All,
I haven't got a 222 but I have made a 1/12th scale model DUKW. This was originally fitted with a fore/aft diff and left/right diffs on each axle. I had the same problems with one wheel spining and loss of drive to the other wheels. I think varying oil viscosity works in high speed applications like racing cars but in low speed applications like these military vehicles the effect is limited. I ended up locking all the diffs and haven't had a problem with lots of under steer but gained significant improvement over rough or splippery ground. With its rear wheel steering the 222 model steering should be good even without axle diffs.
If I was to get a 222 I would like to experiment with the two speed transmission to give really good climbing and slow speed performance coupled with a reasonable road speed. I'm not saying that there are any problems with the model as supplied but I just like to fiddle and make a long project out of the build.
222 drive train issues
-
Allan Richards
- Posts: 743
- Joined: Thu Jul 12, 2007 10:34 am
- Location: Kent
- Been liked: 10 times
-
Lawrence Godson
- Posts: 165
- Joined: Thu Jul 12, 2007 7:06 pm
- Location: Westchester, suburb of Chicago, USA
-
Ad Wouterse
- Posts: 292
- Joined: Thu Jul 12, 2007 4:32 pm
- Location: The Netherlands
- Been liked: 2 times
Larry,
The values for the differential fluids are used internationally for RC cars.
The higher the value, the thicker the fluid, the higher the internal friction in the diff, which results in less diffing-out of individual wheels.
The 1000000 value oil Patrick uses (or 100 K as it is mentioned in the car lingo) is very thick. It didn't even know that it excisted, despite many years of big-scale car racing
. It might work on the 222 as an alternative for fixed differentials.
Steam oil is a lubricant used for the steam cylinders on model locomotives. It is water and heat resistant and quite thick.
Patrick has described the proper way to change the differential fluid. You have to disassemble the diff, clean all the parts (spider gears, shafts, washers-where applicable), reassemble the small parts, add the new fluid and finally mount the cap with the big outer gear.
Pay attention to the way all parts are mounted during disassembly and don't loose the little parts.
A nice instruction video can be seen here (kill the sound
).
This concerns a standard diff, there might be some more/less parts in the 222 diff.
The values for the differential fluids are used internationally for RC cars.
The higher the value, the thicker the fluid, the higher the internal friction in the diff, which results in less diffing-out of individual wheels.
The 1000000 value oil Patrick uses (or 100 K as it is mentioned in the car lingo) is very thick. It didn't even know that it excisted, despite many years of big-scale car racing
. It might work on the 222 as an alternative for fixed differentials.Steam oil is a lubricant used for the steam cylinders on model locomotives. It is water and heat resistant and quite thick.
Patrick has described the proper way to change the differential fluid. You have to disassemble the diff, clean all the parts (spider gears, shafts, washers-where applicable), reassemble the small parts, add the new fluid and finally mount the cap with the big outer gear.
Pay attention to the way all parts are mounted during disassembly and don't loose the little parts.
A nice instruction video can be seen here (kill the sound
).This concerns a standard diff, there might be some more/less parts in the 222 diff.
Cheers,
Ad
Ad
-
Alfredo Campanini
- Posts: 104
- Joined: Thu Jul 12, 2007 10:36 am
- Location: PARMA Italy
-
Patrick O'Donnell
- Posts: 90
- Joined: Thu Jul 12, 2007 12:01 pm
Hello All,
Sorry Dave and Alfredo I got it back to front
Ad, you certainly have alot of knowledge about these diffs. and I would like to thank you for all your technical information.
Allan, Yes I think you might be right about the diffs and "tuning" them with oil as even with the stuff I use I can still get diffing-out on wet English lawn grass and when trying to go up a slope diagonally and having one wheel coming off the ground at the top of the slope. I like your idea of a two speed gearbox for climbing as at present I think the 222 is built for speed. How do I fit a two speed gearbox?
Sorry Dave and Alfredo I got it back to front
Ad, you certainly have alot of knowledge about these diffs. and I would like to thank you for all your technical information.
Allan, Yes I think you might be right about the diffs and "tuning" them with oil as even with the stuff I use I can still get diffing-out on wet English lawn grass and when trying to go up a slope diagonally and having one wheel coming off the ground at the top of the slope. I like your idea of a two speed gearbox for climbing as at present I think the 222 is built for speed. How do I fit a two speed gearbox?
Patrick
Rene, "Would you like a ride in my little tank?"
Rene, "Would you like a ride in my little tank?"
-
Ad Wouterse
- Posts: 292
- Joined: Thu Jul 12, 2007 4:32 pm
- Location: The Netherlands
- Been liked: 2 times
Hello Patrick,
A first relatively easy and affordable step to improve the overall performance of the drive train would be to block the central differential. That means that you will still have traction on one axle if one of the wheels on the other axle diffs-out.
