By Everard Cunion, August, 2011
This paper glider is not a Rogallo wing in the strict sense because it does not use the airflow that results from its flight to hold its shape. However, its shape resembles that of the early (1970s) standard Rogallo hang gliders, which inspired its design.
It is asymmetric and it tends to be unstable in pitch, but it is simple to construct and – when you launch it just right – its glide is impressive. It is easy to build, requiring no cutting, gluing, or the adding of weights, but it is tricky to launch.
I claim copyright on this design from 1979.
Lay two sheets of paper on a flat surface, overlapping as in the first photo. Note the slight open ‘V’ at the tail, which is optional.
Fold the ‘ear’ back.
Next, turn the whole thing over.
Fold the other ‘ear’ back to form the nose.
Fold in half lengthwise and crease the fold.
At this stage, you can see there is more weight of paper at the nose than the tail, which is correct. The aerodynamic centre is at about the quarter chord point.
Fold and crease to form one leading edge.
Turn over and repeat…
Most paper darts rely on a crease in each half to approximate an aerodynamic shape. You could do that here, but to obtain the desired Rogallo shape, use both hands to roll it tightly.
When it springs back out, you should be left with a partial cone. When you have rolled both halves, the result resembles the standard or conical Rogallo. (So called because it consists of two partial cones.)
Next, add a ‘Concorde’ kink near the nose. How near? A bit nearer than in the photo (as it turned out – it dived with the kink that far back.)
Because it is unstable and its launch technique a critical acquired skill, it needs still air, so it is suitable only for flight indoors or in absolute calm outdoors.
Hold between thumb and two fingers at the tail, and gently push it until it starts to fly, and which point – if you get it right – it flies out of your fingers and begins a graceful glide across the room.
If, when you feel your launch angle and speed is right, it tends to stall, move the camber aft slightly. If it tends to dive, move the camber forward.
Practice, practice, practice! And patience…
Space flight and hang gliding (including a photo of Francis Rogallo flying his own invention)