Props for O-300 M4
Posted: Mon Jun 21, 2021 5:36 pm
I have the O-300 powered early version of the M4. It is equipped with a 74/60 prop, which seems highly unsuitable for this engine/airframe combination.
Static rpm is about 2200rpm. During take off roll it gets to a little above 2300rpm and only if I do a very shallow climb will it ever reach 2400. At those rpm's that equates to about 80 (2200rpm), 88 (2300rpm) and 100hp (2400rpm). Seems to me the prop is way over pitched for what is supposed to be a STOL aircraft (within the limits of its engine). There are 45hp left in the engine which I can never get to.
Does anyone have some real life figures for using a 76" dia. prop around 51 to 53" pitch? They are on the TCDS, so it's an option. It's what the average Cessna 170 used with the same engine. Whatever made Maule pick this prop for the M4?
Static rpm is about 2200rpm. During take off roll it gets to a little above 2300rpm and only if I do a very shallow climb will it ever reach 2400. At those rpm's that equates to about 80 (2200rpm), 88 (2300rpm) and 100hp (2400rpm). Seems to me the prop is way over pitched for what is supposed to be a STOL aircraft (within the limits of its engine). There are 45hp left in the engine which I can never get to.
Does anyone have some real life figures for using a 76" dia. prop around 51 to 53" pitch? They are on the TCDS, so it's an option. It's what the average Cessna 170 used with the same engine. Whatever made Maule pick this prop for the M4?