I have to sleep on it, but removing the internal gears and mounting a fixed bushing or shaft between the outgoing shafts is the first option that crosses my mind. The other parts of the centre differential can be maintained and no further modifications are required.
As I mentioned earlier, a Torsen differential could be an alternative. As far as I know there is only one company manufactering these for models, Fioroni in Italy. They have an agent in the UK, Horizon Hobby Co : http://www.horizonhobby.co.uk/autoonlin ... meset.html . It might be worth investigating the possibilities, dimensions & prices.
The Torsen differential works the other way around. If one wheels loses traction the power is led to the other wheels.
By only using a Torsen centre differential the result would be the same as with blocking the existing differential.
Using Torsen differentials centre, front and rear would almost be an optimum, for the 222 that is, not for your wallet.
A two speed gearbox is another matter. It will certainly improve torque and scale speed, but I am afraid that it might increase the traction problems. Modifications to the differentials would still be required.
Radical modifications to the 222 would be necessary to accommodate the two speed gearbox, without any guarantee for success.
A first relatively easy and affordable step to improve the overall performance of the drive train would be to block the central differential. That means that you will still have traction on one axle if one of the wheels on the other axle diffs-out.
I have to sleep on it, but removing the internal gears and mounting a fixed bushing or shaft between the outgoing shafts is the first option that crosses my mind. The other parts of the centre differential can be maintained and no further modifications are required.
As I mentioned earlier, a Torsen differential could be an alternative. As far as I know there is only one company manufactering these for models, Fioroni in Italy. They have an agent in the UK, Horizon Hobby Co : http://www.horizonhobby.co.uk/autoonlin ... meset.html . It might be worth investigating the possibilities, dimensions & prices.
The Torsen differential works the other way around. If one wheels loses traction the power is led to the other wheels.
By only using a Torsen centre differential the result would be the same as with blocking the existing differential.
Using Torsen differentials centre, front and rear would almost be an optimum, for the 222 that is, not for your wallet.
A two speed gearbox is another matter. It will certainly improve torque and scale speed, but I am afraid that it might increase the traction problems. Modifications to the differentials would still be required.
Radical modifications to the 222 would be necessary to accommodate the two speed gearbox, without any guarantee for success.
Cheers,
Ad
Ad
-
Armortek
- Site Admin
- Posts: 2892
- Joined: Tue Jul 10, 2007 10:30 am
- Location: Winchester, England
- Been liked: 3480 times
Ad
The 222 uses the same differentials as the Hobao Hyper 7 and Hyper 8 off road nitro powered r/c cars. Upgraded standard differentials and full blown Torsen differentials are readily available. Torsen units are manufactured by Ofna and by other "hop-up" parts suppliers. These units are frequently available on E-bay. Just type in "Hyper 7 diff"
In our tests these differentials did not make a great deal of difference. I believe this is because we run at to slow a rotational speed for the Torsen gears to work effectively. Locking the centre diff does help with off road performance but does stress the drive train if you try doing high speed tight turns on tarmac.
Regards
Mark
The 222 uses the same differentials as the Hobao Hyper 7 and Hyper 8 off road nitro powered r/c cars. Upgraded standard differentials and full blown Torsen differentials are readily available. Torsen units are manufactured by Ofna and by other "hop-up" parts suppliers. These units are frequently available on E-bay. Just type in "Hyper 7 diff"
In our tests these differentials did not make a great deal of difference. I believe this is because we run at to slow a rotational speed for the Torsen gears to work effectively. Locking the centre diff does help with off road performance but does stress the drive train if you try doing high speed tight turns on tarmac.
Regards
Mark
Armortek
-
Alfredo Campanini
- Posts: 104
- Joined: Thu Jul 12, 2007 10:36 am
- Location: PARMA Italy
Hi all,
I have just called the Fioroni factory, regarding their Torsen diff.
They have answered that it is not suitable, for two reasons: first, as Mark has said here upon, the Torsen can work only at an hight speed, second their Torsen is suitable for RC cars with a weight of 4-5 Kg. approximately 1/15 of how the 222 is and it would be destroyed in little time.
I have just called the Fioroni factory, regarding their Torsen diff.
They have answered that it is not suitable, for two reasons: first, as Mark has said here upon, the Torsen can work only at an hight speed, second their Torsen is suitable for RC cars with a weight of 4-5 Kg. approximately 1/15 of how the 222 is and it would be destroyed in little time.
Alfredo
-
Ad Wouterse
- Posts: 292
- Joined: Thu Jul 12, 2007 4:32 pm
- Location: The Netherlands
- Been liked: 2 times
Mark and Alfredo,
Thank you very much for your combined input. It clearly narrows down our choices.
