2025 World KidWind Challenge

Each team competing in the Wind Challenge will need to run their wind turbine through multiple distinct tunnels at the World KidWind Challenge, each with their own unique focus. All tunnels draw wind through the tunnel creating a much cleaner and more stable airflow. The size of the wind tunnel testing space is 48” x 48” x 48”. Keep in mind, though, that the walls move in a bit when the tunnel is running.

Each team must find time to test their wind turbines in the wind tunnels during Worlds when they are not participating in the other scheduled Competition Elements.

Tunnel Specifics

Depending on your grade you will need to receive turbine performance scores in each of the following tunnels:

There will be a timer at each tunnel, each team will need to be out of the tunnel in 5 minutes from set up to testing.

Tunnel 1: Low Speed (3-3.5 m/s)

10 points

Tunnel 2: Medium Speed with Yaw Test  (4-4.5 m/s)

10 points

In this tunnel your wind turbine will be placed on a Lazy-Susan that can rotate. Ten seconds into the test, we will rotate the Lazy Susan AT LEAST 90 degrees and lock the table in place, so that the turbine is turned out of the wind. Be sure to consider how you might modify your design to best perform during this Yaw Test. For more details on our Yawing Tunnel, see this guide.

Tunnel 3: High Speed (at least 6 m/s)

10 Points (MS & ES) | 5 Points (HS)

This is our fastest (regular) wind tunnel. For elementary and middle school teams, this tunnel will be worth a maximum of 10 points. For high school teams, this tunnel will be worth just 5 points, because you have an additional tunnel - the SUPER Tunnel.

Efficiency

5 Points

While you are testing in the High Speed Tunnel, will also test the efficiency of your wind turbine. Efficiency is calculated by measuring your rotor diameter and wind speed in the wind tunnel. With these two variables, in addition to your average power output, we can calculate how efficiently your turbine converts wind energy into electrical energy.

Tunnel 4: Super Tunnel (HS Only)

5 Points - Energy Output | 5 Points - Endurance

We have constructed a new wind tunnel that can produce speeds of up to 11 m/s. Our team has been testing different ways to measure power and energy data from turbines in the super tunnel. As of April 17th, we plan on measuring the Wh generated over a 3 minute test. We are also experimenting with a water pumping test that will measure how high your turbine can pump water during the test, in addition to how much water you can move from container A to container B during the test.

The judge at the Super Tunnel will instruct the team on how the hold down system works. Teams will be responsible for making all adjustments and taking the necessary steps to install the hold down system parts to secure their turbine for testing.

The turbine hold down system for the Super Tunnel consists of the following:

• 2 slotted grooves at the outer edges (left and right sides) of the 48” by 48” by 48” test chamber.
• 4 - 6” long T-nuts are in the slotted grooves, 2 on each side of the tunnel.
• 2 wooden cross pieces .75” thick by 1.5” wide by 48” long with holes at each end, that will be used to hold down the turbine base when connected to the 6” long T-nuts in the slotted grooves. The wooden cross pieces holding down the turbine's base will be held in place by a wing-nut on each 6” long T-nut.

For the first minute of the test, we will modulate the wind speed between 1-6 m/s.

For the last minute of the test, we will gradually increase the speed of the tunnel from 6 m/s to its maximum speed of 10 m/s, 1 m/s at a time. Teams will control this process and give the tunnel operators the go ahead for each speed increase. Turbines will be awarded 1 point for every m/s above 5 m/s they survive. If you survive to the 10 m/s max will be awarded 5 points for endurance.

Wind Tunnel Testing Protocol

During tunnel testing, teams must run their turbines through each tunnel. Each team will receive a set number of tokens at check-in that they must trade-in to test their turbine in the wind tunnel.

Each tunnel will use a different color token and one tunnel run requires one token. You can assume that you will receive 2-3 tokens per tunnel, meaning 2-3 active runs per tunnel. Once the number of teams attending Worlds has been confirmed, we will finalize the number of tokens to be distributed.

Each tunnel will have a visible timer. Each team will have just 4 minutes to get their turbine set-up in the tunnel and complete their test. Tunnel judges can add additional time to the timer at their discretion.

Tunnel Testing Protocol

1. TOKEN: Hand 1 tunnel token to the tunnel judge. Be sure the color of the token corresponds to the color of the tunnel.
2. TURBINE SET-UP: Place your turbine in the tunnel and connect the wires to the data logging hardware.
3. FANS START: The tunnel judge will turn on the fan and let the tunnel and turbine get up to speed. This will take about 30 seconds.
4. GO/NO GO CALL: At the 30 second mark, the tunnel judge will ask if you want to run a trial. You can say YES or NO.
5. DATA COLLECTION:
   • If you say NO (you do not want to run a trial): Remove the turbine, collect back your token, make any adjustments and go to the back of the line.
   • If you say YES: The 30 second trial begins. The only way that a test can be redone is if judges determine that there has been a Catastrophic Failure because your turbine has failed and/or your output has dropped to ZERO.

During the solar judging session, we will provide two types of solar arrays (two styles of lighting systems):

• **Solar Blast **- A bank of lights approximately 1 meter square positioned 1 meter off the table.
• **Solar Tracker **- A solar lamp that can move up and around the solar structure, in an arc to simulate a changing sun position.

Students will place their solar structure/device under the solar array to an optimal position. Students will be able to turn on any switches, microcontrollers, or other controls that are part of their solar project during the judging session to demonstrate performance.

Your solar structure will be tested during your 30-minute judging session. Teams can expect to be evaluated on the following criteria: circuit design, functionality, inspiration, creativity, aesthetics, materials, and knowledge about solar power.

We will have an additional solar array set-up in Hall A for open testing during the event. While this solar array is not the same Solar Blast, it will allow teams to tinker and test their structure prior to judging.