beginner or if you have passengers aboard. Anyway one of the trainings to become a pilot is to make the airplane bank up to 60°.

Each time you start the flight simulator, you have to decide whether you are going to learn flying or just get fun doing mad things. There is nothing bad with the fun. The more fun you make, the better understanding of the aircraft you get. That's one use of a flight simulator and it's good for your security. But you also have to train calm and realistic flying. Either you make a mad flight or you make a serious flight to mimic a real flight. Don't mix these two modes.




Turning on the ground


The picture below shows the tachometer instrument. It displays how many hundreds of Rotations Per Minute the engine is doing:





Start the flight simulator. Type the Page Up key a few times, till you get the engine rotation speed to 1,000 RPM (like displayed above). (Typing the Page Down key decreases the engine speed.)

At roughly 1,000 RPM, the airplane will roll on the runway, but it will not accelerate nor take off.

Type the "." key (Shift-; on Azerty keyboards). The airplane will make a sudden little turn to the right. If you keep the "." key down the airplane will halt. When you type the "." key, you activate the brake on the right wheel of the airplane. That makes the airplane turn right and halt.

To activate the brake on the left wheel, use the "," key.

The "," and "." keys simulate two brake pedals located at your feet on a real airplane. This way you can control both the speed and turn of the airplane on the ground. (Some airplane, like the Hunter, can turn on the ground only by using this method.)

(For the hackers amongst you who own an Azerty keyboard and want to tune in something more practical than "," and "Shift-;" for the differential brakes: being root, edit file keyboard.xml (it is located at /usr/share/games/FlightGear/data/keyboard.xml on my computer). Around line number 300 you should find two lines  <key n="44">  and  <name>,</name>  and a little below two other lines   <key n="46">  and  <name>.</name>. They are explicitly followed by lines mentioning them as "Left brake" and "Right brake". Change the first two lines to  <key n="59">  and  <name>;</name>  and the two further below to  <key n="58">  and  <name>:</name>  to get ";" and ":" for the differential brakes. (59 is the ASCII code of symbol ";" and 58 is the ASCII code of symbol ":".))

The brakes can be very useful when taxiing slowly on the runway. Another (complementary) method exists: you can use the airplane front wheel. In a real airplane this is done by pushing the rudder pedals with your feet. You push with your feet on the side you want to turn towards. In FlightGear two ways exist to control the rudder pedals:
Start the simulator, Type v or V to view the airplane from the outside and keep x down a couple of seconds to zoom on the airplane. Look at the front wheel and keep keypad 0 down. Then keep keypad Enter down. See the front wheel turn. Click on the right mouse button to get in yoke control mode (+ pointer shape). Keep the left mouse button down to get in rudder control mode and move the mouse to the left and to the right. Note that the rudder, that big vertical control surface at the rear of the plane, moves together with the front wheel.

I tend to control the rudder pedals using the mouse when the front wheel is on the ground and using the keypad 0 and Enter keys when the front wheel no more touches the ground. In other words: I keep the left mouse button down when the front wheel touches the ground. This allows for a precise and easy rudder control on the ground. I release the left mouse button when the front wheel no more touches the ground. Then I use the keypad keys 0 and Enter to control the rudder.

A drawback of FlightGear is that you don't see the position of the rudder pedals. To see it, two methods are available:







(Type h several times to toggle between two HUD colors and no HUD. Type H to change the HUD color intensity. Type I to get a simpler HUD (my favorite) (i to get back standard HUD). The sequence of keys I use to get my favorite HUD is h H I. The picture below shows this HUD. The uppermost and large scaled green indicator is the compass. Just below it is the horizontal yoke/mouse/ailerons position. The arrow shows the yoke/ailerons is centered. At the full right of the picture is the engine throttle lever position indicator. The arrow at its bottom shows the throttle is tuned to minimum. At the full left are the trim and vertical yoke/mouse/elevator position indicators (the trim is on the left side, the yoke is on the right side). The short green texts at the top of the picture, left and right from the HUD compass, are the plane GPS position. They are almost unreadable on a standard 800x600 window like below. (Either tune in a black HUD (H) or use a larger window. 1200x900 is fine.) The green HUD texts at the bottom of the window, left and right, contain valuable data. (I don't use them in flight. I rather use them during flight replays.))





This is the airspeed indicator, expressed in knots:





A knot is 1.85325 kilometer/hour. So, if you want to have a rough idea of your speed in flight expressed in km/h, multiply the knots displayed by 2. A knot is 1.15115 miles per hour, so very roughly, 1 knot is 1 mph. (Be careful with these roughnesses. Multiplying by 2 instead of 1.85325 makes a difference of 8%. Now, for example: landing at 65 knots instead of 70 knots makes the landing quite different, even when this is only a difference of 8%... And landing at 80 knots, which is only 14% more than 70 knots, can get you into real trouble.) (Note some aircrafts' airspeed indicators display mph instead of knots.)

