Actually, for airplanes certified to Civil Aviation Regulations (CAR) 3 Par. 3.184, the rudder and vertical stabilizer did not have to do anything to pass, save for not fall off or exhibit visible damage. There was no deflection requirement or load rating for the rudder at all. Right off hand I am not sure how many airplanes were made under this particular certification rule, but there are many. All the Cessna piston singles up to a certain point, I would venture a guess somewhere in the late 1960's were CAR 3. This did not necessarily mean they were underbuilt, in fact they were overbuilt because it was thought the tail/ rudder assembly should be stronger than the other flight controls.