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View Full Version : Barefoot Prop 197 w/LQ9/LY6


03 35th Anniversary
04-21-2012, 12:28 PM
Just a quick question to find out what prop all the footers are running on their 197's.

03 35th Anniversary
04-22-2012, 07:01 PM
Bump......

DooSPX
04-22-2012, 09:50 PM
Call Eric @ OJ. tell him what you want from the prop... i.e. more speed, flatter table, etc.

ncsone
04-22-2012, 09:55 PM
I talked to Bill at Acme a while back and he had recommended a prop that would have supposedly gained +4 mph on the top end for a MCX/Slot 197. Unfortunately, I can not find that email now, but I want to say it was a #541 or 542.

If a prop could gain that much top end on a 197, it would be pretty impressive. I ended up not going that route as I already had 2 OJ's, we don't 'foot that much any more and I thought the 4 glad OJ might give a softer skier pull.

03 35th Anniversary
04-24-2012, 07:23 AM
The 541 and 542 are both for 1" shaft.

DooSPX
04-24-2012, 09:41 AM
The 541 and 542 are both for 1" shaft.

Give Eric a call.... 800-359-9730

EJ OJPROP
04-24-2012, 10:03 AM
What are you currently running?

03 35th Anniversary
04-24-2012, 02:04 PM
I have 3 props, 14.5 x 21, 14 x 20 and a 13.7 x 17.5 or 19.5 (I can't remember off hand.) all 4 blade props.

EJ OJPROP
04-24-2012, 03:31 PM
Which size do you prefer? Would be a 19.5 with the slot. What is max MPH/RPM's?

Sodar
04-24-2012, 04:06 PM
The wuss won't take it past 40mph.

Apparently this thing bolted to the motor is all show and no go!

http://www.mastercraft.com/photopost/data/500/Copy_of_IM000354.JPG

DemolitionMan
04-24-2012, 04:45 PM
The wuss won't take it past 40mph.

Apparently this thing bolted to the motor is all show and no go!

http://www.mastercraft.com/photopost/data/500/Copy_of_IM000354.JPG

:D:D:D

cbryan70
04-24-2012, 05:38 PM
03 are you serious? Are you looking for the best table or what? You can turn as big of a prop as you want. I would go with there new 5 blade

03 35th Anniversary
04-25-2012, 07:27 AM
The boat in the picures below was a carbon copy of mine.

The only 2 differences were the barefoot plates (Mine is HYD and his was Manual) and the props.

The way the 2 were propped his would spool up faster out of the hole, I had more mid range power, and he had more topend.

The second picture is why I can simply just see what was being used on that boat. All any of us can remember is that it was a 3 blade prop.

03 35th Anniversary
04-25-2012, 07:32 AM
Which size do you prefer? Would be a 19.5 with the slot. What is max MPH/RPM's?

13.7 x 19.5 is the one I like the best.

It seems to preform better than the other 2 but the big difference I see with it, it does a lot better on fuel.

EJ OJPROP
04-25-2012, 11:12 AM
What MPH and RPM do you see with the 19.5?

Kyle
04-25-2012, 02:54 PM
Sorry for the thread jack

Eric, I got a '93 ps190 and I'm turning a 13.7 x 17.5 four blade at 5100 ish rpm at 47 mph on gps stargazer. Can I turn a 19.5 or what do you recommend.

Rockman
04-25-2012, 03:47 PM
The boat in the picures below was a carbon copy of mine.

The second picture...

Yes, looks like a big pile of carbon! :D

Don't think that will buff out though...


Johnny-Where you been at these days for work?

RM

03 35th Anniversary
04-25-2012, 04:44 PM
What MPH and RPM do you see with the 19.5?

48.5 @ 5100 IIRC

I will have it out in a couple of week and take note of some various speeds/rpm.

03 35th Anniversary
04-25-2012, 06:45 PM
Yes, looks like a big pile of carbon! :D

Don't think that will buff out though...


Johnny-Where you been at these days for work?

RM

I'm stuck in Chattanooga, TN. till July.

