Two methods are presented for dynamically scaling store models for wind-tunnel store-dropping studies. For each method the model and. proto¬type Mach numbers are assumed to be necessarily equal and the Reynolds number effects are assumed to be negligible. The light-model method gives exact simulation of the store motions except that the vertical displacements are deficient. This deficiency is reduced as the vertical ejection veloc¬ity is increased or it can be eliminated by accelerating the parent model upward at the instant of store separation. The heavy-model method, in which the parent model is stationary, gives complete simulation of the store motion except that the short-period longitudinal oscillation is too poorly damped; this defect is of no serious consequence, during the first phase of a drop because the time during which the store is critically close to the parent model is generally small compared with the period of the longitudinal oscillation. The heavy-model method is generally recom¬mended for store-dropping studies; however, it is often impossible to make the models sufficiently heavy and with the proper, moment of inertia. If such is the case, the light-model method is required.nA brief description of the method of conducting store-dropping tests in the preflight jet of the Langley Pilotless Aircraft Research Station at Wallops Island, Va., is given.
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