The Axes of an Airplane and Their Purpose

Controlling and steering an airplane is much different than driving a car. For one, stability and maneuvering is vastly different. Boats and cars both two dimensional whereas an aircraft is three dimensional. The three dimensions that determine an aircraft’s stability are its axes. The axes are what control the roll, pitch and yaw.

What are roll, pitch and yaw? Imagine, if you will, three lines. All three lines form intersecting right angles at the airplane’s center of gravity.

Roll: rotation around the front to back axis. Imagine a string running a straight, horizontal line starting from the airplane’s nose all the way to its tail. Now, if the airplane rotated about this string, it would be rolling.

Pitch: rotation around the side to side axis. Imagine another piece of string running in a straight, horizontal line across the wing span from one edge to the other. If you turned or rotated the string, the airplane would be pitching up or down.

Yaw: rotation around the vertical axis. Now, if you take the same piece of string used in the pitch example but instead of rotating, moved it back and forth this would be creating yaw.

Roll,-Yaw,-Pitch_lg_0

The purposes of roll, pitch and yaw.

Roll: Rolling an airplane allows the airplane to make a turn. As covered in the previous lesson, lift is vertical. When an airplane banks or rolls into a turn, the vertical lift becomes horizontal. The horizontal component of lift is what turns the plane. The ailerons rolls the airplane and allows it to turn.

The ailerons can be found on the outer edge of the wing. One on each wing. Both ailerons move in opposite directions. So if the left aileron is up, the right one will be down and vice versa. When an aileron is up, lift is decreased bringing the wing down. When the aileron is down, lift is increased bringing the wing up. This allows the airplane to roll.

aroll

Pitch: The elevators control pitch. The elevators can be found on the horizontal tail surface of an airplane. They move up or down. Unlike the ailerons, they move in the same direction in unison. The movement of the elevators decreases or increases lift on the tail which tilts the plane’s nose up or down.

712-l3-elevator-pitch_lg

Yaw: The rudder controls yaw. The rudder can be found on the aircraft’s vertical tail fin next to the elevators. It moves from side to side. The rudder’s movement pushes the tail either to the left or right. The rudder is crucial along with the ailerons in turning an airplane smoothly.

712-l4-rudder-yaw_lg

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Finding Your Stability

When you take the exam for your Private Pilot License, you’ll most likely come across the phrase longitudinal stability. When the FAA talk about longitudinal stability, they mean pitch stability. Is the airplane’s nose pitching up and down?

On any map or globe, longitude is shown as a vertical line. It’s the same with an airplane. This is why longitudinal stability refers to the pitch of the airplane. An airplane that is flying along in smooth and level flight is said to be inherently stable. An airplane that is inherently stable will require less control.

Most airplanes are designed that if you pull up on the yoke and then let go, the nose will come up and then go back down returning to equilibrium. Test it out sometime when you’re flying. Pull the yoke back. The elevators will move up and the nose will pitch up. Release the yoke and the elevators will return to neutral position. The airplane will return to equilibrium.

If the airplane oscillates or bounces up and down as if riding a wave, the oscillation or wave will eventually get smaller and smaller until the airplane returns to equilibrium. Below is a picture of an airplane oscillating.

400px-Phugoid8

What determines the longitudinal stability of an airplane? The location of the center of gravity in relation to the center of lift and tail down force. Most aircraft are designed so that the center of gravity is in front of the center of lift. Look at the picture below.

ABobH

The center of gravity causes the airplane to want to dive down nose first. The center of lift wants to uplift the airplane as if it was attached on a string. The down force on the tail pushes the airplane downwards tail first. All three of these elements cause the airplane to stay flying in the sky. Let’s talk about these three more in detail.

The center of gravity or weight is located in front of lift. It’s the point over which the airplane is balanced. To better explain this, imagine a seesaw or teeter totter. In the center of the seesaw is a small post on which it is balanced. This post is the seesaw’s center of gravity.

seesaw

Lift or center of pressure is the force that directly opposes the weight of an airplane. In other words, it is the opposite of the center of gravity. By opposing the aircraft’s weight, lift holds the aircraft in the air. Lift is produced by the motion of air rushing across the plane.

