Unmanned Aircraft Systems 

Activity One: Propeller Design Challenge 

Educator Notes 

Learning Objectives 

Students will 

• Apply the steps of the engineering 

design process to successfully 

complete a team challenge: 

– Design and build a propeller car. 

– Test the design, and then improve it 

based upon the car’s performance, 

including the propeller’s thrust. 

• Explain how Newton’s third law of 

motion plays a role in moving vehicles 

with propellers. 

• Work as a team and communicate effectively. 

• Reflect on the design process and discuss it with the whole group. 

Challenge Overview Suggested Pacing 

Students will work together as a team to design and build a propeller using the engineering design 60 to 120 minutes 

process. The team will build a propeller car that travels a given distance with the shortest average time. 

National STEM Standards 

Science and Engineering (NGSS) 

Disciplinary Core Ideas 

• MS-ETS1-1 Engineering Design: Define the criteria and constraints of a design problem 

with sufficient precision to ensure a successful solution, taking into account relevant 

scientific principles and potential impacts on people and the natural environment that may 

limit possible solutions. 

• MS-PS2-2: Plan an investigation to provide evidence that the change in an object’s motion 

depends on the sum of the forces on the object and the mass of the object. 

• PS2.A Forces and Motion: The motion of an object is determined by the sum of the forces 

acting on it; if the total force on the object is not zero, its motion will change. The greater the 

mass of the object, the greater the force needed to achieve the same change in motion. For 

any given object, a larger force causes a larger change in motion. All positions of objects 

and the directions of forces and motions must be described in an arbitrarily chosen 

reference frame and arbitrarily chosen units of size. In order to share information with other 

people, these choices must also be shared. 

Crosscutting Concepts 

• Structure and Function: The way an object is shaped or structured determines many of its 

properties and functions. 

• System and System Models: A system is an organized group of related objects or 

components; models can be used for understanding and predicting the behavior of systems. 

Science and Engineering Practices 

• Developing and Using Models: A practice of both science and engineering is to use and 

construct models as helpful tools for representing ideas and explanations. These tools 

include diagrams, drawings, physical replicas, mathematical representations, analogies, and 

computer simulations. 

• Planning and Carrying out Investigations: Scientists and engineers plan and carry out 

investigations in the field or laboratory, working collaboratively as well as individually. Their 

investigations are systematic and require clarifying what counts as data and identifying 

variables or parameters. 

• Analyzing and Interpreting Data: Scientific investigations produce data that must be 

analyzed in order to derive meaning. Because data patterns and trends are not always 

obvious, scientists use a range of tools—including tabulation, graphical interpretation, 

visualization, and statistical analysis—to identify the significant features and patterns in the 

data. Scientists identify sources of error in the investigations and calculate the degree of 

certainty in the results. Modern technology makes the collection of large data sets much 

easier, providing secondary sources for analysis. 

Technology (ISTE) 

Standards for Students 

• Empowered Learner: Students leverage technology to take an active role in choosing, 

achieving, and demonstrating competency in their learning goals, informed by the learning 

sciences. 

– 1d: Students understand the fundamental concepts of technology operations; 

demonstrate the ability to choose, use, and troubleshoot current technologies; and are 

able to transfer their knowledge to explore emerging technologies. 

Standards for Students (continued) 

• Innovative Designer: Students use a variety of technologies within a design process to 

identify and solve problems by creating new, useful, or imaginative solutions. 

– 4c: Students develop, test, and refine prototypes as part of a cyclical design process. 

Mathematics (CCSS) 

Mathematical Practices 

• CCSS.MATH.PRACTICE.MP5: Use appropriate tools strategically. 

Mathematical Practices (continued) 

• CCSS.MATH.PRACTICE.MP6: Attend to precision. 

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Unmanned Aircraft Systems 

Challenge Preparation 

• Read the introduction and background information, Educator Notes, and Student Handout 

to become familiar with the propeller design activity. 

• Gather and prepare all supplies listed on the materials list. 

• Build a sample propeller car to show students (see Appendix C for instructions), but do 

not show them a finished propeller as it may influence students’ designs. 

• Set up a testing station where students can test their propeller cars on a smooth, flat 

surface. This area should include a tape measure or marked masking tape on the floor 

so students can measure how far their propeller car travels. 

Materials (per group) 

Building Supplies for Propeller Car 

 See list of materials in Appendix C, Propeller Car Instructions. 

