ML Boatworks 1/8th Scale Newton 172 Extreme Prop Walk

[Greg Stamatis]

Anyone have any ideas regarding setup or trim to overcome prop walk at high speed? The boat is fast, rides pretty well (a bit loose), but it likes to walk. Just finished the boat and sealed with epoxy. Not painted yet, but have done some test runs. Can make modifications to the hull and setup if needed.

Motor: NeuMotors 1527 1Y
ESC: HYDRA XLX2, 8S, 33.6V WATER COOLED ESC, 20A PEAK BEC
Batteries: 8S
Rudder: Speedmaster Dual Pickup Tapered Rudder Assembly - Unmodified. Left side of transom, 2.25" left of prop center and leading edge just back of prop trailing edge.
Turn Fin: Rattlesnake RC Turn Fin for 1/8 Scale - Neutral alignment (no toe in or toe out)
Prop: Octura X450 Polished and Balanced
Drive: Rigid flex drive - no offset and neutral to centerline

I'm new to 1/8 Scale FE and new to this forum. Any help or suggestions are greatly appreciated.

 

[Neal Hyland]

Greg,

Sorry i can offer you any advise but i am building exactly the same hull and setup right now. it won't be finished for a few months but would love to hear your feed back on it and setup once you get it dialled in.

 

[Rod Fonda]

Hi Greg,,you mentioned the prop was polished and balanced.Maybe a silly question, Has the prop been sharpened?,by sharpening the leading edge,gradually thinning/tapering down the back of the prop blade, from around 3/16-1/4" back from the leading edge , a blunt or fat edge will usually cause a prop to walk..Otherwise the boat will probably need some turn fin trimming or there's other alignment issues,, I don't have any experience with these types of boats

 

[Samuel Hagan JR]

Does it pull while at speed or acceleration?

 

[ChrisHerzog]

Pics and/or vid would be helpful.

 

[RaceMechaniX]

Greg, Your symptoms seem to point to the prop. Are you running a 2 blade or 3? I assume 2. Try a X450/3. Many FE boats seems to manage prop walk better with 3 blade props.

 

[Don Ferrette]

Greg can you post a pic or two of the transom set up? Does it pull/walk harder when you accelerate vs. at speed? Is the rudder stock length or did you cut any off the bottom? How much of the rudder blade is below the prop centerline? It's possible it's not a prop issue but rather a lack of rudder blade surface area in the water, been there and done that more than once. For what it's worth I've never liked tapered rudders on scale hulls.

 

[FloridaScaleBoater]

For what it's worth I've never liked tapered rudders on scale hulls.
I second that

 

[Hydro Junkie]

It could also be the rudder needs to be readjusted for more left when it's centered. My 2000 Elam requires the rudder right face to be close to parallel to the boats centerline to prevent it from walking. I'm running a two blade Prather stainless prop that's been balanced, sharpened and polished, either a 250 or 255 IIRC

 

[Don Ferrette]

It could also be the rudder needs to be readjusted for more left when it's centered. My 2000 Elam requires the rudder right face to be close to parallel to the boats centerline to prevent it from walking. I'm running a two blade Prather stainless prop that's been balanced, sharpened and polished, either a 250 or 255 IIRC

Yup. To start out I set every boat up no matter what it is with the right side of rudder blade parallel to hull centerline.

 

[Samuel Hagan JR]

Greg, Your symptoms seem to point to the prop. Are you running a 2 blade or 3? I assume 2. Try a X450/3. Many FE boats seems to manage prop walk better with 3 blade props.

I got a 3 blade on mine and when I accelerate for the start it pulls bad right but racing it doesn’t pull.

 

[Greg Stamatis]

Greg,

Sorry i can offer you any advise but i am building exactly the same hull and setup right now. it won't be finished for a few months but would love to hear your feed back on it and setup once you get it dialled in.

Will do. It was a fun build.

 

[Greg Stamatis]

Hi Greg,,you mentioned the prop was polished and balanced.Maybe a silly question, Has the prop been sharpened?,by sharpening the leading edge,gradually thinning/tapering down the back of the prop blade, from around 3/16-1/4" back from the leading edge , a blunt or fat edge will usually cause a prop to walk..Otherwise the boat will probably need some turn fin trimming or there's other alignment issues,, I don't have any experience with these types of boats

The prop has also been sharpened some. Turn fin is square to centerline.

 

[Greg Stamatis]

Thank you all for the great responses. Apologize for not responding sooner. Have been out in the boonies away from i-net.

 

[Greg Stamatis]

Does it pull while at speed or acceleration?

Pulls at speed. Accelerates straight up to 2/3 throttle. Any more throttle and she pulls.

 

[Greg Stamatis]

For what it's worth I've never liked tapered rudders on scale hulls.
I second that

Any suggestions for a good dual pickup parallel rudder?

 

[Greg Stamatis]

It could also be the rudder needs to be readjusted for more left when it's centered. My 2000 Elam requires the rudder right face to be close to parallel to the boats centerline to prevent it from walking. I'm running a two blade Prather stainless prop that's been balanced, sharpened and polished, either a 250 or 255 IIRC

Taking the boat out tomorrow. Will try this. Thank you.

 

[Greg Stamatis]

Greg can you post a pic or two of the transom set up? Does it pull/walk harder when you accelerate vs. at speed? Is the rudder stock length or did you cut any off the bottom? How much of the rudder blade is below the prop centerline? It's possible it's not a prop issue but rather a lack of rudder blade surface area in the water, been there and done that more than once. For what it's worth I've never liked tapered rudders on scale hulls.

The rudder is full length. Will post some pictures, however she's not pretty yet. Sealed with epoxy, not painted yet. Wanted to get some test runs just in case some hull work is needed.

 

[Greg Stamatis]

Yup. To start out I set every boat up no matter what it is with the right side of rudder blade parallel to hull centerline.

Will try that. Thank you. It currently is centered.

 

[shoboat]

Greg,

Change out the tapered rudder and I bet it goes straight.
If the propeller is not thinned properly it could be part of
your problem as well. I would be happy to look at your
propeller if you would like.

Thanks,

Mark Sholund