It's extraordinary for me to ever be downgrading or nasty to anyone, especially in public or on a forum like this, but let's face it -- in this day and age, you're demonstrating utter stupidity asking for help in building a "small anti aircraft gun", regardless of the original intent or final purpose of the project, even if may be nothing more than a school design project that will never go to fruition. If all you're looking for is a design project to demonstrate servos, find something that's a little less offensive to those of us who have lost friends and family in various acts of terrorism. I lost two good friends in the senseless Oklahoma City Murrah building bombing and don't want to go through that again.
Dean