prop pitch

[Birdseye]

anybody know how to measure the pitch of a prop?

i have tried putting a flat rule across the face and measuring the "drop" at the leading edge of the next blade. also measured the angle which is about 20 deg. trouble is, the pitch of the blades varies from root to tip anyway.

so how do i do it?

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[MLBURGE]

Firstly measure the circumference of prop at two thirds the diameter and mark this in the form of a straight line on a flat surface. 12" prop the circumference is taken at 8" so 8 x pye (3.142) 3 1/7 = 25 1/7 " so this would be the length of line drawn in that case.

then nail a piece of string at one end of the line and place the prop face up so that the start of the string is at the trailing edge of the blade at two thirds the diameter, then pull the string tight so it touches the trailing and leading edge of the prop. The vertical height measured at the other end of the line and the string will be the pitch of the propeller.

You can also try- circumference at two thirds diameter divided by blade width, multiplied by trailing and leading edge measurement.

so 25"/ 5" x 1 5/8 = a pitch of 8 1/8"



hope this helps bit difficult to explain without diagram


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[MLBURGE]

forgot to mention have a careful look all around the prop hub you may find the size stamped --. 14 x 11 would be 14" diameter and 11" pitch

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