Scania Rally Truck

[Mad Ax]

In the older part of the wood.  Here I had some problems - the path is on a slope, and the rig is so top-heavy that it leans hard and falls over a lot.  Apart from adding more weight under the floor and stiffening up the springs and ARBs, it's hard to know what to do about this.  It was very hard to drive here.

Deep in the woods is a hollow where the water gathers, and the passage of walkers and horses has turned it into a crater field that the 1.9 wheels struggle over.  The low sump guard doesn't help either, as it catches on a lot.  But I'm reluctant to raise the ride height because it'll top over even more.

I had intended to glue the lens covers on the front lights before I went out, but I forgot.  I'm regretting that now, as they got filled with mud.

[Mad Ax]

Deeper into the woods, I had to turn on the lights.  This is the roof light on the lower setting.

Out of the woods and onto open plains.  I've no idea what this big expanse of old tarmac is for.

Now we're in a dip to the left of the distant trees in the pic above, and the light has gone.  This is quite a steep climb, and parts of it are wet clay.  Despite slipping the wheels a little, the truck got up it with no bother.

The lights are very effective, but the chalk paths cause a lot of glare, so I mostly ran on the lower setting to save my night vision.

This is one of my favourite parts of the walk.  We're in another wood, much older and tighter, but with some really good paths.  The truck was very smooth over the rough ground, the lights didn't jump or vibrate at all.

[Mad Ax]

At the end of this woodland I normally double back and do the final 5-6 miles of the walk in mostly open fields, but the light had diminished so much that I couldn't see where I was going.  The lights on the truck were superb, but I haven't finished the rear floodlamp yet so I had nothing to show me where my feet are going.  At this point I decided to call it early, and head for home.

This lane takes me almost directly back to the van, but it's very dark, with overhanging trees and uneven ground, and hard to walk on in the dark.  The truck lights, being low to the ground, don't shine down into the potholes so it's hard to tell how deep they are.

This creepy long-exposure shot only shows a tiny section of the lane.  It's arrow straight for farther than the eye can see and quite oppressive in the dark.

So, I chose to divert into the adjacent field.  It's much nicer walking under the clouds than under the trees.  I also had a little assistance to help light my way.

[Mad Ax]

That is a flare.  There was some kind of exercise going on Salisbury Plain, which was only just starting to kick off at this point.  This was the first of many flares.  I'm not sure what fires these - there's a distant boom, then about 6 seconds later a bright orange light falls from the sky, then just hangs there for what feels like an age, casting a second sunset over the trees.

The firing range starts just the other side of those trees, although the exercise is probably some way past that.  As well as the flares, there was shelling also - I could hear the shells being fired from way off to the left somewhere, and about 5 seconds later the most incredible boom as they landed almost dead ahead, with a crashing echo that rolled across the plain like thunder.  Awesome, and really quite scary when you think about what it's all for.

Back on the lane, lights on full blast.  You can see how deep it makes the shadows.

This puddle seems to exist in perpetuity.  Distant flare for artistic effect.

And there you have it - 4.29 miles from one battery, including having the torches on for much of the way, lots of weight in the truck, and some boggy ground to cover.  Not to mention the front tyres being almost completely flat.  I only had another .16 of a mile to finish the walk, but I'll take that - I think that's on a par with previous excursions, so the old motor and new transfer case hasn't affected my runtimes at all.

Back at the van.  At this point I had a perfect view down over the plain, I could see some kind of muzzle flash as some shells were fired but they were landing softly.  There were a few more big loud ones but whatever was firing those was a long way off to the west.

[Mad Ax]

In the cold light of morning, the previous night's mud was very much evident on the white truck  

I've got a lot of cleaning to do before I can paint this rig...

Fortunately the inside stayed dry, because I haven't finished my arches yet.

[Mad Ax]

So, how did it go?

In a word - epic.  Faultless.  Perfect.

Well, alright, not perfect - the sump guard catches on things and prevents me backing off them, the suspension is still too soft and it tips over too easily.

Also the new transfer case is very loud and gets annoying after a couple of miles - I guess being screwed to the hard floor and the body acting as an echo chamber doesn't help.  I found it was better if I stood off to one side.

