Pop quiz hotshot...prop pitch

[Baker]

I will admit I have always been baffled by the terminology of prop pitch. We talk about it in inches. My prop is 24 inches of pitch and there is nothing that I can see while looking in the pitch plane that represents 2 feet(24 inches). I did learn what it meant yesterday....finally!!! There are likely many people on here that know what it means. But I asked around my part of the world and many otherwise very knowledgeable people could not explain it.

Can you???

 

[rochepoint]

Theoretical distance it would travel in one revolution with no slippage........

 

[AusCan]

Theoretical distance it would travels in one revolution with no slippage........

That it!

I get my head around the "no slippage" term by thinking of the prop slowly turning in a semi-solid like butter.

 

[FlyWright]

Rotate your prop through jello for one full revolution and the pitch is the distance it traveled through the jello.

 

[Baker]

WoooHooo!!!! Jello shots for all!!!

 

[greysailor]

Ha! John, if you were a prop job crop duster instead of a jet jockey, you might have known that answer! ��

 

[FlyWright]

Ha! John, if you were a prop job crop duster instead of a jet jockey, you might have known that answer! ��

ROFLMAO!

 

[Baker]

Ha! John, if you were a prop job crop duster instead of a jet jockey, you might have known that answer! ��

But they have variable pitch propellers....

 

[greysailor]

But they have variable pitch propellers....

Yep....but that just determines how much Jello they cut per revolution! Break out another round of Jello shots!
Sure is some nice looking "boat bling" you have there...should be good for a little extra speed and fuel economy.

 

[Ski in NC]

What makes pitch tricky to measure is that as you get further from the center, the blade angle changes. The blade is curved so with each say 10deg of rotation, the amount of advance is constant from hub to tip. So blade angle changes as you get further from the hub. Need a jig of some sort to measure pitch.

 

[Baker]

I can tell I got a little more performance out of them. Maybe a knot or knot and a half. Funny thing is i didn't lose that much RPM. I can still get 2950 on a 2800 RPM engine. And I just started an 8 day trip so this bitch is loaded up. Oh well. I at least know that I'm not working her too hard.

 

[Nomad Willy]

I agree John,
Let'um sing and w/o too much load.
Like a truck climbing a hill. Work'in like they could do it forever.

Ski,
There are props designed to have the same pitch all around a given diameter. Like my MP prop from Michigan. The "MP" stands for "machined pitch". I like my old skewed blade prop better. Looking for an excuse to haul the boat and stick it back on. Kinda thin though. Been ground uppon by too many "prop men" .. probably.