How to battle the infamous mono single torque roll?

[Hotrods]

Anyone out there have any tricks up their sleeve to battle the torque roll on single motor mono? I have tried offset weight to the starboard side and small props. Any suggestions?

This a sport boat let that be clear---
44 step bottom mono
5692 1090kv
10-12S
SF240
been running X447 round ear

[CraigP]

I run the outside corner of my trim plate down lower. The plates are not square across the bottom. This is a much smaller boat, 29”, so not sure how effective it will be with a big boy. But worth a try, I would suspect...

[fweasel]

Offsetting the propshaft to the right of the keel line will help, but you'll need to redrill the transom or install a wet well to accomplish that. Too large of a diameter prop, or dull blades can do it too.

[Fluid]

None of the big monos in my clubs exhibit much if any torque roll, it may be a characteristic of the OP’s hull. How far over does the hull lean? Does it exhibit chine walk too?

Lowering the trim tab on the right side could help. How about a few pics of the transom.


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[rol243]

also a nice sharp and well balanced prop does help.

[martin]

I run the outside corner of my trim plate down lower. The plates are not square across the bottom. This is a much smaller boat, 29”, so not sure how effective it will be with a big boy. But worth a try, I would suspect...

Craig is you right hand trim tab fitted lower down the transom than the inner edge of that tab or is it just lowered by the adjusting screw pushing the rear tip lower.

[CraigP]

The trim is mounted square across the transom. Yes, it’s the adjusting screw that skews it. It is not lower than the back of the transom, that would create drag running straight. This is an old K Racing Runabout trick... The plate was called a Cavitation Plate, articulated with a foot pedal by the driver. Those boats turned left, so they would set the static turnbuckles to bias the left outside edge lower to help hold the boat up in the turns and help reduce catching a chine, which is a bad thing!

[Hotrods]

None of the big monos in my clubs exhibit much if any torque roll, it may be a characteristic of the OP’s hull. How far over does the hull lean? Does it exhibit chine walk too?

Lowering the trim tab on the right side could help. How about a few pics of the transom.


.

IMG_2523.jpg

CG is at 30%, yes it chine walks, it will lay on the port side at full throttle, now I do realize that I have a ton of power in a boat of this size and this could be a lot of it. Just trying to tune it out.

[martin]

That looks to be a very narrow hull for a 44" boat looking at the layout of the hardware or is the picture deceiving.

[CraigP]

Ahhh, I see... The trim only has a single screw adjustment... seems to boat could use a longer trim, what do you guys think? For me, I like them moved out, closer to the sides... Can get more turn reaction there.

[Hotrods]

That looks to be a very narrow hull for a 44" boat looking at the layout of the hardware or is the picture deceiving.

I do have a large 1/4 inch drive and large rudder as well, but the hull is 9" wide

[CraigP]

IMG_2523.jpg

CG is at 30%, yes it chine walks, it will lay on the port side at full throttle, now I do realize that I have a ton of power in a boat of this size and this could be a lot of it. Just trying to tune it out.

That’s interesting, prop torque should raise the port side. You got a big motor, but motor torque only reacts on the boat during accelerations mostly, whereas prop torque is constant, well, as long as the prop is in the water!

Does the boat rest on a table pretty evenly on its keel? It won’t stay there, but you can tell if is side weighted. I had to add ballast to the port to compensate for the servo/rudder gear on the right. If it’s got a weight bias in it, then you get all kinds of dynamic reactions, like prop torque, interacting with the static weight distribution. Funny things can happen... CG sounds about right to me.

[rol243]

the total drive line from motor / shaft / stinger should be moved over to the Starboard Side by up to 1/4 inch. this will make life alot harder for the prop torque to lift the left Port Side. lowering the trim tab on Port side will help but will also add drag to the hull. the prop looks to be high in Pitch so maybe you could also try a prop with less pitch and see how she goes.

