An inexpensive and ready made restraint is a screwdriver and an inexpensive dog leash that has a little metal ring on one end and the loop hand hold on the other. Just stick the screwdriver through the metal ring into the ground and take the loop end under the left horizontal stabilizer, up over he back part of the fuse right in front of the fin, then down under the right half of the stabilizer. Then just drop the loop over the screwdriver. Simple and cheap yet effective.