Note the airspeed indicator displays the speed of the aircraft compared to the surrounding air, not the speed compared to the ground like a car speed indicator does. If the plane is halted on the ground and there is a 10 knot wind blowing towards its face, the airspeed indicator will display 10 knots airspeed, although the plane doesn't move...

When the airplane rolls over the runway at more than 40 knots, you must prevent the front wheel from touching the ground. During take off, once over 40 knots you make the front wheel leave the ground by pulling a little bit on the control yoke (on the mouse).

The picture below shows the front wheel slightly lifted. Don't overdo this. Keep the airplane's white nose cover well below the horizon. You just need to lift the plane's nose a little.





The reason why you must raise the front wheel is it is not designed to roll at high speeds. It would shimmy.

Question: if the front wheel no longer touches the runway, how do you steer the airplane? Answer: still using the rudder pedals. Indeed the rudder pedals are linked to the tail rudder, that big vertical moving part at the tail of the plane:





At air speeds above 40 knots, the rudder is adequate to steer the airplane.

The rudder pedals command both the front wheel and the rudder at the airplane's tail. So, just move the rudder pedals...

Note the front wheel and the tail rudder don't make the airplane turn exactly the same way. So when the rudder takes over the front wheel, you must adapt the rudder pedals angle. That means fast typing keypad 0 and keypad Enter (or hold the left mouse button down and tightly control the rudder with the mouse).

Once you trained all this, you are able to keep the airplane straight on the runway when taking off.

An advice: say the airplane is heading too much to the right. You type keypad 0 a few times to make it turn back to the left. Well don't wait till the trajectory is corrected. Type keypad Enter a short while before the airplane reaches the direction you wish. Otherwise it will go turning too much to the left. (If you use the mouse, things are much easier and precise.)

So, two methods exist to steer the airplane on the ground: the differential brakes on the side wheels and the rudder pedals. This is essential to aviation: at least two ways to perform each important function. This is called redundancy. If one method fails, you use the other method, even if that second method is not optimal. Sometimes three or even more ways exist to perform a given task.

Don't overdo turning on the ground, especially at high speed. That would make the plane fall sideways and be damaged. Make use of the simulator to try this out (fun mode).

(Why does the airplane drift to the left when it rolls on the ground, making you have to compensate with a little push on the right rudder pedal (about two keypad Enter hits)? Main reason is the flow of air produced by the propeller. It blows along the airplane body, but also it turns around the airplane body. The upper part of that slight vortex pushes the vertical tail to the right. That makes the front head to the left.)

You can center all yoke and rudder controls by typing 5 on the keypad. This is a good preflight precaution. Sometimes it can "save your life" in flight. (Note the trim is not centered by keypad key 5 (see below).)

A little problem in flight is the mouse drifting away from the center of the screen. After a while, you get the yoke centered by placing the mouse quite far from the center of the screen. Two solutions exist:
Before you type F3 to make a snapshot, better put the mouse in standard mouse pointer mode. Only then type F3, then Enter to close the little report window. Then click the right mouse button to get back to mouse yoke control (+ shaped pointer).




So, two methods exist to turn in the air?


Indeed. You can use the wing ailerons (steered by the yoke/mouse) or you can use the tail rudder (steered by the rudder pedals / the keypad keys 0 and Enter).

Why these two ways? Because we need redundancy, of course, but especially because they are very complementary:



So, you tend to turn by using the ailerons in normal flight and by using the rudder when close above the ground at low speed. Yet one method never completely cancels out the other. You still need the rudder at high altitudes and speeds. Reciprocally you have to use the ailerons a little bit when close to the ground, to keep the wings level with the horizon. (Actually you must use the ailerons even when taxiing slowly on the ground, when there are strong side winds, to prevent the airplane being tilted and blown aside.)

Best never make quick and strong movements with the rudder. On the ground at high speed this can make the airplane tumble aside. In flight at low speed it can cause a very dangerous stall. In flight at high speed it can cause all kinds of aerodynamic and physical discomfort. Try to make slow movements with the rudder. Make slow tunings at a time and take your time to stabilize their consequences. (Only the ailerons allow for nervous movements.)

I recommend you train to turn with the rudder in flight. Fly at a low speed of about 70 knots. Try to keep the altitude stable by increasing and decreasing the engine power. Maybe best a quite low altitude. Use the rudder to get to a target, to maintain a heading, to make turns to a new target... See how the plane yaws. Learn to anticipate rudder control. Don't try to make steep turns. Use the yoke/ailerons to keep the wings level.