[Hotrods]

That is what I thought as well on the torque, this could be more of a prop rotation issue as well. Yes all the steps on the keel touch on a flat surface.

[Hotrods]

the total drive line from motor / shaft / stinger should be moved over to the Starboard Side by up to 1/4 inch. this will make life alot harder for the prop torque to lift the left Port Side. lowering the trim tab on Port side will help but will also add drag to the hull. the prop looks to be high in Pitch so maybe you could also try a prop with less pitch and see how she goes.

Yes I will be trying some 14 series props this weekend, any other suggestions on props? The prop is the picture is a stainless 235 it created a lot of transom lift in my opinion

[martin]

That is an extremely narrow hull @ 9" wide for a 44" long hull + a big powerfull motor producing lots of torque, I have a 41.5" mono that is 12" wide. Most 30 - 32" monos are 9" wide running much smaller less powerfull motors.

[martin]

Are you actually running 10s - 12s on this motor if so your getting 40000rpm unloaded on 10s & 48000rpm unloaded on 12s.

[CraigP]

For comparison, my DF29 is 9.75” at the transom on 29” Hull Length, not including the stinger... That’s a ratio of 0.336 Martin’s boat is 0.29

The Op’s Boat is 0.205! That baby is a torpedo! You might have to live with some handling issues or run the boat slower. Seems any water/torque disturbance will set it to rockin’

[Hotrods]

Are you actually running 10s - 12s on this motor if so your getting 40000rpm unloaded on 10s & 48000rpm unloaded on 12s.

Lol, yes, and it is a blast to run, very exciting, Temps are in the high 90's with a X447 with the tips knocked off.

[Hotrods]

For comparison, my DF29 is 9.75” at the transom on 29” Hull Length, not including the stinger... That’s a ratio of 0.336 Martin’s boat is 0.29

The Op’s Boat is 0.205! That baby is a torpedo! You might have to live with some handling issues or run the boat slower. Seems any water/torque disturbance will set it to rockin’

https://www.youtube.com/watch?v=VG6yG8h2mdo

[Fluid]

Well, a hull of this length with such a narrow beam is going to lean over with any powerful setup. If it exhibits chine walk then the strut probably needs to be raised, how much depends but at least 1/4”. This will settle the hull and prevent it having to balance on the sharp keel - which exacerbates both torque roll and chine walk. Too much speed for the specific hull design can cause uncurable problems.

Moving the strut to the right should not be necessary, I’ve seen too many big monos run just great with a centered strut. Given the nature of a narrow hull, it may always lean to some extent, but the chine walk may be cured.

BTW, running an R/C boat with a person on the same water is very dangerous and will void any insurance. Flat stupid, sorry.



.

[Hotrods]

Well, a hull of this length with such a narrow beam is going to lean over with any powerful setup. If it exhibits chine walk then the strut probably needs to be raised, how much depends but at least 1/4”. This will settle the hull and prevent it having to balance on the sharp keel - which exacerbates both torque roll and chine walk. Too much speed for the specific hull design can cause uncurable problems.

Moving the strut to the right should not be necessary, I’ve seen too many big monos run just great with a centered strut. Given the nature of a narrow hull, it may always lean to some extent, but the chine walk may be cured.



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That is what I was thinking as well. Much appreciated.

[rol243]

i have the big Deltaforce 53 inch mono and due to the large prop it runs , the strut had to be offset 3/16 inch as i didn,t want to lower a tab to create extra hull drag. some monos don,t need strut offsets but some do i have found. lowering prop pitch and giving a larger diameter does work well. Hotrods, the Octura 235 is not a lifting prop so maybe your g.o.g is nose heavy abit.

[kfxguy]

Anyone out there have any tricks up their sleeve to battle the torque roll on single motor mono? I have tried offset weight to the starboard side and small props. Any suggestions?

