This semester has been really busy. My favorite class is EGR 200. In this class, we learn how to work with CATIA and complete the conceptual designing of an aircraft. Prof. Helbling made this class very interesting. CATIA is Windows-based and thus it generally has a steep learning curve and everyone feels at ease after a couple of weeks. We ended our CATIA classes by developing a rough scaled model of our conceptually designed aircraft. Figure 1 shows the aircraft.

Figure 1: Rough scaled model of Dassault Falcon 50

The aircraft that our team build was an improved version of the Dassault (R) Falcon 50. We added winglets to it and did some preliminary calculations to find its effect on our range, lift-drag ratio and various other calculations. The team came up with an 8% increase in range just because of the addition of winglets at its cruising speed of 0.8 Mach. We also improved our lift/drag ratio by incorporating a better lift producing airfoil. The team then built a scaled and as-accurate-as-it gets model in CATIA and then used the 3-D Printer present in the AxFab Building to build a 3-d Model of our aircraft which would be tested in the wind tunnel. The following figure shows the 3D model.

The flow visualization was done in the wind tunnel using a white fluid that was applied on the wings section of the aircraft. It was used to visualize the flow when the wind tunnel was run. It was run at two different angles of attack. 2 deg was selected as the first one because it was the cruising AOA for the chosen aircraft. Flow visualization was also done at 14 degrees, since it was the calculated angles. The following pictures will show the neatly attached flows at 2 deg and accuracy of the calculated stall angle. Note that in stall, reverse flow occurs which is quite interesting.

At AOA of 2 degrees, observe the neatly attached flow on the wing sections.

At AOA of 14 degrees, the reverse flow is observed. This is the calculated stall angle.

The classes ended with the team giving a presentation on what kind of changes were made. The list of sub-sections were: Introduction, Preliminary Ideas, Refinement, Preliminary Analysis, Final Decision and Final Analysis, Recommendations and Conclusions.

It was the best class I have ever had yet!!