Flight Dynamics of a Navion Aircraft
After a semester of Flight Dynamics we were assigned this project to tie in everything we had learned and to test our grasp of the subject. The project was split into three parts. The first part consisted of analyzing the flying qualities of Navion aircraft. This included the flight dynamic modes and mode shapes. These were computed from the linear models presented in this report. The following are the results.
| Eigenvalue | Damping Ratio | Frequency(rad/s) | Mode |
|---|---|---|---|
| -2.4352+2.6461i | 0.6772 | 3.5961 | Short-Period |
| -2.4352-2.6461i | 0.6772 | 3.5961 | Short-Period |
| -0.2005+0.2593i | 0.6118 | 0.3278 | Phugoid |
| -0.2005-0.2593i | 0.6118 | 0.3278 | Phugoid |
| Eigenvalue | Damping Ratio | Frequency(rad/s) | Mode |
|---|---|---|---|
| -5.8461 | N/A | N/A | Roll |
| -0.5077+2.3598i | 0.2103 | 2.4138 | Dutch Roll |
| -0.5077-2.3598i | 0.2103 | 2.4138 | Dutch Roll |
| -5.733e-4 | N/A | N/A | Spiral |
The second part consisted of modifying the dynamic models to account for a sensor pod attached to the aircraft. The shape of sensor pod was a 3 foot cube attached to the aircraft via an 8 inch cylinder with a 4 inch diameter. We assumed that the sensor pod had its own flying qualities and so therefore they could be determined independently and just added to the aircraft's. It was also shown that the sensor only affected the longitudinal modes. Those are presented below.
| Eigenvalue | Damping Ratio | Frequency(rad/s) | Mode |
|---|---|---|---|
| -0.00399 | N/A | N/A | N/A |
| -0.595 | N/A | N/A | N/A |
| 0.293+0.513i | 0.497 | 0.591 | Phugoid |
| 0.293-0.513i | 0.497 | 0.591 | Phugoid |
So the total modes were the following.
| Eigenvalue | Damping Ratio | Frequency(rad/s) | Mode |
|---|---|---|---|
| -2.133+4.382i | 0.4377 | 4.874 | Short-Period |
| -2.133-4.382i | 0.4377 | 4.874 | Short-Period |
| -0.508+0.295i | 0.865 | 0.588 | Phugoid |
| -0.508-0.295i | 0.865 | 0.588 | Phugoid |
Finally the third part consisted of performing a parametric trade study on the geometry of the pod to determine how the dynamic modes and mode shapes change as a function of the size of the sensor pod. The results are presented below.
After the in-depth analysis of the Navion aircraft before and after the addition of the sensor pod, several observations and conclusions can be made. The only modes that were significantly affected were the Phugoid and rolling modes, which was predicted through theory. Overall the flying qualities of the Navion aircraft remained within acceptable parameters making the Navion an excellent aircraft.
*DISCLAIMER: This was a group project i.e. I did not do the analysis, evaluations, and write up by myself. It was a collaborative effort between myself and Alex Naber (B.S. Aerospace Engineering, Georgia Tech 2017).