The helicopter department of the Institute of Aerodynamics and Flow Technology is involved in the collaborative development of a computer-based framework for conceptual and preliminary rotorcraft design together with the DLR Institute of Flight Systems and the DLR Institute of Structures and Design. The aim of this framework is to provide tools for the evaluation of diverse rotorcraft concepts regarding a mission and requirements specification, for the sizing of the main rotorcraft components (rotors, engines, fuselage, empennage, etc.) and for the rapid estimation of flight performance and flight characteristics of a specified rotorcraft configuration. Furthermore such a framework enables the systemic assessment of the potential of new technologies taking into account various possible future scenarios. Conversely it can reveal the effects of changes in general conditions (e.g. availability of raw materials, new electrical systems) on the optimal design of a rotorcraft.
Figure 1 illustrates the DLR rotorcraft design process. Despite the modular architecture of the framework, it features a seamless integration and very high level of automation of the entire process, ranging from conceptual design to multidisciplinary predesign. In the conceptual design stage a software module based on handbook methods and statistics is used for the assessment of various rotorcraft configurations in regard to a mission profile and a requirements specification. These considerations include a sizing procedure for the main components of each rotorcraft configuration. Subsequently selected designs can be evaluated, refined and optimized using the disciplinary modules (geometry, aerodynamics, mass estimation, structures, engines, and flight mechanics) of higher fidelity in the preliminary design loop. As the calculation methods of the predesign modules rely mostly on physical models, they are also suited for the evaluation of unconventional configurations, for which statistical data is only sparsely available.
The helicopter department of the Institute of Aerodynamics and Flow Technology plays a key role in the development of the DLR rotorcraft design framework, contributing the following work:
IIn the project RIDE (Rotorcraft Integrated Design and Evaluation, 2010-2012) a solid foundation for a computer-based framework for preliminary rotorcraft design has been laid at DLR: A software environment has been set up and design tools for sizing and evaluation of conventional rotorcraft configurations were developed, integrated into the framework and coupled together in a process chain.
In 2014 the follow-on project EDEN (Evaluation and Design of Novel Rotorcraft Configurations) has started with the aim to enable the design and evaluation of unconventional rotorcraft configurations (e.g. compound helicopters, tilt-rotor aircraft) within the DLR rotorcraft design framework. A particular challenge is the both computationally fast and physically accurate modelling of aerodynamic interferences between the aerodynamically effective components (rotors, fuselage, wings/tail surfaces). Thus the main focus of the institute AS in the project EDEN lies on the development and integration of such models into the DLR rotorcraft design framework.