Note: For data comparison purposes, each car should be made with the same materials 

to eliminate extra variables. 

Building Supplies for Propeller 

 Various materials (e.g., plastic, cardboard, popsicle sticks, paperclips, paper plates, etc.) 

Safety 

Review all safety tips before building the propeller car. All safety guidelines are identified in 

Appendix C with the Propeller Car Instructions. Adult supervision is required for building and 

testing the propeller car. 

Introduce the Challenge 

• Provide context for this activity using the Introduction and Background, Educator Notes, 

and Student Handout information in this guide. 

• Ask students to share what they know about drones. 

– Define a drone as an aircraft without a human pilot aboard. 

– Explain that a drone is a type of unmanned aerial vehicle (UAV). 

• Discuss how a drone’s propeller/s generate lift to counteract the force of gravity. 

– Review Newton’s third law of motion with students and how it applies to lift and thrust. 

– Discuss the different considerations for propeller design, including number of blades, 

blade length, shape, pitch, twist, and surface area. 

• Share the video “Let’s Open Up the Skies with AAM.” 

https://www.youtube.com/watch?v=lKf0Y317AJw 

• Explain the role of engineers in designing technology to solve problems. Use the video 

“Intro to Engineering” (https://www.youtube.com/watch?v=wE-z_TJyziI) to introduce the 

engineering design process. 

– Explain that engineers must adhere to design criteria and constraints, including 

budget and time limitations. 

• Divide the whole group into teams and distribute the Student Handout, Propeller Car 

Instructions (see Appendix C), and scratch paper to each team. 

• Explain the details of the challenge, including the design criteria and constraints. 

Share with Students 

Brain Booster 

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. 

Learn more: 

https://www.grc.nasa.gov/www/k12/airplane/propeller.html 

On Location 

Did you know NASA is leading the 

nation’s efforts to quickly open a 

new era in air travel called 

advanced air mobility, or AAM? A 

new future for city transport is in 

the works at NASA—a future 

where both people and packages 

will take to the air. In fact, 

researchers at NASA’s Ames 

Research Center in California’s 

Silicon Valley are developing 

technologies for AAM airspace 

management to make it possible. 

Researchers have already 

studied, designed, and tested 

tools and technologies that could 

be used in the near future to 

manage the airspace for small 

drones flying at low altitudes, even 

in complex urban landscapes! It is 

giving a leg up to the emerging 

world of passengers and goods 

traveling smoothly above our city 

streets. 

Learn more: 

https://www.nasa.gov/ames/utm/ 

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Unmanned Aircraft Systems 

Criteria Constraints 

All car bodies must be identical. Each team will follow instructions and build 

the same basic car to which the propeller will attach. 

The propeller car cannot be pushed or tapped by team members to “boost” or 

move the vehicle forward. 

The propeller design must attach securely to the motor with the propeller hub 

attachment (the water bottle threading). 

All test cars must be powered by the same number of propeller turns (for 

rubberband cars) or the same type of battery cell (for motorized-propeller cars) 

(e.g., one 9-V battery). 

The thrust from the propeller must move the car forward. 

The propeller car must move a minimum of 1 m (100 cm). 

Facilitate the Challenge 

Ask 

• Engage students with the following questions: 

– What is thrust? 

 How is thrust created? 

 How do propellers generate thrust? 

– How does the mass of an object affect the force needed to move it? 

– Does the propeller size vary according to the size of the aircraft? 

– Are all propellers the same? 

– What makes some propellers more efficient than others? 

Imagine 

• Allow students to ask questions about the challenge. Ensure they can clearly define the problem as well as all design criteria and 

constraints. 

• Ask students to draw a propeller design individually. 

– Reiterate to students that the goal of brainstorming is to come up with many different ideas and possible solutions. 

– Remind students not to criticize others’ ideas during a brainstorming session. At this stage, all ideas are welcome. 

– Students could research various propeller designs for some ideas of different shapes. 

Plan 

• Students will now share and compare their individual drawings with their team and discuss which features should be integrated 

into the team design. 

– What parts or features of a propeller might make it better at producing thrust? 

– What is the best feature of each individual’s design and how can it be included in the team design? 

• Encourage students to combine their ideas and draw a solution for a propeller design. 

– Ensure that students label each part with its function along with the materials it is being made from. 

– Each design should incorporate at least one design idea from each team member. 

