Induced Rolling Moment Characteristics of the M 557 a Streamline Bomb

A model of a streamline bomb with fixed cruciform fins has been tested in the R.A.E. 8 ft x 6 ft tunnel, to examine possible reasons for the discrepancy between the rolling moments derived from free flight tests and results obtained from previous wind tunnel tests. A range of Reynolds numbers was covered corresponding to the previous tunnel test and free flight values. The effect on rolling moment of a nose probe and a launching lug, which were present IX the flight tests but not represented III the previous tunnel tests, also was investigated. The results show that the induced rolling moment was not significantly influenced by Reynolds number, for the range covered. At incidence a large change in rolling moment resulted for the addrtion of the nose prohe and it was shown that thrs rolling moment depended critically on the geometric accuracy of the spherical nose of the probe itself.