There's no obvious solution to that.  I could take it apart and check the mesh, although it isn't adjustable.  I suppose I could fill it with grinding paste and run it in the drill chuck for a few minutes to see if it smooths it out.

The gears are about twice as wide as those in the previous case, so maybe I could find someone to machine them down.  That would probably help a lot, but it's a lot of work and risk.  Or I could try to grind off the corners myself and leave a smaller mesh area, which should quieten it down, but again, with the risk that I damage the gears and they don't mesh at all.

But otherwise, it was fab.  I was terrified that the old motor wouldn't like running backwards, or that the new gearing would be too low, or that I'd continue to have overheating problems, but I had none of that.

The truck will run at just over walking pace in low gear.  That's fine for me, although the motor is running fast.  2nd gear is too fast, really, but means I can run at walking pace with a lower motor speed and less noise.  I worried it might be too much load on the motor, but even after long runs on grass the motor wasn't even warm to the touch.  I really couldn't fault it.

The dash light was great.  This is an RGB LED that tells me what mode the truck is in.  Green = normal (inertia-based) throttle and steering.  Blue = cruise control.  Purple = direct (crawler, non-inertia) mode, for instant throttle and steering response when traversing difficult areas.  Red = failsafe (should warn me if the radio connection is lost and bring the truck to a full stop).  Sometimes it's hard to tell if the mode has responded, and this gives me an instant visual indicator.  In the final truck, this will be mounted behind the dash panel so it's less obvious and won't make the cab glow like a beacon.

The torches were good.  TBH they are bright enough that I could rotate the outer ones outwards to give a wider spread, which might be nice.  I mostly ran them at around 1/3 output.  Even that is too bright to look at when it's coming towards me, so I think I need to add another setting where they are barely on, for when other walkers are coming towards me.

The cage worked, it stayed shut and stopped a lot of rattles that have plagued the truck since its first test run.

I'd lost a bit of enthusiasm recently having put so much time into it - so much time untested, wondering if it was all going to fail drastically once I got out on the trails - but this has really got my energy back.

I'm sure I'm going to have some great excursions with this truck later in the year.

 

[Nick G]

Sounds like the Scania is getting there., the lights are certainly very effective ! I suspect they were using parachute flares over the plain . Those hang in the air for quite a long time.

[Nikko85]

Glad it all went well. Looks like an epic project in many ways. 

[JimBear]

It's great to see that you've come such a long way with this, @Mad Ax. There is some serious work in the electronics department, it would have me sent off to Arkham Asylum in no time flat.

 

[Mad Ax]

OK!  Updates.

Honestly, building this truck is a somewhat exhausting experience.  It's like one of those beautiful, fickle, temperamental girlfriends - the type that one day makes you feel like the luckiest person alive, and the next day has you tearing your hair out in despair.

So - wheels and tyres.  My long-term plan for this truck has always been to use the FTX tyres that came with a used Outback 2 that I bought a couple of years back.  They are the perfect tyre for this truck - the scale is spot on, they have a nice, wide, chunky tread, and they work well off road.  There are just 2 problems:

a) they are far too soft, and are almost completely flat with all the weight in this truck

2) the plastic wheels are not scale, and are far too light - they really need some weights added to stop the truck toppling over.

Both of these issues are solvable, except they are pre-glued, so I can't fix them.  That means buying new wheels AND tyres.

I was always planning on buying more FTX wheels and 3D-printing some big hubs to go over them, for a more scale look, but I decided to have a very quick look on Aliexpress to see if there was something suitable.

I got these.

All metal (apart from the plastic beadlock ring) and very, very heavy.

I opted not to buy the tyres right away because I wasn't 100% sure they'd fit.  However, the FTX Outback also came with another set of tyres, which I had always assumed were also FTX tyres.  If those fit, then the ones on the plastic rims should fit, right?

[Mad Ax]

These ones fit perfectly.  They're not the tyre I want - they just don't look right - but they do fit.

They look good on the truck, too.  Not as good as the other ones, but good.

Confident that the FTX tyres would fit, I went back online and ordered 2 pairs.

[Mad Ax]

The next day, they arrived.

I'm sure you've worked out where this is going.

No, they don't fit.

The bead on the FTX tyres is too big.  I tried and tried, and I tried and I tried and I tried, and they just wouldn't fit.

