I do remember somewhere in the back of my mind that someone did order low geared F's, believe they
were F-3's as a matter of fact. Dick has a good point on the high ratio ring/pinion problem. The
ring gear was limited by case size and mounting so that if you wanted a high ratio it took a smaller pinion and when you could no longer machine a pinion small enough you had to cut the teeth
right into the motor output shaft. To reduce tooth loadings (force vs area) the fine spline or
83:20 (or so) was introduced which put more teeth in mesh to handle the load. Reduction is still\
a little over 4:1 just handled a bit different.