– Teams should create a plan for building and testing their design efficiently: 

 Who will be responsible for which parts of the build and test? 

 Does everyone have a fair share of the work? 

 How long should each step take? 

 What will the team do if something does not work as planned? 

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Unmanned Aircraft Systems 

– Before students commit to building their propellers, encourage them to share their design with other teams. 

– Engage students with a discussion about why they selected their design as well as why they chose certain materials, number 

of propeller blades, shape, and other unique features attributed to their engineering design. 

Create 

• Each team will build an identical basic car (see Appendix C). However, students will need to design different propellers from the 

various materials provided to generate enough thrust to drive the propeller car forward. 

• The step-by-step instructions provided allow students to create a basic propeller car to serve as a control during the engineering 

design challenge. 

• The only variable students will change is their propeller design. Applying the engineering design process will help students build, 

test, and redesign their propellers as appropriate. 

Test 

• Set aside a designated test area in the room for students to test their propeller cars on a smooth, flat surface. Make sure students 

know that this is the only location in the room for testing their vehicles. 

• Each team will use the designated test area to test their prototypes. The propeller car must travel a minimum of 1 m (100 cm). 

Students will record the time (in seconds, s) it takes the propeller car to travel 1 m for each trial in the data table and will then 

calculate the average time the propeller car travelled that distance. Students will also write down what changes they made from 

their previous design and document their observations for each set of trials. Please review the example table below. 

Average Time = Total sum of all test times recorded during a trial 

Number of tests during a trial 

Design 

number 

Test 1 

time, s 

Test 2 

time, s 

Test 3 

time, s 

Average time, 

s 

Change from previous 

design 

Observation 

1 20 19 19 19.3 N/A The car was very slow. 

2 18 17 16 17 Made the blades longer Moved a little faster, but blades 

cannot be any longer. 

3 12 11 10 11 Removed 1 blade The time it took the car to travel 

1 m was much faster. 

4 28 32 46 35.3 Made the blade angle 

steeper 

The car moved very slowly 

because the battery was almost 

dead, so we are excluding this 

test as an outlier. 

4 8 8 9 8.3 No change (replaced the 

battery) 

After replacing the weak battery, 

the car was faster than expected. 

Improve 

• After each test, students will improve their propeller blade design based on the results of their experiments and their 

understanding of Newton’s third law of motion, including transfer of energy, forces, and motion. 

• When students improve their designs, there are several factors they may change, including (but not limited to) number of blades, 

how propellers are twisted, area or shape of the blade, position, and propeller material. 

• Students will collect data and record the changes made to their engineering designs. 

Share 

• Engage students with the following discussion questions: 

– How is NASA’s mission for advanced air mobility (AAM) related to the design challenge? 

– What were the different steps you had to complete to get your team’s design to work correctly? 

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Unmanned Aircraft Systems 

– What physical forces came into play during this challenge? Explain. 

– How did your propeller design provide thrust? 

– What did your data tell you about your team’s propeller design? 

– What type of redesign changes did your team make to improve your vehicle’s performance? 

– What do you think may account for any differences in your propeller car’s performance as compared to vehicles created by 

other teams? 

– What was the greatest difficulty your team encountered while trying to complete this challenge? 

Extensions 

• Students can add measured weight (pennies, washers, etc.) to the propeller car to discover how much mass their vehicle can 

transport. 

• Students can add measured weight (pennies, washers, etc.) to specific locations (front, back, and/or middle) of the propeller 

car to find out if the distribution of weight impacts the performance of the vehicle. 

• Students can add multiple batteries to the motorized propeller car to compare and contrast the vehicle’s performance. 

Reference 

Rocket Races NASA Activity. https://www.nasa.gov/sites/default/files/atoms/files/rockets-guide-20-rocket-races.pdf 

Resources 

STEMonstrations: Newton’s Third Law of Motion 

https://www.youtube.com/watch?v=dCF--YOjiOw&feature=youtu.be 

Exploring Drone Aerodynamics With Computers 

https://www.youtube.com/watch?v=hywBEaGiO4k 

Making Skies Safe for Unmanned Aircraft 

https://www.youtube.com/watch?v=gK2jDwPrDTA 

NASA Armstrong Fact Sheet: Unmanned Aircraft Systems Integration in the National Airspace System 

https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-075-DFRC.html 

Advanced Air Mobility National Campaign Overview 

https://www.nasa.gov/aeroresearch/aam/description/ 

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Unmanned Aircraft Systems 

Activity One: Propeller Design Challenge 

Student Handout 

Your Challenge 

Design and build a propeller that will generate enough thrust to drive the propeller car forward 

a given distance in the shortest average time possible. 

