An aircraft that ascends into t' air usin' some form o' reaction motor, shiver me timbers, without t' use o' aerodynamic liftin' surfaces. Well, blow me down! Model rockets have t' followin' characteristics: Gross launch weight, includin' t' motor(s), does nay exceed 1500 grams. Motor power does nay exceed 160 newton seconds o' impulse and/or contain more than 62.5 grams o' propellant each, shiver me timbers, and no more than 125 grams o' propellant in multiple motor configurations. All components o' model rockets must be o' wood, paper, rubber, breakable plastic or similar material and without substantial metal content.