A screw (thread) is a subset, as is a circle, but the inference is the blades are fixed in all but one rotational axis and so spin
The actual explanation of “a curve on the surface of a cylinder or cone such that its angle to a plane perpendicular to the axis is constant” doesn’t really work here
I thought heli is more like a screw. (Not claiming that it is, but that was my understanding)
The word is not “heli” though. It’s “helico”.
Like in the helicoprion (a shark with a spiral think on it’s mouth) or a helicograph (a tool to draw spirals).
A screw (thread) is a subset, as is a circle, but the inference is the blades are fixed in all but one rotational axis and so spin
The actual explanation of “a curve on the surface of a cylinder or cone such that its angle to a plane perpendicular to the axis is constant” doesn’t really work here