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STEM LEARNING:

Advanced Air Mobility: The 

Science Behind Quadcopters

Student Guide
2 | ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE

ADVANCED AIR MOBILITY (AAM)

When most people think of aircraft, they usually think 

about airplanes that travel at great speeds and cover 

large distances while flying routes between airports. 

More and more, however, new types of aircraft are 

transporting people and equipment to urban and rural 

locations where traditional airplanes cannot access. 

These new aircraft range in size from small cargo 

carrying drones to passenger-carrying air taxis, and 

carry out short range missions. 

NASA is leading the nation to quickly open this new era 

in air travel called Advanced Air Mobility, or AAM. The 

vision of AAM is that of a safe, accessible, automated, 

and affordable air transportation system for passengers 

and cargo capable of serving previously hard-to-reach 

urban and rural locations. 

According to recent NASA-commissioned market 

studies, by 2030 there will be as many as 500 million 

flights per year for package delivery services and 750 

million flights per year for air taxi/metro services. AAM 

will help ensure this new airspace is properly managed.

Compared to airplanes and helicopters, the aircraft that fly in this new airspace are small. This, along with where they 

fly, makes it unrealistic to continuously track or control these aircraft using radar or satellite technology. Many of these 

aircraft are Unmanned Aerial Vehicles, or UAVs, meaning they are self-flying or autonomous.

Figure 1. AAM is a system of safe, accessible, affordable, and 

automated air transportation for passengers and cargo in urban 

and rural locations. Credit: NASA
ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE | 3 

QUADCOPTERS

Some of the aircraft controlled in the AAM system are 

quadcopters, similar to commercially available drones. The 

term quadcopter refers to the fact that they use four propellers 

to fly.

Several manufacturers are working on larger versions of 

quadcopters capable of carrying cargo and people. In fact, 

several prototypes have already flown! Prototypes are working 

models used by engineers to test whether a design works as 

expected.

ACTIVITY 1: DESIGN A PACKAGE DELIVERING 

QUADCOPTER

You have been assigned to create a package delivering 

quadcopter. Sketch the design of your vehicle below and label 

it to explain its parts. Then, explain how your vehicle will carry 

packages while ensuring the safety of people and objects.

Sketch:

Figure 2. NASA scientists use this quadcopter for 

experimentation. Credit: NASA, David C. Bowman
4 | ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE

In 1687, English scientist Sir Isaac Newton published his now famous three laws of 

motion. These laws describe how forces and objects interact to affect motion. Newton’s 

third law of motion states that for every action, there is an equal and opposite reaction. 

When a quadcopter’s propellers spin, they push air downward. Using Newton’s third 

law, this represents the action. For Newton’s law to be true, there must be an equal and 

opposite reaction. This reaction is an upward force pushing on the quadcopter. Once 

this force exceeds the force of gravity pulling the quadcopter downward, the quadcopter 

begins to move up. 

ACTIVITY 2: NEWTON'S THIRD LAW EXPERIMENT

Materials: Balloon, bendable straw, tape, pin, and pencil with eraser

Procedures:

1. Bend straw into a 90 degree angle.

2. Insert the long end of the straw into the balloon.

3. Tape the balloon to the straw.

4. About halfway along the long end of the straw, push a pin all the way through the straw.

5. Insert pin into the eraser on the pencil.

6. Before trying it, write down what will happen if you blow up the balloon and let it go (your 

hypothesis).

What is your hypothesis?

 ____________________________________________________________________________________

 _____________________________________________________________________________________

Explanation:

_____________________________________________________________________________________________________________

_____________________________________________________________________________________________________________

_____________________________________________________________________________________________________________

_____________________________________________________________________________________________________________

_____________________________________________________________________________________________________________

NEWTON’S THIRD LAW AND QUADCOPTERS

Figure 3. Newton’s third law 

explains the upward motion of 

a quadcopter. 

Figure 4. This is 

what activity 2 looks 

like when completed. 

