Re aeroplane propellers why do they sell them 7ins X 6 ins?

Question

Re aeroplane propellers why do they sell them 7ins X 6 ins?

Answer 1

This size suits a vast range of engines starting from .19 upto .45 and are used for the full range of aircraft from high wing trainers to the mid-wing and low wing aerobatic models. The 7" is the prop dia and the 6" is the pitch. Most of these props are made of fibreglass/plastic and wood and  can withstand speeds of upto 22,000 RPM. The former can absorb some hard landings but the wooden ones break easily.

Answer 2

The second number is not the angle, but how many inches the prop would move forward in one revolution without slippage.

Answer 3

the first figure is the diameter of the prop & the second figure is the pitch of the blades ( i.e. the angle of the blades)

Answer 4

Shouldn't this question be in the "hobbies" section?