Stratospheric Flight (eBook)

In this book, Dr. Andras Sobester reviews the science behind high altitude flight. He takes the reader on a journey that begins with the complex physiological questions involved in taking humans into the 'death zone.' How does the body react to falling ambient pressure? Why is hypoxia (oxygen deficiency associated with low air pressure) so dangerous and why is it so difficult to 'design out' of aircraft, why does it still cause fatalities in the 21st century? What cabin pressures are air passengers and military pilots exposed to and why is the choice of an appropriate range of values such a difficult problem? How do high altitude life support systems work and what happens if they fail? What happens if cabin pressure is lost suddenly or, even worse, slowly and unnoticed?

The second part of the book tackles the aeronautical problems of flying in the upper atmosphere. What loads does stratospheric flight place on pressurized cabins at high altitude and why are these difficult to predict? What determines the maximum altitude an aircraft can climb to? What is the 'coffin corner' and how can it be avoided? The history of aviation has seen a handful of airplanes reach altitudes in excess of 70,000 feet - what are the extreme engineering challenges of climbing into the upper stratosphere? Flying high makes very high speeds possible -- what are the practical limits?

The key advantage of stratospheric flight is that the aircraft will be 'above the weather' - but is this always the case? Part three of the book investigates the extreme atmospheric conditions that may be encountered in the upper atmosphere. How high can a storm cell reach and what is it like to fly into one? How frequent is high altitude 'clear air' turbulence, what causes it and what are its effects on aircraft? The stratosphere can be extremely cold - how cold does it have to be before flight becomes unsafe? What happens when an aircraft encounters volcanic ash at high altitude? Very high winds can be encountered at the lower boundary of the stratosphere - what effect do they have on aviation?

Finally, part four looks at the extreme limits of stratospheric flight. How high will a winged aircraft will ever be able to fly? What are the ultimate altitude limits of ballooning? What is the greatest altitude that you could still bail out from? And finally, what are the challenges of exploring the stratospheres of other planets and moons?

The author discusses these and many other questions, the known knowns, the known unkonwns and the potential unknown unknowns of stratospheric flight through a series of notable moments of the recent history of mankind's forays into the upper atmospheres, each of these incidents, accidents or great triumphs illustrating a key aspect of what makes stratospheric flight aviation at the limit.

Dr. Andras Sobester is an aerospace engineering lecturer at the University of Southampton in the Faculty of Engineering and the Environment. He holds a Research Fellowship funded by the Royal Academy of Engineering and the UK Engineering and Physical Sciences Research council. The remit of the Fellowship is to investigate technologies for the reduction of the environmental impact of the next generation of passenger airliners. In particular, his research is aimed at the design of airframe surfaces for minimizing the noise footprint of aircraft, while maintaining their performance.

His other research areas include high altitude flight (including lighter-than-air systems), the multi-disciplinary design optimization of aircraft, the mathematical description of geometries used in aerospace engineering, as well as machine learning technologies underpinning the use of high fidelity computer simulations in aircraft design.

---

In this fascinating book, Dr Andras Sobester narrates the past, present , and future of stratospheric flight and gives a detailed analysis of the science behind it. The book is divided into four parts. The first chapter in Part I describes the race for stratospheric passenger travel, the story of the Comet 1, and the loss of G-ALYP and G-ALYY, as well as fatigue design and testing today. The second chapter continues with the transatlantic race and the limits of commercial long distance flight, including information on Steve Fossett and the Virgin Atlantic Global Flyer as well as stratospheric balloon flight. Chapter 3 looks at Concorde and the design challenges of high altitude passenger transport, including Space Shuttle maneuvers in the stratosphere. This part ends with an analysis of airspeed margins in stratospheric flight, as well as flight in low density air and jet engine operation, including stalling, at high altitude. Part II opens with a chapter on the design considerations for emergency descents. Chapter 6 looks at unpressurized flight, as well as gliding, in the stratosphere, while the following chapter considers hypoxia and its effects. The remaining two chapters in this part consider cabin air systems, the cost of air conditioning, ice at high altitude, and the short and long term health effects of stratospheric flight on air- and cabin crew. The first two chapters in Part III look at outside the airplane: the weather, tropical storms, temperature shears, and clear air turbulence. The environmental impact of stratospheric flight is considered, including the effect on the ozone layer and the use of biofuels at low temperatures. Part IV looks at the way ahead and considers flight in the upper stratosphere, commercial suborbital flights, and unmanned missions to the stratosphere. The book ends with an analysis of the future of stratospheric flight.This book thus shows that, beyond the solved and unsolved design riddles and forensic engineering efforts to understand flaws, the modern stratospheric airliner is an incomparably complex, wondrous and awe-inspiring engineering achievement.