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The design and development of flying qualities for the C-17 military transport airplane
Published in Mark B. Tischler, Advances in Aircraft Flight Control, 2018
The C-17 is a long-range, air-refuelable, turbo-fan-powered, high-wing, heavy military cargo aircraft built around a large, unobstructed cargo compartment. It has a swept wing that uses supercritical airfoil technology and winglets to achieve good long-range cruise performance. A photograph of the airplane flying in its cruise configuration is shown in Fig. 1. Technologies that combine to achieve the C-17’s exceptional short-field landing/performance are the large externally blown flaps (EBFs), full-span leading-edge slats, spoilers, high-sink-rate landing gear, anti-skid braking, thrust reversers, head-up displays and sophisticated fly-by-wire flight control system. Figure 2 is a photograph of the airplane just prior to touchdown and Fig. 3 shows the pilot using throttles and head-up-display (HUD) guidance to perform the precision landing.
Force and Moment Analysis
Published in George Emanuel, Analytical Fluid Dynamics, 2017
One exception is the transonic analysis of Inger (1993), where the drag of a supercritical airfoil in inviscid flow is evaluated. Figure 15 is a sketch showing the principal features of the flow field in which the freestream
Drag force and drag coefficient
Published in Mohammad H. Sadraey, Aircraft Performance, 2017
A cambered airfoil has typically a crest, and a lifting surface with such an airfoil has a crestline. The crest is the point on the airfoil upper surface to which the free stream is tangent. The crestline is the locus of airfoil crests along the wing span. The drag increase due to compressibility is generally not large, until the local speed of sound occurs at or behind the crest of the airfoil. Empirically, it is found for all airfoils except the supercritical airfoil that at a 2%–4% higher Mach number than that at which M = 1 at the crest, the drag rises abruptly. The Mach number at which this abrupt drag rise begins is called [16] the drag divergence Mach number.
Numerical study on technical and conceptual improvements to a civil aircraft trailing-edge flap using passive/active flow control
Published in Engineering Applications of Computational Fluid Mechanics, 2021
From the above analysis, the reasons for the CLs of the baseline aerofoils lower than those of the highly optimized multi-element aerofoils such as 30P30N can be determined: The low-speed performance of a clean supercritical aerofoil is poor, and the upper surface flow is approximately horizontal;The wide slot reduces the up-wash effect of the flap on the main element;The severe separation fails the large deflection flap.