A wind-tunnel investigation has been made at low speeds to deter-mine the flow-field characteristics and ground influence on an airplane model having an untapered, unswept wing with an aspect ratio of 8.3 equipped with jet-augmented flaps. Jet-augmented-flap deflections of 55° and 850 were investigated with the jet-blowing energies covering a range representative of that of the output of current jet airplanes. The high lift coefficients associated with the jet-augmented flaps were greatly reduced when the wing was in the proximity of the ground. The adverse effects of the ground increased rapidly as the wing approached the ground, as the jet-deflection angle increased, or as the momentum coefficient increased. Associated with these reductions in lift coef¬ficient were reductions in both drag coefficient and nose-down pitching-moment coefficient. No ground effect was noted on the model with either a jet-augmented-flap deflection of 55° when the model was mounted higher than 3 chords above the ground or with a jet-augmented-flap deflection of 850 when the model was mounted more than 5 chords above the ground.
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