Engine control


An airplane engine is a technological wonder. It is the most powerful, efficient, lightweight and reliable fuel energy plant commonly available.

On the bottom left, below the instrument panel you find the magneto switch / engine starter:





To see the switch, either type P to get the schematic instrument panel or type Shift-x to zoom out (x or Ctrl-x to zoom back in).

Move that switch with the { and } keys (use the Alt Gr key on Azerty keyboards).

You probably know the fuel inside a car engine is ignited by electric sparks. A car engine contains an electric magneto to create the electricity for the sparks. An airplane engine contains two such magnetos: the "left" one and the "right" one (redundancy...). When you put the magneto switch on OFF, both magnetos are switched off. Hence the engine can't run. (Putting the magneto switch on OFF is a way to shut the engine down. Yet you shouldn't use it because it causes residues to deposit inside the cylinders.) When you put the magneto switch on L you are using the left magneto. On R you are using the right magneto. On BOTH you use both. In flight you have to be on BOTH.

Why do you have the possibility to use the left and right magnetos alone? This can seem useless, since you fly using both. The reason is each time you start the engine in order to fly, you have to verify each magneto separately. So you put the magneto switch on L, then on R, slowly. That way you check each of them. If everything is OK, then you put the magneto switch on BOTH. Should one of the two magnetos fail in flight, the other one will keep doing the job. The failure of one magneto is rare, the failure of both together is almost impossible. If during the pre-flight check it appears one of the magnetos fails, you have to cancel the flight.

You surely already started the simulator and typed { to shut the engine down. So now you want to start it back on. Type } three times in order to put the magneto switch on BOTH. To start the engine press the Space Bar. Keep it pressed a few seconds, till the engine is started.

You can also turn the magneto switch and start the engine by clicking left and right of the switch (normal mouse mode). Type Ctrl-c to see the two click sides highlighted by yellow rectangles.

If you turn the switch to OFF, the engine noise stops. If you quickly turn the switch back to L, the engine starts again, though you didn't turn the switch to START. The reason is the propeller was still rotating. You should have waited till the propeller came to a halt. Then, placing the switch on L, R or BOTH won't start the engine. (Once the engine is halted, always place the magneto switch to OFF.)

Now about the throttle:




You already know you increase the engine power by pushing that throttle lever in (Page Up key). You decrease the power by pulling the lever out (Page Down key). You can also click left and right of the lever (middle mouse button for quicker moves, Ctrl-c to highlight the left and right halves).

What means "increase the power"? Does it mean you increase the amount of fuel delivered to the engine? Yes, but this is not enough to fully understand what you are doing. You need to be aware that the engine is also fed with a huge amount of air. The engine's cylinders burn an intimate mixture of fuel and air. Fuel alone wouldn't burn. Only a mixture of fuel and air can detonate and move the engine pistons. So when you push the throttle in, you increase both the fuel and the air fed to the engine.

The amount of air compared to the amount of fuel matters a lot. The proportion of the two has to be tuned closely. This is the purpose of the mixture lever. The picture below displays the mixture lever, far too much pulled out:





When the mixture lever is fully pushed in, you feed the engine with an excess of fuel. When the lever is pulled out completely, there is an excess of air. The correct position is in between. Usually quite close to fully pushed in.

When you start the engine and when you take off, you need a fuel-rich mixture. That means the mixture lever pushed in. A fuel-rich mixture allows the engine to start easily. It also makes the engine a little more reliable. The drawback is that a part of the fuel is not burned inside the engine. It is simply spilled away. This makes the engine more polluting, it decreases the energy the engine can deliver and it slowly degrades the engine by causing deposits of residues inside the cylinders.

Once in stable flight, you have to pull the mixture lever a little, to get the optimal mixture. Check this out by doing the following. Start the simulator. Put the parking brakes on with key B (that is Shift-b). Push the throttle in to its maximum. The engine RPM are now close to the maximum. Slowly pull on the mixture lever (using the mouse in normal pointer mode). You will see the RPM increases a little. You get more power, without increasing the fuel intake. You spill no more fuel in the engine and it pollutes less. If you continue to pull the mixture lever, the RPM will decrease back away, because now there is too much air. The excess of air slows the explosions down inside the cylinders and decreases the explosion temperature, hence the thermodynamic yield decreases. You have to tune in the optimal mixture. You can check you get the optimal tuning by the fact you get the highest RPM. (Another method is to check the engine exhaust temperature. Roughly, you need to get the highest temperature.)

