6x6 Oshkosh HEMTT

[yoraish]

Hi everyone,
some time ago I started building a 6x6 truck, but I wanted it to be a little more scale. So here I am starting the new build, that will eventually (and hopefully) be an Oshkosh HEMTT- - -6x6!!!

I first started with the chassis plates- just 2 long pieces of thick aluminum



Leaf springs done too. I made them using thin aluminum, I hope they'll hold up. Looking good so far.





The leaf springs connectors and shackles are made out of cutting board, working well.



Mounting an axle



I plan on using the following with this build:
Saturn 27T motor (stock wheely king- that's what I've go right now)
RC4WD Hammer Transfer Case
RC4WD R3 2 Speed Transmission
Wheely King axles

As you may know the transfer case and the transmission are being used on the Trail Finder 2. What means my chassis should be as wide as the one of the Trail Finder 2. I've been told the inner width of that chassis is 86mm, can someone please confirm that or tell me the right length? Thanks.
I want to start building but if I guess the distance between the 2 chassis plates the arriving parts (tranny and transfer case) are not going to fit.

As I'm waiting for these parts to arrive as well as to another pair of wheels,
we are celebrating the new Jewish year. So I want to wish you "Shana Tova"- Happy new year, and keep on building!

To be continued,

Yorai

[Absurd]

Can't wait

[yoraish]

Managed to place the steering servo today:





Current state with wheels on:



I hope everything will arrive in the following week...

To be continued!

[yoraish]

New parts!! New parts everywhere!!!

So today I got most of the parts I ordered (except the wheels), and build continued full speed- which means very slowly, because I'm not such an experienced builder .


(They are so beautiful )

First thing I noticed when I tried connecting the WK driveshafts to the transfer case is that they almost fit. The simple solution was to make the U-joints a little wider.



Snug fit.



Next step was to mount the transfer case on to the chassis. As you can see I connected it upside-down. It is not such a big deal, but it shortens the wheelbase in about a centimeter.



With spacer:



Ahhhh, because I drill really wrong...



TaDaDamTamTam Transmission!



Lining up these holes was a real pain!



I am going to work on the rear axles on the following days, se you soon.

To be continued.

[yoraish]

Some updated had been made, and it's show time!

It took a while to figure out how to give the rear axles maximum flex and yet keep the driveshafts connected. The solution I came up with was to simply put two shock-absorber bodies like so:



They limit the travel of the axles.

A link to keep the axles upright



Small servo controlling gear shifting. I broke another one while testing.



Started working on the cab!! I assure you it won'tlook too good, but that's the way of learning.









That's all folks!

To be continued.

[yoraish]

A little progress..
Wheels finally arrived! The chassis look and perform pretty well.
Some work was done on the cab, especially on the mount to the chassis, I'ts far from complete.









I need to get myself some more aluminum for the cabin, and another material for the bed, any suggestions?

To be continued.

[Debonair]

I had an idea of what this truck was but I had to Google 6x6 Oshkosh HEMTT to see exactly what you are building. Looks great so far. I like the aluminum cab. Do you plan of welding/brazing it together at some point or just using hardware like it is now?

[yoraish]

Originally Posted by Debonair

I had an idea of what this truck was but I had to Google 6x6 Oshkosh HEMTT to see exactly what you are building. Looks great so far. I like the aluminum cab. Do you plan of welding/brazing it together at some point or just using hardware like it is now?

I'm going to keep on building the cab this way becaude I have no experience in welding or brazing. I actually think it will look quite good after painted

[Debonair]

I agree. The bolt heads all over the place will look neat. I look forward to your updates.

[yoraish]

Slow progress, that's what I've got right now.

I took the truck out for some test runs that did they're job, helped me find some problems!
The first and main one was with the front axle. It kept "swinging" on the leaf springs.
My solution was to add another bolt to let the spring hold better on to the axle:
Stronger springs!



The second problem was with the rear axles, the limiting spring-less shock absorbers were not aligned properly. I moves on side a bit further, hope it won't hurt its performance.

I also found the time to, finally, organize the electronics.
I think i'll improve the battery placement..



I used lego parts to protect the cables.



To be continued.

[yoraish]

A long time with no update, soon.. soon...

But in the meantime I have a small question for you guys.
While I was running the truck I was annoyed by the open diffs. I have the option of closing them on two axles, which ones are the one that should be closed?
In my opinion I should close the middle and front, but what to you think?

[monkeymagic9]

I'd lock the front surely.

But locking both rears seems like it'd cause handling issues, maybe some limited slip units.. but then again I have 0 experience with 6x6's.

[yoraish]

Some updates

Got some aluminum sheets









Started building the rear bed



I used the body mount parts from my wheely king and made this





(electronics will be arranged again with place for the battery)

As soon as I get some morebolts the roof will join in



To be continued.

[lonleycreeper]

Beyond cool, going to be following this.

[doc.hamilton]

Yoraish,
What an awesome build you've got going there! I think your fabrication skills are phenomenal.

Any postings of running video?

Cheers,
Todd

[yoraish]

Originally Posted by doc.hamilton

Yoraish,
What an awesome build you've got going there! I think your fabrication skills are phenomenal.

Any postings of running video?

Cheers,
Todd

Thanks

No running video yet. I'm waiting for my new servo to arrive, and then, hopefully, I'll be able to lock some diffs and give this truck some abilities!

[yoraish]

I'm still waiting for my servo to arrive..
Meanwhile I take a look at that:



That's the wiring for the new servo, I got to this design after long searching and asking around.
It basically means the servo will be powered staight off the battery but controlled from the receiver ( red wire cut in the receiver end).

To be continued.