[TC6] Blast From the Past [WIP]

[D3K]

UPDATED 13/2 2015:

So my entry is finished, and I decided to redo the first post in the topic to make it easier to find info regarding the finished project.

A little backstory regarding this MOC:

Firstly, it has been designed specifically for this contest, over the last month-ish. I initially was going to make a more modern truck with the same pneumatic loop function, but then I thought it would be fun to make it more of a tribute to the brilliant B-model of the 8868, which I think many people have not had the pleasure to enjoy.

When that had been decided, I had to figure out how to adapt the concept into studless form, while still keeping the scale and functions (and the rather ugly form factor) of the original model, as well as what other features to add to it.

So, I ended up with this:

It looks a bit messy, I know, nut hopefully the rest of the pictures along with the video will leave you with a good impression

The features are as follows:

• Motorized (RC) functions:
  

1. Rear wheel drive from a vertically mounted PF L-motor
   
2. Steering with correct angles on both front axles from a PF Servo motor
   
3. Dumpable bed from a PF M-motor
   
4. Pneumatic loop for the loading action from dual small pumps driven by a PF M-motor
   

• Independent double wishbone suspension on both front axles
  
• Rear live axle suspension with leaf springs (flex axles)
  
• Dump bed flap opens via chains when bed is dumped
  
• Openable doors
  
• Adjustable seats
  

A close up of the cab and left arm. As you can see, I have added doors The exposed tan 3L pins are unfortunately a necessity, as they function as a mechanical stop when the arms are lifted.

...that open! And behold: There is even a steering wheel and lots of instruments!

The business end of things. The claw is based on the same principle as the original, but use of modern parts and some redesigning has left it stronger and more reliable.

Uppermost position of the arms. It is actually dependent on the added weight of the load (for example a wheel) for the pneumatics to function in the right order. If there is nothing there, the arms will start to lower before the claw is fully opened.

Another view

Dumping bed in full tilt position. The chains on either side work to open the flap (?) at the back

Here is a view of the valve used to toggle the cylinder that toggles the valve for the action. It is connected to the arms, so when the arms move up, the valve moves up, and then release air into the toggling cylinder, that then "reverses" the cycle, opening the claw and lowering the arms. As they move back down, this valve is then moved down, the toggling cylinder switches the action valve, the claw closes, the arms rise, and cycle repeats. Absolutely brilliant system!

Here is a view down through the roof, where you can see the previously mentioned "toggle cylinder" and the "action valve". Also visible is the upside-down servo motor used for steering.

Here is a view of the rear when the bed is raised. The M-motor in the middle is for the dump bed LA. The upside-down mounted M-motor to the left in the picture drives the dual pumps in the right of the picture.

Lastly, here is a video showing off the functions in real life:

Hope you like my model and hope to cash in on some of those nostalgia point Erik Leppen talked about

Edited February 13, 2015 by D3K

[Brickthus]

Excellent! Nice to see a MOC with a pneumatic loop.

Have you used loops in other MOCs too?

You could consider doing variable pneumatic control for the steering!

Mark

[Erik Leppen]

You're gonna win so much nostalgia points with this :D

The original model has always been one I particularly liked, because of the odd looks and the interesting pneumatics. Good to see you kept both, but added more functionality to it and motorized the whole thing. You even added suspension!

Although the container looks too "bulky" compared to the original, but oh well. All in all I like it a lot. Great job :)

[Rishab N]

Wow I've never been a fan of the 8868 B model, but this looks really good. Still need to get my hands on an original 8868

[D3K]

Thanks! Not going to be able to make any progress for more than a week, but will get back with more pics and info when i do!

Excellent! Nice to see a MOC with a pneumatic loop.

Have you used loops in other MOCs too?

You could consider doing variable pneumatic control for the steering!

Mark

I haven't used one before, no. But it was really interesting to make one, and get all the levers and the timing of things right! Concidering using some longer tubes in some places, to get a slight delay before the pressure builds up.

Also looking into fitting another pump, as it is a bit slow now

You're gonna win so much nostalgia points with this :D

The original model has always been one I particularly liked, because of the odd looks and the interesting pneumatics. Good to see you kept both, but added more functionality to it and motorized the whole thing. You even added suspension!

Although the container looks too "bulky" compared to the original, but oh well. All in all I like it a lot. Great job :)

Thanks, I'm glad you like it!

Nostalgia points is what I'm going for! Too bad a lot of this community is probably not familiar with the original

Wow I've never been a fan of the 8868 B model, but this looks really good. Still need to get my hands on an original 8868

The original is definitely not a looker, but the interesting thing was no doubt the pneumatic loop, as far as I know a unique feature in this model, never seen before or after

[D3K]

I have updated the original post with new pictures, info and video

Have a nice weekend, time to drink some beer!

[Meatman]

This is fantastic.

[Josephiah]

Nicely done - always loved the ingenuity of the pneumatic loop in original.

[Rishab N]

Just wondering what exactly is a pneumatic loop?

[D3K]

Just wondering what exactly is a pneumatic loop?

Oh, sorry if things were unclear

In effect, it means the pneumatic functions are self-controlled, as long as there is air coming. The output port of the IR receiver/SBrick just drives a pneumatic pump, which builds up pressure in the system, and then the actions are executed in the (hopefully) correct order, and then repeated. So I don't have direct control of either of the valves via remote, the only thing I control from there is the pumps. When air starts flowing, it executes functions in the following order depending on where the arms/claw is when the cycle begins:

Claw closes -> arms lift -> claw opens -> arms lower -> claw closes -> arms lift -> and so on and so forth. As long as the pumps go, this cycle will keep on repeating itself

[Rishab N]

That's very clever thanks for the explanation

[Kumbbl]

That's very clever thanks for the explanation

just buy an old 8868, build the B-model and admire this mechanism... very impressive indeed...

BTW: great reincarnation of this b-model legend :thumbup:

[arik]

Well done! I'm not familiar with the original model, but I'm sure you captured the spirit of it well. It's always pleasure to see complex pneumatic mechanisms in action!