YouTube's ONLY Complete Private Pilot Ground Course (Lesson 1)

Summary

In this YouTube video, Josh introduces a free Private Pilot ground course. Lesson one covers the four forces acting on an airplane: lift, weight, thrust, and drag. Lift is the upward force created by airfoil design and relative wind. Weight is the downward force from the aircraft's load. Thrust propels the plane forward, overcoming drag, which opposes movement. The video explains different types of drag and how they affect flight, emphasizing the importance of understanding these forces for controlling an aircraft.

Takeaways

• 🚀 **Introduction to Forces in Flight**: The script introduces the four fundamental forces acting on an airplane during flight: lift, weight, thrust, and drag.
• 🛫 **Lift Explained**: Lift is the upward force generated by relative wind and wing design (air foil) that counteracts the force of gravity.
• 📉 **Weight as a Downward Force**: Weight is the sum of all loads on the aircraft, including people, fuel, baggage, and the aircraft itself, and it acts downward through the center of gravity.
• ✈️ **Balance in Steady Flight**: In steady, unaccelerated flight, lift and weight are equal, maintaining the aircraft's altitude.
• 💨 **Thrust as Forward Force**: Thrust, created by engines and propellers (or rotors in helicopters), propels the aircraft forward and must overcome drag.
• 🔙 **Drag as Resistance**: Drag opposes forward movement and includes two types: parasite drag, which increases with airspeed, and induced drag, which decreases as airspeed increases.
• 📊 **Types of Parasite Drag**: Parasite drag is divided into form drag, interference drag, and skin friction drag, each affecting the aircraft differently.
• 🔍 **Importance of Aerodynamic Understanding**: A basic understanding of aerodynamics is essential for controlling an aircraft and understanding how adjustments to one force affect the others.
• 📈 **Lift to Drag Ratio (LD Max)**: There's an optimal airspeed where the aircraft experiences the least drag, known as the lift to drag ratio or LD Max.
• 🔄 **Forces Interaction**: Changes in one force, such as increasing thrust or lift, will affect the balance with other forces, causing the aircraft to climb or descend.
• 🎥 **Continuing the Course**: The script encourages viewers to continue with the playlist for further lessons on flying an airplane.

Q & A

What is the main focus of the video series?

The main focus of the video series is to provide a complete and free Private Pilot ground course, teaching everything needed to earn one's wings as a pilot.

What are the four forces that act on an airplane in flight?

The four forces that act on an airplane in flight are lift, weight, thrust, and drag.

What is lift and what causes it?

Lift is the upward force that picks the aircraft up away from the ground. It is caused by relative wind and the wing design, which pilots refer to as an air foil.

How does weight affect an airplane and what does it include?

Weight is the combined load of all the people, fuel, baggage, cargo, and the aircraft itself. It opposes lift and acts downward through the center of gravity.

What is thrust and how is it typically created?

Thrust is the force that propels the aircraft forward. It is typically created by an engine and propeller working together or a rotor for helicopters.

What is drag and why is it important?

Drag is a rearward force that opposes forward movement of the aircraft, making it difficult to move forward. Understanding drag is important for pilots to control the aircraft efficiently.

What are the two types of drag that a pilot should be concerned about?

The two types of drag that a pilot should be concerned about are parasite drag and induced drag.

How does parasite drag increase with airspeed?

Parasite drag increases exponentially with airspeed, which is why training aircraft cannot fly super fast due to the high parasite drag at high speeds.

What is induced drag and how does it relate to lift?

Induced drag is created as a direct result of lift. As the wings direct the relative wind above and below the wing's surface to create lift, they also create induced drag.

What happens to the relationship between lift and weight when the aircraft is in steady, unaccelerated flight?

In steady, unaccelerated flight, lift and weight are equal, meaning the aircraft is not climbing or descending.

How does increasing thrust affect the aircraft's flight when it is in level flight?

When thrust is increased during level flight, the aircraft starts to climb because the lift becomes greater than the weight.

What is the lift to drag ratio and why is it significant for pilots?

