4WD

 

OK, I got a bit frustrated with the lack of traction on rougher ground so I added a 4WD system. Basically I have added a second motor to drive the other set of rear wheels so now both sets of rear wheels are driven. I wish I could find a way to lock the diff's on each axel, then it would be true 4WD. As it is, it is a thousand times better than it was and now has full traction on rough and uneven surfaces. I might play around with the suspension spring rates, this would improve the traction even more. 

Tank transporter complete

I say complete but what I really mean is nearly complete. I have decided to add more power to the tractor unit by adding a second motor and drive axel. It wont be four wheel drive as I have no way to lock the diffs but it will be as close as I can get plus loads of power.

The trailer has been a pain. The four wheels where dragging really badly on sharp turns so I decided to add steering to the trailer wheels. The mechanism was fair easy but driving it a different matter. The first attempt was a large 60kg 12v servo. It was fine until the trailer was heavilt loaded then did not have enough power. Attempt two was a 1000N linear actuator. The wheels now turn under load but can not be linked in with the tractor steering so has to be done at the same time. It works, not elegant but it works and the trailer now turns, no more dragging wheels.

I had to loose the winch from the trailer as I needed the spare channel for the steering actuator, I might add a new one in at a later date. 

I now have a driver who's head moves. I have link this with the turn control. 

The driver also has his own stereo and can play music in the cab.

Radar system was added to top of cab and spins.

Loads more detailing has been added, to much to mention but it is now starting to look the part and will be ready for filming on the set date.

 

Nearly there

 

Loads of work done on the tank transporter over the last few weeks. Glass is in, smoke generator working, sound working and the paint detailing is coming along nicely.  The trailer has also had a lot of work done on it with the actuator fitted meaning the rear ramps now move up and down. I have added a winch which can actually pull 100kg, took some doing but it can winch the tank up onto the trailer. 

Weight is a bit of a problem or lack of it. The rear wheels spin a bit to much because there is not much weight over the back axel. I have added some weight  which helps a bit. Ideally I need to work out how to lock the diff plus in an ideal world four wheel drive would be better. The transporter will pull the tank fine but over rough ground or even grass might be a problem due to lack of traction rather than lack of power. 

Tank Transporter

 So the transporter is now taking on a life of its own and has developed a custom look, partly due to the spec we have been given but also artistic licence. Today it was all about testing and seeing if the small 300w 24v motor can haul 100kg of tank and trailer. It did really well. Not sure how it would do uphill or over very rough ground but on a flat surface it was awesome. 

There is still so much work to do but the test was successfull. Ride height looks far better as well with the larger 150mm wheels on the back over the 80mm ones I was going to use and loading the tank was easy. 

Elephant tank transporter

 I have been working on the new tank transporter. We need this as part of the filming requirements for the tank. The idea is that the tank transporter will pull up and the tank off loaded. It does not need to be a copy of any existing transporter, infact the brief is to make it look Sci-fi so I can have a bit of fun with this one.

What I did not realise is the size of this thing in 1/6 scale. I think the whole build will be nearly 3m long. 

It should be a fairly straight forward build. 

The hardest thing will be the suspension as it has to be set for the weight of the lorry but I am not sure what the final weight will be. The tractor will be made from 1.5mm steel and the chasis on both tractor and trailer will be steel box section. Tractor wheels will be 200mm pneumatic, tryes taken from a couple of old mountain boards. Trailer wheels will be smaller at 80mm keeping the trailer as low to the ground as possible making it easy to load the tank.

Four wheel steering linkage all made up from 8mm road and eyes.

Suspension is 18mm carbon steel used to create leaf springs all fully adjustable.

Cab is made from 1.5mm steel. Main tractor body is made from 2mm steel.

Starting to come together. This is just the basic structure in steel.

The 2 and 1.5mm steel is so nice to work with plus does not weight to much.

The whole truck was mocked up in cardboard first to get the overall look and dimensions.

The motor is a 350w 24v motor and transaxcel from an old mobility scooter which should be more than powerful enough to move the truck and trailer with the tank loaded. It wont go fast but that is not the point. The trailer  platform will be made from plywood edged with alloy keeping the weight as low as possible. 

Fifth wheel is very simple and will not be automatic so the trailer will have to be manually removed when needed.

Complete at last.

 The tank will soon have a staring role in a film, small independant film, but some interesting cinematography is planned using models. With that in mind the tank is now being dressed for its role. It has had a few items added that are needed plus a bit of netting camo. I will work on the rest of the dressing over the next few weeks, not demanding from a building point of view but definately good fun.

New sound system has been fitted and is awesome. I have managed to get lots of volume and bass from the speakers at last plus I have worked out how to map loads of sound samples onto the same track to create a very layered sound. I will go into more details about the sound system I build as I start on the Elefant transporter over the next few months.