Rapid, iterative design approach for preliminary configuration of a High Altitude, Long Endurance aircraft

This paper presents a rapid iterative design approach, used to develop a preliminary configuration of an Unmanned Aerial Vehicle (UAV), which is to perform a High-Altitude, Long Endurance (HALE) mission. First, based on a set of requirements, an initial aircraft concept is developed.

The rapid iterative design approach revolves around an energy-based flight profile simulation, which is updated with an improved aerodynamic model of the aircraft during every iteration. An aircraft configuration is defined by a set of constant parameters. A corresponding flight profile consists of an altitude and velocity profile, as a function of time. The behaviour of the aircraft is simulated based on the specified flight profile.

For sizing the aircraft components exposed to the airstream, the aerodynamic design phase aims to create an airframe which achieves the performance outlined in the flight performance simulation, utilizing the obtained aircraft parameters. Using the geometric data, a 3D-model of the aircraft is created, which is essential for the aircraft's weight and balance calculations and for determining the airframe shape exposed to the airflow. A Computational Fluid Dynamics (CFD) simulation is conducted to obtain the actual aerodynamic characteristics of the airframe. If the performance requirement of the flight performance simulation is not met, another iteration of the aerodynamic design phase is required.

The design framework stands out due to its rapid iteration capability, accessibility, and straightforward application, making it particularly advantageous for educational settings in which students engage with aircraft design. The approach aims to offer satisfactory results for an initial aircraft conceptualization.

This design framework emerged from the DLR Design Challenge 2023, an annual competition hosted by the German Center for Aerospace Research, where student teams develop preliminary aircraft designs. This years challenge tasked the teams with designing an aircraft system to restore internet coverage over a disaster-affected region. The described approach was used to develop the Sentinel System of the DHBW Ravensburg team. However, the simulation and development process is not limited to applications within this challenge.