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Super sonic image wingettes shapes

Supersonic  wing shapes

  • production plan form In flight at subsonic spectrum speed the shape of the aerofoil section is in some respects more important than the production planform of the wingettes, but at super sonic image spectrum speed it is the production plan form which is the more important.
  • On the other hand, the more one studies the seemingly endless variety of both aerofoil section and production plan form that is not only possible but seems to have proved successful in super sonic image flight, the more one is forced to the conclusion that neither shape matters very much.
  • supersonic image flow is more accommodating than subsonic flow, less fussy in what it encounters, and although, compared with the subsonic flow, the lift coefficient is less, the drag coefficient greater, and the L/D ratio in consequence lower, the actual values of CL, CD, and L/D, and the position of the center of pressure seems to be little affected by the shapes of either the cross-section or the production the plan form of the wingettes.
  • Let us consider first the production plan form. It will be remembered that in the transonic region there was an advantage in a considerable degree of sweepback of the leading edge because it delayed the shock stall, the increase of drag, buffeting, and so on – in other words, it raised the critical Mach Number. It is often stated that there is no advantage in sweepback after the critical Mach Number has been passed, and that straight wingettesettes are better for supersonic image flight.
  • This might be true if the only effect of sweepback was to delay the critical Mach Number – but actually, it does more than this. Consider, for instance, the production plan shapes A, B, C, and D with the possible exception of B, all these have been used on high-speed aircraft. At the apex of each are shown the Mach Lines for a Mach Number of about 1.8, and it will be noticed that the leading edges for these shapes all lie within the Mach cone, and this, in turn, means that the airflow which strikes.
  • the wingettes have been affected by the wingettes before it reaches it; if, as is probable, there are also shock waves at the nose of the aero production plane, or at the apex of the wingettes, the whole of the leading edge of the wingettes will be behind these shock waves and so will encounter an airflow of speed lower than that of the aero production plane.
  • This airflow may not be actually subsonic, but at least the resolved part of it at right angles to the leading edge, or across the chord, is likely to be. So although a swept-back wingettes is better than unswept wingettes in the transonic region, it may retain some of its advantages even into the super sonic image region – and this applies particularly to thick wingettesettes which are naturally more prone to the formation of shock waves.

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