How to battle the infamous mono single torque roll?

[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.



.

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.