The down force on the tail is final piece that keeps the airplane stable and flying. There are two factors that attribute to the down force on the tale. (1) Design. (2) Air or wind.
The tale is purposefully designed as an upside down wing. Let me explain in more detail. The curvature of a wing is called the camber and is crucial in creating lift. Since a wing’s camber is curved, the air flowing over the top of the wing is much faster than the air rushing beneath. This causes low pressure above the wing and high pressure beneath. This large difference in pressure is one of the factors that creates lift.

Remember that the tail of a plane is just an upside down wing. Because the tail is upside down, the pressure in air is switched. The air beneath the wing is accelerating and the air above is going slower. This causes the air beneath to have high pressure and the air above to be low. This difference in pressure between both wings generates lift and helps keep the airplane balanced.

If you’re still confused or have more questions, I’d suggest looking up the Bernoulli effect.

 

Bernoulli_effect

Slow Flight
If an airplane slowed down, the wind rushing over the tail would decrease. Three elements would become unequal. The center of gravity would have more weight than the down force on the tail. This would cause the tail to come up and the nose to dive down. So, the down force on the tail is what helps make the airplane stable as far as pitch and speed are concerned.

Changing the Center of Gravity
It’s difficult to change the center of pressure in an airplane, but easy to change the center of gravity. By moving luggage around in an aircraft or adding passengers, the center of gravity is changed. But be careful when changing an airplane’s center of gravity because it can cause the airplane to become less stable.

Aft CG Limit
– Aft: towards the tail or back of airplane
– CG: Center of Gravity
There is a limit to how far aft luggage or weight can be loaded until the airplane loses stability. The same goes for how far weight can be moved towards the center of pressure or front of the airplane. When weight is moved to the aft CG limit, the airplane will become less stable because there is a decreased in down force on the tail. This will cause the airplane to have a slower stalling speed but higher cruising speed. On the other hand, when weight is moved behind the center of pressure the airplane will want to nose up and enter a stall. The aircraft will become less stable and less efficient.

Here it is broken down in bullet points.
Weight Moved Aft CG Limit
– Cruising speed decrease
– Stall speed increase
– More efficient, less stable

Weight Moved Forward CG Limit
– High stall speed
– More longitudinal stability
– More stable, less efficient

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Always Know Your Instruments!

Instruments can be very confusing at first to learn and little bit intimidating. I’m still learning to master them. I’m still figuring out what exactly they all mean and how I should use them.

Today, I went under hood. Which translates to I had use foggles to instrument training. This training requires you to wear foggles so you can’t see outside the airplane. All you can see are your instruments. It forces you to learn your instruments.

Before I started my instruments training, I’d always been confused why pilots who’d flown in the clouds would talk about disorientation. They’d tell about times when they flown in clouds where they had no visibility and they quickly became confused and disoriented. I didn’t understand how anyone could feel disorientated while in a small plane where you feel every bump. I thought, wouldn’t you be able to tell if you started flying upside down or sideways? Wouldn’t gravity let you know?

Today, I realized for the first time exactly what they’d meant. When I put on the glasses, I couldn’t see my outside world. All I could see was my instrument panel. It was as if I’d flown into a cloud and couldn’t see anything around me. It was a little bit nerve racking. And I quickly realized how one could easily become disorientated.

As I watched my instruments and did a standard turn, my body could feel the plane start turning but I had no idea which way. It’s interesting that your body can feeling the motion of turning but not the direction. I never understood this until now.

Below I’ll go over the instruments and their uses.

AIRSPEED INDICATOR
airspeed-gauge-labels
An airspeed indicator shows how fast airplane is moving through the air. It calculates this by measuring the difference between total air pressure and static air pressure from the pitot tube.

