A Conceptual Design and Synthesis program was created to identify the conceptual design and sizing variables that most influenced the design of a propeller driven High Altitude Long Endurance Unmanned Aerial Vehicle (HALE UAV). Sensitivity Analysis of the endurance performance was isolated to three main categories and subsequently further broken down into sub-categories as follows:
1. Cruise Altitude
2. Cruise Velocity/Cruise Lift Coefficient
Aircraft Wing Geometry
1. Taper Ratio
2. Aspect Ratio
3. Wing Profile
A range of payload weight fractions from 5% to 15% was considered, as well as a takeoff weight range from 2,000 lbs. to 20,000 lbs. The takeoff wing loading was taken as the independent variable and varied between 5 lbs./ft2. Several general observations can be made with respect to the characteristics studied.
The following results are generalized across the range of the wing loadings and takeoff weights considered. The greatest sensitivity was to altitude, then aspect ratio, and taper ratio. The effect on overall endurance performance of changes in Wing Profile and Lift Coefficient were surprisingly small for the wing profiles used and the range of lift coefficients considered. The effects of changes in altitude on overall endurance performance were the least surprising; nevertheless, they were still quite large. In addition, the results obtained from increasing the Aspect Ratio from 22 to 35 were the most surprising as they were contrary to expectations due to competing aerodynamic and structural characteristics.
A Conceptual Design and Synthesis program was created and used in the comparison of the effects on endurance performance of a variation in numerous geometry, operational environment, and configuration related variables. The sensitivity of endurance performance to these variables was studied, and the degree of relative sensitivity to these variables was identified.
Available at: http://works.bepress.com/aaron-altman/18/