Question: why a mixture lever? A car contains no mixture lever and drives fine. There are two answers. First is a car is not an optimal device. An airplane is, hence it needs fine tunings. Second and more fundamental answer is a car operates at constant altitude. So the mixture tuning can be tuned in once and forever by a garagist. A plane rises in the air. The higher the altitude, the less dense the air is. Hence the openings or pumps that let the air into the engine have to get wider or pump stronger in order to inject the same weight of air into the cylinders. So when you gain altitude, you have to pull a little on the mixture lever to keep an optimal fuel/air mixture. When you descend back to the ground, you have to push the lever back in. (Actually, if you live at sea level and you move to a new location high in a mountain country, and you take your car with you, you should ask a mechanic to adapt the mixture tuning of your car. Should you drive your car back to sea level, it will drive fine but it will be less powerful and more polluting... I suppose modern cars contain some electronics to control this.)

You have to take the mixture lever seriously. It allows you to burn less fuel for the same speed and distance, hence to fly farther away and pollute less. It can also cause serious trouble. Suppose you go flying at high altitude and pull on the mixture lever accordingly. Then you descend back in order to land. But you forget to push the mixture lever back in. The fuel/air mixture will become far too rich in air and the engine will simply halt. You may think the engine is failing and panic, while you only have to push the mixture lever back in...

When landing, you have to tune back in a mixture that is a little too rich in fuel. This means pushing the mixture lever in. That way the engine becomes a little more reliable and will be better adapted to a decrease in altitude.

I wrote above that placing the magneto on OFF is not the right way to stop the engine. The right method is to pull the mixture level. First pull the throttle out completely, to get the engine to minimum power and fuel consumption. Then pull the mixture lever, till the engine stops because the mixture contains too much air. This ensures the engine doesn't get poised by spilled fuel residues. Finally, turn the magneto switch to OFF to ensure the engine won't start back accidentally (for example because strong wind makes the propeller turn).

An important warning: you may think the RPM indicator reflects the engine power. Wrong. Two things make the RPM increase: the engine power and the airplane speed. To check this, fly to a given altitude then pull the engine power to minimum. Try out diving to the ground then rising back to altitude. You will see the RPM varies strongly. It rises while diving and decreases while rising, together with the plane speed. Though you didn't tune the engine power. One pitfall of this is when you intend to tune the engine power in for landing. Suppose you're flying fast. You know the ideal RPM for landing is around 1,900 RPM. So you pull the throttle till you get 1,900 RPM. You think you tuned in the appropriate RPM. You think you shouldn't bother any more about it. But now the plane's speed decreases. Hence the RPM decreases. A few minutes later, you get the low flight speed you wanted. You don't see the RPM is now at 1,000. Far too slow. You will either lose altitude or stall. Or both. So, be cautious with the throttle and with the RPM indicator. Either pull on the throttle more steadily or be mentally prepared to push it back in quickly.




Wings and speed


Fly with full engine power. Diving the nose a little makes you lose altitude and raising the nose a little makes you gain altitude. You may think this is quite logical. The plane travels in the direction it is heading; the direction the propeller is heading. This is not the appropriate way to think about it. It would be fine for a rocket, but not for an airplane. A rocket is lifted by its engine, while a plane is lifted by its wings. That's a huge difference.

Get a big rigid square of cardboard, hold it horizontally in your hand with your arm stretched out and make it do fast horizontal movements while rotating your torso. When the cardboard moves flat through the air, it experiences no lift force. If you twist your arm slightly to give the cardboard a slight upward angle, you will feel it tends to lift in the air. There is an upward force acting on the cardboard. That's the way a wing holds a plane in the air. The wings have a slight upward angle and lift the airplane. The more angle you give the cardboard, the more lift force. (Till you give it too steep an angle. Then you will rather feel a brake force. The cardboard is "stalling" (see below).)




What matters is the angle the wings travel through the air. That's the angle of attack.

I wrote above that when the wings travel through the air with no angle, they don't lift. This is false. It would be true if the wings were a flat plate like the cardboard. But they aren't. The wings are a slightly curved airfoil. That makes them create a lift even when traveling through the air at no angle. Actually, even with a little negative angle of attack they still create a lift force. At high speed the airplane flies with the wings slightly angled towards the ground! This is not very important...




The angle at which the wings travel through the air matters, something else matters too: the speed. Take the cardboard again in your hand. Hold it with a given slight angle and don't change that angle. Check that the faster you move the cardboard, the more upward lift force it experiences.
To make things a little more complicated: when rising in the air, the airplane tends to lose speed. When descending, it tends to gain speed.

That's all a matter of compromises. If you want to fly at a constant altitude and at a given speed, you will have to tune both the engine power and the yoke/elevator (or better: the trim (see below)), till you get what you want. If you want to descend yet keep the same speed, you have to push the yoke a little and decrease the engine power. And so on. You constantly have to act both on the engine power and on the yoke. (During a normal flight one doesn't make things that complicated. Simply tune in a comfortable engine power level then forget about it and rely on the yoke and trim for the altitude.)