OK - other options?  Let's try some plastic beadlocks.  I can always 3D print some different faces.

I've had these wheel for 15 years or so, and never used them.  They came with a used truck.

The tyres fit but they won't go over the hubs.

Ok...  Deep breath.  Back to plan A - buy some FTX rims, because I know they'll fit the axles, and just glue the danged things on.

[Mad Ax]

Meanwhile, with new wheels and tyres on the cards one way or another, I could get rid of the temporary spare tyres and fit 2 of the old FTX wheels and tyres into the spare rack.

Old tyres.  These came with my first ever CC01, more years ago than I care to remember.  They are hard as oak.

I cleaned up the FTX wheels and fitted them.  Perfect.  They were a little off-centre (somehow my mountings for the brackets didn't get drilled correctly on the bed floor) so I made some new spacers to centralise them.

Finally, with the spare wheels position formalised, I could start thinking about how to fit the light units.  I was going to use the stock Scania rear light clusters to save cost, but mount them up on high so they don't get damaged on the trails.

I hadn't planned to close off the rear of the body, but it seemed the best way to mount the lights was off an upright part.  I made this one from 2mm plasticard.

[Mad Ax]

My rear body mount brackets were getting in the way of these upright panels, so I had to do some re-drilling....

and cutting and filing...

to make space.  Test-fit only at this point.

Recessed slightly so the light units clear the cage.

[Mad Ax]

Sunday morning would be my last Workshop Sunday for a while, as I have 2 weekends of racing ahead of me, so I got into the shop early to make more progress on this truck.

First thing I wanted to do was trim the spare wheel brackets so I could move the rear closing panels forwards a little to clear the roll cage.  I also took the opportunity to move the left upright inboard of the L-section bracket to give me a little more space on the left, as that one had wandered from where it was supposed to be and it was proving hard to get the light unit in.

I also added L-section to the uprights to secure the closing panels / light units on.

To secure the LEDs, I used the stock light unit backplates but with the mounting brackets cut off.

Also made these little spacers to go inside the recesses under the light units.

thus.  This looks so cute I want to leave it like this, but it's only here to stop the body panel from distorting when I torque down the screws.

like so

[Mad Ax]

Fitted, with LEDs in place

Next thing on the list was the rear floodlamp.  I wanted something to cast a gentle glow behind the truck so I can see where my feet are going in the dark.

I used this square lamp from a Toyota Hilux High Lift (I never had that kit but I bought the chrome and lens parts for my vintage Bruiser body, these have been rolling around in the spare scale parts tub for years).

Scribble marks show outline of where important parts are behind the panel, which could interfere with my fittings.

I then spent the next hour rooting through every box I could find for the clamps for the square lamp.  Eventually I turned to a High Lift manual to discover there aren't any - it screws directly into its mount on the bumper.  Gah.

So, the solution is to drill and tap into whatever I want to mount this to, which in this case is 4mm ID tube.  It's very cheap aluminium, so won't hold much of a thread.  My plan was to drill to 1.5mm and use an M2 tap, but a) I don't know if I have an M2 tab and 2) I definitely don't have a 1.5mm drill any more, because they all snapped.

Gah.  So, M3 it was.

If I could drill right through and put a nut on the other side, that would be fab - but I couldn't, because a screw needs to go through the middle.

In the end I settled for drilling it to 2.5mm then putting a stainless screw in to make the thread - a tap would be too aggressive and not leave me with any meat to screw into.

[Mad Ax]

This was a fiddly thing to make and a bit rushed, but I can tidy it later if it works.

Fitted

Seems to work well and the lamp feels secure.  Hopefully that screw doesn't pull out.

Plumbing in the wires

done

[Mad Ax]

All fired up and working

At this point, I wasn't sure what to do with myself.  I still had a lot of day left, but my next challenge was those wheels and tyres.  I still love those metal beadlocks - they're perfect, if only they can be made to fit!

One option is to abandon the locking ring and use superglue.

This is how they look with the tyres fitted, no locking rings.

Perfect.  Correct FTX tyres front, those other ones (which fit the beadlocks but don't look so scale) on the rear.

[Mad Ax]

But we still have this problem - and this is a big problem.

The obvious solution is stiffer foams - but from where?  I hunted around to see what I had, but nothing was going to work.  I looked online, but the only things I could find were for bigger tyres - I didn't want to wait another 10 days for a delivery from China to find it wouldn't fit properly.

