4x4 Dakar Rally Truck

[the_ghetto_rig]

Ok..I'm gonna need help with this one...

Here's my inspiration:

and here's what I got so far:

I'm using aluminum c-channel for the frame, square steel stock for frame cross-members, MRC axles and ESC, and Mini-LST2 tranny
I've got Tamiya "reefer" wheels coming and gonna throw some 1.5 Dirt grabbers on 'em..should look a bit like the one on the right:

I'm using the Bruder's dimensions for a basis, but since it's got 3 axles and I'm building a 4x4, I need help to determine the placement of the rear axle..What's a good track width to wheelbase ratio I can use to figure it out? Thanx in advance!

 

[blukon98]

Can't wait to see some progress, ill be keeping an eye on this one

 

[fred0000]

i'll be keeping an eye on this one aswell, as for finding the wheelbase, couldnt you just find a known measurment in your referance picture, for example one of the tires, say its 38" tire (one of the rims might be better, as tire sizes are usualy smaller then advertized), then you can get a scale for that picture, and find out how many inch wheel base the reverance pic is, then calculate it down to the scale your building.

 

[the_ghetto_rig]

i'll be keeping an eye on this one aswell, as for finding the wheelbase, couldnt you just find a known measurment in your referance picture, for example one of the tires, say its 38" tire (one of the rims might be better, as tire sizes are usualy smaller then advertized), then you can get a scale for that picture, and find out how many inch wheel base the reverance pic is, then calculate it down to the scale your building.

Yeah, that's prob'ly what I will do, but this is my first "absolutely-from-scratch" scale build, and if someone has already figured out scale dimension ratios, I don't want to "re-invent the wheel" :mrgreen:..

 

[fred0000]

Yeah, that's prob'ly what I will do, but this is my first "absolutely-from-scratch" scale build, and if someone has already figured out scale dimension ratios, I don't want to "re-invent the wheel" :mrgreen:..

its hard finding info, I found this

http://www.dieselpowermag.com/features/1008dp_dakar_rally_kamaz_dakar_t4_race/photo_06.html

I dont think its the exact body/truck you are building. but some usefull info as I think wheel and tire size would be roufly the same accross the trucks.

"The Kamaz Dakar Rally race trucks are four-wheel drive, have a 165-inch wheelbase, run 50-inch-tall (14R 20) tires"

i'll keep looking when I have the time, 16.5" wheelbase seems like alot, some of the stuff I was reading about the unimog dakar trucks was something like 128" wheelbase (wikipedia) 12.8" sounds a bit more suitable, but we shall see, good luck, I cant wait to see it start to shape up.

 

[the_ghetto_rig]

thanx for the help, fred0000...I guess I could have just googled: "dakar wheelbase" ...This build is actually closer to 1:16, which would put my wheelbase around 10.3", which is exactly where the 3rd axle is hangin'..
Now I gotta figure out a leaf set-up, once I see how heavy she's gonna be...

 

[m00nst0ne69]

I can't wait to see the finished product. I have a lexan cab and an AX 10 awaiting!

 

[the_ghetto_rig]

OK..making progress..I got my wheels and shocks,..got the chassis tacked together..VERY happy with how placement is working out..the track width will be on the money...the tranny is nestled nicely between the rails (which are PERFECTLY wide enough to allow me to bolt the leafs into the hub screw locations on the axles..and the reefer wheels look F'n SWEET! ;-)

 

[the_ghetto_rig]

OK..got one rear leaf/shackle set-up..Front (left) shackle is stationary, rear moves...I think I might make it longer, tho..right now the leaf is 2.5" eye-to-eye (or about 40" scale) ...any thoughts?

 

[mototodo]

It looks GREAT! The springs may do the job. The MRC axles are light and narrow so it depends on how stiff the spring is and how heavy the rig turns out. The springs will soften as you drive it so it's hard to know how effective they are until you get it out on the trail. As a point of reference, Tamiya Highlift springs are about 5" long. I am running Highlift springs with wider and heavier TLT axles on my MAN and I get some decent articulation, all things considered.

The bolt holding the leaf to the axle looks a bit suspect. It's not a problem if the truck is going to be a shelf queen. However, if you are going to drive it like a true Dakar camion then you should consider a u-bolt arrangement. Otherwise, that tiny bolt is likely to strip right out of the axle casing.

Good luck!

>Subscribed.

 

[the_ghetto_rig]

The bolt holding the leaf to the axle looks a bit suspect. It's not a problem if the truck is going to be a shelf queen. However, if you are going to drive it like a true Dakar camion then you should consider a u-bolt arrangement. Otherwise, that tiny bolt is likely to strip right out of the axle casing.

Good luck!

>Subscribed.

Thanx for the feedback!..Yeah the set-up as-is will surely fail..the leafs pictured are actually just poly strapping that i'm using for mock-up and measuring purposes..I've got a recoil spring on the way...I like the u-bolt option (for both looks and function), but it will require me to to buy a 6-32 die that I may never use again...but I guess it's only $2-3...

 

[the_ghetto_rig]

The springs may do the job. The MRC axles are light and narrow so it depends on how stiff the spring is and how heavy the rig turns out.

In order to get scale performance out of this rig, I will be weighing down the chassis (inside the channel) and not the wheels..It will be HEAVY, so
I've got the shocks to figure out too (internally-sprung stock MRC)..LOTS of trial and error!:mrgreen:

 

[SlickRockSpider]

ubolts would be the most scale but rcbros sells leaf spring kits that do not use unbolts.

both ends of your leaf spring move ????


Evan

 

[the_ghetto_rig]

nope..just the rear shackle moves, the front is stationary...the shackles are #43 offset links...

 

[mototodo]

Here are some u-bolts that I made for MRC axles. The rod is 2-56 which I found in 12" lengths with the aileron push rods at the hobby shop. I found some 2-56 nylon lock nuts, too.

I discovered that the 2-56 rod fits into the MRC shock ends and M3 0.5 fits right into the MRC link ends.

Build thread is here: http://www.rccrawler.com/forum/showthread.php?t=167566&highlight=ford+farm+truck

 

[the_ghetto_rig]

Thanx Mototodo! The pics and info are PERFECT! I'm gonna give it a shot...

 

[elvis]

YES! It reminds me of one of the best vids on youtube! My favorite parts are when these things are passing race trucks and motorcycles and the best part at 4:34 when it's like 4 1/2 feet off the ground!

http://www.youtube.com/watch?v=4gUMFN8JPpU

 

[mototodo]

I forgot to mention, there is a nut/spacer between the leaf spring and the clamping plate. Without the spacer, the plate flattens the leaf too much.

Good luck!

 

[the_ghetto_rig]

OK..more progress...:mrgreen:

While waiting for driveline parts (thanx again Paul !) and an esc (thanx Bob!), I started to work on the body a bit..filled in the hole in the roof that held the lights, started the layers of Krylon Plastic Fusion and rough-cut the..uh...what's the back of a Dakar truck called? :roll:..anyway, I found something that works perfect AND
I won't be getting anymore junk supermarket ads :mrgreen::mrgreen::mrgreen:... also painted and weathered the wheels...

After agonizing for days how I was going to get articulation, high-speed durability, and scale looks out of the suspension set-up, I opted to keep the first two qualities and scrap the last...and right now everything is epoxy'd in place until I know for sure it will work,
And when I do the front i will prob'ly braze as much as I can...Very happy with the flex I'm getting out of this set-up..

 

[the_ghetto_rig]

Got the body shaped and the tires shaved and mounted...gonna put the fenders in the body tonite prob'ly..