A very interesting exercise you can perform with the simulator is to fly straight with full engine power. Get maximum speed while keeping in horizontal flight. Then you decrease the engine power to minimum. And you pull steadily on the yoke to keep the plane at constant altitude. The plane slows down steadily, meanwhile you pull more and more on the yoke. Since the speed decreases the lift of the wings would decrease, but you compensate the loss of speed by increasing the wing angle of attack. (This proves the plane does not necessarily travel in the direction its nose is heading. In this experiment we make the nose rise in order to stay at constant altitude.) Once the plane is severely slowed down, and the nose is strongly heading upwards, you may hear a siren yell. That's the stall warning (see below). The angle of attack of the wings is too strong. The wings are now braking the airplane instead of lifting it. The plane quickly loses altitude. Whatever you pull on the yoke, you're falling. The only thing you can do is push the yoke forwards, make the nose dive, gain speed and glide towards the ground. Possibly push the engine throttle back in to full power.

Question: is it better to control the airplane's speed and altitude with the yoke or with the throttle? Answer: it depends on what exactly you intent to do and on the situation you are in. In normal flight, as said above, you tend to set a comfortable engine power level, forget about it and rely on the yoke and trim. During take off and landing the procedures are quite strict about the use of yoke and throttle. You do the opposite: control the speed with the yoke and trim, control the altitude and descent speed with the engine throttle. That will be discussed in chapters below.

For long range flights, to spare fuel costs or for ecological concerns, one can fly a plane in "economy mode". The you try to tune the wings angle of attack so they brake the less, you try to tune the engine, you try to find the most appropriate speed and altitude... Its all a matter of compromises. You will often fly slower than the usual cruise speed.




The flaps


The flaps are situated at the rear of the wings, aside the plane's body:





Deploy the flaps and pull them back in by using the flaps control lever:



 

You can either click on it with the mouse or use the [ and ] keys. Key [ to retract the flaps one step, ] to deploy them one step. Type v to view the plane from the outside and try out [ and ]. (On the schematic instrument panel the flaps lever is located at the lower right.)

There are four flaps steps:
There is a security risk. Do not deploy one flaps step above 110 knots. Do not deploy two or three flaps steps above 85 knots.

The flaps brake the plane at high speed. This is one more reason not to forget to pull the flaps back in once you fly above 85 or 110 knots.

My favorite way to know the flaps position is to type Shift-right arrow. Then quickly Shift-up arrow to get back to front view. Another method I use is to make sure the flaps are fully retracted by quickly typing [ several times. Then type ] the exact amount of times needed.

The role of one flap step is to increase the wing lift. The wing lifts more at a given speed. Hence you will get in the air a little sooner during take off. It also has the effect to make the plane fly with the nose a little more downward. This is handy: it allows to keep an eye on the runway while rising in the air. It allows a better view on the runway during landing.

The role of two or three flaps steps is to brake the plane. This is mandatory when landing, because the airplane glides very well. If you cut down the engine power completely, sure the plane will descend, yet too slowly. You need to deploy two or three flaps steps in order to brake and really descend towards the ground.

The fact that the flaps brake during landing makes you need more engine power during the landing. This can seem odd. Why not simply throttle the engine down to minimum and use less flaps steps? The answer is it's better to have a strongly braking plane and lots of engine power, because then the plane reacts faster to your commands. Should the engine fail, then retract flaps as needed...

Trying to take off with two or three flaps is a bad idea. This can sound fun, but beware: suppose you deployed one flaps to take off. Yet you forgot to pull the flaps back in. Later on you encounter a emergency situation and you need to gain altitude very fast. You deploy one flaps step. Actually you add one flaps step to the flaps step already out. So now you have two flaps steps. Hence the flaps are braking and you fail to gain altitude... Whenever you feel the plane is behaving really odd and seems unable to rise in the air, or even keeps falling whatever your efforts and the engine power, think maybe you deployed more than one flaps steps.

Redundancy... What can you do if the flaps don't deploy and you really need to brake? Answer: slowly push the rudder pedals on one side. This will make the plane present its flank to the air stream and brake. Compensate the turning by using the ailerons (yoke). This is not a very comfortable way to brake and you should train it before using it close to the ground. (I tried to use both the full flaps, the rudder to an extreme and the throttle to minimum. You really loose altitude very quickly...)




The stall


A stall is an emergency situation, at whatever altitude. It means the plane is flying too slowly hence the wings travel through the air at too strong an angle. The wings suddenly start braking the plane instead of lifting it. It is especially dangerous when close above the ground. It is dangerous even at high altitude because you lose part of your control over the plane.

