Part 4 o' 7. Begad! This video shows t' construction sequence for makin' a Rogallo win' glider that is boosted into t' sky by a model rocket. They are often called flexie gliders because t' win' is flexible and can be rolled up and stored in a small space. Begad! In model rocketry, they are used in t' National Association o' Rocketry's flexie contest.