- Before working with students, conduct a few test flights to determine how challenging this activity will be for students. Develop at least one "sky hook" design to attach to the UAV that can pick up and carry a payload.
- Create a payload for your students to attempt to retrieve (see description below)
- Charge batteries for the UAV, including spares.
- If your UAV model includes a detachable camera, remove that from the UAV for this activity. Though not strictly essential, we recommend this to make the UAV lighter (which will make batteries last longer) and help students focus on the activity (instead of taking photos or videos).
Making the Payload
The payload you make for your students to retrieve should be lightweight and have something that is easy to "grab" with the UAV "sky hooks" that your students design.
It is difficult to maneuver a UAV precisely enough to pick up a payload. Make sure your payload makes it as easy as possible for students to succeed.
We recommend using magnets in your setup. Magnets allow UAVs to successfully "latch onto" a payload if they get reasonably close to it, even if the connection isn't perfectly on-target. We strongly suggest incorporating a magnet into the payload the UAVs are supposed to retrieve; and letting students know that the payload contains a magnet. The "sky hook" that students design can include a magnet as well, to make it especially easy to connect with the magnet in the payload. Another alternative is for the sky-hook to include a metal (steel or iron) object, such as a paper clip or small washer, that the magnet in the payload will be attracted to.
If you use magnets, the strong neodymium (or rare-earth element) magnets work best. They generate a much stronger magnetic force in a lightweight magnet than the traditional ceramic magnets achieve.
A simple, lightweight, magnet-bearing payload can be made from a small cube of Styrofoam with a magnet taped (securely!) to its top. A Sytrofoam cube about one inch on each side works well. Another approach is to cut out a few squares of corrugated cardboard - about an inch on each side - and tape them together in a stack to form a roughly cube-shaped package. The magnet can be taped to the top, or can be placed in between layers of cardboard.
You may want to place the payload in the center of a circular object (such as a plastic plate or Frisbee) when you set it in the Flight Area for students to retrieve. The plate or Frisbee can help with students' depth perception when trying to judge precisely where to fly their UAV to latch onto the payload.
There are several times during this activity when you can assess student performance. Proper actions by the students should result in successful flights, while inappropriate behaviors are likely to result in poor flights.
- Are the students' sky-hook designs safe?
- How well do students work as a team in designing their sky-hooks?
- Are the students' sky-hook designs lightweight enough for the UAV to carry once the payload is attached?
- Are the students able to fly the UAV to the payload, grab it, and bring it back to the starting location? If they are unable to complete this task, is their sky-hook design sound (and the failed flight simply a matter of insufficient piloting skill and experience)?
- If the class is timing the flights, does each group retrieve the payload within the time limit? How does each group's time compare with other groups?
- Did the students use sound engineering practices in planning, building, testing and revising their sky hooks?