As it is unlikely that we will be doing any high speed tight turns on the tarmac with the 222, locking the centre diff still looks promissing to me. Just to be on the safe side a spring loaded locking device, something similar to a servo saver, might do the job.
What are your thoughts about that guys ?
Thank you very much for your combined input. It clearly narrows down our choices.
As it is unlikely that we will be doing any high speed tight turns on the tarmac with the 222, locking the centre diff still looks promissing to me. Just to be on the safe side a spring loaded locking device, something similar to a servo saver, might do the job.
What are your thoughts about that guys ?
Cheers,
Ad
Ad
-
Adrian Harris
- Posts: 5073
- Joined: Thu Jul 12, 2007 10:46 pm
- Location: Berkshire (UK)
- Has liked: 1419 times
- Been liked: 1594 times
I have spent some time looking into this, having seen a 222 get stuck with a wheel in the air at Duxford earlier this summer. I'm nowhere near even having a running chassis so I'll leave the experimentation up to the runners 
The thickest diff oil I could find was 300K, from a company called Team Associated (http://www.teamassociated.com). They refer to it as gear diff lube.
Other than Milliput, this is the thickest filler for the diffs I could find.
Adrian.
The thickest diff oil I could find was 300K, from a company called Team Associated (http://www.teamassociated.com). They refer to it as gear diff lube.
Other than Milliput, this is the thickest filler for the diffs I could find.
Adrian.
-
Allan Richards
- Posts: 743
- Joined: Thu Jul 12, 2007 10:34 am
- Location: Kent
- Been liked: 10 times
Ad / Patrick,
I think my fears over changing diff oil has been highlighted in that the low speed and high torque will reduce the effectiveness of doing this. The Torsen diff sounded hopefull but again this appears to be a high speed device. Marks comments about locking the diffs causing extra stress on the drivetrain is also true as it will be necessary for the wheels to occasionally slip if wind up or tight cornering on grippy surfaces occurs. I don't see a simple solution, but the ideal solution would be to lock the diffs when going slowly over slippery ground or climbing etc. Putting milliput in the diffs would lock them but it woud be a crude one way solution.
As for two speed transmissions this again woud not be easy to do and would require a good workshop facility and competence to design and fit. I wod start searching for a transmission with HPC gears or the Robot Wars sites.
I think my fears over changing diff oil has been highlighted in that the low speed and high torque will reduce the effectiveness of doing this. The Torsen diff sounded hopefull but again this appears to be a high speed device. Marks comments about locking the diffs causing extra stress on the drivetrain is also true as it will be necessary for the wheels to occasionally slip if wind up or tight cornering on grippy surfaces occurs. I don't see a simple solution, but the ideal solution would be to lock the diffs when going slowly over slippery ground or climbing etc. Putting milliput in the diffs would lock them but it woud be a crude one way solution.
As for two speed transmissions this again woud not be easy to do and would require a good workshop facility and competence to design and fit. I wod start searching for a transmission with HPC gears or the Robot Wars sites.
Allan Richards
-
Alvin McCall
- Posts: 16
- Joined: Sat Jul 14, 2007 1:35 pm
- Location: katy Texas
- Been liked: 1 time
One idea would be to ask Armortek who the diff manufacture is and if it a sealed unit. If its sealed then different viscosity silicone oils could be used, the silicone ranges from 1000 wt to 50,000 wt several rc sites give a lot of info on tuning the diff with different wt oils, 7000 wt front diff, 10,000 rear, various wt’s for terrain the model is run on.
During a turn the inside wheel travels a shorter distance, and therefore can spin at a slower speed than the outside wheel, which has to go farther. Since both are on the same car, it would be difficult for that to happen without the invention of the differential. A diff allows one wheel to spin faster than the other, which improves handling in corners. In four-wheel-drive vehicles a third diff is used in the center, to allow the front and rear wheels to travel at different speeds as well.
Without any friction with the ground, the system would transfer power to the wheel with the least resistance, and result in a loss of speed in a corner and over bumps. We've all seen Subaru commercials explaining that having power to the wheels that grip (have the most resistance) improves handling. The way that is controlled in RC vehicles is with silicone diff fluid (and in some diffs thick grease). This acts as a "limited slip" differential, and allows the wheels to spin at different speeds - but maintain power delivery to the wheels with more traction. The thicker the oil, the closer to a solid axle the diff acts, and the thinner the closer to an open differential it is.
It is by controlling the diffs with fluid viscosity that we alter the handling characteristics of a car for faster acceleration or more steering
During a turn the inside wheel travels a shorter distance, and therefore can spin at a slower speed than the outside wheel, which has to go farther. Since both are on the same car, it would be difficult for that to happen without the invention of the differential. A diff allows one wheel to spin faster than the other, which improves handling in corners. In four-wheel-drive vehicles a third diff is used in the center, to allow the front and rear wheels to travel at different speeds as well.
