About this Blog

This is about the combination of two interests, Radio Control vehicles and Science Fiction models. Its also about vehicle design. The models have to satisfy two main precepts.

1. The vehicles have to work, ie be driveable, but not nescessarily win any races or rock crawling competitions.

2. The main thing is that they have to look cool.

Monday, 22 June 2015

Creeper 6X6 part 3

Creeper 6X6 Part1
Creeper 6X6 Part2


I was pretty unhappy with the look of the body sitting so high on the chassis. I contemplated abandoning this body and trying something else ( this would have been the second body to be abandoned for this project). Before committing to scrapping the body, I thought to try lowering the stance of the chassis a bit by the use of some shorter shocks, to see if that would improve the proportions enough. I found some red anodised shocks on Ebay from China for $5.00 a pair. That's an incredibly cheap price so I figured what the hell, if they're crap and it doesn't work I haven't lost too much. As it turns out they are well machined and nicely finished except ... they are not actually filled with silicone fluid but with a tiny amount of some mineral oil and the pistons are a really loose fit. I cleaned out all the oil and filled them with silicon fluid but with the pistons are so loose in the bore and have two slots rather than holes, they don't do much damping. However they hold up the chassis and it doesn't look too high now so I am continuing on with this body. They also look a lot better and match the anodising on the wheel beadlock rings and suspension links, plus the black springs are nicer.




I also started on outfitting the electronics into the chassis and actually took it for a test spin... it works! The turning circle is large compared to the 4 wheel steering of the toybash truck, and it's even larger when the diffs are locked, however it climbs well. The center axle is at this stage unlocked as it does not have the switch mechanism being made out of  the axle halves that don't have the molding for it. I am thinking of permanently locking the diff for that axle for the superior climbing performance.




The Turnigy Ubec will supply the power for the lights via the nylon connector in the photo above. I also got some switch boards from Pololu.com which will allow the lights to be switched on and off from the third channel of the radio control. This was suggested by someone on the RPF forum where I have been running the Toybash truck project at the same time as this blog. Its really tiny, smaller than a postage stamp and I haven't wired it in yet to see if it works, that's the next task.



Happier with the sit of the body I couldn't resist filling in the detail well on the top and started some panel work.


The tranparent blue parts at the rear are two halves of a little water pistol that comes in party prizes. Anything made of the right sort of plastic, styrene, ABS or acrylic is a candidate for use as detail parts. The white domed shapes are the buttons from a scrapped washing machine.

More soon...

Creeper 6X6 Part1
Creeper 6X6 Part2


Sunday, 7 June 2015

Toy Bash Truck part 3

I made up pairs of headlights using some Cree Led aluminium penlight torches I got from China on Ebay. The torches worked out costing about $4 each which I thought was a pretty good deal. They claim they put out about 1000 lumens, I suspect it may be a bit lower than this but they are incredibly bright for their size and only use 1 AA battery at 1.5 volts. They conveniently unscrew at the business end making for a really nice lens and reflector housing, and are easy to mount and solder some wires to.

 


I wired them up 4 in series thus requiring a 6 volt supply. The battery for the chassis is 7.4 volts so I am employing a Turnigy Ubec which can deliver a switchable 5 or 6 volts at 3amps from any input battery between 2s or 6s which in LiPo battery speak means between 7.4 and 22.2 volts. These 4 penlights are only pulling 1 amp from the battery so there is plenty in reserve.




The Ubec is wired to a little adapter which is made from a deans connector plug and socket soldered back to back with the feed wires coming off the positive and negative at the join. The join is then covered with some suitable heatshrink. It is a convenient way of plugging it in between the battery and the speed controller. The lights are wired to a servo extension lead with one end cut off and the appropriate end plugs into the servo style female connector on the output of the UBEC which stands for ( Universal Battery Eliminator Circuit). In the old days of RC you used to have an extra separate battery for the receiver, servos and any other electrical systems it is this legacy battery that is supposedly being eliminated by the UBEC.



The lights are switched by a push button toggle switch mounted on the side of the cab which when painted will just look like a  random bit of detail. It probably would be cooler to make a switch that can be controlled from the transmitter, I am only using 2 of the three channels, but that was laying around in a box so I used it. I like to use whatever is to hand where possible.


