# Design of a Human Muscle-Powered Flying Machine
## 1 Introduction  
One of human's earliest dreams was self-powered flight, a theme present in various legends and myths. In 1934 (11 July), [PERSON] from Germany constructed and built the first human-powered aircraft (HPA) named Zaschka that flew about 20 m unassisted at Berlin Tempelhof Airport [1]. In Germany and Europe, great interest in developing muscle-powered, flapping-wing aircraft (ornithopter) persisted in the mid-1930s, but no successful flights were achieved. One of the most notable flights of this period was made in Italy in 1936 by [PERSON] in a pedal-powered high-wing monoplane named Pedaliante [2]. However, [PERSON]'s aircraft fell short of a HPA since it could not take off using only the pilot's muscles. The second HPA to leave the ground unaided (Sumpac--Southampton University's Man-Powered Aircraft) was made in November 1961 in England by a group at Southampton University. The longest known flight of SUMPAC (Figure 1a) was 650 m (best of 40 attempts). On 2 May 1962 [PERSON] from de Havilland Aeronautical Technical School flew 908 m using Puffin HPA [2]. At that time, scientists knew that a human-powered aircraft must be ultra-light and fly at very low speeds, necessitating a study of incompressible aerodynamics at very low Reynolds numbers. Unfortunately, information on such aerodynamic phenomena was scattered, making it hard to gather and correlate, while the structural challenge lies in achieving the lightest possible design [3]. The most famous competitions, leading to genuine technological progress of HPAs, were sponsored by the British industrialist [PERSON]. In 1959, he offered PS000 for the first human-powered flight around a one-mile figure-eight course; [PERSON] won 18 years later with the Gossamer Condor (Figure 1b). [PERSON] then offered PS100,000 for the first human-powered flight across the English Channel, which [PERSON] won on 12 June 1979, pedaling the Gossamer Albatross across the 21-mile strait [4; 5]. The details of the construction of these two successful HPAs and their successor the Albatross II are provided in the [PERSON] report [4]. On 23 April 1988, the muscle-powered aircraft Daedalus [6; 7] was constructed at MIT (Figure 1c), piloted by Greek cycling champion [PERSON], set a new distance record of 115.11 km from Iraklion in Crete to Santorini. Unfortunately, the flight concluded with an unsuccessful landing when a sudden gust of wind caused the right wing to break, resulting in a low-altitude crash into the water just 7 m from the shore. After setting the record, the Deadalus HPA was extensively studied [8; 9]. A condensed log of weights and a detailed description of the aircraft's construction are presented by [PERSON] [9], along with several proposed formulas for predicting the weight of HPAs, intended for use in the preliminary sizing and optimization of such aircraft. [PERSON] and [PERSON] [10] analyzed the limits of sustained human-powered production using the Daedalus flight as a basis. They found that elite athletes could maintain continuous mechanical power output at 70% of their maximum oxygen uptake for over four hours with proper supplementation of a glucose-sodium drink. During the flight, [PERSON] consumed nearly four liters of this drink, maintaining a heart rate below 142 beats per minute without signs of fatigue. Based on this research, it was estimated that [PERSON] could have remained airborne for up to five hours, contingent upon calm weather conditions with wind speeds not exceeding 1 m/s. Figure 1: Selected human-powered aircrafts (**a**) SUMPAC, (**b**) Gossamer Condor, (**c**) Daedalus (source: Wikipedia). [PERSON] and [PERSON] [11] found that structural design conditions for HPAs differ from those defined by a v-n diagram (plot of an aircraft's velocity versus load factor) due to their low maximum speed, potential to enter large sideslip angles, non-rigid structure, and requirement for calm meteorological conditions. The demand for extreme lightweight necessitates a structural design with smaller safety factors.