This is me scratch-built Black Brant II, me bucko, designed for 18mm motors. Begad! I took measurements off me larger, out o' production Estes Black Brant II (D-engine powered) t' come up with this 73% downscale. I absolutely love how it turned out! Lookin' forward t' flyin' it a whole bunch more, and hopefully with less breeze next time! Open Rocket file/plans available at www.RocketryForum.com Enjoy!