Having finally got the 222 to a rolling chassis and running on home built electronics, I was, like many disappointed with the off road performance, in fact the on road wasn't good either. The slightest obstacle and came to a stop with one wheel off the ground.
Investigation shows this to be a combination of things. At this point I had filled the diff’s with steam oil and this did provide quite a bit of torque, certainly enough to cope with flat ground.
The big problem was the axles were not articulating and consequently one wheel looses contact, coupled with the hard rubber tyres which unlike the real thing does not “give” enough to maintain contact. We are now up against some of the aspects and physical properties that do not scale very well.
Having read the forum comments on the 222 drive problems, I decided to look at the spring and the suspension travel.
I made dummy telescopic shock absorbers in place of the standard bolt that runs down the spring centre. They give more travel and can be fine tuned and locked with an opposing grub screw. Without enlarging the drive shaft holes in the chassis it gives a total of 19mm of wheel lift on a flat level surface. Reluctant to start carving the chassis about I decided to go with this.
I agree with others comments the springs do not perform to scale. Had an look around for a softer spring to try, most coil, wire size combinations did not look right.
I made a test rig to clock the spring action before attempting any mods, the test was only for static loading but it gives an indication of what the spring will do. Most coil springs will produce fairly linear results with this test.
A common temper for spring material is in the 600+deg C range (dark blue to dark green ).
Clock springs which have to be more compliant are tempered at 530 Deg C.
After much deliberation I re-tempered a spring to 535 deg C ( done in a kiln ) and compared test results. More give and a slightly softer spring, the down side is when completely compressed fully, some 3/32” of permanent set was measured. After more deliberation I decided this was acceptable in order to have a more realistic spring and all the springs have been re- tempered.
There diff’s have been filled with 3000 silicone oil and the 222 now will slowly traverse the garden hose without “diffing out”
Now to fit the body