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6x6 Truck Having built a replica of my Old 1:1 Landrover 90 :-(http://www.rccrawler.com/forum/axial-scx-10/308067-another-d90-uk.html). I wanted to have a go at building another truck. This time I decided to not make a replica of anything but scratch build a 6x6 off-road capable truck. As money was always going to be an issue I picked the Maverick Scout as a base vehicle. (http://www.wheelspinmodels.co.uk/i/86177/) It is a Chinese rip off of an Axial. Is RTR so for £120 supplied a donor vehicle plus a 2.4GHz radio and other electronics. Originally I was going to use an Axial Betty body cut down for the cab. However Axial don’t seem to be making them any more so the search was on for a new body. Ebay came up trumps with a New old stock Tamiya Bullhead body for a reasonable amount. http://i20.photobucket.com/albums/b2...0/DSCF0326.jpg Next, I bought a 1 Metre length of 12mm x 12mm box section steel from B&Q. I then made a wire template of the bends I wanted to make in the chassis rails. Using a propane torch I heated the box section and then bent it to shape. http://i20.photobucket.com/albums/b2...0/DSC_0004.jpg http://i20.photobucket.com/albums/b2...0/DSC_0005.jpg Having achieved the correct shape I then cut the box in half using the bandsaw at work. http://i20.photobucket.com/albums/b2...Picture017.jpg Using the skid from the Scout I set the width of the centre section of the chassis and then pulled the front and rear of the rails in about 5mm on each side to help with the clearance for the suspension and then brazed in a couple of cross members to secure the rails, and then started to mock up the front suspension. This is 3 link with a panhard rod and chassis mounted steering servo. http://i20.photobucket.com/albums/b2...Picture029.jpg http://i20.photobucket.com/albums/b2...Picture024.jpg http://i20.photobucket.com/albums/b2...Picture023.jpg http://i20.photobucket.com/albums/b2...Picture021.jpg http://i20.photobucket.com/albums/b2...Picture020.jpg http://i20.photobucket.com/albums/b2...Picture019.jpg |
Then on to the rear drivetrain. For this I wanted to try a walking beam style axle using just 1 diff/axle centre. I started by prototyping the drive system on a scrap piece of Perspex. http://i20.photobucket.com/albums/b2...Picture034.jpg This is was done with the meccano gears and chain I plan to use in the final assembly (more of this later), Using the measurements from the prototype I then milled (again at work) 4 side plates from 6mm Aluminium plate. These I then pocketed for the bearings for the output and input shafts and the main pivot bearings. I also made to smaller plates recessed for the other main pivot bearings. http://i20.photobucket.com/albums/b2...Picture035.jpg Next were 4 round nylon pieces to offset the outputs enough to stop the wheels rubbing on the side plates. These were also through drilled and recessed for bearings. I then cut the 6 shafts I needed to make the 4 output shafts and 2 input shafts. The shafts had flats filed on them for the grub screws to secure the gears and to slot into the rear diff and the 4 output shafts were crossdrilled for the hex pins and threaded for the wheel nuts. Next to pieces of steel tube were cut and pressed into 2 of the main pivot bearings. These were then pressed into the small plates and then bolted to the main side plate and the second bearing was then pressed onto the tube and into the recess in the side plate, a further bearing was then pressed into the tube to provide support for the input shaft. http://i20.photobucket.com/albums/b2...0/DSCF0328.jpg http://i20.photobucket.com/albums/b2...0/DSCF0329.jpg The axle casing was then cut down and drilled to allow the tubes to be secured in the case. The tubes were then inserted and marked to be drilled and tapped for securing to the cases. The Diff was built up using the crown and pinion gear from the Scout ,the centre from an Axial diff and the sun and planet gears from a Wheely king diff to give an open diff with all metal gears. This was then all assembled and then mounted to the chassis using a couple of aluminium links and metal rod ends fixed to a removable steel box section crossmember. http://i20.photobucket.com/albums/b2...Picture027.jpg With this done I could then mock up the front and rear propshafts. The front was easy I just used the original Scout rear propshaft which was spot on. The rear was a little less straight forward and is made up of various bits I had laying around and the original Scout front propshaft. http://i20.photobucket.com/albums/b2...Picture026.jpg http://i20.photobucket.com/albums/b2...Picture025.jpg |
