Pitch Propeller Nomenclature and Repitching
Omar Filipovic
Sensenich aluminum fixed-pitch propeller model designation system EXAMPLE…_70CM6S16-0-79_ _  Special letter prefix to identify accessories or composition of propeller. Current letters include ‘S’ for STC package and ‘W’ for wooden […]
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Glasair Aircraft Owners Association
Sensenich aluminum fixed-pitch propeller model designation system

EXAMPLE…_70CM6S16-0-79_

_ Special letter prefix to identify accessories or composition of propeller. Current letters include ‘S’ for STC package and ‘W’ for wooden propeller.

70 Basic diameter in inches

C Designates Blade Design

M6 Designates hub configuration…”M6″ for installation on SAE No.2 (Ref. AS 127) flanged shaft with 6/16 (3/8) dia. bolts. “M7″…for installation on SAE No. 2 (Ref. AS 127) flanged shaft with 7/16 dia. bolts.

S16 Designates a 16/4 or 4 inch spacer (extension) thickness.

-0- Designated cut-off in inches from basic diameter.

79 Pitch in inches at .75 radius station.

_ Designates design change

Repitching

Q: What is the maximum amount of repitching that can be done to the 76EM8xxx and 74DMxxx props?

For example, can a 76EM8-0-62 be repitched to 66″?

How many times can repitching be performed?

A: We have Service Memo #86-1.

You can repitch a Sensenich propeller a total of 8 inches from the propeller’s median pitch. In the case of the 76E and 74D series props, both propellers have a 60″ median.

Therefore, in the example above, the 62 has already gone up 2 inches. You can still go up 4 more to the 66 for a total of 6 inches. Then you can go back down to a 64 and that would be your total of 8.

For more information about model-specific Sensenich propellers see this article.