STEM LEARNING:

Advanced Air Mobility: Rubber 

Band Helicopter Engineering 

Challenge Student Guide

www.nasa.gov

National Aeronautics and Space Administration
2 | ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE)

PART 1

BACKGROUND INFORMATION

Imagine looking out your window and seeing a taxi fly by. Or, imagine you could go into your backyard and a drone 

would be delivering food from a local restaurant. These may seem like something from a science fiction movie or cartoon, 

but it isn’t as farfetched as you might think. Within the next few years, people will actually be riding in flying taxis! And, in 

some places, drones are already making deliveries.

With this revolutionary new type of aviation comes the need to monitor and control the airspace they fly in. NASA is 

working with its partners to develop a system called Advanced Air Mobility (AAM). This system helps monitor and control 

the movements of small, low-flying aircraft, such as drones and air taxis operating in both urban and rural areas. To 

minimize their environmental impact, these aircraft are electrically powered and use propellers to create both lift to move 

up and thrust to move forward.

In this activity, you will explore how propellers create lift and the resulting torque that is also created. You will be 

designing the body, or fuselage, of a helicopter to minimize the effect of torque.

Read through the background information below and answer the questions that follow it.

Newton’s Third Law of Motion

Sir Isaac Newton came up with three laws to describe 

the motion of objects. His third law states that for every 

action there is an equal and opposite reaction. We see 

this law in action frequently. For example, if an inflated 

balloon is released, the air comes out one end and the 

balloon moves in the opposite direction. The escaping 

air is the action, and the movement of the balloon is the 

equal and opposite reaction.

Newton’s third law also applies to rotary winged 

aircraft, such as helicopters or drones, because their 

spinning blades create both lift and torque. The blades 

on a helicopter or drone create a downward force by 

pushing the air down. The equal and opposite force is 

the upward force of lift. Assuming lift is a stronger force 

Figure 1. The blades on a helicopter create lift that moves it than the gravity, it moves the aircraft up.

upward. Credit: NASA/ Dan Casper
ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE) | 3 

Torque

In addition to lift, a rotating propeller creates a force in 

the direction it rotates. According to Newton’s third law of 

motion, there must also be an equal and opposite force. 

This force, called torque, acts in the direction opposite of 

the propeller’s rotation. As shown in figure 2, when the 

blades rotate clockwise, the torque acts in the opposite 

direction, counterclockwise. If left unbalanced, the torque 

causes the fuselage of the helicopter to rotate. Engineers 

have devised several ways to compensate for torque. In 

the helicopter shown in figure 2, the tail rotor creates a 

force to balance out the torque which keeps the fuselage 

from rotating. 

Propellers

Unmanned Aerial Vehicles, or UAVs, usually fly below 400 

feet, are electrically powered, and use rotating propellers 

to provide both lift and thrust. The propeller size varies 

according to the size of the aircraft. Small package 

carrying drones only require small, relatively slow 

propellers whereas larger air taxis require larger, faster 

rotating ones. Propellers on some larger aircraft are even 

capable of being rotated to provide lift like a helicopter’s 

blades or thrust like an airplane’s propeller.

Relative to the direction an aircraft is moving, propeller 

blades are angled. The angle, or pitch, of the blades 

determines the direction the air is pushed. The speed at 

which the propellers rotate, along with the pitch of the 

blades, determines how much air is pushed. 

Reversing the direction of a propeller’s rotation reverses 

the direction the air is pushed. Think of it like a screw—if it 

is turned in one direction, it moves down; and if it is turned 

the other way, it moves up.

Figure 2. The force created by the tail rotor balances out 

the torque. 

Figure 4. This computer simulation shows the movement 

of air caused by the rotating of a quadcopter’s propellers. 

Credit: Seokkwan Yoon, NASA/Ames

Figure 3. On some aircraft, the propellers can rotate to 

provide upward lift or forward thrust. Credit: NASA
4 | ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE)

QUESTIONS

1. Explain how the plane shown in figure 5 demonstrates 

Newton’s third law of motion. 

2. The V-22 Osprey is an aircraft that creates lift using 

two propellers that tilt to face upwards. Keeping in 

mind that propellers create torque, how is it possible 

that this aircraft can operate without a tail rotor? 