During a normal flight, a stall should never occur. As a pilot you have to constantly keep the plane well above stall speed. Once the stall siren yells, it means things already have gone very bad.

A stall during take off is particularly dangerous. It's a diverging phenomenon and you cannot get out of the stall before the plane hits the ground. While standard procedures and training makes this event unlikely, it has killed many people. Quite dangerous in that regard are some underpowered little aircraft build by amateurs.

Some little airplanes are designed to land using a near stall. Planes like the Cessna 172 are designed to make stalls less likely to occur and less deadly when they occur. That's for example one reason why the wing extremities are square. The Cessna is still controllable during a stall and a simple stall and fast descent to the ground should not kill the passengers. (Wind turbulences or a strong bank can make things go worse...)

A stall can make some airplanes go into a deadly spin. Fly for example the F-16 Falcon to some altitude, throttle the engine down to minimum and pull steadily on the yoke to keep the same altitude while decelerating... One problem with the legendary WWII fighter plane Spitfire was during too tight turns the inside wing would suddenly stall completely but not the outside wing.

What can you do during a stall? The procedure can be very different on different planes. You should not trust this tutorial, especially not for such a serious matter. Anyway:
Stall-elegant airplanes like the Piper J3 Cub and the Cessna 172 tend to have roughly rectangular wings. While stall-ugly airplanes like the F-16 Falcon and the Cessna Citation II tend to have trapezoidal wings. The advantage of the trapezoidal wings is they have a better aerodynamic yield. They allow to fly more distance with a same quantity of fuel. The ends of the rectangular wings engender strong turbulences. Those turbulences brake the plane but also they keep the air flowing correctly once the plane stalls...

When you learn to fly a virtual plane, making it stall is a very good exercise:
Try to perform the exercises above with different airplanes. You will notice how elegant the Cessna 172p behaves. First time I tried a stall with the virtual Cessna Citation II, I was at 1,000 feet altitude, which is supposed to be safe. The plane suddenly fell from the sky like a tumbling stone. I was not able to stabilize the plane and it crashed. I was really frightened by that airplane. On second attempt I managed to stabilize before the plane hit the ground. Anyway, from now on I won't fly a Cessna 172p and a Cessna Citation II with the same mood.

If you fly an unknown virtual airplane and wish to know the landing speed, a rule of thumb is you find out the stall speed by experimenting. Then you multiply that speed by a factor of 1.2 or more. (A friend who is Aerospace Engineer told me 1.2.) The stall speed of the Cessna 172p is 40 knots yet its imposed landing speed is 70 knots (minimum 65 knots). That makes a factor of 1.75... I made an experiment landing the virtual Cessna 172p at 50 knots. It virtually falls to the ground, at close to -1000 feet/minutes vertical speed. This seems very hard for the landing gear. Next, while approaching at 50 knots with the Cessna 172p, the runway and most of the ground are completely hidden. This obviously tells a higher speed is mandatory. I would recommend following rules to find a correct landing speed. It must be the lowest possible speed that satisfies all these conditions:
On big jet airliners the flaps make a lot of difference. Bear that in mind when you try to find the stall speed. Make the experiment with the flaps deployed, as they will be deployed during the landing.

The load of the airplane also changes the stall speed a lot, and therefore the landing speed. You land a fully loaded airplane at a higher speed than an empty one.

(Once you get used to landing different airplanes, you get a feeling for the landing speed of an unknown airplane. You just feel the airplane "wants" to land at that speed. I suppose this is because the airplane was designed to land at that speed.)

! In a real airplane the sounds and vibrations tell a lot about the state of the airplane. When all vibrations stop, this means you are going to stall. Then push the yoke to get speed.




The trim


The trim is that dark big vertical wheel with gray dots located at the middle below the instrument panel:





On FlightGear, the keys Home and End are used for the trim. The key Home rolls the wheel upwards while the key End rolls the wheel downwards. You can also click on the upper or lower half of the trim wheel (Ctrl-c for a yellow highlight). Possibly look at the plane from the outside (v or V and x) and move the trim while looking at the elevator.

In first approximation, the trim does the same as the yoke: it acts on the elevator. Turning the trim wheel downwards is the same as pulling on the yoke. Yet there is a key difference between the trim and a real yoke. If you tune the trim, it keeps that tuning. While if you pull or push on the yoke, it goes back to neutral once you release it.

Once in flight, you would keep the mouse/yoke at a given forward (or backward) position. That position is optimal to keep the plane at a roughly steady altitude. In a real airplane, this means you would constantly keep pushing (or pulling) on the yoke. That would be quite uncomfortable. This is where the trim falls in. You tune the trim to impose a default elevator angle. Then you no longer have to push or pull the yoke constantly. In other words: make a global rough tuning with the trim and occasional fast tunings with the yoke/mouse.

