I opened up the folded-over piece on each wing, creating pockets. This is done because you want more weight up front to carry the plane forward. Then one day, I looked at the extra fold of paper that one makes when first folding a paper airplane. I could see it happening in my mind, but not in the real world. This made the paper plane much stronger, and the wings held together even with a hard overhand throw.īut I still wasn’t getting the height that I wanted. 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. One of the first things I tried was to make a more-rigid paper airplane – one that could stand up to a strong throw. You will get impressions – often visual – that suggest you try this or try that. Once you pose a question to your mind, it will begin to work on the problem. 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?” But it could get windy outdoors, and the paper airplanes couldn’t handle the conditions very well.
On weekends, I would take my young son out to a ball field to fly paper planes. 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.
My office was on the 24th floor, overlooking 42nd Street, the New York Public Library and Bryant Park. I have been asked a number of times, “How did you come up with the Kline-Fogleman airfoil?”īack in the early 1960s, I was working as an art director for an advertising agency in mid-town Manhattan. Dick has graciously written this great piece for all of us. The following was written by Dick Kline, inventor of the Kline Fogleman airfoil. Simulations of the open- and closed-loop systems illustrate the bifurcations that arise from varying the vortex strength, bound circulation and/or control gains.Tags: airfoil, KFm Airfoils, kline fogleman Conditions on the control gains to stabilize any of the equilibrium points are determined analytically for the cylinder case and numerically for the airfoil.
The closed-loop system utilizes a linear state-feedback control law. For control analysis, heaving and/or surging are used as input to stabilize the vortex position relative to the body. Filter performance is evaluated using the original flowfield PIV data, and compared with a DMD reconstruction. The DMD-KF is implemented for experimental data from two different setups: a pitching cambered ellipse airfoil and a surging NACA 0012 airfoil. A DMD Kalman Filter (DMD-KF) uses the pressure measurements to estimate the evolution of this linear system, and thus produce an approximation of the flowfield from the pressure data alone. DMD is used here to create a linear system that approximates the flow dynamics and pressure sensor output from Particle Image Velocimetry (PIV) and pressure measurements of the flowfield around the airfoil.
The estimation method is based on Dynamic Mode Decompositions (DMD), a data-driven algorithm that approximates a time series of data as a sum of modes that evolve linearly.
This thesis presents two separate results in the estimation and control of unsteady flow structures: the application of a principled estimation method that generates full flowfield estimates using data obtained from a limited number of pressure sensors, and the analysis of a nonlinear control system consisting of a single vortex in a freestream near an actuated cylinder and an airfoil. Feedback control of unsteady flow structures is a challenging problem that is of interest for the creation of agile bio-inspired micro aerial vehicles.