Hey guys just a quick question, how come on some cessna 172's the edges of the propeller is rounded off and and some its more flat, like it looks cuttoff.
Im trying to add images to show as an example but cannot figure out how to attach it to the post.
thanks
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- barney captain
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Re: Propeller Question
The quick answer is called "minimum induced loss" - a fancy term for describing what type of mission the propeller is to perform. On a 172, with a minimally powered engine, the tapered ends allow a more evenly distributed elliptical distribution of the induce loss. Higher performance engines are less concerned with this and can have squared off ends. Basically it comes down to maximum bite, over just squeezing every drop out of a 160hp engine.
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- kitplane01
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Re: Propeller Question
barney captain wrote:The quick answer is called "minimum induced loss" - a fancy term for describing what type of mission the propeller is to perform. On a 172, with a minimally powered engine, the tapered ends allow a more evenly distributed elliptical distribution of the induce loss. Higher performance engines are less concerned with this and can have squared off ends. Basically it comes down to maximum bite, over just squeezing every drop out of a 160hp engine.
The elliptic ends are better for both efficiency and noise. But as the propeller gets closer to the maximum allowed radius for some particular installation, they need to maximize total area and therefore the cut off tips.
If you want really cool, check out Q-tip props.
Re: Propeller Question
The 172s with the square-tipped props are like that because someone porpoised the landing and ground off the end of it 
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