The trim is an important control. I tend to forget it, for two reasons. First is the mouse makes the trim virtually useless. This is quite unnatural of course. People with a force-feedback joystick/yoke will feel the need for the trim, as well as people flying real airplanes. Second is the trim didn't operate on the particular version of FlightGear I was using until recently...

During take off the trim must be neutral. You have to check the trim is centered before every take off. Also if you abort a landing and start rising back to altitude, put the trim to neutral. Otherwise the plane may buck.

During landing, while flying at a constant speed of 70 knots and a constant altitude of 500 feet, the same applies as for a steady flight: try to get the yoke/mouse/elevator towards neutral position by tuning the trim. On the Cessna 172p this means trim on neutral (except when the plane is loaded). On the Cherokee Warrior II this means the trim a little "pulled".

During the final dive, some people seem to let the trim as it is and use the yoke, others make the dive using the trim and don't use the yoke/elevator. I don't know which is best. I use the yoke.

To know the trim position, use the HUD (h, H and I) or the I-shaped indicator on the schematic instrument panel (P).

The trim movement is very slow. Be patient.

Lots of modern airplanes have a remote control for the trim: a little switch on the yoke, that you can manipulate easily with your fingers. So you don't have to duck to roll the big wheel.




What direction am I flying?


Four basic methods exist to know what direction you are flying:






! During a real flight in a real airplane, you are supposed to cross-check all direction indicators once in a while.

Memorize the directions: North is 0°, East is 90°, South is 180° and West is 270°.




A realistic take off


By now I assume you are able to keep the airplane on the runway while taking off (rudder) and you're able to fly straight, descend peacefully, gain altitude steadily, make gentle turns (yoke)... No need you perform this all perfectly. Yet a basic and approximate control of the airplane has been acquired.

Rules during take off:
So, you need to take off and rise in the air at a steady speed of around 75 knots.

Problem: since the front wheel is slightly lifted and the flaps are one step deployed, the plane will rise from the ground already at 55 knots. That's well below the desired flight speed of 75 knots. What to do then? Answer: as soon the two rear wheels lift from the ground, push the yoke forwards a little. Keep the plane close above the ground. (The aim of this is: should a wind blow from the rear occur, the plane will fall from only a few feet hight.) (Please do not train to keep the plane exactly two feet above the ground. Doing so would be dangerous. Do allow the plane to rise slightly while it accelerates, but, simply put: do not favor this tendency.) So, keep it close above the ground while accelerating, till a speed of about 70 knots is reached. Then switch to the opposite mode: now you must pull on the yoke to prevent the plane from going above 75 knots. Force the plane to rise in the air, so it doesn't gain speed. Keep in control. If the speed goes below 75 knots, push a little on the yoke. If it rises above 75 knots, pull a little on the yoke. Till you reach 500 feet above the ground.

This is the procedure I use to take off. I assume you just started FlightGear; the airplane is at the start of the runway and the engine is turning at minimum power:









500 feet above the ground is the minimum flight altitude above open land. Above a city the minimum altitude is 1,000 feet.

If you take off from KSFO heading to the West, you have city areas in front of you and left of you. So, once you reach 500 feet above the ground, best turn to the right.
Don't forget to center the rudder. If the rudder is pushed to one side, this will brake the plane. It makes the plane move sideways through the air, with its flank aerobraking.

Don't forget to retract the flaps.

! During a real take off you must keep in touch with the control tower. You also have to constantly look in all directions to check no other airplane is coming in your direction.

An aviation classic is the ground effect. It's the fact a wing lifts better when close above to the ground. That too makes the wheels leave the ground at quite a low speed, a speed at which the airplane cannot really fly. While you are accelerating a few feet above the runway, you are in ground effect. If you know about it, ground effect is an advantage because it makes flying close above the ground more secure. The airplane behaves a tiny little bit like a hovercraft. If you are not aware of the ground effect, it can cause problems. For example it can make you think the airplane has enough speed to rise in the air, while it has not.

! During a real take off, if the engine halts below 500 feet, you are not allowed to turn and try to glide and land back on the runway. You only have enough height to try to turn and land back if you are above 500 feet when the engine halts.

! Before a real take off you have to go through check-lists. A checklists makes you verify, tune and tighten a list of items. You have to follow a long checklist before you enter the runway and a short checklist before you accelerate to take off.