At this point I assembled both walking beams onto the axle and stuck the wheels on mounted the centre gearbox and Holmes Hobbies 40T motor and threw on a speed controller strapped on a battery and checked the steering and drive train. This all proved to be ok but the rear track was much to wide . Still time for a quick spin in the back yard . Sorry no pictures or video. This showed that the rear drive worked but not very well. The original design didn’t have enough tension to stop the input gear from slipping. A bit of head scratching and by lengthening the chain one link I could add to rollers to wrap the chain further round the centre gear. This gave more gear mesh with the chain and stopped the slippage. Again test drove the modified drivetrain and it worked, on the flat, but as soon as I tried to drive the easy route on my rock pile I discovered the next problem. The torque from trying to drive over the rocks was sufficient to stretch and break the stainless steel chain. Back to the drawing board. I checked the interweb and on ebay found a supplier that did 6mm pitch pin and plate chain and some suitable (with modification) gears. The chain and six gears came to about £25 plus postage which was about £60 less than any other solutions I looked into. (http://www.ebay.co.uk/itm/2207094724...9#ht_625wt_698 & http://www.ebay.co.uk/itm/2207094724...9#ht_625wt_698) The gears were drilled and cut to length ready to be brazed to the shafts. With the shafts completed the axle casing was cut down a further 15mm each side thus reducing the track of the rear by 30mm overall. The whole axle was then assembled . http://i20.photobucket.com/albums/b2...0/DSCF0331.jpg http://i20.photobucket.com/albums/b2...0/DSCF0325.jpg http://i20.photobucket.com/albums/b2...0/DSCF0324.jpg From here I now need to work out how to make the rear suspension work, I am going to try leaf springs but mounted inverted. I hope by doing this the springs will stop the torque reaction that lifts the inside front rear wheel when turning whilst allowing the beam to flex over things. I am just waiting for the springs to arrive. |
Now that I have rolling chassis I moved onto making the load bed. Again B&Q supplied the steel this time 10mm x 10mm L section. This was brazed together to form a rectangular bed with a couple of extra cross members to facilitate fitting it to the chassis. I also fabricated a roll bar from brake line and brazed this to the steel frame. The floor of the bed will be made from 6mm ply. http://i20.photobucket.com/albums/b2...Picture037.jpg http://i20.photobucket.com/albums/b2...Picture036.jpg At this point the wife decided she wanted a model so has adopted this project as hers once it is finished. That’s where I am at for the moment, next will be fitting the cab to chassis and then mounting the load bed. More soon. :) |
Great build so far, almost everything being hand made is sweet! Good job "thumbsup" |
Great job! Love the walking beam and rear links. "thumbsup" |
Whoa, that things gonna be a beast!:evil: |
Excellent work"thumbsup" Subscribed! |
Thanks for the comments. Small update. Started to mount the body and trim it to fit and give the look I am after. http://i20.photobucket.com/albums/b2...0/DSCF0341.jpg http://i20.photobucket.com/albums/b2...0/DSCF0340.jpg http://i20.photobucket.com/albums/b2...0/DSCF0339.jpg Few pictures of the rolling chassis. http://i20.photobucket.com/albums/b2...0/DSCF0333.jpg http://i20.photobucket.com/albums/b2...0/DSCF0332.jpg http://i20.photobucket.com/albums/b2...0/DSCF0334.jpg Pete. |