This a sport boat let that be clear---
44 step bottom mono
5692 1090kv
10-12S
SF240
been running X447 round ear

Well what’s the inside of the boat look like? Reason I ask is you may have it way off balance. If you do then that would cause issues. The prop you have shouldn’t be causing you issues unless it’s not sharp, from the looks of it, it looks pretty thick on the leading (cutting) edge. If that’s the case then that’s definitely an issue. It also appears that your shingle is mounted too low. If the prop is too deep in the water that will cause it to roll. You need to concentrate your main weight towards the center of the boat. On a mono I don’t like to counter weigh it to counter roll, lower center of gravity seems to work better in my experience.

Something else that will cause instability is if the rudder is too narrow or too short or it has slack or if the steeering rod isn’t thick or rigid enough to keep the rudder in control.

I’d also imagine if the motor is mounted more flat in the hull vs at an angle that may amplify torque roll.

Most of the time is just the prop is too deep and if you have a narrow hull then there’s a chance it sits lower in the water at speed because of its lesser width. Just my .02



Edit. I just looked at your pic again. My suspect is your rudder is at least 1” too short. It’s hella short. That will definitely cause it to roll. No doubt about that. I know you’ll lose a mph or two but you have to decide what’s more important. You can always pick it back up by optimizing things. You really need to move on from octura props and try some abc props, I’ve found that the equivalent similar prop in an abc vs octura, it’s about 8-10mph faster.

[fweasel]

I'm stumped that he says the hull is rolling to the left/port side which in my mind, has nothing to do with the prop/motor since they would produce roll in the opposite direction.

[rol243]

thats very true i didn,t realize it was left and not right rolling.

[Hotrods]

Yes that is why I have this post, it rolls to the port side. And I have three different lengths of rudders on it. It’s not the rudder. I am back to stock length now on the rudder. All weight is centered and low as possible except for the esc being on the starboard side now.

I'm stumped that he says the hull is rolling to the left/port side which in my mind, has nothing to do with the prop/motor since they would produce roll in the opposite direction.

[Hotrods]

65732984-91FD-4AB1-B880-5C2E125B941A.jpg here is a pic when I had the ESC on the port side

Yes that is why I have this post, it rolls to the port side. And I have three different lengths of rudders on it. It’s not the rudder. I am back to stock length now on the rudder. All weight is centered and low as possible except for the esc being on the starboard side now.

[Hotrods]

That is an extremely narrow hull @ 9" wide for a 44" long hull + a big powerfull motor producing lots of torque, I have a 41.5" mono that is 12" wide. Most 30 - 32" monos are 9" wide running much smaller less powerfull motors.

It is 39.5 running surface with a 4” overhang

[Hotrods]

What Abc props for a mono with this kind of RPM?

Well what’s the inside of the boat look like? Reason I ask is you may have it way off balance. If you do then that would cause issues. The prop you have shouldn’t be causing you issues unless it’s not sharp, from the looks of it, it looks pretty thick on the leading (cutting) edge. If that’s the case then that’s definitely an issue. It also appears that your shingle is mounted too low. If the prop is too deep in the water that will cause it to roll. You need to concentrate your main weight towards the center of the boat. On a mono I don’t like to counter weigh it to counter roll, lower center of gravity seems to work better in my experience.

Something else that will cause instability is if the rudder is too narrow or too short or it has slack or if the steeering rod isn’t thick or rigid enough to keep the rudder in control.

I’d also imagine if the motor is mounted more flat in the hull vs at an angle that may amplify torque roll.

Most of the time is just the prop is too deep and if you have a narrow hull then there’s a chance it sits lower in the water at speed because of its lesser width. Just my .02



Edit. I just looked at your pic again. My suspect is your rudder is at least 1” too short. It’s hella short. That will definitely cause it to roll. No doubt about that. I know you’ll lose a mph or two but you have to decide what’s more important. You can always pick it back up by optimizing things. You really need to move on from octura props and try some abc props, I’ve found that the equivalent similar prop in an abc vs octura, it’s about 8-10mph faster.