Design Criteria and Constraints 

Criteria Constraints 

All car bodies must be identical. Each team will 

follow instructions and build the same basic car to 

which the propeller will attach. 

The propeller car cannot be pushed or tapped by 

team members to “boost” or move the vehicle 

forward. 

The propeller design must attach securely to the 

motor with the propeller hub attachment (the water 

bottle threading). 

All test cars must be powered by the same number 

of propeller turns (for rubberband cars) or type of 

battery cell (for motorized-propeller cars) (e.g., one 

9-V battery). 

The thrust from the propeller must move the car 

forward. 

The propeller car must move a minimum of 1 m 

(100 cm). 

Ask 

• Discuss ways to design a propeller that will provide enough thrust to push or drive the test 

car forward. 

– What variables affect propeller performance? 

– What type of material will you use to build your design? 

– What size and shape will your propeller be? 

– How many blades will you include, and how will you design them to move the vehicle 

forward? 

– Does your team have any questions before you begin? 

Fun Fact 

For decades, NASA has used 

computer models to simulate the 

flow of air around aircraft in order 

to test designs and improve the 

performance of next-generation 

vehicles. NASA recently used this 

technique to explore the 

aerodynamics of a popular small, 

battery-powered drone, a modified 

DJI Phantom 3 quadcopter. The 

simulations revealed the amazing 

yet complex motions of air due to 

interactions between the vehicle’s 

propellers and X-shaped frame 

during flight. 

Learn more: 

https://www.nasa.gov/imagefeature/ames/exploring-droneaerodynamics-with-computers 

Career Corner 

Claudia Herrera is an aerospace 

engineer in the Aerostructures 

Branch at NASA’s Armstrong 

Flight Research Center in 

California. She conducts ground 

tests and analysis on the 

structures of a variety of vehicles 

before they take flight. Click on the 

link below to learn more about 

how Claudia did not let poverty 

interfere with her aspirations of 

working at NASA. 

Learn more: 

https://youtu.be/MUa2E_M-b1A 

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Unmanned Aircraft Systems 

Imagine 

• Brainstorm and think about ways to design a propeller that can provide enough thrust to drive the propeller car forward. 

• Research propeller designs by NASA or companies in the flight industry to inspire ideas for your build. 

Plan 

• Draw your design on a separate piece of paper. 

• Each design must incorporate at least one design idea from each team member. 

• Label each sketch with dimensions and include the materials needed to build a model or prototype. 

• Before building your propeller, share your design with your teacher and/or another team to compare designs. Explain to the whole 

group why your engineering design is unique or similar to other team designs. 

Create 

• Your team will construct a propeller using only the materials provided by the teacher. 

• Your team will build a basic propeller car using the step-by-step instructions provided. 

Test 

• The propeller car must travel a minimum of 1 m (100 cm). 

• The propeller car cannot be pushed or tapped by team members to “boost” or move the vehicle forward. 

• Each team will conduct tests at the designated test area. 

• On a sheet of paper, create a data table like the example below. 

• After conducting each test, record in your data table the time it took your propeller car to travel 1 m (in seconds) and calculate 

the average time for the tests in each trial. Your team will also write down what changes were made from your previous propeller 

design. Be sure to write your observations for the trial of each design. 

Average Time = Total sum of all test times recorded during a trial 

Number of tests during a trial 

Design 

no. 

Test 1 

time, 

s 

Test 2 

time, 

s 

Test 3 

time, 

s 

Average 

time, 

s 

Change from 

previous design 

Observation 

1 N/A 

2 

3 

4 

5 

Improve 

• Your team must conduct tests and systematically improve the design after each trial. 

• Record observations during the tests that will help you modify your design for the next trial. 

• Redesign your propeller configuration to improve the thrust of the propeller car and reduce the time traveled. 

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Unmanned Aircraft Systems 

Share 

You will be presenting your propeller design to the whole group. In preparation for sharing, review the following items with your team. 

You can create a video or slide presentation to present your data. Decide who will be the spokesperson for your group. 

• Reflect on the engineering design process and explain how your team used the step-by-step process to create your final design. 

