Hey there, been browsing this forum for a lonnnnnnng time now - - posting every now and then

Thought I'd give LDD a try, normally I freestyle build everything, and there are two large fire/rescue projects I've been working on a for a long time now (Which I won't post until they are done)

But I don't mind sharing my progress with the stuff I'm trying out in LDD

As such, here is an Oshkosh 8x8(x8) Tactical Fire Fighting Truck (IN PROGRESS!)

The real truck doesn't have 8 wheel steering, however I decided to keep all the axle modules the same, and it will be that much more awesome

The 15L crossed black lift arms on the wheels are a moc up of the size of the third party tires I'm going to put on this beast.

It will have a water pump, bumper nozzle, roof nozzle, all remotely controlled

1L Motor for each axle (4 total, on one V2 receiver with dedicated battery pack)

Servo for steering

RC Buggy motor for water pump (x8 pumps)

1M motor for each nozzle rotation

1M for each nozzle elevation (Nozzle operation might be done with a fancy gear box to reduce amount of motors)

Additional batter pack for steering, water pump and nozzles

Edited March 29, 201410 yr by fasterthanlight

Can you share the LDD?

I hope you know that using just one Servo on 8 axles with Unimog tires is not going to work very well. There will be way too much friction, plus the weight of this giant.......

Anyway aside from that this looks like a very interesting project. I hope the water pump and everything will work out well!

Thanks for posting. I also would consider using more than one Servo for steering.

You may also want to consider that if

all the axle modules the same

then the wheels are only going to turn the same angle. You'd really want the outside pair of axles to turn a greater distance than the inner pair.

Owen.

Thanks for posting. I also would consider using more than one Servo for steering.

Will consider double servo, I don't own one yet so I have no idea what its capable of. Plenty of room in the central lower half of the frame to build out different options in real life if that is the case.

You may also want to consider that if

then the wheels are only going to turn the same angle. You'd really want the outside pair of axles to turn a greater distance than the inner pair.

Owen.

Axle modules are the same, but steering ratio for each differs appropriately.

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re: the water pump, I'm using 40t gears so that I can offset each set of two pumps by 90º (didnt bother wasting my time in LDD to draw that aspect out, not important) so that at any give time there is always one set of pumps pushing air, that way torque is low because its only two pumps really pushing, and hopefully that keeps the RC rpm's up enough to actually create some decent pressure into the water tank.

Can you share the LDD?

Will share it once I make some more progress :)

Update:

- Double servo, and steering system updated

- Water pump updated, no longer dependant on 40t gears. Also reinforced

- Some minor body work

- Lots of small tweaks and fixes throughout

Don't worry, I won't spam the forum with minor updates, I'm just bored right now and procrastinating on my studies

Edited March 29, 201410 yr by fasterthanlight

very interesting project...

That's a big truck! very cool, keep at it.

Thanks everyone.

Worked on the crew cab, includes opening doors, opening roof hatch, seats with SCBA bottles mounted in them. Working arm rests too...

Edited March 29, 201410 yr by fasterthanlight

Very nice details.

This thing should output a lot of water!

- A lot of body work done.

- Doubled up on the shocks due to potential weight concerns

- Re-located their mounting position to the top of the suspension arms, as to have them on the bottom ones runs the risk of them popping out of the ball joints of the hubs

- Water tank roughed in, with openable hatch on the top

- Ground ladders added

- SCBA bottles are now yellow with a green stripe, just to add some colour to this grey beast

Parts Count so far: 3368

Edited March 29, 201410 yr by fasterthanlight

Good lord that looks impressive and expensive. Keep up the hard work. Also it seem it would be easier if TLG made a 1/2 panel.

Very cool project. Looking forward to the updates :)

Thanks everyone. It certainly is going to be a beast, and an expensive one too.. however I have a huge stockpile of DBG liftarms and parts already.

The front of the truck is taking me forever to model.

I had to switch around the front two axles because the L motors would stick out strangely in the front of the truck

Built the two monitors, both with rotation and elevation control. Trying to tie it all together now

You might want to try reinforcing the suspension arms with a 3L liftarm, so there is no risk of any ball joints popping out.

Yea I'll probably do that in real life when building it...

Almost done the cab, lots of tricky angles to work with ...

This is MASSIVE. And it looks super cool! Are you sure the wheels won't touch the arches when at maximum steering angle when the suspension is compressed?

That is pretty damn impressive, and it looks great! What is the part count as of now, and what do you estimate it will be when it's finished?

4500 parts so far -- over 1000 just in pins

Width is 25 studs

Length is 109 studs (so far)

Probably close to 6000 parts when all is said and done

I'm hoping the weight isn't an issue for the third party tires I'm using... We'll just have to see... =/

This is MASSIVE. And it looks super cool! Are you sure the wheels won't touch the arches when at maximum steering angle when the suspension is compressed?

I'm not too concerned about that, there is plenty of room around the tires as it is, and when its actually built, the shocks will push the suspension arms down about half a stud more than they do currently.

There won't be too much suspension travel to begin with, this is just an industrial sized off roading vehicle, not a rock climbing device. The real truck is geared to dirt roads (limited access roads etc) and being able to climb steep hills when it needs to

Edited April 7, 201410 yr by fasterthanlight

Wow what a massive truck! Can't wait to see it built in real bricks

Thanks

I've hit a bit of a road block ...

I'm going to have to re-think how I manage the nozzle elevation, as when I was spec'ing out this beast I treated the drive functions as "one output" on the receiver. I now realize that I will have to split up the 4 L motors across two outputs. Which leaves me one function short ...

I think I will have to make the elevation of the nozzles for both bumper and roof mounts to be controlled by one motor...

Functions will be as follows

Battery Pack 1

1 - Drive (x2 L-motors) front axles

2 - Drive (x2 L-motors) rear axles

3 - Steer (x2 Servos)

4 - Water pump pressure (1 RC Buggy motor)

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Battery Pack 2

5 - Nozzle selection (1 M motor with pneumatic valve to switch water pressure from bumper nozzle to roof nozzle)

6 - Bumper nozzle rotation (1 M motor)

7 - Roof nozzle rotation (1 M motor)

8 - Bumper & Roof nozzle elevation (1 M motor, with possible manual gearbox selection to bring back independent nozzle elevation)

And now as I write this I realize there might be a mechanism I can whip up that will tie into the water valve control that will also switch which nozzle is currently being operated

I've figured it all out! I've rebuilt the entire nozzle elevation/rotation mechanisms

I've built a nice gear box system that will tie in (through linkages) with the water pressure switch.

The switch already has a mechanism that protrudes the two 5L orange liftarms from the side of the truck when you select which output you want.

The longer 9L orange liftarm will be part of the linkage system that will tie in with the orange 20T bevel gear in the second picture.

This way, when you choose which nozzle the water will pump through, it automagically selects the proper nozzle to rotate and elevate with the M motors

Whee!!

Edited April 7, 201410 yr by fasterthanlight

Tires arrived in the mail today... These things are MASSIVE

Very nice, I want one!!!!!!