Abstract:

This Technical Memorandum describes the results of an initial investigation into the dependence of leading-edge pressures on various parameters. The motivation for this work resulted from the observation of a directional stability disturbance which was observed from wind-tunnel test data at low Reynolds number, which appeared to occur at the incidence at which the drag curve versus the square of the lift initially departed from its linear characteristic. Clearly, the leading-edge pressure coefficient at the most highly loaded section of the wing had reached some maximum value. One of the main concerns was whether this effect would prove to become worse at flight Reynolds numbers, and whether the critical incidence would change.

The results of this investigation indicate that wing section maximum (negative) leading-edge pressures, for sections which are leading-edge stallers, are strongly dependent on both Mach and Reynolds number.An initial attempt has been made to provide a means of predicting maximum leading-edge pressures.

Format: PDF.