• List two things you learned about how engineers solve problems through your participation in the design challenge. 

• Discuss the results of your testing and share details with the whole group. 

• Why did you have to test your team’s design a few times before getting it to work the way you wanted? 

• What were some tradeoffs or compromises your team made during the challenge? 

• Compare and contrast your team's propeller design with another team’s design. 

– Did your design have similar features in common with other team designs? 

– What did you learn from looking at other teams’ projects and discussing them? 

• If you had more time, what would you do to improve your propeller? 

• What was the most innovative solution among all the teams? 

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Unmanned Aircraft Systems 

Appendix C.—Propeller Car Instructions 

C.1 General Instructions and Materials List 

Choose one of the two vehicle designs and gather all needed materials and instruction sheets (C.2 Electric Motor Propeller Car; 

C.3 Rubberband-Powered Propeller Car; C.4 Basic Propeller Template; C.5 Basic Propeller Template Instructions). 

Safety 

• Adult supervision is required for building and testing the propeller car. 

• Before any tool is used, review and discuss safety protocol for proper use of the equipment. 

• Remind students of lab safety (e.g., wear eye protection when building and testing the propeller car). 

• Scissors and craft knives have sharp edges and points. Students should handle tools with sharp edges with care. 

• Use appropriate electrical safety precautions around any wires or surfaces that might generate or conduct electricity. 

• Keep fingers, body parts, and other objects away from spinning propeller blades. 

• If using a glue gun, even with low-temperature or cool-melt glue, set up a glue gun station for safety and supervision. 

Materials List 

General Building Supplies for Basic Propeller Car 

 2 thick plastic water bottles (no larger than 1 liter) (Note: For data comparison purposes, each group’s car should be made with 

the same type of water bottle to eliminate extra variables.) 

 5 water bottle caps (additional) or 4 commercial hobby wheels and 1 additional bottle cap 

 2 straws and 2 wooden skewers, or 2 10-cm commercial hobby axles 

 Various propeller building materials (e.g., plastic, cardboard, popsicle sticks, paperclips, paper plates, etc.), or a commercial 

propeller may be used for Activity Two: Propelling the Payload With Electric Propulsion 

Tools 

 Stopwatch or timer to record propeller car motion (1 per team) 

 Low-temperature hot glue gun and glue sticks 

 Tape (for construction) 

 Duct tape (optional) 

 Scissors or craft knife 

 Pen, pushpin, or nail (to make wheel holes—these can also be predrilled by the educator if desired) 

 Metric ruler 

 Marker 

Additional Materials for Electric Motor Propeller Car 

 Small electric hobby motor, direct current (DC), 1.5 to 3 V or 3 to 12 V 

 9-V battery (recommend having extra batteries charged and ready for testing) 

 9-V battery clip connector 

 2 pieces of electronic wire (to extend wiring to motor or battery clip connector if necessary) 

 Wire strippers 

 Electrical tape (for wire connection) 

Additional Materials for Rubberband Propeller Car 

(Note: Some extra materials have been added in case there are malfunctions, system failures, or damaged parts.) 

 1 plastic cap (additional, any type) 

 1 wooden skewer 

 9 rubberbands (approximately 3 mm (1/8 in.) wide and 90 mm (3 1/2 in.) long) 

 3 large paperclips 

 2 small paperclips 

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Unmanned Aircraft Systems 

C.2 Electric Motor Propeller Car Instructions 

Gather all needed materials and review the Motorized Propeller Car Tutorial video: https://youtu.be/uPxmCzMyBII. 

Step 1: Create the cargo bay access window. 

Lay one of the bottles on its side and cut a rectangular hole 

that extends approximately 4 cm from the bottom of the bottle 

to approximately 7 cm from the top of the bottle. 

The rectangle should be between 4 and 5 cm wide. 

Step 2: Mount the axles. 

Cut a straw into two 8-cm pieces. Each straw should be wider 

than the water bottle. 

Use low-temperature hot glue or other adhesive to attach the 

straws to the water bottle on the opposite side of the 

rectangular hole that was cut in Step 1. Place the straws 

(axles) far enough apart so the weight is distributed evenly. 

Cut a wooden skewer into two 11-cm pieces and slide the 

wooden skewers through the straws. 

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Step 3: Create the wheels. 