Without any friction with the ground, the system would transfer power to the wheel with the least resistance, and result in a loss of speed in a corner and over bumps. We've all seen Subaru commercials explaining that having power to the wheels that grip (have the most resistance) improves handling. The way that is controlled in RC vehicles is with silicone diff fluid (and in some diffs thick grease). This acts as a "limited slip" differential, and allows the wheels to spin at different speeds - but maintain power delivery to the wheels with more traction. The thicker the oil, the closer to a solid axle the diff acts, and the thinner the closer to an open differential it is.
It is by controlling the diffs with fluid viscosity that we alter the handling characteristics of a car for faster acceleration or more steering
-
Armortek
- Site Admin
- Posts: 2892
- Joined: Tue Jul 10, 2007 10:30 am
- Location: Winchester, England
- Been liked: 3480 times
Hi Alvin
Mark is not in the office at the moment however I beleive this information is what you need:
'The 222 uses the same differentials as the Hobao Hyper 7 and Hyper 8 off road nitro powered r/c cars. Upgraded standard differentials and full blown Torsen differentials are readily available. Torsen units are manufactured by Ofna and by other "hop-up" parts suppliers. These units are frequently available on E-bay. Just type in "Hyper 7 diff" ,
and they are sealed units
Hope this helps
Gill
Mark is not in the office at the moment however I beleive this information is what you need:
'The 222 uses the same differentials as the Hobao Hyper 7 and Hyper 8 off road nitro powered r/c cars. Upgraded standard differentials and full blown Torsen differentials are readily available. Torsen units are manufactured by Ofna and by other "hop-up" parts suppliers. These units are frequently available on E-bay. Just type in "Hyper 7 diff" ,
and they are sealed units
Hope this helps
Gill
Armortek
-
Patrick O'Donnell
- Posts: 90
- Joined: Thu Jul 12, 2007 12:01 pm
I think we are getting away from the challenge of solving the diffing out problem. I think the diff. is not the problem. The 222 loses grip, I think, because one of the wheels can come off the ground because either the springs are two stiff or the suspension travel is not enough. I have filed-out the holes which the drive axles go through to give the maximum scale suspension movement available and this has improved cross country operations, but it still sometimes raises a wheel off the ground causing diffing out. This I can live with and being aware it can happen might improve my driving.
The 222 is a scale 1/6 model with scale suspension and scale springs traveling over 1/1 full sized ground and is not a 1/8 buggy or trucky with over length soft springs and super-extended suspension.
I wonder if the 222 could have slightly less stiffer springs there might be less chance of diffing-out?
The 222 is a scale 1/6 model with scale suspension and scale springs traveling over 1/1 full sized ground and is not a 1/8 buggy or trucky with over length soft springs and super-extended suspension.
I wonder if the 222 could have slightly less stiffer springs there might be less chance of diffing-out?
Patrick
Rene, "Would you like a ride in my little tank?"
Rene, "Would you like a ride in my little tank?"
-
Ad Wouterse
- Posts: 292
- Joined: Thu Jul 12, 2007 4:32 pm
- Location: The Netherlands
- Been liked: 2 times
Hello Patrick,
Give up on the diffs ? No way. If I can lay my hands on the proper friction material, I will attempt to modify a spare centre diff into a locked version with an adjustable overload protection. It looks allright on the drawing board
The modification of the holes for the drive shafts is a good way to increase the maximum wheel travel. The only limitation left then is the maximum allowable length of the bolts that keep the upper and lower wishbones and the springs together. The springs should keep in contact with both wishbones and the ground clearance should be observed at the same time.
Finding alternative springs is not as easy as it sounds. In practice it is a balancing act between a smooth off road ride and sufficient ground contact. Softer springs will allow easier crossing of bumps, harder springs will ensure good ground contact. I think that Armortek has done a good job on finding the best compromise.
Give up on the diffs ? No way. If I can lay my hands on the proper friction material, I will attempt to modify a spare centre diff into a locked version with an adjustable overload protection. It looks allright on the drawing board
The modification of the holes for the drive shafts is a good way to increase the maximum wheel travel. The only limitation left then is the maximum allowable length of the bolts that keep the upper and lower wishbones and the springs together. The springs should keep in contact with both wishbones and the ground clearance should be observed at the same time.
Finding alternative springs is not as easy as it sounds. In practice it is a balancing act between a smooth off road ride and sufficient ground contact. Softer springs will allow easier crossing of bumps, harder springs will ensure good ground contact. I think that Armortek has done a good job on finding the best compromise.
Cheers,
Ad
Ad