Supersonic air travel has been a reality for quite some time; however, it has been limited almost entirely to military application with the only successful exception of the Concorde, which ended in disaster and was quickly discharged. There were two fundamental problems with the Concorde, efficiency and the Sonic boom. Because the Concorde was designed for supersonic flight, it was incredibly inefficient at lower subsonic speeds. In fact, the efficiency was so bad that there were concerns that in the case of an engine out, the pilots might struggle to land as they would have to land at a very high speed relative to other aircraft. The Sonic boom made this problem worse. Because it was so loud, the Concorde was banned from overland travel in most of the world. This meant that it wouldn't be able to reach supersonic speeds (and highest efficiency) until it was in international waters, resulting in a

very short period of time flying at the altitude and speed it was designed for.

I decided to tackle the problem of efficiency. Air particles react very differently at subsonic vs supersonic speed, it's the reason the Sonic boom exists. Therefore, airfoils specifically designed for subsonic or supersonic flight are very different, mostly because they rely on different laws of physics to generate lift. At subsonic speeds, the Brownian laws of physics apply, but at supersonic speeds, the Newtonian laws of physics have to be applied. This was the problem with the Concorde. With only one airfoil available for both subsonic and supersonic speeds, it was inherently less efficient than any wing designed for one or the other.

The idea of the Bi-directional Flying wing is to use two separate airfoils for subsonic and supersonic flight, both optimized for their Sonic speed. The control to test the experimental design against was the wing of a Boeing 737, one of the most common commercial aircraft and with blueprints and other information, such as airfoils, readily available.

For the airfoil that would be used at subsonic flight, a standard NACA 4-digit series airfoil would be used. This is because this series of airfoils are some of the most common airfoils used by subsonic planes, including the NACA 2412, the airfoil used by the most produced aircraft ever, the Cessna 172 Skyhawk. To find the optimized airfoil, a wide range of NACA airfoils would be tested in a program called JAVAFOIL, a program designed to analyze any airfoil. Testing a wide range of airfoils, the NACA 4412 was found to be the most efficient throughout subsonic flight. The lift to drag ratio was used to represent efficiency because the higher that number is, the more lift the wing is generating for less drag, which is exactly what a wing wants to do. Finding the airfoil to use for supersonic speeds was significantly more difficult. JAVAFOIL, although extremely capable, could not output lift and drag data past Mach 1. Using a research paper, it was discovered that one of the most efficient supersonic airfoils was the NACA Langley 11% supercritical airfoil. After more research, it could be predicted how that wing would behave at supersonic speeds.

With theoretical data ready, physical testing would be necessary to support or reject the data. After testing in a homemade wind tunnel, the physical data was within 90% of the theoretical for both the experimental subsonic wing, and the control Boeing 737 wing. T-tests showed that the difference between the two data sets was significant, meaning the wing designs were substantially different to create different results.