Thrust reversal system

A method of managing the thrust of a rocket motor having a nozzle and a combustion chamber having a wall, the nozzle being aft of the combustion chamber, comprising the steps of

• providing ports in the wall of the combustion chamber adjacent the nozzle,
• forming a plenum chamber about a portion, at least, of the wall of the combustion chamber,
• establishing an effective throat for the plenum chamber outboard and forward thereof for the flow of gases therefrom, and
• diverting a portion of the combustion chamber gases to the plenum chamber through the ports in the combustion chamber wall,
• the area of the throat of the plenum chamber being less than the total area of the ports whereby the changes of gas flow direction occur at subsonic velocities at which friction and change in momentum of the gases effect the smallest losses.

A thrust reversal system for a rocket motor having a wall defining a combustion chamber, a portion of said wall forming a conical rocket motor aft dome having a central nozzle therein,

• a plurality of outlet ports formed in a circumferential band in the wall of the aft dome, each of said ports communicating exteriorly of the combustion chamber,
• a piston cover mounted on the motor and normally held in a first position against the aft dome to seal said ports to permit normal operating combustion pressure within the combustion chamber, said cover being movable to a second position to uncover said ports,
• stop means formed on the rocket motor to limit the extent of movement of said cover,
• releasable means normally retaining said cover in said first position,
• said cover, when released by said releasable means, being moved to said second position by pressure in said combustion chamber, and
• means to control the time of movement of said cover from said first position to said second position, wherein said control means comprise shock absorbing means disposed between said cover and said stop means.