Human Birdflight

In a land before time, there once was the Quetzalcoatulus, a huge Pterosaur the size of a Cessna 172. It was estimated to weigh something around 250 kg and have a wingspan of about 5 m. Very impressive, considering the limited force and power density of muscle fibre. Nevertheless, these guys are long long gone.

Since the very beginning of civilization, humankind has been longing for the skies. The first reference we found, the babylonian Myth of Etana, is about four and a half thousand years old! One of the oldest refrence in western culture is the story of Icarus and Daedalos in ancient Greek mythology. It still has such presence that many people we talked to in the last years instantly thought of that legend, when told about our exoskeleton. Many attempts were made throughout ancient history, but it took until about 1500 CE for the "first engineer", Leonardo da Vinci, to analyse the concept of flight in a more rigorous manner. Sadly he didn't solve the mystery back then, but he created detailes schematics and also built prototypes of flying machines. Around 1800, craftsmen and engineers started to figure flying out. Sir George Cayley worked out many important aspects of heavier than air flight and constructed a glider in 1804 proven to be worth it's salt. Shortly after, Albrecht Berblinger, the Tailor of Ulm flies his own contraption down German slopes. Both works fail to be taken seriously by their peers. The wall finally breaks down at the end of the 19th century, when Otto Lilienthal and his brother Gustav finally get the gist and build their "Flugapparat" (flying apparatus). They also experimented with flapping flight, but had to realize that humans are not strong enough for this method of propulsion. The Wright Brothers then added an engine and propeller to the outfit and the rest is history. Since then, flying has become ubiquitous with planes nowadays weighting more than five hundred tonnes. Great! But only half of the dream, the pioneers had back then. Because flying in an aircraft is nice, but it doesn't fulfil this ancient dream of spreading your arms and just flying like a bird! You can't feel the lift on your arms and the wind in your face when sitting in an airplane.

Modern Work in Flapping Flight and Unsteady Aerodynamics

Several inventors and scientists have investigated the concept of flapping flight since 1900. Selected pieces from the large body of work can be found below.

Natural Flyers

• 1962 - Greenewalt - Dimensional relationships for flying animals
• 1979 - Rayner - Power requirements
• 1994 - Marden - Power requirements vs. size of birds
• 2007 - Tobalske - Biomechanics of bird flight
• 2010 - Berg, Biewener - Wing and body kinematics of takeoff and landing flight
• 2015 - Cranell, Tobalske - Kinematics and aerodynamics of avian upstrokes during slow flight

Fluid Dynamics, Aerodynamics, Aeroelastics

• 1934 - Theodorsen - General Theory of Aerodynamic Instability and the Mechanism of Flutter
• 1992 - Send - The Mean Power of Forces and Moments in Unsteady Aerodynamics
• 2009 - Pesavento, Wang - Flapping Wing Flight Can Save Aerodynamic Power Compared to Steady Flight
• 2012 - Platzer et al. - Flapping Wing Aerodynamics: Progress and Challenges
• 2014 - Thielicke - The Flapping Flight of Birds - Analysis and Application
• 2016 - DeLaurier - The development of an efficient ornithopter wing
• 2018 - Send - Project BigBird XL: Commercial Use of the Bending/Torsional Drive
• 2021 - Zurman-Nasution, Ganapathisubramani, Weymouth - Effects of aspect ratio on rolling and twisting foils

Powered Exoskeletons

This topic is developing fast. A few quotes:

• 2001 - Schiele, “Development of a Human Arm Exoskeleton for Space Robotics Telepresence: From Biomechanics to Mechanism Design”, ESA Final Report, EWP – 2161
• 2013 - Kim et al. - Lower Limb Exoskeleton
• 2015 - Gopura et al. - Overview Paper for exoskeletons
• 2017 - Sui et al. - upper-limb exoskeleton and mechanisms Some names of exoskeletons: Rupert, ESA X-Arm-2, NEUROExos, NREX, Stuttgart Exo-Jacket

Control systems

What you need is a bilateral teleoperation system (developed since the 1960s). Or a brain-computer-interface, if you find one. A few hints:

• 1997 - Zeng, Hemami - An overview of robot force control, Robotica, volume 15, pp 473 –482
• 2011 - Haddadi - Stability, Performance, and Implementation Issues in Bilateral Teleoperation Control and Haptic Simulation Systems, PhD Thesis, Queen’s University, Kingston, Ontario, Canada
• 2011 - Aguirre-Ollinger et al. - Impendance control and inertia compensation
• 2015 - Lee, Payandeh - Haptic Teleoperation Systems, ISBN 978-3-319-19556-8
• "A brain-computer interface that evokes tactile sensations improves robotic arm control" - Flesher et al., Science 372, 831–836 (2021)

Recent work on human flapping flyers

• In 2006 James DeLaurier finished building an ornithopter capable of carrying one person.
• In 2010, also in Toronto, the Snowbird lifted off.
• In 2011, the inventor Douglas C. George published his latest design of the Project Falcon. He calls it "A Biomimetic, Battery-Powered Robotic Exoskeleton Ornithopter", which follows a similar idea to Fluglicht.
• The fake "Human Birdwings Project" by Floris Kaayk aka. "Jarno Smeets" explored the public reception of human birdflight. It was very well produced on a shoe-string budget and shows excellently how exciting the idea is for many people.

Further reading: Technology and Calculations