Launchers as Passive Controllers

You are here: Homepage > Search

Launchers as Passive Controllers

J. E. Cochran

Results are reported of an investigation into the passive control capability of launchers for free-flight rockets. Cause of free-flight rocket dispersion (principally thrust misalignment), the general concept of passive control and the potential of launchers as passive controllers are discussed. Control of important free flight rockets by altering launch conditions is treated as a preliminary step. Next, launcher conditions caused by rocket imperfections are considered. The concept of 'nonlinear frequency response' of a launcher/rocket system is used to define frequency bands which result in favorable launch conditions. Although only limited numerical results are obtained, they indicate that for a non-tip-off, light-weight (as compared to the rocket) launcher, or sub-launcher, of the type considered there are two frequency bands, one very high and one fairly low, within which the launcher is very effective as a passive controller of rocket dispersion. For a tip-off launcher, the results are similar, but operation within a low frequency band produces better control. Theoretically, dispersion can be reduced to less than fifty percent of the 'rigid launcher' value. (Author)