Also managed to get a short (and not very good) video of the chassis running. http://s20.photobucket.com/albums/b2...t=DSCF0336.mp4 I am hoping to use leaf springs (mounted inverted) to control the beams, stopping them from spinning right over and from lifting the wheels due to the torque reaction. Pete |
Wow subscribed. Yeah the beams wanting to flip because of the traction could be an issue, but fun to watch "thumbsup" |
def fun to watch, but i can see problems in your future, time to put some sort of limit on that. how does it turn with that huge wheelbase? |
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Turning circle is not as bad as I imagined but not brilliant but then it was never going to be. I suspect the open rear diff helps a lot. I suspect that when I can get all the wheels to stay on the ground it may actually get worse due to the extra drag. We will see. Pete. |
Very cool Pete. I'll be watching this one. |
Small update real life has been getting in the way so not much progress. Made a front bumper. http://i20.photobucket.com/albums/b2...0/DSCF0346.jpg http://i20.photobucket.com/albums/b2...0/DSCF0344.jpg http://i20.photobucket.com/albums/b2...0/DSCF0343.jpg http://i20.photobucket.com/albums/b2...0/DSCF0342.jpg Mounted the rear bed to the chassis and relocated the electronics to under the cab. http://i20.photobucket.com/albums/b2...0/DSCF0348.jpg http://i20.photobucket.com/albums/b2...0/DSCF0347.jpg http://i20.photobucket.com/albums/b2...0/DSCF0345.jpg And the obligatory flex shots. http://i20.photobucket.com/albums/b2...0/DSCF0349.jpg http://i20.photobucket.com/albums/b2...0/DSCF0351.jpg Still waiting on the leaf springs from America to sort the beams flipping over. Need to paint the cab and clean and paint the chassis. Make the wooden part for the bed, then it will just need the detail parts like headlights, exhaust stacks and mount the batteries in false fuel tanks. Oh and rebuild the front axle to install the axial spool and modify the shafts to allow for a better turning circle and make some covers for the beams. So not too much left to do really. Pete. |
Very cool project. It reminds me of this. If you look closely, you can see the chain drive on the left rear. Keep up the awesome work! |
Well the leaf springs have arrived :ror: However whilst waiting for them to arrive I realized that the way the chain drive was routed might have been contributing to the torque reaction. http://i20.photobucket.com/albums/b2...0/DSCF0367.jpg The centre gear rotates in the same direction as the beam wants to lift in. So by re-routing the chain and adding a nylon tension wheel I now have this layout:- http://i20.photobucket.com/albums/b2...0/DSCF0368.jpg A quick test drive showed that this has cured the issue with the beams lifting under load. "thumbsup" Having sorted that out I decided to use the leafs as they were intended and rebuilt the rear suspension. I just need to add an anti-wrap bar to stop the axle centre from trying to flip and all will be finished with the drive train. http://i20.photobucket.com/albums/b2...0/DSCF0363.jpg I have made some progress with making the detail parts for the cab (exhaust , wing mirrors) http://i20.photobucket.com/albums/b2...0/DSCF0352.jpg http://i20.photobucket.com/albums/b2...0/DSCF0353.jpg http://i20.photobucket.com/albums/b2...0/DSCF0355.jpg http://i20.photobucket.com/albums/b2...0/DSCF0356.jpg http://i20.photobucket.com/albums/b2...0/DSCF0357.jpg http://i20.photobucket.com/albums/b2...0/DSCF0358.jpg http://i20.photobucket.com/albums/b2...0/DSCF0359.jpg http://i20.photobucket.com/albums/b2...0/DSCF0360.jpg http://i20.photobucket.com/albums/b2...0/DSCF0361.jpg And have painted the load bed and installed the wooden bed itself. http://i20.photobucket.com/albums/b2...0/DSCF0362.jpg http://i20.photobucket.com/albums/b2...0/DSCF0366.jpg More soon, Pete. |
"thumbsup"That is AWESOME!!!! Keep up the great work!!!"thumbsup" |
amazing driveline! why is the bed so high? |
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this picture shows why. http://i20.photobucket.com/albums/b2...0/DSCF0351.jpg Pete. |
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