This is the checklist I follow when I take of the virtual Cessna 172p on FlightGear. It is very short compared to a real checklist. Anyway I know I can go into (moderate) trouble if I don't follow it. I had to build up the discipline to follow it carefully each time:



Landing


When I was a boy, I had a simple yet fairly good flight simulator on my Sinclair ZX Spectrum home computer. I could do everything with it, except landing. I always crashed the plane, or reached the end of the runway before stopping. One day a real pilot saw me trying to land. He had never seen a flight simulator, but he had no problem to recognize each flight instrument and ground feature on the screen. He told me what to do. Decrease engine power, increase engine power, push the nose down, pull the nose up, turn a little left, turn a little right, get the flaps out... We made a perfect landing on the second attempt.

Just like for take off, landing is partly a procedure, partly rules you have to stick to. You have to adapt constantly.

Same basic rules apply as for take off, yet in reverse order:
(If you know what you are doing you are allowed to use a speed a little below 70 knots: 65 knots.)

Following rules are essential during the whole procedure of landing:
The reason why the yoke/elevator is used to tune the speed is this method allows for fast reactions and fine tuning. It is more important to tune the speed closely than the altitude.

If you are both a little too high and a little too slow, simply push the yoke a little and both problems will be solved together. No need to use the throttle. Use your mind...

You have to get aligned with the runway. That means your flight direction has to match the middle line of the runway (drawing (a) below). In order to arrive at this, don't aim at the start of the runway (b). Rather aim at a fictitious point well ahead of the runway (c). And begin to turn gently towards the runway well before you reach that fictitious point (d). Note the turns and bankings you make for these flight corrections are often very soft. You wouldn't even notice them on the turn coordinator. This is one example where you better rely on the outside horizon line than on the inside flight instruments.





Try to get aligned with the runway as soon as possible. Constantly apply the alignment procedure. The closer you come to the runway, the better the alignment should become. At tip: if you see that the two sides of the runway form an equal angle towards you, like / \ , this means you are above the middle line of the runway (supposing that middle line extends in front of the runway). So, if you see the runway neatly / \ and it is perfectly in front of you; in the middle of your flight direction; everything's fine. But if the runway is neatly / \ and it is situated to the right or to the left, this means you should have turned earlier to align. Now you sure are above the middle line extending from the runway, but you are flying in a wrong direction, away from that middle line and from the runway start...

My favorite landing procedure for the Cessna 172p is roughly this one:






Once the plane is halted or at very low speed, you can release the b key (if you used it) and add a little engine power to taxi to the parking or hangar.

To shut the engine down:
To set the parking brakes in, type B.

You must be mentally prepared to abort landing anytime. Whatever happens: an order from the control tower, a wrong speed or landing angle, a wrong alignment with the runway, a strong blow of wind, birds flying over the runway... retract the flaps to one, push the engine to maximum, center the trim and get back to high altitude. Then either you restart the landing procedure or you go for another airport. The pride of a pilot is to make only safe landings.

Don't try to find "the ideal distance" to start diving to the runway. The procedure above proposes you start diving when the white engine cover starts eating the runway edge (provided you fly at 70 knots with one flaps step) (the altitude doesn't matter). Best is you train to land while starting the dive earlier and while starting to dive later. You need to be trained to increase or decrease engine power according to what is needed. During a real landing, depending on the airplane's weight, the wind speed and other random things, the "ideal" moment to dive is unpredictable. As experience builds up, you will better feel the right moment.

If you want to make things simple for your first landing trainings, make use of the fact the runway at KSFO is very long. Wait a little more before you begin the dive: let the nose "eat up" the whole length of the leading part of the runway (let the successive pairs of white strips on the runway disappear below the airplane nose). Then lower the flaps to three steps and decrease the engine to minimum. Dive to keep the speed around 70 knots and try to keep aligned with the runway. You will end the dive quite far beyond the runway start and at a high vertical speed, but who cares. Make the final rounding. Keep aligned with the runway and try to fly close above it. Keep pulling more and more on the yoke/mouse, to keep the airplane flying. Yet avoid it rising in the air. Till the wheels touch the ground. Then just keep the airplane on the runway, using the rudder. Once the speed is below 40 knots, push the yoke/mouse and keep key b down to brake.

If you are a newbie, you probably won't succeed to apply the procedure perfectly. My advice: invent your own, more simple procedure. Then regularly come back to the procedure listed here and read it again, to get hints and ideas to better your procedure. Till you get it. Also best read other landing procedures. Send me a mail if you find interesting differences. Analyze your own procedure. If it implies to fly at very low speed, it is dangerous because a blow of wind from the rear will make the plane fall. A probable problem with your procedure is the plane needs a lot of runway length to land. If you look at the runway start you will see there are successive groups of white stripes. I land the Cessna 172 always well before the last group of stripes. If you are a real beginner, your procedure surely will make the plane tilt over or crash once in a while. The procedure listed here is safe. Train your procedure, again and again. The more you train it, the more you will become able to use the one listed here. That's the way I learned to land...

! In a