TRBenj
04-25-2012, 07:04 PM
The 2 pieces of the puzzle that you need to supply are:

1) Where does your boat make its peak hp? (I would expect a NA 6.0L to peak in the 5400-5600 range... not sure if/how the SC affects that).

2) A known data point (WOT RPM vs. GPS speed with a known prop).

Then you prop it to turn at or near the peak hp level at WOT. That will maximize top end. If youre currently overpropped (which may very well be the case) then if you go to a prop with less pitch, you should gain holeshot, midrange power and top end as well.

Kyle
04-25-2012, 11:39 PM
The 2 pieces of the puzzle that you need to supply are:

1) Where does your boat make its peak hp? (I would expect a NA 6.0L to peak in the 5400-5600 range... not sure if/how the SC affects that).

2) A known data point (WOT RPM vs. GPS speed with a known prop).

Then you prop it to turn at or near the peak hp level at WOT. That will maximize top end. If youre currently overpropped (which may very well be the case) then if you go to a prop with less pitch, you should gain holeshot, midrange power and top end as well.

Yes but you also told me a few months back that the blades can flex causing pitch change. How do we factor that in. My speed doesn't change past 4700-4800 so there is 300-400 rpm that are not doing anything.

Does a higher pitch flexing compensate for the lower pitch flex?

EJ OJPROP
04-26-2012, 07:00 AM
Sorry for the thread jack

Eric, I got a '93 ps190 and I'm turning a 13.7 x 17.5 four blade at 5100 ish rpm at 47 mph on gps stargazer. Can I turn a 19.5 or what do you recommend.

Higher pitch will decrease the low end as well as drop RPM relative to speed, you may see a slight increase in top end, 1-2 MPH. I would not suggest a 19.5 with a 5.7 engine as it may not allow the engine to see max RPM.

Kyle
04-26-2012, 10:50 AM
Higher pitch will decrease the low end as well as drop RPM relative to speed, you may see a slight increase in top end, 1-2 MPH. I would not suggest a 19.5 with a 5.7 engine as it may not allow the engine to see max RPM.

Thank you Eric.

I guess I will save my money then. Just figured I would ask since nothing happens after 4700 rpm speed wise but the engine can turn another 400 rpm without change. I was thinking that a 19.5 would lower my rpm by 300 ish rpm but I would still get performance to 4800. The prop I'm running now is a monster out of the hole and I figured that a little less hole shot would not matter that much.

Again Thanks for the advice.

TRBenj
04-26-2012, 11:56 AM
Yes but you also told me a few months back that the blades can flex causing pitch change. How do we factor that in. My speed doesn't change past 4700-4800 so there is 300-400 rpm that are not doing anything.

Does a higher pitch flexing compensate for the lower pitch flex?
I have seen worn out props that act like youre describing. They turn consistent speed vs. rpm at skiing speeds, but flex at WOT, causing extra RPM's that dont translate to speed. I consider props like that to be either worn out (if old and springy) or simply inefficient (meaning they dont turn RPM's into speed very well at the top end).

I have little experience with the newer XMP OJ's out of the few Ive tried for the 1.23's (lower prop RPM), but I know someone who saw the exact same behavior youre describing with a new XMP on a 1:1 boat. The last few hundred RPM didnt speed the boat up.

In his opinion, the Acmes arent as susceptible to this phenomenon... they turn RPM's into speed a bit better. You may want to try a comparable sized Acme... my guess is that it will turn similar RPM's at skiing speeds, but will drop your revs slightly at WOT, if it bites and pushes the boat instead of flexing.

I would not expect a steeper prop of the same design youre using now to help performance in any way.

Kyle
04-26-2012, 12:48 PM
Will I get more speed out of a 3 or 4 blade?

I don't want to have a footin prop and a slalom prop and I need one that holds speed in a course like my 4 blade.

EJ OJPROP
04-26-2012, 01:13 PM
I have seen worn out props that act like youre describing. They turn consistent speed vs. rpm at skiing speeds, but flex at WOT, causing extra RPM's that dont translate to speed. I consider props like that to be either worn out (if old and springy) or simply inefficient (meaning they dont turn RPM's into speed very well at the top end).

