When I attended Oshkosh last year, I saw some J-3s with mixture control knobs that were not the normal knob on the end of the control cable. Instead of the usual knob to pull, they had an elbow, with one end screwed onto the control cable, and the other end having a round knob on it. One of the problems with the mixture control is getting a good grasp on it to shut the fuel valve to the off position. This knob was on the end of the elbow sticking into the cabin about a half inch, which would make it much easier to grasp it. Anyone have such a knob, and know where they can be purchased?