yes thats true.
Team 151 in NH has done some prototyping of the "projectile minibot" and it's very inconstant. This is because the initial force that a spring or piston would provide would have to have little tolerance for the minibot to hit the plate between 2-4 Newtons. Meaning, X amount of force will hopefully be provided by the spring....every single time. Also if that plate shatters, your team is going to get some harsh criticism for making a very unsafe robot.
Be sure to check out an official FIRST Week 0 competition on Feb. the 19th in Nashua, NH. There will a 2011 official field, scoring system (that was made by FIRST), the Game design committee and special guests! Contact
paradisem1@gmail.com for more info