[rhuggins42]

My group is playing around with building a screw vehicle similar to the Fordson snow motor (see http://www.youtube.com/watch?v=Jj7ZugSMrHw ) and think we will do it electrically, perhaps with fork lift motors. ANybody have any advice. Suspect that the device will need low RMP, high torque. Any advantage between AC or DC forklift motors??

 

[Woodsmith]

That was a great video, shame you don't have an original vehicle but, hey, you are building one!
Welcome to the forum.

The easiest and cheapest solution would be to use two matching fork lift DC motors, one for each screw with a controller each and a 'WIGWAG' joystick control with forward/reverse built in. Each screw can then be controlled by a joy stick each and you can have independent speed and direction for forwards, backwards, turning (wide and on the spot) and going sideways.

It will be good to see how this develops. Any photos or plans we can see?

Also what are you planning to use it for and for what speed and range?

 

[rhuggins42]

this is really great input. Can you make any suggestions about what manufacturer of DC Motors might be best. i anticipate making my own motor controllers, and since it may be going down narrow paths, some form of articulation might be the way to go.

this is meant to be an off-road vehicle for mining exploration applications. it must cross water, mud and broken ice. we are envisioning motors on both the front and back of each screw, for redundancy. right now we are in the materials testing phase for the threads : a doped UHMW plastic is a good possibility. pictures soon.

speed: slow. distance: all day. ANY suggestions or comments, plelase!

 

[JRP3]

I think AC or Sepex would be easier to reverse than series DC.

 

[mizlplix]

Your thread size will dictate the vehicle weight, as you specified "float" as a criteria. The threads need to be foamed solid with polyurethane to be rigid and light weight.

OK, another criteria was to articulate, necessitating four threads, each with it's own motor and controller. I would forget redundancy as an electric motor is so very reliable. Just carry a spare with a spare controller.

Articulation can be done electric or hydraulic. Each requires power....Battery power....I would opt for a pair of electric screw actuators for articulation. It would not be needed except for extreme tight corners. The threads would be reversible and speed variable for most general steering. Throw in an axial pivot also, as each vehicle half need not be on the same plane.

Lastly, LOTS and lots of Batteries. LiFePo4, nothing else will even come close to floating.

Then how do you recharge it at days end when you are in the out-back?

Good luck, it is an ambitious project, but fascinating.

Miz

 

[Salty9]

I would make the threads replaceable in sections as they will be subjected to much greater wear than the cylinders.