Tham khảo tài liệu 'aircraft design projects episode 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Project study advanced deep interdiction aircraft 221 McCormick10 a Aspect ratio Fig. Section lift coefficient versus angle of attack Fig. Vortex induced flow lift capability is not appropriate in this situation. As shown on Figure the max. lift coefficient will not be reached until exceptionally high nose angles have been pulled. When the aircraft is on or close to the ground . on take-off and landing such high angles will cause the aircraft rear fuselage structure to scrape the runway. The geometry of the aircraft will limit the max. attitude to about 15 . At this angle Figure shows that the CL is approximately . Therefore the limit of lift generation on or close to the runway will be set by the aircraft tail scrape angle of 15 . For flight away from the ground the max. lift coefficient will be set by the limit of controllable angle of attack. Constraint analysis As the initial mass weight and aerodynamic estimates have now been made it is possible to conduct a constraint analysis to determine if the original choice of thrust and wing loading values are reasonable. As these were derived from data on other aircraft it is likely that a better selection can improve the design. This process will also indicate which of the constraints on the problem are most critical. 222 Aircraft Design Projects The equation below as developed from the specific excess power relationship in Chapter 2 is the general form of the constraint function Tssl Wto j8 a q P CDo WTO S k1 n2 Wto S q P 1 V dh dt 1 g dV dt In order to draw the constraint diagram thrust versus wing loading it is necessary to determine the values of the coefficients etc. to be used in the equation. These are defined below List 1 TSSL engine static sea-level thrust WTO aircraft take-off weight S aircraft reference wing area W aircraft weight at the condition under investigation T engine thrust at the condition under investigation List 2 p aircraft weight fraction for the case under .
