I'm surprised no one as mentioned Spin Stabilization has and IS Playing a major role in sounding rocket design for unguided Full size rocketry since the very beginning of the space age. Nearly all the early sounding rockets were designed to obtain a given roll rate during boost and coast phases of their flights. Some were even fitting with "despin" apparatus to slow or stop the guidance spin just before payload deployment...some really fun stuff. just about every payload design has as part of it's preflight testing a high speed spin test.
Model Rockets can use spin for various effects, at the cost of some altitude. increasing spin incrased drag reducing altitude. it doesn't take much misalignment of a single fin to induce some roll in the models flight.
the easiest way to induce spin is to assymetric sand fin or fins. or build up or bend a lower fin tip corner (as is done on all varients of the Bull-PUP). Adding spin tabs or canting fins also works but must be symmetric or some rather violent tail whipping can occur. It only takes the tinyest of cants to induce a good amount of spin so be careful how much you add. When I built my first Omaga 2-stage booster for my original cinaroc back in the 70's I decided to assymetric airfoil all 8 fins on the bird, making sure to align them all with the lift going in the same direction. WOW! we can't watch my first single stage super-8 flim as it gives you a headache the spin is so fast. Made for some interesting smoke trails, somewhere I have a few pics of that flight, I may not have scanned them yet