The lift to drag ratio, or LD Max, is significant for pilots because it represents the airspeed range where the aircraft can achieve the least amount of drag possible, which is crucial for efficient flight.

Outlines

00:00

🚁 Understanding the Four Forces of Flight

In this introductory lesson of the free Private Pilot ground course, Josh and his father-in-law Mike explain the fundamental aerodynamic forces that act on an airplane during flight: lift, weight, thrust, and drag. Lift is the upward force generated by the wing's design and relative wind. Weight is the downward force resulting from the combined load of everything on board the aircraft. Thrust is the forward force created by the engine and propeller, and it must overcome drag, which opposes forward movement. The lesson also introduces the concept of parasite drag, which increases with airspeed, and induced drag, which is related to lift and decreases as airspeed increases. Understanding these forces is crucial for a pilot's training and performance on the written test.

05:01

🌪️ Balancing Forces for Optimal Flight

The second paragraph delves into the relationship between the aerodynamic forces during steady, unaccelerated flight, where lift equals weight and thrust equals drag. Josh demonstrates how changes in airspeed affect these forces, using a real flight example. When thrust is increased, the aircraft climbs because lift exceeds weight. Conversely, when the aircraft's lift is increased by raising the nose, airspeed decreases due to increased induced drag overpowering thrust. The concept of the lift-to-drag ratio (LD Max) is introduced, which is the airspeed where the least amount of drag is experienced. This understanding is essential for controlling the aircraft and is a foundational aspect of pilot training.

Keywords

💡Aerodynamics

Aerodynamics is the study of how air moves over and around objects. In the context of the video, aerodynamics is crucial for understanding how forces like lift, weight, thrust, and drag affect an airplane's flight. The script emphasizes the importance of aerodynamics as a foundation for a pilot's training, as it governs the airplane's interaction with the air.

💡Lift

Lift is the upward force that counteracts the weight of the airplane, allowing it to become airborne. It is generated by the wing's design, known as an airfoil, and the relative wind. The video explains that lift is critical for flight and is equal to weight in steady, unaccelerated flight. An example from the script is when the pilot discusses how increasing thrust can lead to more lift, causing the airplane to climb.

💡Weight

Weight in the video refers to the downward force exerted by gravity on the airplane, which includes the mass of the aircraft, its fuel, passengers, and cargo. It acts through the center of gravity and opposes lift. The script mentions that understanding weight is essential as it directly impacts the balance and control of the aircraft.

💡Thrust

Thrust is the force that moves the airplane forward. It is typically generated by engines and propellers or rotors in helicopters. The video explains that thrust must overcome drag to propel the aircraft. An example given is that when the pilot increases thrust, the airplane's speed increases, which in turn increases lift, causing the aircraft to climb.

💡Drag

Drag is the force that opposes the forward motion of an airplane. The video distinguishes between two types of drag: parasite drag, which increases with speed, and induced drag, which decreases as speed increases. Understanding drag is vital for pilots to maximize efficiency and control the aircraft's speed.

💡Center of Gravity

The center of gravity is the point at which the average weight of the airplane and everything on board is concentrated. The video mentions that if the airplane could be hung from this point, it would balance perfectly. This concept is important for understanding the aircraft's balance and stability.

💡Parasitic Drag

Parasitic drag, as discussed in the video, includes form drag, interference drag, and skin friction drag. It is the drag that does not contribute to lift and increases with speed. The script uses the analogy of sticking a hand out of a car window to explain how speed increases the force of drag.

💡Form Drag

Form drag is a type of parasitic drag caused by the shape of the aircraft, which disrupts the smooth flow of air around it. The video suggests that aircraft with less streamlined shapes will experience more form drag, affecting their aerodynamic efficiency.

💡Induced Drag

Induced drag is created as a byproduct of lift. The video explains that as the wing generates lift by directing air, it also creates induced drag. This type of drag is interesting because it decreases as airspeed increases, which is counterintuitive compared to parasitic drag.

