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prop for 350 dd
- Thread starter scooter
- Start date
SwampMatt
Well-known member
I've got a 350 DD with a 72x32 prop and I sometimes wish i had less prop - not more. That'd allow me to spin it at a little higher RPM where there is more horsepower. Every boat is different, but I don't think my 350dd would move over a bump with a 34 on it.
You say he's seeking a 32 or 34.
just a thought, but you may want to change that to you are seeking a 72 x 30 or 32.
I don't know what difference narrow blade or paddle blade brings to the mix. I'll learn something if someone points that out.
You say he's seeking a 32 or 34.
just a thought, but you may want to change that to you are seeking a 72 x 30 or 32.
I don't know what difference narrow blade or paddle blade brings to the mix. I'll learn something if someone points that out.
A
Anonymous
Guest
Depends on the prop MFG too, different companies recommend different pitch prop.
If you are dead set on a wood prop, I'd definitely call the mfg before buying one.
When I was looking for my first prop, everyone on here recommended an adjustable composite prop, and I have to say I am super glad I heeded that advice.
Check out my ad in the classifieds. My buddy is selling his Warp Drive and your friend could run it as a 5 blade and have a spare blade. Or he could use the Bowtie hub and run it as a 4 blade. If that was still too much, he could use the straight 6 blade hub and run the prop as a 3 blade.
He won't be sorry if he goes with an adjustable prop, and the Warp Drive works great for direct car motor. Lots of throttle response and that is a very good thing.
If you are dead set on a wood prop, I'd definitely call the mfg before buying one.
When I was looking for my first prop, everyone on here recommended an adjustable composite prop, and I have to say I am super glad I heeded that advice.
Check out my ad in the classifieds. My buddy is selling his Warp Drive and your friend could run it as a 5 blade and have a spare blade. Or he could use the Bowtie hub and run it as a 4 blade. If that was still too much, he could use the straight 6 blade hub and run the prop as a 3 blade.
He won't be sorry if he goes with an adjustable prop, and the Warp Drive works great for direct car motor. Lots of throttle response and that is a very good thing.
A
Anonymous
Guest
I had a SB 400 dd it tuned a 72/34 paddle
Blew it put an old 350 on it. It'll turn a 70/32 just to the power ban. No overrev but motor is smoking a little Have to keep this one together till the end of Hunting season.
Blew it put an old 350 on it. It'll turn a 70/32 just to the power ban. No overrev but motor is smoking a little Have to keep this one together till the end of Hunting season.
Robby Bondurant
Well-known member
I talked to Tim at Florida Airboat Propellers and he said that a 72X30 is what he recomends for dd 350's. I was told by a few people to get a 74X32 or a 72X32 but I took my prop to him yesterday to get it cut down and pitch taken out.
I put a 76X32 on my dd 350, which is like brand new, totally redone, and I could only turn the 76 2200 RPM's. He is going to cut 4 inches and take 2 degrees out, balance it, re-tip it, and refinish it for $235.
I will have it back by the middle of next week and could let you know how it does.
P.S.- I'm talking about wide blades with all of these props.
I put a 76X32 on my dd 350, which is like brand new, totally redone, and I could only turn the 76 2200 RPM's. He is going to cut 4 inches and take 2 degrees out, balance it, re-tip it, and refinish it for $235.
I will have it back by the middle of next week and could let you know how it does.
P.S.- I'm talking about wide blades with all of these props.
SwampMatt
Well-known member
Robby We all know what you mean, and I'm not trying to be picky at all, it's just an opportunity to make something clear about pitch numbers.
You mention that they are taking 2° out, I think referring to the change from "32" to "30".
Well, those numbers are not in reference to degrees. They are "inches of forward movement" (or somthing to that effect - I don't know the technical terrm)
Imagine a drywalll screw being turned into a piece of wood. You turn the screwdriver ONE TURN and it goes in maybe 1/8 inch. If so, then the threads of that screw have a .125 pitch.
To take it back to the world of a 72/32 prop, if you could spin your prop ONE REVOLUTION and have it move forward (not counting resistance, efficiency and all that other jazz) and the distance it moved forward after turning one revolution would be 32 inches.
Now, I know there are scientists who would balk at my definition, but for the most part, that's what those numbers mean. It's not degrees.
Just a little FYI
May you use the info in good health!
matt.
You mention that they are taking 2° out, I think referring to the change from "32" to "30".