Credit: NASA
ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE | 5 

7. Blow through the short end of the straw to inflate the balloon and let it go.

8. Observe and record your observations.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

9. Using Newton's third law as evidence, explain why the balloon and straw moved as they did.

_______________________________________________________________________________________________________

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MOVEMENT OF A QUADCOPTER

For a quadcopter to fly, it must be capable of three different types of movement: 

vertical movement, lateral movement, and rotational movement. Based on Newton’s 

third law, each of these can be achieved using the quadcopter’s four propellers.

When the propellers spin, they push air 

down. Similar to a helicopter, pushing the 

air down is the action in Newton’s third law 

of motion. The reaction is a force, called lift, 

which pushes the quadcopter up. Each of 

the propellers will create lift, and the total 

lift for the quadcopter will be the sum of 

the four propellers’ lifts. The total force of 

the lift must be stronger than the force of 

gravity for the quadcopter to take off. Once 

in the air, the quadcopter can hover with 

no vertical movement by having the forces 

of lift and gravity equal.

When the force of lift acts straight upward, 

the quadcopter moves vertically. But, 

when lift acts at an angle, it can also move 

laterally. This is because part of the force of the lift is upward and part of it is to 

the side, resulting in lateral movement that can be from side-to-side or forward 

and backward.

Lateral movement occurs by varying the speed of the propellers. Increasing the 

speed of the two propellers on one side of the quadcopter and/or decreasing the 

speed of the two propellers on the other side creates uneven amounts of lift on 

the two sides. The lift created on the side with the faster spinning propellers is 

greater than the lift created on the opposite side. The result is that the quadcopter 

moves in the direction of the side where less lift is created.

Figure 5. Drones move in three 

different ways.

Figure 7. When lift acts at an angle, it 

causes lateral movement. 

Figure 6. Gravity and lift act on 

a quadcopter. 
6 | ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE

The final type of movement happens when the quadcopter 

rotates. This type of movement relies on a force called torque, 

a twisting force that causes rotation. When a propeller spins, 

this force is produced. And, according to Newton’s third law of 

motion, an equal and opposite force is produced as well.

We see this in action when we look at a helicopter like the one 

in figure 8. When the blades on top of the helicopter (the rotor) 

spin, torque is created. The equal and opposite force rotates the 

body of the helicopter in the opposite direction of the blades’ 

rotation. Since this would make the helicopter unusable, a tail 

rotor is added. It creates a force that counteracts the torque and 

stops the helicopter from rotating uncontrollably.

Torque also affects a 

quadcopter when its 

propellers spin because 

each propeller individually 

creates torque when 

it rotates. All four torques are added up to determine the total torque acting on 

the quadcopter. Engineers have come up with a clever way of counteracting this 

torque—two of the propellers spin clockwise and two spin counterclockwise as 

shown in figure 9. This results in two propellers creating torque that acts clockwise 

and two creating torque that acts counterclockwise. Thus, the forces cancel each 

other out.

This torque can also be used to create rotational movement for the quadcopter. 

In figure 9, when propellers one and three rotate, they produce counterclockwise 

torque (remember, equal and opposite). If these propellers rotate faster than 

propellers two and four, the counterclockwise torque acting on the quadcopter will 

be stronger than the clockwise torque acting on it. This results in the quadcopter 

rotating counterclockwise. Of course, if propellers two and four rotate faster than 

propellers one and three, the quadcopter will rotate clockwise.

While having pairs of propellers rotating in opposite directions 

effectively controls the torque acting on the quadcopter, it 

presents a new problem for engineers. If propellers spin in 

opposite directions, two of the propellers push air upward while 

two push the air downward. When you combine these forces, 

the total lift is zero and the quadcopter cannot take off. To 

overcome this, engineers use two different propeller blades. In 

figure 10, you can see that the leftmost propeller has the left 

edge higher in the front while the other has the right edge higher. 

This design changes the direction the air is pushed by the two 

propellers, meaning that when they spin in opposite directions, 

they actually push the air in the same direction.

Figure 8. This S-64 heavy-lift helicopter uses the tail rotor 

to balance out the torque created by the rotor. Credit: 

NASA, Tony Landis

Figure 10. Propeller blades can have different angles. 

