Many forces act on an airplane when it flies, and the airplane is designed to either mitigate or amplify the effects of these forces. In a coordinated turn, an airplane banks (around the longitudinal axis, to prevent slipping) and yaws (along its vertical axis, to change direction). Current wing designs generate adverse (unfavorable) yaw when banking. During the turn, the airplane yaws in the opposite direction of the turn, requiring a vertical stabilizer and rudder to ensure a coordinated turn.

The purpose of this project is to create a wing design that counteracts these problems by generating proverse, or favorable yaw. A secondary purpose is to make this wing as efficient as possible in cruise. To achieve these goals, I vary the angle of attack along the span of the wing, such that the down-aileron action on the wing that moves up leads to a reduction in drag, instead of an increase in drag as is the case in wings with a constant angle of attack

There are 3 wing designs for testing, each using the same NACA 2412 airfoil. This airfoil was chosen because it is a relatively common airfoil for airplanes, including but not limited to the Avia B-534, Baumann BT-120 Mercury, Bell 65 ATV, and many Cessnas including the Cessna 172, the most-produced aircraft in the world (Lednicer 2-73).0

The first wing design is the Reference Wing. This wing is the control wing and is modelled after current methods of wing design. It maintains an angle of attack of 3 degrees throughout the length of the wing and has a 188mm wing span. The second wing is the A-Wing. This is a tentative first wing design based on research conducted. It has varying angles of attack, which is the key to its proverse yaw. It too is 188mm in length.

The last wing is the E-Wing. This wing was optimized using The Model. It also includes varying angles of attack, generates proverse yaw and is 188mm in length. The biggest difference between the E-Wing and the A-Wing is efficiency in cruise: the E-Wing is ~4 times more efficient than the A-Wing.

After all of the wing designs were finalized in CAD programs FreeCAD and Blender, they were 3D printed using PLA (Polylactic acid) plastic and the MakergearTM M2 3D printer. The final wing designs were 1/2322.57 the size of a cessna 172 wing. These were then tested in a homemade wind tunnel and the resulting yaw angles were measured using a protractor and a Samsung Galaxy S5 camera. The dimensions of the wind tunnel are 1718" x 171/8" x 50"

The Model takes data from JavaFoilTM (a program designed to calculate lift and drag of an airfoil in different conditions) and uses Google Spreadsheets to calculate yaw, bank and efficiency of different wing designs. The Model accurately predicted yaw characteristics for the 3 wing designs: Adverse for Reference Wing, proverse for A-Wing, and proverse for E-Wing.

The results were as predicted, negative angles representing proverse yaw while positive angles representing adverse yaw. The Reference Wing generated adverse yaw average of 15.40, A-Wing generated proverse yaw average of -37.73° , and E-Wing generating proverse yaw average of -7.6o. To conclude, wings can be designed to generate proverse yaw, but the unfortunate catch is a decrease in overall efficiency of the wing.

The characteristics of the wing will need to be studied throughout the flight envelope. Future studies could include more advanced airfoils and morphing wing designs to optimize efficiency:

Applications for this wing are primarily for flying wing designs that promise highly efficient, high speed travel. Current flying wings have many problems, such as directional stability and yaw, and my advanced design has the potential to unlock the promise of flying wings and move these designs into the mainstream in aviation.