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Thiết kế kỹ thuật máy bay chiến đấu Episode 3 Part 1

Tham khảo tài liệu 'thiết kế kỹ thuật máy bay chiến đấu episode 3 part 1', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 470 THE DESIGN OF THE AEROPLANE A heavy wing in the sense that a large mass is spread predominantly along the Y-axis giving rise to the moment of inertia A table 2-7 . Under-wing stores wingmounted engines fuel spread along the wings and tip tanks all help to make A large increasing the tendency to predominance over the moment of inertia B of the masses spread out fore and aft along the X-axis fuselage . Aeroplanes with mass spread out mainly along the fuselage Bl A 1 tend to recover from spins more easily than when the wing is heavy B A 1 fig. 13.5a. An inefficient body section i.e. one producing low body damping. This is a reason for the various strakes which appear on fuselages especially near the tail designed to generate favourable anti-spin vortices. Deficiency in side area which again produces low damping. Shielding of the rudder by the tailplane fig. 13.6. The use of power in a spin can have a seriously inhibiting effect upon recovery. As we saw in chapter 11 propwash is destabilising and it reduces the effective angles of attack of the fin and fuselage strakes and the effective angles of deflection of the rudder and elevator surfaces. Spin recovery Because stall-spin misbehaviour continues to be a major cause of accidents and because there is so much sometimes confused argument and debate about recovery techniques it is valuable to look at a number of historical precedents spanning the period 1918 to the present. All aeroplanes can be made to spin if they are seriously enough abused. Those which are claimed to be spin-proof usually have been designed in ways which limit their ability to be abused badly enough - for example the Aircoupe F-1A with the simplomatic controls from which the rudder pedals were eliminated so that the pilot could not yaw the aeroplane as a prelude to autorotation. Most conventional aeroplanes with a single engine in the nose can be caused to recover from spins using what the British call Standard and the American call Basic .