Will it remove torque twist... an extra gear added to one SCX10 type gearbox output?

[Tommygunn]

As the title says, will having an extra drive gear on one of the outputs(see photo), allowing the two prop shafts to rotate in opposite directions, completely or partially reduce torque twist/body roll under power?

 

Cheers,
Tom.

 

 

Edited May 7, 2020 by Tommygunn

[jjh23]

Not sure I’m missing something here but the car wouldn’t work if the shafts were moving in opposite directions??

[stimpy]

Moaning!

Righto, had to do a bit of remembering to answer in part this!

 

You do not state what rig you have but here is my generic answer...

 

So, an extra gear won’t do anything by itself but yes you are right opposing driveshaft rotations will help. For this you need an axle that can be flipped . 
 

Other things that can help:

 

1. If it is an AX based tranny you can mirror the set up to bring the motor forward facing which helps with weighting. ( Do the google search - all over RCCrawler.com)

2. 4 link set ups with upper links close to the mid axle line and opposing triangulation between upper and lowers ( there are other small details).

3. Overdrive / Underdrive gears.

 

Quick fixes:

1. Forward weight biasing.

2. Weighting at hubs.

3. Mess about with shock oil / springs and preload settings. ( this does however mean it will not react in a neutral way in other situations). 

Goodluck! 

[Tommygunn]

Yes,  the shaft rotation has already been accounted for, so some modification of the opposite side of one of the pumpkins will be in order.

 

The truck is an SCX10 clone:

 

 

By an extra gear, I meant, so as to impart an opposite rotation for one of the prop shafts, as per the design of the gearbox above.

 

I already tried flipping the gearbox around a 180(can't remember what impact it made on torque twist, don't think it was much) but I experienced a strange phenomenon which I never got back to resolving and have just remembered:

 

 

Also, I have loaded the shock springs to about twice the tension on the one side to try and counter the effect.

 

Cheers,

Tom.

Edited May 8, 2020 by Tommygunn

[stimpy]

So, from the pic you have posted I have some points of note:

 

1. Your transmission has not been mirrored nor rotated.

2. Your biggest weight - the battery - is at the back.

3. You could angle your front shocks back a little in general.

3. I can see no weighting. 
 

Nice looking chassis mind 👍 

[Andy-Roo]

Is there a reason why you don’t have sliders/chassis plates either side?  With sliders in place you can mount your ESC/RX on one side, or other, and mount the battery at the front.  
 

[Tommygunn]

That's an early photo of mine for model reference, see below for the latest.

 

I might experiment with the rotation of the gearbox again in the future. I'll shift the top of the shocks further inboard and dial back the spring tension a little, or a combination thereof, and see how it fairs. I'll leave the extra weighting for now but I have considered some lead 'ingots' in the past, specifically up front mounted on the bumber.

 

Tom.

 

 

 

 

Edited May 8, 2020 by Tommygunn
Photo size

[Tommygunn]

Andy,

It didn't come with them but you can see from the above photo, just taken, that I have done my best as is.

 

Tom.

[stimpy]

Looking much better there. Need to double check the tranny mirror - remind me which wheel is lifting on the front?

 

Re the battery, if you can reposition it so it sits longitudinally towards the front that will be much better ... 

 

Sonr bother with ingots in the bumper. Bottom line you want what weight you have to have near the front then any extra much lower - hubs if possible else wheels ... 

 

Borh front and rear shocks angle in towards skid direction , will soften initial small bump movement  but offer more support on climbs ... 

[Tommygunn]

I received my gearbox  a week or so ago and I have installed, tested it and it works perfectly. Also flipped and tapped the rear axle.

 

I should clarify that it was not an issue of, for instance, one of the front wheels lifting under torque when on a steep climb. I wanted a gearbox with opposing outputs to prevent the 'equal and opposite' reaction of the body rolling in one direction while the drive train was rotating in the other, and this would happen on the flat, when accelerating and low to high speeds.

 

It worked! The body stays upright and there is no body roll evident at all.

 

As a side note, I climbed a children's slide (45 degrees?) with no effort whatsoever and zero body roll or lift of any axle.

 

Very happy.

Tom.

 

 

Edited October 29, 2020 by Tommygunn

[Tommygunn]

Stimpy,

No room under the body with this 3S 5000mah pack, or even one of my 2S packs.

 

Tom.

[stimpy]

Looking much better Tommy and I’m glad it has sorted your issues out 👍.

 

With regards the front mounted battery, have a look at scx10ii pics and you’ll see what we mean.... 

 

but glad you are sorted! 

[Tommygunn]

Stimpy,

The 5000mah 2 and 3S packs I use are way too big to fit in any other orientation when the body is on. To have the battery front to back I would have to cut out the Jeeps front firewall, dash and some of the seating.

For now I'm perfectly content.

 

Tom.