First plane I flew with a gyro was a big Fleet Bipe. The owner had it on the rudder just to help keep it on the runway. The owner couldn't fly the plane but it was a fantastic build so a couple of us flew it at shows for him. If you forgot to turn it off after take off the gyro would fight you when you tried to use rudder. At the lake bed there are a couple of older fellows that can still fly but after about 5 minutes they get too tired to keep there planes level so the gyro is a life saver for them, gives them a chance to land when they are too pooped to poop. I just haven't had to use one yet but the day may come. If it was in the advertisements the fellow may be able to sell a few.