Well, those numbers are not in reference to degrees. They are "inches of forward movement" (or somthing to that effect - I don't know the technical terrm)
Imagine a drywalll screw being turned into a piece of wood. You turn the screwdriver ONE TURN and it goes in maybe 1/8 inch. If so, then the threads of that screw have a .125 pitch.
To take it back to the world of a 72/32 prop, if you could spin your prop ONE REVOLUTION and have it move forward (not counting resistance, efficiency and all that other jazz) and the distance it moved forward after turning one revolution would be 32 inches.
Now, I know there are scientists who would balk at my definition, but for the most part, that's what those numbers mean. It's not degrees.
Just a little FYI
May you use the info in good health! matt.
Robby Bondurant
Well-known member
Thanks for clarifying that. I never knew that's what it was. It's always neat to learn something new.
papee
Well-known member
moodfood":19f63vru said:Robby We all know what you mean, and I'm not trying to be picky at all, it's just an opportunity to make something clear about pitch numbers.
You mention that they are taking 2° out, I think referring to the change from "32" to "30".
Well, those numbers are not in reference to degrees. They are "inches of forward movement" (or somthing to that effect - I don't know the technical terrm)
Imagine a drywalll screw being turned into a piece of wood. You turn the screwdriver ONE TURN and it goes in maybe 1/8 inch. If so, then the threads of that screw have a .125 pitch.
To take it back to the world of a 72/32 prop, if you could spin your prop ONE REVOLUTION and have it move forward (not counting resistance, efficiency and all that other jazz) and the distance it moved forward after turning one revolution would be 32 inches.
Now, I know there are scientists who would balk at my definition, but for the most part, that's what those numbers mean. It's not degrees.
Just a little FYI
matt.
I've read this worded in one way or another a hundred or more times, but somehow this just sunk in. I see now that this means that if you have say a 30" blade, and a 50" blade, both pitched, (say a 36) the same. The actual degree or angle of the blade would be more on the shorter blade than the longer. Is this correct?
Papee
If the pitch is 32 inches on a 10" 0r 10' prop it don't matter, the degrees of the angle of attack will be exactly the same because it is formulated that there is an assumed NO slippage. Length doesnt have any effect on the inches of pitch. Therefore both and all in between lengths at 32 inches of pitch will have the same degrees of angle of attack of the blade.
They may or may not have the same or even similar blade profiles though. This is all relative so its nothing more than a way to compare props it certainly doesnt measure anything in the performance department its just a way to identify props and thats about all.
Scotty :lol: :lol:
If the pitch is 32 inches on a 10" 0r 10' prop it don't matter, the degrees of the angle of attack will be exactly the same because it is formulated that there is an assumed NO slippage. Length doesnt have any effect on the inches of pitch. Therefore both and all in between lengths at 32 inches of pitch will have the same degrees of angle of attack of the blade.
They may or may not have the same or even similar blade profiles though. This is all relative so its nothing more than a way to compare props it certainly doesnt measure anything in the performance department its just a way to identify props and thats about all.
Scotty :lol: :lol:
Bear it measures a lot in the performance dept. I think. If you put a 32 prop where you need a 48 it won't work. It doesn't tell you about the snap folks refer too. Also for every 2" in length it is basically the same as 2" in twist. So a 76"dia. with 32" of twist is the same basically as a 74" dia. with 34" of twist. at least thats what I have been told and it worked that way back in my DD days of wooden props. Nowadays I just worry about setting them all the same and at an angle that accomplishes the rpms I am looking for and the thrust that is generated. You see for the kind of running I do when Stan picks the trails static thrust is important becuase it is just like being tied down on the trailer. We chainsawed a couple of trees outta the way to get in to a place the other night and we werre going downhill, I was a little aprehensive about the uphill return trip but got r dun, just another one to add to the story book as they say.
I was commenting on the issue of inches pitch relating to length and degrees of AOA. Its just numbers of measurment of the prop. It does not measure anything else.
Youy may, from experience or trial and error, infer or deturmine performance fctors about changes in prop specs. The prop specs are only a measurement for the prop nothing else.
Its a semantics thing I guess. Communications aint easy sometimes.
Scotty :lol: :lol:
Youy may, from experience or trial and error, infer or deturmine performance fctors about changes in prop specs. The prop specs are only a measurement for the prop nothing else.
Its a semantics thing I guess. Communications aint easy sometimes.
Scotty :lol: :lol:
Robby Bondurant
Well-known member
A wide blade will give you more low end push against a stick prop. A stick prop will have more snap and turn up faster but wont have that low end push to run ground.