Halftrack steering questions
Posted: Tue Oct 15, 2019 10:57 pm
I would like to try and build a German sWs halftrack, and am having trouble trying to figure out how to make it steer. I can only think of a couple of ways to do it.
1) The easiest way is to use a gearbox that drives both tracks at the same time, and relies on the front tires for steering. This is how the Torro M16 US halftrack works, but the longer & heavier track runs of the sWs would tend to drive it in a straight line, no matter which way the front wheels point. (I have found this out from locking the differentials on multi-axle 1/14 scale trucks. Without a powered front axle to help pull it through a turn, it just wants to go in a straight line).
2) Although I can use a separate gearbox for each track and a simple Tamiya DMD control unit like the T-01 to control them; that doesn't allow for me to somehow synchronize the movement of a servo that controls the front axle steering. (Because the DMD unit plugs into the rudder and throttle channels of the receiver, and a steering servo would just be a third channel that doesn't relate to the DMD). I know that people have used a Y-harness to make two separate servos function together, but I don't know how a Y-harness would connect to both the DMD and the servo without screwing up the DMD.
3) The real things used a system whereby when the steering wheel was turned more than 15 degrees, it would interact with the braking system and cause that side's track to slow; allowing the non-retarded track to help steer the vehicle. So, the most prototypical thing would be to use one motor driving an axle with a differential, and using some kind of braking system that works in concert with the front axle. And, while that might be the coolest thing to have; trying to actually make something like this work would probably drive me to drink!
Any thoughts (or experience) you folks have will be greatly appreciated. (I went through all of the electronic threads and couldn't find anything similar). Thank you. -Mike
1) The easiest way is to use a gearbox that drives both tracks at the same time, and relies on the front tires for steering. This is how the Torro M16 US halftrack works, but the longer & heavier track runs of the sWs would tend to drive it in a straight line, no matter which way the front wheels point. (I have found this out from locking the differentials on multi-axle 1/14 scale trucks. Without a powered front axle to help pull it through a turn, it just wants to go in a straight line).
2) Although I can use a separate gearbox for each track and a simple Tamiya DMD control unit like the T-01 to control them; that doesn't allow for me to somehow synchronize the movement of a servo that controls the front axle steering. (Because the DMD unit plugs into the rudder and throttle channels of the receiver, and a steering servo would just be a third channel that doesn't relate to the DMD). I know that people have used a Y-harness to make two separate servos function together, but I don't know how a Y-harness would connect to both the DMD and the servo without screwing up the DMD.
3) The real things used a system whereby when the steering wheel was turned more than 15 degrees, it would interact with the braking system and cause that side's track to slow; allowing the non-retarded track to help steer the vehicle. So, the most prototypical thing would be to use one motor driving an axle with a differential, and using some kind of braking system that works in concert with the front axle. And, while that might be the coolest thing to have; trying to actually make something like this work would probably drive me to drink!
Any thoughts (or experience) you folks have will be greatly appreciated. (I went through all of the electronic threads and couldn't find anything similar). Thank you. -Mike