The following was written by Dick Kline, inventor of the Kline Fogleman airfoil. Dick has graciously written this great piece for all of us. Thank you Dick!
I have been asked a number of times, “How did you come up with the Kline-Fogleman airfoil?”
Back in the early 1960s, I was working as an art director for an advertising agency in mid-town Manhattan. My office was on the 24th floor, overlooking 42nd Street, the New York Public Library and Bryant Park. I had no knowledge of aerodynamics back then, but I loved to make paper airplanes and would occasionally sail one out the window and watch it fly over the park and the library.
On weekends, I would take my young son out to a ball field to fly paper planes. But it could get windy outdoors, and the paper airplanes couldn’t handle the conditions very well. I couldn’t throw them very
hard without having them collapse. So I asked myself, “How can I make a paper airplane that I can throw hard into the wind, have it climb up and when it reached the apogee automatically level off by itself and go into a nice long glide?”
Once you pose a question to your mind, it will begin to work on the problem. You will get impressions – often visual – that suggest you try this or try that. One of the first things I tried was to make a more-rigid paper airplane – one that could stand up to a strong throw. By making an extra fold on each wing running from leading edge to trailing edge and then taping them tightly together, I created a fuselage. This made the paper plane much stronger, and the wings held together even with a hard overhand throw.
But I still wasn’t getting the height that I wanted. I could see it happening in my mind, but not in the real world. Then one day, I looked at the extra fold of paper that one makes when first folding a paper airplane. This is done because you want more weight up front to carry the plane forward. I opened up the folded-over piece on each wing, creating pockets. Now each wing had a step about half-way back from the leading edge on the underside of the wing. I gave the plane my best pitch. It took off directly into the wind and climbed up about as high as a telephone pole, then leveled off and went into a nice long glide. That’s exactly what I was looking for. It’s what I had imagined. Mind you, this did not happen overnight. It took many attempts until I was able to get it to perform the way I wanted it to. For example, the depth of the steps on both wings had to be equal . If one step was deeper than the other, it would affect the flight, and the plane would not fly straight and true. Or, if the folds did not meet where the fuselage started in exactly the same position on each side, it would also cause the plane to fly poorly. I had probably made over 100 paper airplanes before finding my solution. Equal pockets on both wings and perfect alignment of both wings. That combination made for the perfect flight.
For the next four years, I tried to interest toy companies, but without success. Then, one day a photo-retoucher who was doing work for me came into my office. Floyd Fogleman was a pilot and model-airplane builder as well as a retoucher, and I gave him a demonstration of my paper airplane, launching one down the hallway. He went running after it and came back, saying “I think you’ve got a whole new concept in aerodynamics here.” He noted that the paper airplane appeared not to stall, but continue flying and was extremely stable in flight. We
decided to apply for a patent after he took one of the planes home and translated it to balsa wood. It flew with the same characteristics as the paper models. Two years later, we had our first US patent, #3,706,430.
I now believe that every discovery starts with a question. Imagine some guy – maybe an accountant – in an office a long time ago. And he made mistakes as he wrote down his numbers. He was using a wooden pencil,
but was always misplacing his rubber eraser. He probably asked himself, “Why can’t I find that eraser when I need it?” One day, it occurred to him to put the rubber eraser on the end of the wooden pencil. Today, almost every wooden pencil comes with a rubber eraser on its end.
So if you want to begin an interesting adventure, start by making an observation and then asking yourself a question.
To make use of Kline’s Airfoil in your own project, here is a diagram below of the different bends of the foam to create the plan wings airfoil.