Mark the center of each bottle-cap wheel with a marker. Use a 

pen or pushpin to make a small hole in the center of the 

marking. Make sure the hole is a little smaller than the wooden 

skewer (axle) diameter so it is a tight fit. 

When using thick plastics, use a nail or a craft knife to make 

the holes larger. 

Step 4: Mount the wheels. 

Gently push a skewer through the center of a bottle-cap wheel. 

Slide the skewer through a straw and push into the center of a 

second bottle-cap wheel. 

Repeat with the other two wheels and skewer. 

Make sure the wheels are as straight as possible. 

Note: Wobbly wheels make it difficult for propeller cars to move 

forward. 

Step 5: Wire the motor to the 9-V battery clip. 

Strip the wires connected to the 9-V battery clip. 

Connect the wires from the 9-V clip to the proper terminals on 

the motor. 

• The negative terminal is designated by a “–” sign. Connect 

the black wire to the negative (–) terminal on the motor. 

• The positive terminal is designated by a “+” sign. This is 

where the red wire will connect to the motor. 

If the wires are too short, simply add additional cabling to extend 

the wires from the 9-V battery clip to the motor. 

Note: Some DC motors do not designate a positive and negative 

terminal. If this is the case, simply wire each cable from the 9-V 

battery clip to a terminal on the motor. 

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Unmanned Aircraft Systems 

Step 6: Connect the battery. 

Attach the battery to the connectors on the 9-V battery clip. 

Your motor should run. If not, your battery may be dead, or 

wires may be touching. Troubleshoot the issue. 

Now detach one of the battery connectors to turn off the power 

to the motor. 

Step 7: Tape the 9-V battery to the car. 

Neatly organize the cables inside or along the side of the test 

car. 

Place and center the 9-V battery near the front of the car. It 

should be taped perpendicular to the body of the car. 

Note: Before moving to the next step, ensure that the propeller 

car is balanced. 

Step 8: Connect the hub to the motor. 

Mark the center of the top of a bottle cap with a marker. 

Using the marking as a center point, use a pen to create a small 

hole through the top of the bottle cap. 

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With the bottom of the bottle cap facing toward you, secure the 

bottle cap to the shaft of the motor. 

The bottle cap should be placed about halfway between the tip 

of the motor shaft and the motor. 

Use a moderate amount of low-temperature hot glue or 

adhesive on the inside of the bottle cap to ensure a tight fit. 

Note: The bottle cap (propeller hub) should not sag or rub 

against the motor or the bottom of the water bottle. 

Step 9: Connect the propeller attachment to the propeller 

hub. 

The purpose of the propeller attachment (see photo) is for you 

to attach and reattach the propellers you design or redesign to 

the propeller hub. 

Do not use glue to connect the propeller attachment to the 

propeller hub, because you will need to attach and reattach 

your propeller designs to it. 

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C.2.1 Propeller Attachment Instructions for Activity One, Propeller Design Challenge 

After building either the rubberband-powered or electric motor propeller car, choose one of the options below for attaching propeller 

designs to the propeller car for Activity One: Propeller Design Challenge. 

You have two options when using the propeller 

attachment. 

Option 1: 

Safely cut the threading off of a water bottle. You can use the 

base of this threading to attach your propeller designs to the 

system. 

Option 1 example 

Option 2: 

Safely cut the threading off of the second water bottle, but use 

some of the plastic from the neck of the second water bottle to 

create your propeller design. 

Option 2 example 

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C.3 Rubberband-Powered Propeller Car Instructions 

Gather all needed materials and review the Rubberband-Powered Propeller Car Tutorial video: https://youtu.be/1lNd5Q8Cb2w 

Step 1: Create the cargo bay access window. 

Lay one of the bottles on its side and cut a rectangular hole 

that extends approximately 4 cm from the bottom of the bottle 

to approximately 7 cm from the top of the bottle. 

The rectangle should be between 4 and 5 cm wide. 

Step 2: Mount the axles. 

Cut a straw into two 8-cm pieces. Each straw should be wider 

than the water bottle. 

Use low-temperature hot glue or other adhesive to attach the 

straws to the water bottle on the opposite side of the 

rectangular hole that was cut in Step 1. Place the straws 

(axles) far enough apart so the weight is distributed evenly. 

Cut a wooden skewer into two 11-cm pieces and slide the 

wooden skewers through the straws. 

Step 3: Create the wheels. 

