Sunday, August 15th, 1948, Francis and Gertrude Rogallo took their prototype flexible wing out to the field at Merrimac Shores in Hampton, VA to see how it might fly. Their first successful flexible wing kite was made from some chintz curtains that had hung as a cabinet skirt in their new house. The old pattern didn’t match Gertrude’s choice of colors for the new kitchen, so the old chintz fabric was, in Rog’s words, “handy.” It also proved to be a fortuitous choice. Chintz is a glazed fabric, and its lack of porosity made it a great material for a kite. Later studies showed that porous ‘parachute material’ yielded only about half the lift as non-porous cloth.
The planform for the revolutionary wing was drawn and cut out by Rog, and Gertrude did the sewing. The leading edges had a small amount of extra fabric sewn in for stiffness, but not much. It was nearly identical in shape to the earliest hang gliders, with the leading edges the same length as the keel, but it was completely flexible.
No pictures were taken that day, and no film exists, but the die was cast. For many reasons, both simple and complex, it would be over a decade before the flexible wing would begin to get the attention and research Rog knew it deserved. And it was another decade still before its recreational possibilities would begin to become clear.
The story of the simplest airfoil isn’t a simple one at all, but it’s a great one, and completely worth telling. Today seems like an auspicious day to start…