The cockpit has been started but still has more work to come. A 1/16 Bruder Toys man sits in the seat. I'm thinking of making some sort of space helmet and converting his rolled up sleeves to be more space suit like.

I made up some tanks from PVC pipe end caps and the next size up pipe which has had a slice removed from its circumference to bring it closer to the outside diameter of the caps. Mounting pieces were made from 10mm foamed PVC, first a hole is made of the same diameter of the pipe and then sections are cut to suit. these slightly domed end caps are getting hard to find. All the new stock at the hardware store have totally flat ends which are not as interesting a shape and I can make those myself easily enough with a disc of flat sheet.




The chassis was shortened at the front to fit the body work that has been built, but yet to be detailed. The olive green radiator looking shape is a leftover spare part from a Tamiya Wild Willy Jeep kit.



More soon...

Saturday, 30 May 2015

Toy Bash Truck part 2

I finally completed constructing the chassis.The creeper chassis plates have been extended by some aluminium angle and channel section. The plates are held apart by some 6mm and 8mm aluminium rod spacers that have been drilled on the mini lathe and threaded at both ends to accept M3 cap screws.



The shocks have been mounted to the link mounting points on the axles with the links moved inboard. A piece of silicon fuel tubing has been inserted as a flexible bush into the hole in the shock shaft to allow some angular movement.


The top of the shocks use the mounting system that is included with the Hot racing shocks. These include a couple of silicon O rings and an aluminium ball shaped insert to allow for angular movement.


A styrene tray was made by heating some styrene with a hot air gun at specific points and bending it onto a wooden form one bend at a time. The trick is to shield the parts that need to remain flat so that only the plastic at the bend area gets heated. It is secured to the frame with some philips headed plastic screws salvaged from some old toy or appliance dis-assembly. The battery, speed controller and receiver are held on with self adhesive velcro. The battery is further sandwiched by some yellow EVA foam cut from a child's learn to swim surfboard.


The speed controller is a Castle Sidewinder 3 which can control both brushless and in this case a brushed motor using two of the 3 connectors. It can also be programmed through a Castle link and USB cable from your computer. It is set to crawler mode which gives a no delay reverse which I like as well as a drag brake at idle. The rear steering servo connects to a Hobby King servo reverser then to a Y connector with the front steering servo giving 4 wheel steering. Due to the 4 wheel steering it has a very small turning circle and is very maneuverable.

Unfortunately as expected the top heavy body tends to flop over to one side or another as can be seen below.


A solution to fix this was to attempt to make a sway bar. After some fiddling about this was made from some 2.5mm piano wire and a couple of small brass plates. Only the rear had enough room to fit this as the motor gets in the way at the front.This turned out to be entirely successful at curing the flop. A small DuBro collar secures the ends of the sway bar into the original shock positions on the axle. The piano wire is pretty old as can be seen by the surface rust, it'll need cleaning and possibly some paint. The hole that the sway bar pivots in has to be slightly bigger, preferably elongated into a slot to allow for the fact that the pivot position does not match the apparent pivot of the 4 link suspension. Its needs some play to compensate.




Here you can see the result of adding the sway bar with a nice level body.


I think the body probably sits a bit too high overall, but there's not a lot I can do about that at this point. I am going to add a bunch of tanks hanging down at the sides which may cure that perception. There is still some more volume to add to the body work at the front so that will help as well.

I completed the detailing of the top and nearly finished the rear.




The yellow part of the rear platform was originally from the top of the cabin of the dozer. The dark grey checker plate floor was from one of the rubbish trucks. The two black shapes that say Dick Smith upside down on them are the servo cases of my very first radio control unit from about 1980. They've sat in a box for nearly 35 years waiting for the right spot to glue them. Got a small amount to add to the back and then finish the front before the grey primer to see how its all looking.

The chassis also needs some paint. The worst part about that is having to dis-assemble and then re-assemble everything over again.

More soon...

Friday, 22 May 2015

Creeper 6X6 part 2 chassis

Creeper 6X6 part 1 is here

The original post for this from 2011 got accidentally deleted while I was trying to add a link to the next part, so I am going to recreate it here for a part 2.