Mark the center of each bottle-cap wheel with a marker. Use a 

pen or pushpin to make a small hole in the center of the 

marking. Make sure the hole is a little smaller than the wooden 

skewer (axle) diameter so it is a tight fit. 

When using thick plastics, use a nail or a craft knife to make 

the holes larger. 

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Step 4: Mount the wheels. 

Gently push a skewer through the center of a bottle-cap wheel. 

Slide the skewer through a straw and push into the center of a 

second bottle-cap wheel. 

Repeat with the other two wheels and skewer. 

Make sure the wheels are as straight as possible. 

Note: Wobbly wheels make it difficult for propeller cars to move 

forward. 

Step 5: Create the anchor for the rubberbands. 

Use the pushpin and the nail to create two holes on opposite 

sides on the mouth of the bottle. Ensure the holes are large 

enough so the straightened paperclip will be able to slide 

through both sides. 

Put the straightened paperclip through one hole, then slide it 

through the center of another paperclip that will be used as an 

anchor, and then out the other hole in the neck of the bottle. 

Bend the ends of the paperclip up and in, locking the paperclip 

in place. 

Step 6: Make the propeller. 

Note: This is an example of a basic propeller that can be used 

for the Propelling Your Payload With Electric Propulsion activity. 

Students will design their own propellers for the Propeller 

Design Challenge. 

Cut off the top portion of the second water bottle. Make a 

horizontal cut on the side of the bottle right before the plastic 

starts to angle toward the neck of the bottle. 

Safety reminder: Hold the bottle top firmly by its cap so 

the scissors do not accidentally contact your supporting 

hand. 

Starting at the cut edge of the bottle, make two cuts directly 

across from each other, cutting straight down and as close to 

the bottle cap as you can. 

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Repeat until you have four to eight equal sections or propeller 

blades. Gently fold them back to a roughly 90° angle (as shown 

in the picture). 

Mark the center of the bottle cap (propeller hub) on the propeller 

with a marker. Use a pushpin to make a small hole in the center 

of the marking. 

Make sure the hole in the bottle cap is a little smaller than the 

wooden skewer (axle) diameter, so it is a tight fit. Do not put 

the skewer in yet. 

Step 7: Prepare your propeller. 

Use the pushpin to poke a hole in the extra bottle cap. 

Use the steel nail to widen the hole a little more. 

Cut a circle out of the bottle cap. It does not have to be perfect. 

Place the skewer in from the top side of the propeller bottle cap 

(propeller hub) and push it in about 4 cm. Put hot glue on the 

underside of the propeller hub to help hold the propeller hub 

onto the axle. 

Note: The purpose of the propeller hub (see photo) is for you to 

attach and reattach the propellers you design or redesign to the 

propeller car, so it is important you do not use glue to connect 

the propeller itself to the propeller hub (bottle cap). 

Make a thick ring of hot glue, 3 cm away from the propeller hub 

on the skewer. Let it cool, then put the plastic circle you just cut 

out onto the skewer. 

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Step 8: Attach the propeller. 

Use the pushpin to make a hole for the propeller’s axle. Make 

the hole at the bottom (base) of the bottle on the same side as 

the cargo bay opening. 

Use the nail to make the opening big enough for the skewer to 

go in and spin freely. Place the axle through the opening. 

Shorten the skewer so there is about 6 cm inside the cargo 

bay. 

Pull one end of a small paperclip and open it slightly. Hot glue 

the other end of the paperclip onto the skewer that is on the 

inside of the cargo bay opening. Glue the paperclip so that it 

will not come off the skewer (propeller). 

Weave together two sets of three rubberbands into a loose 

knot, as shown. 

Connect one end of the rubberband knot to the paperclip 

attached to the propeller skewer. 

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Connect the other end of the rubberband knot to the paperclip 

attached to the mouth of the bottle. 

Your propeller will be loose at this point; this is to be expected. 

Safety reminder: Be sure you are wearing eye 

protection when stretching the rubberbands. 

Step 9: Twist the propeller. 

Twist the propeller by its axle—do not put your finger between 

the blades to spin it. Propellers will usually need to be twisted in 

a clockwise direction, but if your propeller spins backward or not 

at all, try turning the other direction. 

Twist until the rubberbands double over on themselves. Usually 

this will be more than 100 twists. Keep hands and fingers clear 

of the propeller. 

When you are ready, place the propeller car in the designated 

test area and release the propeller! 

