FREE-FLIGHT INVESTIGATION AT TRANSONIC SPEEDS OF DRAG COEFFICIENTS OF A BOATTAIL BODY OF REVOLUTION WITH A SIMULATED TURBOJET EXHAUST ISSUING AT THEnBASE FROM CONICAL SHORT-LENGTH EJECTORS

摘要

Four 7.5° boattail bodies of revolution with secondary air scoops were tested in free-flight to find the change in drag coefficient when a simulated turbojet exhaust issued from conical short-length ejectors. Models 1 and 2 each had single scoops and a spacing ratio ι/dp of 0.587,nWhereas- model 3 had two scoops and the same ι/dp as models 1 and 2. Model 4 had a single scoop and an ι/dp of 0.097. All models tested had the same diameter ratio ds/d_ of I.256. The results indicated that the jet-on total drag coefficients were lower throughout the test Mach number range than corresponding jet-off values of the forebody drag coef¬ficient. Furthermore, it appeared that increasing the corrected weight-flow ratio by doubling the number of secondary scoops increased the increment between jet-on and jet-off drag coefficients.