EXPLORATORY WIND-TUNNEL INVESTIGATION AT HIGH SUBSONIC AND TRANSONIC SPEEDS OF JET FLAPS ON UNSWEPT RECTANGULAR WINGS

摘要

An investigation has been made in the Langley high-speed 7- by 10-foot tunnel by means of the transonic-bump technique to determine the lift augmentation of several Jet-flap configurations. Thrust-recovery characteristics of some of the thick-wing configurations were also determined. The investigation covered a Mach number range from O.40 to 1.10, and a maximum momentum coefficient of 0.50 was obtained at a Mach number of 0.40.nThe results of the investigation indicated that the lift can be increased at any Mach number by blowing downward through a number of closely spaced holes along and near the trailing edge of the wing. The ratio of Induced circulation lift to the lift component of the Jet reac¬tion increased with Mach number up to high subsonic speeds and then decreased through the transonic speed range. The Induced circulation lift was greatly reduced when the Jet location was moved from near the trailing edge to the 73-percent-chord line. A Jet-augmented flap which used blowing from a slot on the upper surface in combination with a round trailing edge lost its effectiveness at Mach numbers of 0.60 or greater.nA l6-percent-thick wing with blowing rearward from a slot at the trailing edge showed a drag reduction about equivalent to the Jet momen¬tum throughout the Mach number range investigated. In contrast to this, a wing of similar geometry but with blowing from slots on the upper and lower surfaces near the maximum-thickness point showed drag reductions that were less than the Jet reaction at transonic Mach numbers.