Figure 9. Propellers spin in different 

directions to cancel out the torque. 
ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE | 7 

ACTIVITY 3: DETERMING THE MOVEMENT OF A QUADCOPTER

Directions:

• For this activity, use the diagram shown in figure 11 to see the location of, and

direction of rotation for, each propeller.

• Assume that, when rotating as indicated, each propeller creates lift that acts as

an upward force on the quadcopter.

• The quadcopter weighs 408 grams (g), meaning that the force of gravity pulling 

it down is 4 Newtons (N).

Rules for Determining the Movement of the Quadcopter:

1. Rules for determining vertical movement: To calculate the total lift, add up the lifts created by each of the four 

propellers. 

• If the total lift is greater than the force of gravity (4 N), the quadcopter moves up. 

• If the total lift is equal to the force of gravity (4 N), the quadcopter doesn’t move vertically. 

• If the total lift is less than the force of gravity (4 N), the quadcopter moves down.

2. Rules for determining lateral movement: 

• If the lifts of propellers 1 and 4 add up to more than the lifts of propellers 2 and 3 added together, it moves right.

• If the lifts of propellers 2 and 3 add up to more than the lifts of propellers 1 and 4 added together, it moves left.

• If the lifts of propellers 1 and 2 add up to more than the lifts of propellers 3 and 4 added together, it moves 

backward.

• If the lifts of propellers 3 and 4 add up to more than the lifts of propellers 1 and 2 added together, it moves 

forward.

3. Rules for determining rotational movement: 

• If the lifts of propellers 1 and 3 add up to more than the lifts of propellers 2 and 4, it rotates counterclockwise.

• If the lifts of propellers 2 and 4 add up to more than the lifts of propellers 1 and 3, it rotates clockwise. 

• Otherwise, there is no rotational movement.

Figure 11. Top view of a 

quadcopter showing propellers 

rotating clockwise and counterclockwise.
8 | ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE

Using the rules for determining the movement of the quadcopter, determine and fill in the missing information in the chart:

Lift Produced (N)

Vertical Movement 

(None, Up, or Down)

Lateral Movement 

(None, Right, Left, 

Forward, or Backward)

Rotational Movement 

(None, Clockwise, or 

Propeller Counterclockwise)

1

Propeller 

2

Propeller 

3

Propeller 

4

1.25 1.25 1.25 1.25 Up None None

1.2 1.2 0.8 0.8 None Backward None

0.25 0.25 0.5 0.5 Down

1 1.5 1 1.5 Clockwise

1.5 0.5 1.25 0.75 None

0.5 0.5 None None

2 1 1 1

0.25 1 1 0.25

1. Why does NASA believe that there will be a need for AAM as an air traffic management system in the near future?

2. If a system like AAM is not put in place, what sort of problems might arise?

3. Hovering is when an aircraft is in the air but remains motionless. For a quadcopter to hover, why must the forces of 

lift and gravity be equal?

READING COMPREHENSION QUESTIONS
ADVANCED AIR MOBILITY: THE SCIENCE BEHIND QUADCOPTERS STUDENT GUIDE | 9 

1. In science, a law describes what will happen under certain conditions every time, whereas a theory explains why 

something happens. Why is Newton's third law of motion a law and not a theory?

2. Sir Isaac Newton devised three laws of motion. Investigate these laws. How would his first and second laws of 

motion be important in determining how a quadcopter works? 

3. Read through the article found at https://www.nasa.gov/aero/taking-air-travel-to-the-streets-or-just-above-them/. 

What is NASA’s role in AAM and what other groups or organizations are involved?

4. Some air taxi prototypes have two rotors on top and no tail rotor. How is this possible when the rotors produce 

torque? 

GOING FURTHER

GLOSSARY

Advanced Air Mobility (AAM)—a safe and efficient air transportation system for short range aircraft

Lateral movement—movement to the right, left, forward, or backward

Lift—force that pushes upward (against gravity)

Newton’s third law of motion—for every action, there is an equal and opposite reaction

Prototype—an early model of something that can be used to test its functionality 

Rotational movement—spinning around an axis

Torque—a twisting force created when something rotates

Unmanned Aerial Vehicle (UAV)—small aircraft that can be remotely or autonomously controlled

Vertical movement—movement up or down
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