Wed May 16, 2018 9:56 am by cornbinder89
Hochkiss drive refers to a common differential/axle.
Semi floating, 3/4 floating and full floating, refers to how the loads are carried on the rear axle. A full floating axle both the axial and radial loads are carried on the axle housing itself, and the axle shaft is "floating" in that it see's none of these loads, the other two, the axle shaft itself carries some of these loads.
Over square is a way of saying the engine bore is larger than the stroke.
Fork and blade, is where the two connecting rods aren't on a common journal side by side, like most V engines but interposed with each other. The centerlines of the cyl are the same,(and therefore the rods are also) so one connecting rod ends in a forked end and the other a blade that fits between the fork rod. It allows the V engine to be shorter than if the cyl have to be staggered to put the connecting rods side by side. A rather complex and weak system. Another way to accomplish the same thing is to have one connecting rod a "Master rod" and the other connecting rod connects to this rod and is a " slave" rod. Radial aircraft engines often use this system. It is stronger than fork and blade, but can lead to complex timeing as the slave piston doesn't doesn't exactly match the crank throw.
Slipper vs. trunk skirts: A trunk type piston the bottom of the piston is the same all around, like a piece of tube cut off. A slipper skirt has portion of the skirt cut away, so it is longer in line with the pin then 90 degs to the pin. The allows the piston to come lower in the bore and still miss the crankshaft counter weights and also allows the pin to be higher in the piston and still articulate enough for long strokes.