Here is the Venom Creeper as it is supposed to be, a rock crawling RC vehicle supposedly to compete with the Axial  Rock crawlers. It was not as successful and has since been discontinued and for a little while back in 2011 they could be had new quite cheaply. I got a couple of the kits thinking I could attempt to make a 6X6 chassis. Others had already done this reasonably successfully so I had a go. One thing I particularly liked was the anodised aluminium beadlock rings which are very sci fi in design. The other aspect to the Creeper axles that i liked is they have a switchable diff lock, which means you can either have a working diff for tight cornering or a locked diff for better traction on rough terrain. As I have little regard to the "crawling performance" of these vehicles I thought they would suit my application just fine.

 I started by designing the chassis framework on a CAD program Deltacad.

This design was then printed out onto paper twice and spray glued to some 1.6mm thick lengths of aluminium angle. All the radiuses were then drilled out, after center popping them, using the radius centers marked on the printout. Then using a scroll saw and a lot of blades really designed for wood I cut out the rest of the material that made up the holes in the truss structure. Much careful filing later I had a pair of frames that the rest of the venom assemblies could bolt to.


 What you see here in these pictures is circa 2011. I eventually swapped out the shocks and their mounting positions many times over until I had a suspension system that could hold the weight of the top heavy body without flopping to the side. The added on rear axle is connected to a creeper frame cut in half, with many spacers made from 6mm aluminium rod on my Unimat 3 lathe.




It was quite a fiddle to get it all to work without binding or fouling, especially the front wheels which are turned for steering.




More recently with the new stiffer shock setup there is not the same amount of articulation as shown in the previous photos.

I then turned my attention to the body design and did a number of rough thumbnail sketches. After choosing the one i liked ( at the time, but ultimately abandoned and replaced) I roughly modeled it in Maya to get a sense of the volumes and proportions.







I then built a wood and plywood frame as a basis to start hacking into some 2mm styrene.
However I didn't really like what I had done and it sat around till this year 2015 when I did another thumbnail sketch that got me enthused and cutting plastic.


more soon...

Thursday, 21 May 2015

Toy Bash Truck

More than a year ago now I was looking at the toys in a discount store that may have interesting plastic shapes and found this rubbish truck toy which was not too expensive.

A little bit later I purchased a Bruder large tracked dozer thinking It might be fun to try and use the tracks for something. The cool thing about the Bruder range of toys is that they are all at a standard scale of 1/16 and reasonably accurate to the subject at least as far as most toys go. The pain of the Bruder toy range is that they use no screws in the assembly, its all tabs into slots with barbs that make it fiddly if not downright difficult to pull apart. Anyway it sat around in a box in bits for quite some time.


Some months later I found another of the rubbish truck toys for $3.50 at a thrift store or charity shop as its more commonly referred to in Australia.


Many more months later (only last week) I had the idea to see what would happen if I put them all together. Here is the result of that toy bashing.



Its basically the dozer cabin, back to front, joined to the combination of the two back ends of the rubbish trucks joined end to end, split down the middle and widened. A pile of 2mm styrene ties it all together. Parts off the dozer and the truck are re-purposed for detail bits and pieces along with a few kit parts, a small amount of foamed PVC and more styrene and assorted evergreen strips and textured sheet. A few of the urethane cast parts have also been employed here and there. It has a wooden frame underneath for reinforcement.
The wood is superglued to the plastic parts with thick superglue. The plastic is sanded with very coarse sandpaper to roughen the glossy surface so the superglue has something to mechanically bond to. All the PVC and Urethane parts are also superglued with a sanding treatment first.






The chassis, which is still to be completed, is based on a Venom Creeper seeing as I had a few parts still left over from the Creeper 6X6 project.
Here is the body work balanced on top of the chassis so far to give a rough idea of the way it will sit.




The yellow lump at the back is from the rear of the bruder dozer, here upside down. There is some work still to do at the back and quite a bit more to do at the front including adding a driver figure and fitting a seat. The original cockpit has been cut up as it faced the otherway. I may be able to adapt the existing seat for re-use, its not a sinple exercise at it was all molded in one at an angle with the rest of the interior. Much butchery has had to take place to extract it.
The wheels and tires are the old Axial Rockster beadlocks with Rock Lizards which, true to form, I have had sitting in a box for years waiting for a project to come along.

You can see how messy the bench gets with all the butchering and sanding of parts to get them to fit. I think I'll have to have a clean up before going much further.

More soon...