I have little experience with the newer XMP OJ's out of the few Ive tried for the 1.23's (lower prop RPM), but I know someone who saw the exact same behavior youre describing with a new XMP on a 1:1 boat. The last few hundred RPM didnt speed the boat up.

In his opinion, the Acmes arent as susceptible to this phenomenon... they turn RPM's into speed a bit better. You may want to try a comparable sized Acme... my guess is that it will turn similar RPM's at skiing speeds, but will drop your revs slightly at WOT, if it bites and pushes the boat instead of flexing.

I would not expect a steeper prop of the same design youre using now to help performance in any way.

Tim - Our blades are thicker than that of the other brand. They will not however flex to the point of loosing enough pitch to change MPH. A thinner prop will run a bit better top end, 1-2 MPH, than a prop with a heavier root. While I understand the need for speed, we have always defered to durability and longevity and had thicker blade sections. I can thin a prop down for MPH but it will bend at the slightest impact, which most guys do not prefer to gain 1-2 MPH.

As I said earlier, a higher pitch prop will not help the overall performance, no matter who makes it.

TRBenj
04-26-2012, 01:31 PM
Eric, I do not believe the blade thickness was the concern. The speculation was that the shape of the XMP blade may have been more sensitive to flex at higher (prop) rpm's.

Im not sure what else would explain the phenomena that we're describing here, but feel free to enlighten me! Like Kyle, he saw the last 300-400rpm add little to no speed. Where are those extra RPM's going if theyre not pushing the boat any faster?

Kyle, in theory, the fewer the blades, the more efficient the prop. Ive found the 3-blades Ive run to be a bit faster than the 4's. I think that the large blade surface area found on the modern CNC props largely levels the playing field between 3 and 4-blades, at least for applications with relatively low loads (skiing and footing). If youre show skiing or running a wakeboat with 2k lbs of ballast, I hear the 4's still do better for the big loads, especially out of the hole.

east tx skier
04-26-2012, 01:37 PM
Kyle, in theory, the fewer the blades, the more efficient the prop. Ive found the 3-blades Ive run to be a bit faster than the 4's. I think that the large blade surface area found on the modern CNC props largely levels the playing field between 3 and 4-blades, at least for applications with relatively low loads (skiing and footing). If youre show skiing or running a wakeboat with 2k lbs of ballast, I hear the 4's still do better for the big loads, especially out of the hole.

Tim, it's been a while since I have inspected one up close, but the large blade surface area thing is not necessarily a function of CNC machined props, but rather an Acme design feature. When I compared two similarly sized props, one an Acme and the other an OJ XMP, the Acme had more surface area per blade. This was several years ago. But as far as I know, OJ has not varied the design of their 3 blade props from a blade area perspective. You can see the measurements I took and a side by side picture of the two props in the link below. Both companies make very good props. But, as I'm sure you know, they are different and perform differently.

Acme vs. OJ XMP 13x12 3 Blade Prop Comparison (www.tylerskiclub.com/proptest.pdf)

From the article:

The Acme has an approximate blade size of 8 3/16” across the blade (vertical
in the picture) and 5 1/8” from hub to the edge of the blade. At first glance,
the surface area of the blades appears larger on the Acme. From my
measurements, it appears that the Acme has about 1” on the OJ on the vertical
blade measurement. From hub to edge, they are about the same.

The OJ has an approximate blade size of 7 3/16” across the blade and 5 1/8”
from hub to the edge of the blade.

TRBenj
04-26-2012, 02:29 PM
Doug, youre absolutely right- so far as Im aware, the CNC manufacturing process used on the Acmes and OJ XMP's is not the reason for the large blade surface area. Nonetheless, both CNC props do have a lot more blade surface area as compared to their conventional hand finished counterparts. Youre right that the Acme has more surface area, but the XMP isnt that far behind.

This is a new-ish hand finished OJ for comparison. As you can see, the XMP vs. Legend props are very different in shape, with the hand finished prop having quite a bit less surface area.

