(Follow Foils / Walkalong Gliders / Tumbling Wings)
If there’s an opportunity to explore and demonstrate science we’re for it! Particularly if it’s simple to do.
The tumblewing, is a toy you can make at home which demonstrates the Magnus effect and easy to make (or a fun project to do in class). It works by throwing as a paper airplane, but with some backspin on the blades. The rotation you impart on the blades create a pressure differential with lower pressure above and higher pressure underneath. This difference in pressure creates lift, similar to how air flow over an airplane wings creates lift.
There are quite a few designs. One design provided Prof. Denjinro’s (Yonemura) of Happy Energy (http://denjiro.co.jp/), a popular Japanese science explainer, uses light weight, but rigid card and/or rigid foam to create what he calls a Magnus Flyer. The design (shown here) consisting of a narrow rigid sheet of cardboard or stiff plastic, about 15-20cm long and 3-4cm wide, pushed through a slot in the middle of a rigid circular disk, that has a diameter greater than the width of the blades. The blades are centrally placed in the disk, with the same amount of blade either side But, you could experiment and see what happens if you place them off-centred or add more disks. We’d be interested in your results.
You might find it useful to have the subtitles switched on for Prof. Denjiro’s video, if you do not know Japanese.
Prof. Denjiro also demonstrates another type of tumblewing which looks like a large infinity symbol in cross-section. In the video he says it’s made from the styrofoam, but that could be just the automatic translator as it’ looks more like polypropylene, the same material used for yogurt pots, etc. The type of plastic that is flexible. You can also make this from paper. You’ll probably need to experiment to find a paper that is light enough, but retains it’s shape when bent and moving.
We’ve not found any design instructions, but it quite possibly just cross-sections off the top of one large yogurt pot or a couple of smaller ones. If you are using one large pot, the middle is stapled/glued together to let the ends flare out creating two teardrop shapes touching at the narrow point.
If you are using smaller pots, then cut two strips of plastic one from the top of each pot, without the rim. Cut each circle of plastic, so they flatten and form a long strip of plastic. Don’t worry about getting it flat as you’ll be bending it back into a curve again. With each one, glue the cut ends together, but so the inner surfaces of each touch, creating a teardrop shape in cross-section. Now glue the pointed ends of the two pieces together to create something resembling an infinity symbol.
This version is difficult to throw. There’s virtually no weight to give it the forward momentum, but if you made it light enough, it should gently fall with a tumbling forwards motion. AND! if you provide a small amount of updraft by walking along behind with a flat sheet of cardboard slightly below and angled to push air upwards, you can keep this tumblewing in the air for as long as you have space to move.
Follow Foils / Tumbling Wing
These are another popular design, using a simple strip of lightweight paper folded to give rigidity and create rotation from the air flow in the same way as windvane street signs work. But because these are so light they also can be kept aloft by walking along behind with cardboard and creating an updraft.
Here’s a video by The Paper Airplane Guy showing them in action.
And one by Mrs Nicolson on how to make one with thin, lightweight paper and some simple folds.
Do you have a design that works better? Let us know.