(Hint: Look closely at the propeller blades in figure 6 

and think about what you learned about pitch in the 

Background Information.)

Figure 5. Hot gases coming out the back of a jet 

create thrust. Credit: NASA

Figure 6. The V-22 Osprey can tilt its rotors up for 

takeoff and landing. Credit: U.S. Navy photo by Mass 

Communication Specialist 3rd Class Vincent E. Zline
ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE) | 5 

PART 2

Build Your Helicopter

Materials needed: craft stick, propeller, paper clip, rubber band, piece of 

cardstock, pair of scissors, ruler, and tape.

Directions: 

1. Gather all materials. 

2. Bend paper clip so it forms about a 45 degree angle.

3. Using tape, attach paper clip to one end of the craft stick.

4. Attach propeller to other end of the craft stick.

5. Attach rubber band to both the propeller and the paper clip.

6. Cut out pieces of cardstock, one for each of the following centimeter (cm) 

dimensions:

a 3 cm x 4 cm

b. 6 cm x 8 cm

c. 9 cm x 12 cm

d. 12 cm x 16 cm

Conduct Baseline Testing

In part 1 of this activity, you learned that there must be a force counteracting the torque created by the rotating 

propellers. The helicopter you just built doesn’t have a tail rotor to create this counteracting force. Because your 

helicopter is so small and light, you will be using air resistance to counteract the torque.

If left unbalanced, the torque causes the craft stick to rotate, using too much energy and making it difficult for your 

helicopter to fly. So, you will be adding a fuselage in the form of a piece of cardstock. The size of your fuselage 

determines the amount of air resistance—the larger the fuselage, the more air resistance it creates.

Directions: 

1. Wind the propeller clockwise about 20 rotations and let the propeller go while still holding the helicopter, noting 

which direction the propeller pushes the air.

2. Repeat step 1, but rotate the propeller counterclockwise this time.

3. For the remainder of this activity, always rotate the propeller in the direction that results in the propeller pushing the 

air downward.

4. With no paper attached to craft stick, wind the propeller 35 rotations and let the helicopter go.

5. Record what you observe.

6. Repeat steps 4 and 5 for a total of three trials.

7. One at a time, attach each piece of cardstock to the helicopter, wind it 35 times, let the helicopter go, and record 

what you observe. Conduct three trials with each sized piece of cardstock. After completing the trials, remove the 

cardstock before attaching the next piece.

Hypothesize:

How does the size of the fuselage (piece of paper attached to the craft stick) affect the performance of the helicopter? 

Why?

Figure 7. Completed helicopter before 

attaching fuselage.
6 | ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE)

PART 3

Your Goal: Modify your helicopter so that it will rise between 1.5 and 2.0 meters after being launched.

Criteria: Your helicopter should rise at least 1.5 meters and no more than 2.0 meters.

Constraints: After designing, building, and testing your prototype, you may change one factor.

Ask

What factors can be changed on your helicopter to affect how high it rises?

After you list the factors you can think of, brainstorm with your group or class to develop a list of factors that may be 

changed during the improve stage. List the factors your class brainstormed:
ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE) | 7 

Imagine / Plan

Determine the size and shape of your fuselage (piece of cardstock) and how many times you plan on winding the 

propeller. Sketch your design below and label the size. Then, indicate how many rotations you will wind it:

Create / Experiment

Directions: 

1. With your group, agree upon a design. Then, cut out the fuselage you planned and attach it.

2. Conduct up to three test flights to judge your helicopter’s performance.

Wind it __________________rotations.
8 | ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE)

Answer: 

How well did your helicopter perform and did it perform approximately the same during each test flight?

From the list of factors your class agreed upon, choose one factor that you think should be adjusted on your design. 

Which factor did you choose, how will you modify it, and why did you choose that factor?

Improve

Modify your design by changing only one factor.
ADVANCED AIR MOBILITY: RUBBER BAND POWERED HELICOPTER ENGINEERING CHALLENGE (STUDENT GUIDE) | 9 

Share

Share your design with the class. Explain why you designed it as you did. Then, explain what factor you changed and 

why. After sharing, conduct your final flight.

Answer the following questions individually:

What worked well with your design?

What other factor(s) would you change if you could?

What design features did you see in the other teams’ helicopters that you thought were especially good?
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