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Today, a majority of the produced aircraft share a common baseline design although unconventional designs have shown to be advantageous in certain cases. Using computational design synthesis a constrained solution space can be automatically generated and a high number of design candidates can be quickly explored without fixation on common designs. In this paper, the authors present and discuss a formal, three-dimensional spatial grammar to create different aircraft configurations that adhere to given design constraints. The grammar is built around a case study, the recreation of historic design proposals for a commercially successful, unconventionally configured aircraft, the Lockheed P-38. The results show that the developed 3D spatial grammar is not only able to computationally recreate the six design candidates that were part of the historic designs proposal but to generate further 14 feasible configurations and parametric variants by exploring the solution space more freely and thoroughly. Further, the use of the grammar for computational synthesis of other aircraft designs is discussed.

In 2011, the Technical University of Munich (TUM) offered for the first time a new onesemester project-based aircraft design course. There are many boundary conditions present at TUM regarding course types, contact hours, prerequisites, etc., and the new course must be made to fit into the fixed framework. The lessons learned from the first semester holding the course led to a major iteration of the curriculum, which resulted in the next installment one year later having a completely different structure. Though significant improvements were made from year one to year two and both years’ courses were considered successful, it was apparent that the scope, depth, and overall intensity of the course was still too great for the fixed course structure. Three proposals were put forth for a new approach for year three, and the one selected involved somewhat scaling back the course scope. In contrast to starting out with a conservative approach, violating the framework constraints at the outset led to faster understanding of the boundary conditions and a quicker adaptation to them.

This paper presents the conceptual design of a high-capacity turboprop-driven transport aircraft for short- and medium-range operation. It also depicts the iterative procedure and results of the design process as well as the design methods involved. The aircraft design is based on a market analysis that reveals that the short- and mid-haul markets represent a major fraction of the air transport sector. With two passenger decks and one cargo deck, the turboprop aircraft is intended to operate with a maximum capacity of 420 seats and five tons of cargo over a travel distance of 3,000 km. The design enables operations at airports with underdeveloped infrastructure. Thus, it is especially suitable for fast growing markets in emerging countries. The use of four turboprop engines, each delivering a take-off power of 9.5 MW, enables more energy efficient flight operations on short routes than conventional aircraft types.

Long product life cycles paired with a high degree of uncertainty about the state of the long-term future make the product development process very challenging in the aviation industry. Future customer needs and environmental constraints must be anticipated, which severely increases the risk of failure when developing a new product. This paper presents a scenario-based approach to product development with the goal to better handle uncertainty and mitigate the risks. By exemplarily exploring the potentials of a more personalized air transport system, three alternative future scenarios in 2050 are created. The subsequent derivation of high-level requirements reveals a clear individualization trend of the mobility needs of future customers. Two key customer groups are determined: elderly people whose travel plans are merely motivated by leisure activities, and businesspersons who require a flexible and reliable air transport system with reasonable trip costs. Concepts of operations that were specifically developed for each scenario to meet the respective market constraints and customer needs expose a high potential of a more automated transport system that is able to seamlessly combine several transport modes without the traveler’s interference.

The conceptual development process is the joint effort of designers and future operators to elicit and analyze requirements and to design a system which plausibly meets these requirements. A continuous build-up of a structured product model that explicitly interrelates system design and its metrics to requirements is desirable. However, requirements and system modeling are usually conducted separately using different tools. Moreover, the phases of the development process are often separated in time, personnel, and space. This practice leaves a considerable number of system design decisions untraceable. We address these problems by two propositions: (1) A use case which describes an iterative, concurrent, and continuous refinement process of the requirements and system model, and (2) a framework that allows the creation of an integrated system and requirements model and the gradual application of increasingly rigorous rules on the model. We demonstrate our approach by a simple conceptual aircraft design example and discuss whether our approach is scalable and promotes the reuse of model parts.

Tools and techniques for conceptual design of rotorcraft are uncommon compared to what is available for sizing fixed-wing airplanes. With the goal of being able to easily create a sized helicopter or lift- and thrust-compounding helicopter within a short timeframe after initial exposure to a specification or request for proposals, a software suite was written to facilitate optimization and design space exploration in the conceptual design phase. The nature of the design problem for helicopters, and especially compound helicopters, requires tools for optimization and visualization of a multi-dimensional problem with many objectives and constraints. The software employs built-in optimization for both global and local search using established algorithms, both non-deterministic and deterministic. To let the designer visually explore the design space, novel capabilities are also included that combine well-known techniques for visualizing multi- and hyper-dimensional design domains into a single matrix of linked plots that allows the visualization of the effect of multiple decision variables on many constraints and design objectives. Overall, the software developed proved useful for conceptual sizing of compound helicopters, and the visualization techniques developed for this work proved great potential for a variety of optimization tasks in other disciplines.

An investigation of moving surface boundary layer control is conducted using a simplified model to predict friction drag on aerodynamic surfaces, such as airplane wings. The moving surface is provided by a band moving in the freestream direction on the surface of the wing. Mounted on rotating cylinders, the band moves in the opposite direction inside the wing. The prediction model is based on empirical equations of boundary layer theory with adjustments for compressible flow at certain flight conditions. A theoretical twodimensional friction drag analysis of the drag reduction system is then conducted by showing the influence of band velocity on drag reduction. A notional system integration on the upper surface of an A340 wing is used for a full-aircraft impact analysis. An appropriate calculation procedure is developed for estimating the total aircraft drag of a commercial long-range aircraft with and without the system installed, so that a reasonable study about potential efficacy of the system can be made.