# Design of a Human Muscle-Powered Flying Machine
## 1 Introduction
By selecting operational parameters (v\({}_{\text{max}}\)--maximum operating speed, v\({}_{\text{m}}\)--maneuvering speed, and \(\delta_{\text{max}}\)--maximum sideslip angle), and considering applicable combined cases, one can design a structure with just enough strength and stiffness for its intended purpose. [PERSON]'s review paper [12] highlighted that the aerodynamics of HPAs still has many unanswered questions, particularly regarding the interaction of flexible HPAs with near-ground atmospheric motions. Additionally, there is a lack of scientifically defined structural-limit load criteria for HPA structures. [PERSON] et al. [13] focused on optimizing the wing planform design of a high aspect ratio wing for a HPA. The key findings are that profile drag significantly impacts wing planform design and must be considered, the optimal design for minimizing the power required favors a higher lift coefficient and lower aspect ratio, differing from designs maximizing the lift-to-drag ratio, and multidisciplinary optimization results in a well-balanced design, reducing the power required despite increased wing span, wing area, and total weight. A group of scientists and students from Nihon University developed a special-purpose flight simulator [14] to help break the HPA flight distance world record. The simulator aims to optimize flight paths, power distribution, and aircraft configurations by providing practical training and analyzing pilot performance. It helped to compare ordinary student pilots with athlete pilots to enhance training and design strategies. At the German Aerospace Center (DLR), a 1:3 scale model of a HPA wing section, was tested in an open wind tunnel [15]. Experiments included vibration tests, static and transient investigations, and determined (for low Re numbers) the flutter point. The results of limit cycle oscillations (LCO) due to massive flow separation at high angles of attack were obtained. Building on previous design and testing efforts, the 2006-2007 Virginia Polytechnic Institute team developed a quarter-scale HPA model [16], made structural modifications, and validated these through flight tests. They then focused on developing a full-scale HPA prototype, conducting detailed analyses, securing funding and workspace at the Virginia Tech Ware Lab, and finalizing key components, such as wing spar and airfoil designs, to prepare for the construction and flight-testing phase. A paper by [PERSON] and [PERSON] [17] provides a comprehensive survey of the historical perspective and key design considerations essential for developing HPAs, emphasizing weight, materials, aerodynamics, flight controls, and power trains. The authors defined a critical constraint as the ratio of human power output to the sum of the pilot's mass and the HPA mass (power-to-weight ratio), with a value of 2.0 W/kg or higher, which is crucial for the successful design of an HPA. [PERSON]'s paper [18] demonstrates the successful construction of the first Dutch HPA using only basic high school mathematics and physics, emphasizing simplicity and efficiency. Building on insights from Aerospace Engineering studies at TU Delft, a new HPA design was developed for the Japan International Birdman Rally 2012, incorporating advanced materials, optimized aerodynamics, and improved cockpit and propeller designs for enhanced efficiency. This aircraft flew 70-80 m without failures and is now exhibited at the Avoidrome Aerospace Museum in the Netherlands. [PERSON] et al. 's [19] study focuses on designing a single-seat HPA through multi-disciplinary optimization techniques. The objective function minimizes both the power required and stall speed, enhancing the ease and safety of flight. A parametric synthesis model evaluates aerodynamics, stability and control, weight, and performance characteristics. The 3D vortex lattice method provided efficient aerodynamic evaluations, validated with experimental data, circumventing the high computational costs of CFD tools.