Don’t Lose Balance: Fan Powered Skateboard Design Project

My name is Jeremy Snyder, and under the direction and supervision of my STEM teacher Mr. Scott Kutz (Westlake High School, OH), I helped him create this project based Instructable to utilize and co-teach in our Engineering Honors class.

Lesson Summary

In this lesson, Students will make an electric ducted fan (EDF) powered skateboard while incorporating elements of 3d printing, and laser cutting in their build. They will design parts in Autodesk Inventor to 3d print and cut out on a CNC machine. If a CNC machine is not available for use, students may also use a jigsaw or band saw.

Commentary

This lesson is intended for instruction in an advanced technology and/or engineering program environment. Other content areas that may enhance and contribute to the interdisciplinary aspects of instruction for this lesson include science (scientific ways of knowing). This project should take your students 10-12 days to complete.

Ohio Standards Connection

Strand: Design and Technology

Topic 2: Identify a problem and use an engineering design process to solve the problem

Content statement: 9-12.DT.2.b. Implement, document and present a design process as applied to a particular product, process or problem

Strand: Design and Technology

Topic 3: Demonstrate that solutions to complex problems require collaboration, interdisciplinary understanding and systems thinking

Content statement: 9-12.DT.3.c. Describe techniques for making decisions about the future development of technology

Strand: Design and Technology

Topic 4: Evaluate designs using functional, aesthetic and creative elements

Content statement: 9-12.DT.4.b. Interpret data/information related to product testing to determine revisions and modifications to a design’s function and aesthetics

Supplies

• 3x 5200mAh 3s LiPo battery
• servo tester
• Servo extension cable
• speed controller
• nuts and machine screws
• thicker than ½’’ thick plywood 4'x8'
• 3x 2200Kv Brushless motor
• t connectors
• skateboard trucks and wheels
• hot glue gun
• 3d printer and filament
• CNC machine
• Soldering gun
• duct tape

Step 1: Pre Test

Whole Class Discussion

Define “Design” as it relates to engineering technology. Name the different forms of transportation technology. List the shapes of skateboard bodies. Explain how an environment can affect how different skateboard designs perform. Describe the newest form of transportation you’ve seen and how it’s different from a similar existing form of transportation you’ve seen before?

Step 2: Make Sketches

Have students create at least 5-10 orthographic sketches of possible board designs to come up with ideas for the project. Students may also sketch any and every isometric view that they believe will aid in the design of their skateboard.

Step 3: Take Measurements

Students will measure all their parts to base the rest of their design off of. This this step is extremely important to get right in order to correctly design the rest of their parts of their build. Improper measurements can lead to students making the wrong size parts that need to be remade and can be a real pain. Tools that should be used for with this part of the project include an architects scale and digital calipers.

Step 4: Design on Inventor

Using the measurements you used in the first step, you will need to make certain items for your board you will need to design the EDFs, a way to hold the batteries and EDFs to the board, and a board design. The board design you will use to cut out on the CNC machine, and the rest of the parts you design, you will 3d print to put on the board. It is important to keep in mind how you will attach the parts to the board so that you put the needed screw holes on the parts and the board. It is important that these holes line up correctly or it will be a pain to correct.

Step 5: 3d Print Parts Needed for the Build

This step will take some time and you may need to redo multiple times throughout the build before you get it right. Using the designs on inventor in part 2, students will 3d print all the parts need to incorporate into your build. It is important to ensure that you double check the scale before printing your parts so that everything fits properly and works the right way. If you test fit your parts and they fit incorrectly, your students will need to redesign parts of their print and then reprint it costing precious time and filament.

Step 6: Cut Out the Board

Students will cut out the skateboard part of the build preferably on a CNC machine if available using the board you designed on inventor. If this type of machinery is unavailable, they will need to use other methods to cut out the board and add screw holes such as a jig saw or band saw. It is best if you use at least an inch thick piece of plywood. Don't make the same mistake I made in using 1/2" thick plywood. This was too thin and needed to be braced with an aluminum rod and 2'x2''s before it could support a person's weight. This extra step added time and effort to the build.