💡Lift to Drag Ratio (LD Max)

The lift to drag ratio, or LD Max, refers to the most efficient speed where the least amount of drag is experienced relative to the lift produced. The video mentions that pilots often aim to fly at this speed to maximize efficiency. It is a key concept in understanding how pilots manage speed and control during flight.

💡Trim

Trim in the video refers to adjusting the aircraft's control surfaces so that it maintains a desired attitude without the pilot having to continuously apply pressure to the controls. The script uses the term in the context of setting the airplane for level, unaccelerated flight, which is a stable condition where lift equals weight and thrust equals drag.

Highlights

Introduction to YouTube's free Private Pilot ground course

Teaching the four forces acting on an airplane in flight

Importance of aerodynamics for a pilot's training foundation

Explanation of the written test requirement with a 70% passing score

Description of lift as the upward force on an aircraft

Role of relative wind and wing design in creating lift

Introduction to the concept of weight opposing lift

Definition of weight as the combined load of everything on board

Discussion on the center of gravity and its balance

Explanation of thrust as the force propelling the aircraft forward

Thrust's necessity to overcome drag for forward movement

Differentiation between parasite drag and induced drag

Demonstration of how airspeed affects parasite drag

Types of parasite drag: form drag, interference drag, and skin friction drag

Induced drag's relationship with lift and airspeed

Concept of the lift to drag ratio (LD Max) for optimal airspeed

Practical application of aerodynamics in controlling an aircraft

Visual demonstration of how increasing thrust affects flight

Visual demonstration of how increasing lift affects airspeed

Encouragement to continue learning with the next lesson in the series

Transcripts

welcome to what I believe to be

YouTube's only complete and totally free

Private Pilot ground course throughout

this series I will teach you everything

you need to know in order to earn your

wings as a

[Music]

