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Kỹ thuật máy bay chiến đấu Episode 3 Part 3

Tham khảo tài liệu 'kỹ thuật máy bay chiến đấu episode 3 part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Multibodied-Aircraft Concept 20 VTOL AIRCRAFT DESIGN 20.1 INTRODUCTION This chapter introduces the essential concepts and technologies of vertical takeoff and landing VTOL aircraft design. Although similar in many respects to conventional aircraft design VTOL presents some key differences and pitfalls to avoid. This chapter emphasizes the differences that affect VTOL vehicle layout and sizing analysis. The operational benefits of an ability to take off and land vertically are self-evident. Conventional aircraft must operate from a relatively small number of airports or airbases with long paved runways. For commercial transportation the airport is rarely where you actually wish to go and is usually crowded causing delays in the air and on the ground. The military airbase is highly vulnerable to attack and during a wartime situation the time expended cruising to and from the in-the-rear airbase increases the required aircraft range and also increases the amount of time it takes for the aircraft to respond to a call for support. The first type of VTOL heavier-than-air aircraft was the helicopter which was conceived by Leonardo daVinci but not regularly used until shortly after World War II. The helicopter rapidly proved its worth for rescue operations and short range point-to-point transportation but its inherent speed and range limitations restricted its application. For propeller-powered aircraft the tilt-rotor concept as tested in the Bell XV-15 seems to offer the best compromise between helicopter-like vertical flight and efficient wing-borne cruise. The tilt-rotor concept is the basis of the V-22 Osprey now under development. Helicopters and tilt-rotors go beyond the scope of this book but are discussed in Ref. 68. For jet VTOL aircraft a clear best solution for vertical lift has yerto emerge. Instead there are a wide variety of alternative vertical-lift concepts some tested and some not available for incorporation into a new design. Selection of a best concept .