Parameter Estimation of Fundamental Technical Aircraft Information Applied to Aircraft Performance

Inverse problems can be applied to aircraft in many areas. One of the disciplines within the aerospace industry with the most openly published data is in the area of aircraft performance. Many aircraft manufacturers publish performance claims, flight manuals and Standard Aircraft Characteristic (SAC) charts without any mention of the more fundamental technical information such as CD0 . With accurate tools, generalized aircraft models and a few curve-fitting techniques, it is possible to evaluate vehicle performance and estimate these technical parameters. With this goal a program has been written in Matlab to calculate the fundamental information behind a general aircraft. The current results are promising with more work underway to further improve them. The results shown are for the Northrop F-5. While the results look good, the overall accuracy of the program is only as good as the data provided. For example, the maximum speed reported by a company may assume that the aircraft is in a dive with engines at full throttle. Or, the measurements may be overly optimistic, with an important characteristic such as ground friction during takeoff left out of the picture. If this information is not reported then an accurate analysis is not possible.