ALTITUDE INDICATOR / ARTIFICIAL HORIZON
RCA227
The altitude indicator or artificial horizon shows pilots where the horizon is positioned at. Pilots use the it to help them judge how an airplane is orientated. Are we turning? Are we descending or ascending? The indicator shows the airplane’s wings in relation to the horizon.

ALTIMETER
United_Altimeter_1
The altimeter was once called the Altitude Meter but was shortened to altimeter. It shows the airplane’s height above sea level. It can measuring the height by sensing the change in static air pressure caused by a change in altitude.

TURN COORDINATOR
turn-coordinator
When I first started flying, I’d confuse this with the Artificial Horizon. The turn coordinator is different. It doesn’t show you if the plane is level with the horizon. What it does show you is if your ailerons and rudder are coordinated. It also shows the degrees of bank your turning and your rate of turn. It helps pilots through a turn. It uses a gyroscope to show the rate and direction of a turn.

HEADING INDICATOR
Reference-Instrument-HeadingIndicator_560
This shows the direction in which the airplane is headed. The heading indicator uses a gyro to indicate the direction. It’s much better to use this than a magnet compass for direction. Magnetic compasses are prone to errors which result from the speed of an aircraft.

VERTICAL SPEED INDICATOR
vertical-speed-indicator
The vertical speed indicator shows the airplanes rate of climb or descent by measuring how fast static pressure changes as the aircraft climbs or descends.

My advice to anyone flying, learn these instruments well. You’re life may very well depend on them. They’re important!

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Video of My First Flight Lesson

This video was taken about a month or so ago of my very first flight lesson! I wasn’t very nervous since I’ve flown in small airplanes a few times before. But I was excited! Being able to see the landscape, cars and world from such a high view was thrilling. And sometimes distracting 🙂

https://youtu.be/J_aycIbcYF8

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School of the Kings

When I started doing my ground school studying, I was told about King School. I’d heard many comments about King School. John and Martha King, two very experienced pilots, have a ground instruction kit that they sell. The kit is either videos or books that basically teaches how to fly and what makes flying possible and etc. From the many comments and opinions I received regarding King School, I formed a general picture of them as being over-the-top cheesy/corny but very thorough.

I decided to go with another ground instruction program. I’d thought to myself, those Kings are probably too cheesy for me.

I ended up going with MZeroA by Jason Schappert. His videos are entertaining and won’t put you to sleep. I watched many of his videos all the way til unit 4. Then I started having problems. I’d like to point out that Jason is a very good instructor and knowledgeable. But his MZeroA private pilot course wasn’t as thorough as I thought it’d be. After three units, I began hitting the advanced stuff like density altitude and understanding airspace. I had only 1.6 hours and taken two flights by that time. The ground schooling quickly turned into a snowball of doom. I stopped watching the videos and searched for another outlet.

My instructor gave me a book which was much more thorough. It was made by Piper Aircraft and from the 70’s. I studied through the first chapter and began getting confused when I hit chapter two: radio communications. It didn’t properly teach an airplane’s NAV/COM like I needed it too. Also, I believed some of the information was a little outdated. These days we have GPS and more advanced communication systems than what the 70’s did. Again, I searched for another outlet.

A friend gave me King School Private Pilot Course videos to watch. I remember looking at the folder full of King School videos and thinking about how quickly I’d probably be put to sleep by them. I started watching the videos.

When you set your expectations low, there’s a high chance you’ll be pleasantly surprised.

I was pleasantly surprised. King School had indeed turned out to be thorough. Very thorough. But more than that. It was highly informative and packed full of information. It was also very easy to understand. They could explain the complicated process of stalling an airplane to a two-year-old child and make perfect sense. The videos were corny yes but not as terrible as I’d expected.

In the very first video John King says, “What makes an airplane fly? Money.”

I do have to point out that unless you’re interested, you’re bound to end up bored to death. The King School is probably still the best ground school out there even if very cheesy.

