FUR REFERENCE

The results of pressure-distribution measurements made during high-speed wind-tunnel tests of.atapered wing of NACA 230-series airfoil sections are presented for angles of attack ranging from 0.2° to 21.2 ° and for free-streem Mach num’’ersranging from O.2 to about 0.7. The peak values of minimum pressure coefficient attained were found to correspond b local Mach numbers of 1,2 to 1.4 exoept at angles of attack near the low-speed stall. The highest local Maoh numibermeasured was 1.55. ~ most cases noticeable flow separation was indiaated O * at stresm Mach numbers exceeding those at which peak minimum pressui’e coefficients were reached. At large angles of attack correspending to those very neez the low-speed.stall there was some indication that the flow about the wing broke down when the critical pressure coefficient was reached. A comparison of measured end calculated chordwise pressure dis-tributions for several stations along the span showed satisfactory agreement for purposes of structural design up to the critical Mach number.