Fin deployment method and apparatus

An air vehicle launched from a launcher, the air vehicle comprising:

• a fuselage;
• fins coupled to the fuselage, wherein the fins deploy from an initial stowed configuration in the launcher to a deployed configuration in flight;
• a release mechanism that releases the fins from the stowed configuration, wherein the release mechanism includes a longitudinally oriented pin in a cavity in the fuselage;
• a valve that selectively lets pressurized gasses into the cavity through the valve;
• wherein the pin engages a restraint that engages the fins to maintain the fins in the stowed configuration;
• wherein the pin delays release of the restraint until a predetermined delay time after movement of the release mechanism;
• and
• wherein the pin has a length corresponding to the predetermined delay time.

A method of launching an air vehicle from a launcher, the method comprising:

• using pressurized gasses to move the air vehicle within the launcher;
• when an aft end of the air vehicle reaches openings near the muzzle of the launcher, beginning movement of a release mechanism for releasing the fins of the air vehicle;
• and
• after a predetermined delay following the beginning movement of the release mechanism, using movement of the release mechanism to release a restraint that keeps fins of the air vehicle from deploying;
• wherein moving of the release mechanism is caused by a pressure difference across a base of the release mechanism.