LindbergFoundation

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It’s Almost like Owning A Dragon

fly-dream-love-pretty-quotes-quote-Favim.com-610750

I’ve always wanted to own a dragon. From the time when I was really small, I loved dragons. I’d read about. Look at their pictures in books. Whenever a new movie with a dragon in it came out, I’d have to see it. Dragons were my favorite thing.

But sadly, I knew I could never own one. If they ever did exist, they don’t anymore. Flying an airplane is sort of like owning a dragon. And it’s good enough for me. It’s the closest we humans can come to flying.

After getting over the airsickness and becoming accustomed to flying, it’s becomes this beauty thing. A romance in the sky. You can do anything (almost). Go anywhere. Possibilities are infinite. If you want to get a little crazy, you can fly loops and spins as long as you’ve been trained.

Owning a real dragon would have its dangers I’d imagined. So does flying. If you aren’t trained to fly in the crowd or do fancy aerobatics, then don’t fly in the clouds/bad weather or do any crazy maneuvers. Flying in the crowds, from what I hear, can be a bit scary. Apparently, it’s really easy to become disorientated. You lose your sense of balance. I’m not IFR certified or had any IFR training, so I couldn’t tell you exactly what it’s like.

But what I can tell you is that there is nothing like flying. Nothing like being up in the great blue and knowing that just at your fingertips is the greatest freedom of all.

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Traffic in the Skies

PPL310

SEGMENTED CIRCLE
A segmented circle indicates the traffic pattern at the airport. It’s used to tell the pilot what the pattern direction is for each runway. Runway 16 has a different direction than Runway 34. For example, Runway 16 might have a left-hand pattern and Runway 34 a right-hand pattern.

The segmented circle can usually be found in the center of the airport. It has two L-shaped legs which stick out. These legs are what indicate the traffic pattern. They show how the base and final legs of the pattern should be flown. For example, the L-shaped leg on the south side of the circle corresponds to the base and final legs on the south side of the airport.

The segmented circle must be large and bright enough for the pilot to see from pattern altitude. It should be used when the traffic pattern or runway in use can’t be determined by communicating with ground control or watching other aircraft. A flashing amber light inside the circle or on top of a nearby building means a right-hand traffic pattern is in use.

AirportTrafficPattern

The FAA’s regulations for a traffic pattern is a few lengthy columns that can be found in your FAR AIM. The gist of it is that an aircraft approaching an airport to land will circle or make all turns to the left unless otherwise directed. If you’re coming to an airport to land, you must either circle or make only left turns.

bfa-flightpath7501

A typical traffic pattern is:

  • Rectangular in shape
  • Have five named legs (Upwind, Crosswind, Downwind, Base and Final)
  • One designated altitude

Note: Traffic patterns can vary depending on whether or not the airport is towered or not and its location.

A pattern where all turns are to the left is called a left-hand pattern. In the same way, a pattern that has all right turns is called a right-hand pattern. A left-hand pattern is the standard traffic pattern for airport use. But once in a while you may see a right-hand pattern in use. For example, if a builder or tower obstructs the use of the standard pattern then a right-hand pattern may be used. Also weather conditions could also make a right-hand pattern more desirable.

The pattern’s name comes from its height above ground level. Example, 900ft pattern.

TRAFFIC PATTERN LEGS

1641492

Takeoff / Upwind
Since takeoff is normally made into the wind, this leg is called Upwind.

Crosswind
This leg is at a 90-degree angle from the departing runway.

Downwind
The aircraft starts its descent and flies parallel to the runway.

Base
Is at a 90-degree angle from downwind and opposite of crosswind.

Final Approach
Is aligned with the runway’s center line and into the wind.

Cessna-Takeoff

Let’s take a deeper look.

Upwind/Takeoff
The upwind leg is flown straight to the runway’s center line. Make sure to keep the plane aligned with the runway’s stripe. In order to take off, throttle is pushed forward to full power and yoke is pulled back. The airplane lifts up and off the runway. No turns should be made below 400ft above ground level.

