pic: Frog Force 503 Omnitank Drivetrain (rAC)

[Bryce Paputa]

Originally Posted by Electronica1

The reason I bring this up is that every iteration of the rear drop (my name for this style) hybrid drive I have seen has the wheels all geared the same and has a transmission to switch speeds. I believe that in a pushing match/change of direction the piston would give a little and all the wheels would be on the ground.



Please tell me you aren't using 25 chain for this. From what you described, you might run into the issues the mk1 version of my teams octocanum had. It worked fine in the shop, but in a competition setting, the stresses on the 25 chain from shifting caused our chain to stretch every match, we later found that during defense it could even shred the chain. We tried switching to 35 chain that summer and haven't run into the issue since. If your chain is getting loose now, it won't stand a chance at competition.

We are using 25 chain, it isn't getting loose, it began loose. The tension on the chain doesn't change when shifting with this setup. Once we get the next iteration of this built with the initial chain tension issues fixed we'll be able to test if the 25 is sufficient or not, but teams have shown that it is (118).

Unrelated, here is the CAD: https://drive.google.com/file/d/0B0s...ew?usp=sharing