CMP Ford F-AT Quad...help?

[Richard Coutts-Smith]

Dave, assuming that the winch fairleads are same across the range of CMP's:
The two wire rope sheaves or pulleys are un-braked and measure in at 8 3/4inch diameter, 1 1/2inch thick, mounted on a vertical pin that passes through a boss top and bottom of both sheaves. This gives an overall height of 3 3/4 inches between the two mounting plates. The top mounting plate is as you have marked, going full width under the chassis rail. There is a lower plate that retains the mounting pins, it is the width of the two sheaves combined, and is basically a wide "U" section welded to the underside of the top plate.
The bottom roller I have goes full side to side, but guessing the diameter would be the same, 3 1/2 inch.
You know there is a set of fairleads on the front bumper as well?
Rich.

[DaveW]

Originally Posted by Richard Coutts-Smith

Dave, assuming that the winch fairleads are same across the range of CMP's:
The two wire rope sheaves or pulleys are un-braked and measure in at 8 3/4inch diameter, 1 1/2inch thick, mounted on a vertical pin that passes through a boss top and bottom of both sheaves. This gives an overall height of 3 3/4 inches between the two mounting plates. The top mounting plate is as you have marked, going full width under the chassis rail. There is a lower plate that retains the mounting pins, it is the width of the two sheaves combined, and is basically a wide "U" section welded to the underside of the top plate.
The bottom roller I have goes full side to side, but guessing the diameter would be the same, 3 1/2 inch.
You know there is a set of fairleads on the front bumper as well?
Rich.

My "pulleys" are 12" x 2" scale size...so not too far off.
Not bad for a guess.
Sometimes, a bit bigger is better for scale assembly.

I am still unclear about the second mounting plate.
The "wide U section" you refer to.
I can see part of it in my reference photos, but its still not clear to me
how it mounts, or its actual shape and size.
Its not a big concern, since I am not including every accurate detail, but...



...
"fairleads"...whats that?
You wouldn't be talking about that roller cable guide thingy?
Is that what you refer to "up front"?



...
Where is the cable guide in the rear?
Does it go here(photo)?
Something is missing (on my model) to guide the tow cable under the frame.

[Richard Coutts-Smith]

Better described as a Wide "L" shaped plate...this also holds the guide roller behind the sheaves.
Fairleads = Roller Cable Thingy, or any roller guiding the winch cable.
The fairleads on the front, as shown in your pic, are nice and simple, they can be heavier and more complex than that: swing out rollers to pass the cable hook/eye through.
Just in case.... the wire rope is fed around the outer sheave and forward to the fairlead on the front bumper for when winching is required at the front of the truck.
Rich.

[DaveW]

o-tay!
I have a much clearer understanding of this...thank you.

I may have to reduce the diameter of my pulleys...I don't know.
But I definitely have to add that lower plate.

The fairlead is going to be a small problem, because even at 1/16 scale
those rollers are less than 1 or 2mm diameter...and its hard to roll paper cylinders that small!

I try to produce a "kit" that is self contained
...in other words, doesn't require you to introduce any other materials other than the printed paper parts I supply.
Obviously some builders like to add other materials and alter parts using other materials to be more realistic or detailed.
Its totally up to the builder...but I try not to expect that in my kits.
My kits will produce a basic model, that is complete using only whats supplied.

I may have to come up with a boxy stylized contraption instead.

...
anyway, thanks again for your assistance.
The help here has been great so far!
Thanks again Ian!!

...
I managed to finally sort out a basic design for the Drive Transfer Unit.
Is that what we're calling it?
lol
The unit that connects directly behind the Transmission,
and feeds the front and rear prop shafts/drive axles.
And in this case, also supplies the Power takeoff for the Tow Winch.

Being well hidden under the frame, I didn't want to get carried away with details
or make the assembly too complicated,
but I also had difficulty understanding its overall shape and how it sat within the frame.
Now I understand.




After that, I need to check the alignment of all the drive elements.
No point in continuing if things didn't line up!

I did build the basics of the power takeoff drive shaft, so I could test the closest component.
And I wanted to get the Transfer Unit glued into place, so I needed that connection.

But I also managed to confirm that the lower driveshafts(propshafts) and axles/diffs all line up.
At least close enough to sort out the angles and the propshafts.

[David Herbert]

Dave,
The thing right in the middle of the above picture is almost universally called a "transfer box" in all wheel drive vehicles except in modern articulated loading shovels (and possibly some marine installations) where it is called a "drop box" as it's primary function is to lower the drive-line.
A transfer box can be bolted directly to the back of the gearbox / transmission as in jeeps etc, or be separate as in most trucks.

Also, to be pedantic the pulleys or sheaves are PART OF the fairlead assembly. The front fairlead has a pair of vertical rollers just behind the two horizontal rollers so that sideways loads can be taken. These are just visible in your post #16 middle photo. The use of pulleys at the rear is simply to allow for greater angles without damaging the rope by bending it too sharply.

Great work though, please keep posting.

David

[David Herbert]

I assume that Richard's photos show a winch equipped C60 which seems to have a bigger gap between the rear chassis cross member and the fairlead than a FAT. The top photo in Dave's post #16 shows the vertical legs of the heavy piece of plate that goes under the pulleys, bolted to the face of the rear chassis cross member. On the C60 the vertical legs are welded to the horizontal plate directly above the pulleys but also to something higher up - maybe another horizontal plate above the chassis rails ? There is then a gap of about 5" to the front of the rear cross member, leaving room for the brackets for the rollers to be extended upwards at about 45 degrees to reinforce the vertical plate.

David

[DaveW]

Thanks David for your input.
When I get to the front, I will look at the pulleys up there.

I am a Class A Auto Mechanic as well, but what I know as a "Transfer Case"
may be called something else (eg transfer box)in other countries, and on other types of vehicles, and from different eras.
Thats why I sometimes stumble with the actual names of things.

Here in North America, its generally referred to as a Transfer Case (on a 4x4 vehicle).

Funny thing...in Canada, a prop shaft is on an aircraft.
The tube connecting a transmission to an axle/diff is a driveshaft.

but once, when I was in England, helping my Dad fix his car, we went to buy parts for his driveshaft and they tried to sell us parts for the rear axle/diff.
We did not realize that terms were displaced, and we actually needed prop shaft parts!

...
anyway...
I have been referring to photos of three or four different types of frames/chassis
to get various angles.
And I am aware that cross members and other things are in different places along the frame.
I have a plan of the 4x4 Quad frame, so I am doing my best to keep things proportioned to that.