Four-wheel maneuverability

[chornedsnorkack]

Cars usually have wheels that can roll forward or back, and turn only a limited angle from there. They are controlled by steering wheel for turning and by gear lever for reversing.

What kind of compromises in steering and transmission might make a four-wheeled contraption capable of being driven directly crabwise? And what input devices could a driver use to drive such a car?

[ShaneG_old]

If I'm not mistaken,(which I may be), I think the Early Mitsubishi 3000gt vr4's used a four wheel steering for higher performace driving as an assist because it was such a heavy pig.

Also, I think a few Skylines have had a similar feature.

But the point is, at some point during a highspeed turn, the car would indeed be driving in a 'crablike' manner.

[beaky]

IMHO, only thing that would really be good for is parking.  You could vastly reduce the turn radius, but how fast could one really take a corner with a car like that?

[chornedsnorkack]

[quote]IMHO, only thing that would really be good for is parking.

[scalper_old]

[quote]IMHO, only thing that would really be good for is parking.

[U4EA]

I wish I had a dollar for everytime I got caught "high-speed" crabbing around the bomb dump in a Coleman Tug!

The Colemans were able to do a 180 within their own length.

A time or two a month there'd come a call over the radio from the head-shed tower,  "Echo 10!  Your shop chief would like to speak to you in his office."

[chornedsnorkack]

I wish I had a dollar for everytime I got caught "high-speed" crabbing around the bomb dump in a Coleman Tug!

The Colemans were able to do a 180 within their own length.

Does it have rounded front and back end then?

[U4EA]

Nope!

[chornedsnorkack]

[quote]Nope!

[U4EA]

Uhhhhhhh, could be cause its turn radius, when both the front and rear steer is at full limit, is a foot or so shy of it's length.

Full steer puts the tires at about a 60 angle from centered.....when the fronts are one way and the rears are another, the tug will crab just a tad shy of dead-a$$ sideways!

I'm no geometry expert so I can't logically discuss the specifics.  All I can say is we never actually got out a tape measure and chalkline.....but I almost squished my boss one time by quick-turnin' as he stood next to the driver side door....with the rear bumper!

[chornedsnorkack]

On usual cars, turning steering wheel turns both axles, right?

How are the two axles separately controlled on a Coleman tug?

[expat]

On usual cars, turning steering wheel turns both axles, right?

How are the two axles separately controlled on a Coleman tug?

Same as any tug, Coleman, Schopff, Fresia, clever hydraulics and a computer or two if it is not older than 10 years or so.

Matt

[chornedsnorkack]

On usual cars, turning steering wheel turns both axles, right?

How are the two axles separately controlled on a Coleman tug?

Same as any tug, Coleman, Schopff, Fresia, clever hydraulics and a computer or two if it is not older than 10 years or so.

Matt

I have only seen outside pictures of Coleman tugs. What is the inside like, what kind of driver controls allow 4 wheel steering to be separately controlled?

[expat]

On usual cars, turning steering wheel turns both axles, right?

How are the two axles separately controlled on a Coleman tug?

Same as any tug, Coleman, Schopff, Fresia, clever hydraulics and a computer or two if it is not older than 10 years or so.

Matt

I have only seen outside pictures of Coleman tugs. What is the inside like, what kind of driver controls allow 4 wheel steering to be separately controlled?

In all the tugs I have driven, it is push button control. And not quite sure what you mean by separately controlled? The options are generally, forward wheel steering, rear wheel steering, four wheel steering and the ability to crab, i.e all wheels pointing in the same direction, so you can go forward/backwards diagonally.

Matt

[chornedsnorkack]

On usual cars, turning steering wheel turns both axles, right?

How are the two axles separately controlled on a Coleman tug?

Same as any tug, Coleman, Schopff, Fresia, clever hydraulics and a computer or two if it is not older than 10 years or so.

Matt

I have only seen outside pictures of Coleman tugs. What is the inside like, what kind of driver controls allow 4 wheel steering to be separately controlled?

In all the tugs I have driven, it is push button control. And not quite sure what you mean by separately controlled? The options are generally, forward wheel steering, rear wheel steering, four wheel steering and the ability to crab, i.e all wheels pointing in the same direction, so you can go forward/backwards diagonally.

I mean, a steering wheel is a continuous input control. You could turn your front wheels 60 degrees from centered, or 30 degrees, or 53 degrees - and angle.

But I understand then that there is no separate continuous input control? You cannot turn your front wheels 50 degrees to the right and rear wheels 23 degrees to the right - you only have 3 options by push button, namely 50 degrees to the right if crabbing, 50 degrees to the left if 4 wheel steering, or 0 degrees if front wheel steering.

Correct?