The PA-11 "Cub Special" is really a modified J-3. The solo pilot's position is moved to the front position and the front fuel tank is removed. There is an 18 gallon tank in the wing (2nd tank optional). The eyebrow cowling is removed and a pressure cowl (similar to a PA-18-95) is put in its place. You'll notice that the tailfeathers are the same as the J-3. There are other differences but these are the most noticable.