pilot what's up guys I'm Josh and this

is my father-in-law Mike and this is

lesson one on my totally free Private

Pilot ground course today we're going to

be talking about the four forces that

act on an airplane while it's in flight

this is a super important lesson because

if you have a basic understanding of

aerodynamics this is going to give you a

good foundation that you can start

building on throughout your training

plus these questions might be on the

written test oh I didn't mention that

there's a written test oh yeah there's a

written test and you've got to pass it

with at least a 70% but don't worry I

got you anyway let's take a look at

these four forces that affect our

airplane in flight as you can see these

forces are lift weight thrust and drag

now the first Force you should know

about is lift as you can see this is the

upward force that actually picks the

aircraft up away from the ground and

this is caused by basically two things

relative wind and the wing design now we

Pilots have a super fancy name for this

Wing design we call it an air foil but I

don't want to go into too much detail on

that right now cuz we're going to be

talking about that in more detail in the

next lesson the next Force we need to

consider when flying an aircraft is

weight now weight is simply the combined

load of all the people on board the

aircraft all the fuel any baggage or

cargo you might have and even the

aircraft itself it includes everything

on board the aircraft the other thing

you should know about the weight is that

it opposes lift and acts downward

through the center of gravity now we'll

discuss the center of gravity more in an

upcoming episode but the center of

gravity is basically where the average

weight of the aircraft and everything on

board is centered if you could hang an

airplane from a string and you were to

place a center of gravity directly

beneath the string the aircraft would

balance perfectly now here's something

that may not make a lot of sense yet but

it's important to know in steady

unaccelerated flight lift and weight are

both equal but we'll come back to that

here in just a second next we have

thrust and this is the force that

propels our aircraft forward thrust is

typically created by some kind of engine

and propeller working together or a

rotor for helicopter nerds out there now

the important thing to know about thrust

is that in order to move the aircraft

forward you must first overcome drag

which we depict here as a rearward force

but really this Force just opposes

forward movement and that drag makes it

difficult to move the aircraft forward

and there are two types of drag that you

should be concerned about as a pilot

parasite drag and induced drag what

happens when you stick your hand out of

the window of a moving vehicle the wind

pulls your hand back doesn't it the

faster you drive Drive the more your

hand gets pulled back this is what we

call parasite drag and just like it does

when you stick your hand out of a moving

vehicle parasite drag increases as air

speed increases as you can see from this

chart it increases exponentially with

faster air speeds that's one of the

reasons why we can't fly super fast in

our training aircraft there's way too

much parasite drag holding the airplane

back at high air speeds now there are

actually three different types of

parasite drag and the first one is form

drag in a nutshell form drag is wind

that goes around the shape of the

aircraft how much form drag do you think

an aircraft of this shape would produce

probably a lot right it's not a smooth

round shape that can allow air to

smoothly flow around it another type of

parasite drag is interference drag this

one might be a little bit harder to

understand but this type of drag occurs

when different streams of air flow

create little pockets of turbulence at

different places on the aircraft and

this restricts the smooth air flow

around the surface of the aircraft next

we have skin friction drag this type of

Paras it drag is drag that's caused by

the surface of the aircraft if we were

able to zoom in with a microscope and

look at the skin of the aircraft what

you find is that it's actually not as

smooth as it looks wind can still act on

these little microscopically rough areas

and reduce the speed of our aircraft as

you might have noticed we typically

paint or polish the exterior surfaces of

an aircraft to reduce skin friction drag

but it's never completely eliminated

induced drag is the other type of drag

that affects our aircraft it's created

as a direct result of lift I'm going to

explain this more in the next episode

but our wings direct the relative wind

above and below the surface of the wing

and this creates lift but it also

creates induced drag now induced drag is

kind of weird as air speed increases the

wing gets more efficient and because of

that induc drag actually decreases

here's what's interesting if we were to

look at these two types of drag on a

chart what you find is that parasite

drag increases exponentially with air

speed but induc drag decreases

exponentially with air speed because of

that there's a magical little air speed

range on every aircraft where we can

achieve the least amount of drag

possible when we're out flying around

and a lot of air speeds you're going to

be flying are directly related to this

air speed Pilots often refer to this as

the lift to drag Ratio or LD Max you

might be wondering why it's called the

lift to drag ratio and not the thrust to

drag ratio well just like lift and

weight in steady unaccelerated flight

thrust and drag are both equal but all

these forces are directly related to

each other you're probably wondering why

the heck we're learning about aerody

Dynamics today you just want to get into

the plane and start flying but if you

understand this concept it's going to

help you understand how to control the

aircraft anytime I make an adjustment to

any one of these forces it's going to

cause a change in one of the other

forces now we said that during steady

unaccelerated flight lift and weight are

both equal now that I've got my airplane

trimmed out for for level flight let's

see what happens when I increase my air

speed by increasing my thrust all right

so I'm I've got the airplane all trimmed

out I'm at 1,600 ft uh somewhere around

85 knots watch what happens when I just

increase my thrust Just Watch What

Happens

here I don't have my hands on the

controls but notice the airplane

starting to

climb so thrust and weight are no longer

equal as you can see my wings Start

creating more lift when we accelerate

when I increase my thrust my lift

becomes greater than my weight and the

opposite is true when I decelerate okay

now I'm trimmed out for level un

accelerated flight again at this point

thrust and drag are equal but what

happens if I increase my lift watch my

air speed as I raise the nose of the

aircraft and I'm flying at 80 knots I'm

at 2,000

ft okay so watch my air speed when I

raise the nose of the air L up so I'm

increasing lift right now watch my air

speed yeah that's right the air speed is

bleeding off I made a change before I

increased my lift we were in steady

unaccelerated flight when I increased my

lift I also increase my induced drag and

this caused my drag to be stronger than

the thrust which slowed down my aircraft

understanding these basic principles is

probably the most important step to

learning how to control an airplane and

now that you've watched this video you

haven't understand understanding that

most Pilots don't get in their first

ground lesson if you want to continue

learning how to fly I recommend starting

the playlist where you'll be picking up

with lesson two and there you can binge

watch the series when you take a break

you can pick up right where you left off

thanks for watching see you

[Music]