Fin and nozzle unit for a free-flight rocket

Abstract

The disclosed fin and nozzle unit comprises a generally cylindrical nozzle body having an axial nozzle opening therein for discharging a gaseous propulsion stream, a plurality of fins having pivot means mounting such fins on a rear end portion of the nozzle body for swinging movement between retracted launch positions and extended flight positions in which such fins are swung outwardly from the launch positions through a predetermined angle, such fins having bent or skewed portions which are positioned in the gaseous propulsion stream when the fins are in their retracted launch positions for causing the gaseous propulsion stream to act upon the bent portions so as to produce spinning movement of the rocket when it is being launched, the bent portions being movable outwardly out of the gaseous propulsion stream when the fins are swung outwardly into their extended flight positions to avoid imparting further spin to the rocket during flight. The fins preferably have a conformation which is aerodynamically neutral when the fins are in their extended flight positions. To such end, each fin is preferably bent along a line which is parallel to the axis of the nozzle body when the fin is extended. Detent elements are preferably resiliently biased against detent cams on the fins to hold the fins in their extended flight position. The detent elements also preferably hold additional fin members in their retracted launch position until the first mentioned fins swing outwardly to their flight positions, whereupon the additional fin members are released by said detent elements and are swung outwardly to their extended flight positions by spring means.