EJ OJPROP
04-26-2012, 02:45 PM
Tim - I see the last 200 - 300 RPM not gain much MPH with any prop regardless of who built it. The blade shapes are much different. The other is a more tradtional work boat type shape while ours is not that style. There are may other differences as well, rake and pitch distribution to name two.

Blade thickness is a major factor in top end. A thinner cross section IS faster. I used to thin my tunnel boat props to the point of breaking, in fact they would break and not last very long at all but I could thin a few more MPH put of it. When one of those props breaks you can end up upside down under water. Thin to win we used to say. Last I looked these boats were nowhere near 100 MPH nor do they have numbers on the side. As I said we prefer to build a good all around propeller that will last.

The RPM we see on the ski boats should not cause deflection at all. We still run our "old style" 3-blades on flatbottom v-drives with overdrive transmissions, prop turning faster than engine RPM, turning 5500 to 6500 RPM with no flex issues. You will see more load and pressure on blades with the wakeboats loaded to the gills than you do with a 1:1 turning 5000 wide open

Our current XMP 3-blades do have a different shape, even from our 4-blades. I built the prop pictured, 13 X 13 RC, in 1990 specifically for the CC boat. The blade shape I used was from a wooden pattern originally designed by my great grandfather Oscar in the late 1940's for racing applications.

TRBenj
04-26-2012, 05:13 PM
Eric, the stainless prop pictured above is a 14x16 (Im sure thats what you meant), and I can definitely see the resemblance to the older 3-blade legend design. Your 12" 3-blades still work great on the smaller, lighter vintage CC's. No idea how old this one is, but the shape is pretty much the same.

I can see how thinner blades would make a prop faster (more efficient). I cant say Ive ever noticed any fatigue on any of my CNC props, but I guess we'll see how they stand up to the test of time! Luckily I dont run in a river or lake with any real debris concerns.

I cant say I agree with you on the last few hundred rpm's not adding any speed. I think I understand what youre saying though. The more wetted surface a hull has, the more RPM it takes to push it faster- especially at the high end... so youre getting less speed per extra rpm at the top than you do in the midrange. Still, to say that the last 300-400 rpm can return next to no measurable speed increase seems to be a real stretch. That has not been my experience with the brand X props.

I do realize that there are several parameters that are different in the 2 prop designs, which are not easily measured or communicated I dont have a understanding of how pitch distribution will affect performance, but I do recognize that aft rake will help top end speed by lifting the bow slightly. Whether or not the Acme design is a "work boat type prop" really doesnt matter much to me, I just want the best performance out of my non-100mph ski boats.:D

EJ OJPROP
04-26-2012, 05:24 PM
Was just speaking of the blade shape being of that type on their prop, not a knock at all. This prop is the older style for sure, changes were made on the Legend line.

I'm saying there is a point where the RPM will run away from the MPH, with an Acme or an OJ. I know you have run many props over the years as have I, but there is a wall they all hit. It may not be as deep as 300 RPM but there is a point.

You are correct about rake, number of blades will affect lift as well. Bow lift does allow for a little more MPH but will also increase the size of the wake. I guess we try and make the wake as nominal as possible with our props, for the slalom guys. The boarding props are a different animal all together, some of the rake and pitch distribution has changed on our designs for those props.

TRBenj
04-26-2012, 05:36 PM
Agreed on there being a wall... but I prefer it when Im hull limited as opposed to prop limited. That point comes too soon as it is!

You mention props for slalom guys (I totally understand the rationale, by the way) and the wakeboard guys. What about the barefoot guys?8p

EJ OJPROP
04-26-2012, 05:37 PM
Barefoot guys get the thin ones!

Kyle
04-27-2012, 01:10 AM
Eric.


What does a sharp leading edge do to the top end kind of like a cleaver style prop. I've seen race boats with extremely sharp props. Why do we see blunt edges on our props. Either way of a sharp prop or blunt prop was to run someone over they both would cause serious damage to what they chop up. I am just curious and was wanting to learn something.