that the tips are subsonic while the leading and trailing edges are supersonic

That the tips are subsonic while the leading and

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that the tips a:re subsonic, while the leading and trailing edges are supersonic. The co1'l'esponding change in the quantity apia. = (Ph - Pu)/a. near a tip with the distance from the leading edge (in per cent of the chord) evaluated for a wing with a pentagonal planform at M..., = = 1.61 is shown in Fig. B.10.2. The coefficient apia. is constant in the region between the leading edge aud the Mach cones issuing from the vertex and tips of the wing, on the section confined by the tips and trailing edges, and also by the Mach waye reflected from a tip. A break in the curve cliaracterizing a change in the pressure drop coeRicient occurs on the Mr.lch lines and is a l'esult of the break in the configuration of the wing tip. The found pressure distribution sud formulas (8.9.27) flnd (8.9.28) are used to determine the lift, momeut and ccntre-ol-pressure coeffi- den ts. Figure B.9.4 shows curves characterizing tIlc change in the values of C'II and c p for a pentagonal wing. These values should be
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Ch. S. A Wing in .!I Supersonic Flow 3S1 fig. 8.10.2 Distl'ihuliul\ of the quantity ~l/~=le~;;:~~1 ~1~~ a\\"~th supersonic lea(liDg I'liges (s~c- tioo :1.4) determined provided that i ... ·VM;' - t > I.", tlln XI' i.e. if the leading edge is supersonic. If a wing- has subsonic iealling edges (see Fig. 8.8.1), Lhe flow oYer Lhe section of the surface ilt'lweell the eligt·s and the Mach lines issuing from points E and }{ is aHect('d llr a \'ol'tex sheel. The calculation of lilis flow is associated \\·ith solution of integral equation (8.2.t6) anf! the u~e of boundar~- conditions m.1.15) and (S.1.1G). Such a solution is treated in drtail in Itil. 8. t t. Drag of Wings with Subsonic Leading Edges Let us consider the calculation of the drag of SW('pt wings with subsonic leadin.g edges ill a supersonic flow at an angle of aUl\ci-.. We already kno\\' that the disturbed flo\\' normal to the I!'luling edge is subsonic near such wings. Such a no\\' is all('ntied I)y the o/;er,flow of the gas from the region of increased pressure inlo the region where the pressure is reduced and is the calise of the corresponding force action on the \ving. To calculate this acLion, we cun lise the results of investigating the disturhed Ilow of an incompl'essible fluid near an airfoil in the form of a nat plale arranged in the flo\\' at an angle of attacl, (sec Sec. G.3). The drag coerficient for a thin winq with subsonic iea(ling edges in a supersonic now is (8.11.1) in which ex T is the coefficient of the \\'ing sllction force depen(ling on the sweep anglo Y. of the leadin~ euge and the number M ... : CX•T = T/(q ""Sv.-) (8.11.2) \\'here T is lhe suction force, q~ = p«>Vcoi2 is the \-elocity hea(I, anf!' S", is the> area of the wing planform.
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3B2 pt. I. Theory. Aerodynllmics of lin Airfoil lind II Wing ~:. tt-:'~~leulation of the suc· tion force for a triangular wing with subsonic leading edgl!s To detarmine the force T, we can use tbe relations obtained in Sec. 7.6 for an infinite-span swept wing. This follows from the fact that in accordance with (7.6.18) and (7.6.19), the suction force depends on the change in the axial component of the velocity in the close vicinity of the leading edge of tile
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