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C.3.1 Propeller Attachment Instructions for Activity One: Propeller Design Challenge 

After building either the rubberband-powered or electric motor propeller car, choose one of the options below for attaching propeller 

designs to the propeller car for Activity One: Propeller Design Challenge. 

You have two options when using the propeller 

attachment: 

Option 1: 

Safely cut the threading off of a water bottle. You can use the 

base of this threading to attach your propeller designs to the 

system. 

Option 1 example 

Option 2: 

Safely cut the threading off of the second water bottle, but use 

some of the plastic from the neck of the second water bottle to 

create your propeller design. 

Option 2 example 

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C.4 Basic Propeller Template 

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C.5 Basic Propeller Template Instructions for Activity Two: Propelling the Payload 

With Electric Propulsion 

After building either the electric motor propeller car or the rubberband-powered propeller car, you will need a basic propeller to 

provide thrust for the car. 

Step 1 

Have your Propeller Template ready. 

Measure 7.5 cm from the top mouth of a plastic water bottle, 

and use a marker to carefully draw a line around its 

circumference. 

Step 2 

Neatly cut along the line around the bottle. 

Step 3 

Place the bottle top you just cut out on top of the Propeller 

Template. Looking from the top, align the mouth of the water 

bottle with the center of the template. 

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Step 4 

Each propeller on the template has a number. 

With a marker, write each number on the corresponding plastic 

bottle as shown. 

Step 5 

On the Propeller Template, you will notice four straight lines. 

Draw a line from the neck of the water bottle to each of the 

straight lines. 

Do not cut the plastic yet. 

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Step 6 

Remove the bottle from the template and cut out all four of the 

template’s paper propeller blades. 

Step 7 

Starting with the propeller blade labeled “1,” align the straight 

edge of each paper propeller with the line you sketched earlier. 

Use clear tape to attach each propeller to the plastic bottle. 

Step 8 

Inspect the taped propellers to ensure they are neatly secured 

to the bottle. Cut along the lines slowly. When you are done, 

remove the paper. 

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Step 9 

Gently pull open the propeller blades. 

Step 10 

Finally, screw the propeller attachment onto the propeller hub. 

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Appendix A.—Rubrics 

A.1 Engineering Design Process (EDP) 

EDP Step Novice 

(0) 

Apprentice

(1) 

Journeyperson

(2) 

Expert

(3) 

Level of 

student 

knowledge 

(Score) 

Identify the problem 

(Ask) 

Student does not 

identify the problem 

Student incorrectly 

identifies the problem 

Student identifies part 

of the problem 

Student fully and 

correctly identifies the 

problem 

Brainstorm a 

solution (Imagine) 

Student does not 

brainstorm 

Student generates one 

possible solution 

Student provides two 

solutions 

Student provides three 

or more possible 

solutions 

Develop a solution 

(Plan) 

Student does not 

select or present a 

solution or the solution 

is off task 

Student presents a 

solution that is 

incomplete or lacking 

details 

Student selects a 

solution but does not 

consider all criteria and 

constraints 

Student selects a 

solution that considers 

all criteria and 

constraints 

Create a prototype 

(Create) 

Student does not 

directly contribute to 

the creation of a 

prototype 

Student creates a 

prototype that does not 

meet problem criteria 

and constraints 

Student’s prototype 

meets most problem 

criteria and constraints 

Student creates a 

prototype that meets 

all problem criteria and 

constraints 

Test a prototype 

(Test) 

Student does not 

contribute to the testing 

of the prototype 

Student conducts tests 

that are irrelevant to 

the problem or do not 

accurately assess 

strengths and 

weaknesses of the 

prototype 

Student conducts 

carefully performed 

tests that consider one 

to two strengths and 

weaknesses of the 

prototype 

Student conducts 

relevant and carefully 

performed tests that 

consider three or more 

strengths and 

weaknesses of the 

prototype 

Redesign based on 

data and testing 

(Improve) 

Student does not 

contribute to the 

redesign 

Student does not 

improve the design or 

address concerns 

Student addresses one 

concern to improve the 

design 

Student addresses two 

or more test-based 

concerns to improve 

the design 

Communicate 

results from testing 

(Share) 

Student does not 

communicate results 

Student shares random 

results 

Student shares 

organized results but 

results are incomplete 

Student shares 

detailed, organized 

results with group 

Total 

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