Step 7: Solder Parts

Depending on the speed controller with the motor, you may need to solder the speed controller a to a t connector to fit with the batteries. You will also need to use 3 of your servo extender cables to make an adapter to control 3 different speed controllers at once. You will want to seal these solders with heat shrink, but if that is not available, you can use hot glue.

Step 8: Assemble the EDFs

After 3d printing the parts you will need for the EDF (the propellers and the housing), make sure you are very careful to remove all of the support material well. Failure to remove certain support material on the housing can cause the motor to sit badly and make the propellers off center hitting the housing when they turn. When the housing and propellers are completely clean without any remaining supports, you will need to screw the motor into the mount by putting the screws through the holes in the housing into the motor. You will then put the adapter for the the propellers on the motor and place the propellers you printed on the adapter. Use an Allen wrench to tighten the propeller on the motor.

Step 9: Assemble the Board

If the measurements you took and holes you put in the board and 3d printed parts are right, this step will not take long and you can probably be done in under an hour. All you should need for this step is a screw driver, socket driver or wrench, duct tape, and a hot glue gun. Use the socket driver or wrench to hold the nut while you tighten the bolt with the screwdriver to attach the parts to the board. It is important that these are tight enough so that the EDFs do not rattle on the board. Also keep in mind that tightening the nuts too tight could damage the 3d printed parts. You will then use the duct tape and hot glue to attach the loose wires and parts to the board. Once this is done you can use your 3 pin connector to attach your servo tester to your speed controllers. You can then plug in all the wires and you will have a functioning EDF powered skateboard.

Step 10: Post Test

Part 1: Students will take measurements of their parts and design any additional attachments they need in order to 3d print or cut on a CNC machine.

Part 2: Students will then assemble their skateboard with their parts to try and make the most functional and aesthetically pleasing skateboard they can.

Part 3: Students will test their skateboard and make any additional modifications they need to best utilize their skateboard and optimize performance.

Step 11: Differentiated Instructional Support

Instruction is differentiated according to learner needs, to help all learners either meet the intent of the specified indicator(s) or, if the indicator is already met, to advance beyond the specified indicator(s).

• Arrange students of mixed abilities in teams, and/or pair a student with a strength in one aspect of the lesson with a student with a strength in another aspect of the lesson.
• Give students with evidence of not meeting standard extra help and attention with this project in order for them to perform well and reach their full engineering potential.
• Allow students showing evidence of not meeting standards to just build part of the project such as just the board.
• Allow students demonstrating evidence of exceeding the standards to build a racetrack for their boards to race each other.

Step 12: Homework Connections

• Research skateboards and other fan powered inventions
• Watch videos related to the project or similar topics
• Create more sketches and design ideas at home

Step 13: Technology Connections

• Specify how students use technology within the lesson or homework connections.
• Consider which additional technologies could enhance the lesson or assessment.
• What technologies use the content of this lesson?

Step 14: Extension

• Have students test their boards in the real world to see how functional and usable it is in everyday life.
• Have students design a second board to test different board shapes.
• Have students see what other projects they can make with the EDF

Step 15: Vocabulary

• EDF(electric ducted fan)
• CNC(computer numerical control)- robotic cutting machine
• Design – the conscious effort to impose meaningful order.
• Efficiency – the optimization of use
• Isometric Sketch – A 3D drawing; the front edge (and those parallel to it) will appearvertical. The two lower edges (and those edges parallel to it) will appear vertical. Thetwo lower edges (and those parallel to them) will appear about 30 degrees to thehorizontal.
• lipo(lithium-polymer battery)

Step 16: LiPo Battery Safety Note

This should be obvious, but you should not puncture the battery, don't get the battery wet and don't short circuit the LiPo batteries (they will go boom). Don't be stupid, be safe!