Designer extraordinaire Jude Pullen has designed this desktop wind tunnel to be built cheaply: it’s made of card, wood offcuts, PVC piping, and some clear acrylic sheets for the sides, plus a set of digital scales. And it’s cheap on purpose; this project was commissioned by The Design And Technology Association, which supports schools teaching design and technology. This subject has, in England and Wales, had its funding cut by over 70% since it was first introduced to the curriculum, so teachers need cheap ways to demonstrate the principles of design.
This is a minimal setup; all it measures is the force applied to the scales, from which the user can compare the lift generated by different wing designs. If you wanted to go deeper into engineering, you could add a manometer to measure pressure, an anemometer to measure wind speed, and a tachometer to measure fan speed. There’s also scope to introduce some sort of vapour to visualise the airflow.