Crosswind
This leg is perpendicular to the runway. Before turning crosswind, be sure to look out for other traffic that may be coming straight on in unannounced. This happens sometimes, especially at non-towered airports. During crosswind, the aircraft continues to climb until leveling off at traffic pattern altitude. Next, the aircraft proceeds to the downwind leg.

Downwind
This leg is flown parallel to the runway and at designated traffic pattern altitude. The plane should be configured for 70kts with one notch of flaps. When the aircraft reaches midfield, it begins to descend.

Base
This leg is at a 90-degree angle to the runway. Before turning base, look again for any oncoming traffic. After turning base, add a second notch of flaps. The airplane will automatically decrease its speed. Remember to check the aircraft’s position to the runway and continue a steady descent.

Final
The final leg should be flown aligned straight with runway’s center line. As the aircraft turns final, extend another notch of flaps making the flaps fully extended. Judge the runway height and distance. Use the VASI and PAPI to help determine if you’re too high or low but not fully rely on them. Be sure to look at the numbers as well. As you near the runway low enough to land, look a few hundred feet down the runway. Bring the nose up and flare. The plane should touch down on its mains.

— Disclosure —
I’m currently a student pilot learning to fly. These posts are notes for me to use and come back to when I need to relearn stuff. If anyone else wants to use these posts to learn, go ahead! I love sharing information and experience. But just as a warning, these posts may not be 100% accurate. I wouldn’t bet my life on it and I know someone is bound to point out a few mistakes. I’m only human. But if you catch something that isn’t right, please let me know! Feedback is always appreciated and it’s how I learn. You don’t learn from being correct all the time!

Thanks 🙂

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A Look At Wind Socks

The Wind sock is the oldest and most common wind indicator. It’s cone shaped and made of durable, flexible material. There are three different types of wind indicators. The wind sock, tetrahedron and tee. The wind sock shows the direction the wind is blowing from and lets pilots know which runway they should use for landing/taking off. All wind socks come in various colors and sizes but have to be large and bright enough to see.

Pole Sock

A wind sock on a pole.

When landing, pilots always want to be facing the wind. This allows the wind to act as a counter force against the aircraft and slow it down. Pilots want to make sure the wind sock is pointing towards them as they land. When taking off, pilots want the wind sock to be pointing towards the runway they’re taking off on. This way the wind will act as a tailwind and help give them more lift.

Aircraft flying over wind sock

Aircraft flying over wind sock

The wind sock can tell a pilot how the conditions on the ground are. When the wind sock is full of air, the smaller end is pointing downwind. Depending on the amount of extension of the sock, the velocity of the wind can be determined. Most wind socks are lighted as well for night use by pilots.

Wind sock at night

Other types of wind socks as I mentioned above are tetrahedrons and tees. When I first heard of the tetrahedron, I thought it was the weirdest sounding thing. I still have trouble spelling it. Tetrahedrons and wind tees have more freedom of movement than wind socks do. They swing freely and align themselves with the wind. An important fact to remember is that while wind socks will point downwind, tetrahedrons usually point upwind. This can be very confusing to pilots.

Wind indicators

Wind indicators

Here’s also a video I found online of what I think is a pretty cool looking tetrahedron.

And here are some links to the websites I used as sources for this post.

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All of the Markings Of A Runway

I recently discovered a really great diagram of most of the markings you’ll see on an airport runway. There’s been many times in the past where I was confused about what marking meant what and how I should act. This chart comes from the FFA, making it even better. So, here it is below.

runway diagram

And this is where I found it: FAA PILOT HANDBOOK

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An Elevating Study

Small Plane and Mountain

I’ve just finished studying field and airport elevation. It’s a very short topic and not much to worry. It’s very important but as I said it’s also very short. Field elevation is something pilots will always have to know. So you better learn it. If there are mistakes in the slide show, please let know! I’m a learning student pilot and mistakes are apt to happen. I’d like to get as much constructive criticism and help as I can get.

Here’s a link to the presentation >> Lesson 1.2

Tell me what you think! I love to hear some feedback. And also shoot any questions you have. I just might be able to answer them.

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