Then I had a genius idea.  I tried a few iterations, but here's what I settled on.

[Mad Ax]

Tamiya big rig tyre.

Cut a ring out of the middle of the foam.

Squidge the big rig tyre into the recess cut into the foam.

Stuff the whole lot back into the tyre.

Force the wheel into the tyre.  Note the big rig tyre is 1.7" ID, not 1.9", but it will fit (with some persuasion) and that helps to keep everything central.

[Mad Ax]

So the outcome is a tyre that is pretty gosh darned solid.  There's still some foam betwix'd the big rig tyre tread and the inside of the outer tyre, so there is a little bit of give, and plenty of foam in the sidewalls to give definition and volume.  These tyres are so soft-of-tread and there's so much weight that I very much doubt traction will be an issue.

For some reason I didn't take photos of the tyres on the truck, but I did give it a light run outside to see how it fared.  It went very well - it's not great on tarmac because of the lack of diffs and the stickiness of the tyre, but they didn't slip or fall off.  They'll definitely want gluing - once water gets in they'll slip off the rim - but as a proof of concept, it's a good one.

Plus, being beadlock rims that come nicely apart, I'll at least be able to glue the visible face from the inside, so I don't leave horrible glue marks everywhere like I usually do.

Result.  If I can get the gluing done tomorrow night, I just maybe might be able to take it out for a test run on Friday night.

[Tamiya Fan 1]

The lights are working.(bright !) Really bright, like you pulled your car up.

Weighted wheels might help your top heavy problem? I know you are working on it. I bought beeded wheels with a weighted ring in them for my Jeep and made a huge tip over fix. Thicker oil in the shocks might make it more stabile? (heavier weight) Also could "sintch" the spring on shock down a bit with a locking collar to make springs stronger. Just some ideas you might not have thought of. You fixed the soft tire issue.

For the the noisy gears that are bugging you, maybe some foam around gear case to insulate the sound a bit. But will suck up water if gets wet.

Sratch builds are about over coming what comes up as you go. They are the first one and one of a kind. But overcoming the issues is what is so satisfying!

It is coming along though!   You'll get it their.  Your having fun. Keeps you busy, and thats what it is all about.

[Shergar]

@Mad Ax The semi tyre inside is a genius idea 👍👍👍 Im loving this build, and its spurring me on mojo-wise with one of my build's too.

[Mad Ax]

Life has kind of gotten in the way of things over the last few weeks, and I haven't been able to get out for a long walk for a while - so the latest round of mods have gone untested.  I was able to finish work a little early on Friday, so I made sure my batteries were charging during the morning so I could head straight out as soon as I was done.

The weather here has been pretty good for the last few days.  Some rain Friday morning wasn't enough to wet the ground, and the skies were clear by mid-afternoon.  Daylight Savings began last weekend too, and the sunset is much later than it was just a few weeks back.  It would have been impossible for me to finish a walk in the light just 3 weeks ago, now it's going to be hard to be out until dark!  In fact I might have to make the torches removable, as there's no point in lugging all that weight around if I don't need it.

This update captures the best bits of the walk.  I took 80 photos, and if you like you can view them all here:

https://tcphotos.net/album/egy9

I used my phone for the photos this time, because I wanted to share the walk on Scaletra as soon as I'd finished.  I'm not sure I like the brightness of the phone photos, plus it took way longer because I had to keep getting it out of my pocket and unlocking it.  Next time I'll just use the camera that's attached to the transmitter.

It was 15:30 by the time I got to my usual parking spot, changed into my walking clothes and powered up the truck.  We were ready go to.  Fingers crossed, if all went to plan, we wouldn't be back for a few hours.

The big descent at the start of the walk.  The gravel is very slippery underfoot, but the truck managed it well with the new tyres.

Mountain bikers use this area, and make trails that are the perfect scale for trucking.

Spring sunshine has turned the chalk to concrete.  Some days these ruts are deep enough to drown the truck.

30 minutes into the walk and we reached the Walled Garden.  The cricket club is here.

[Mad Ax]

This is the lowest point of the walk (altitude-wise).  Wellhead Pond isn't the nicest body of water in the world - it's murky, green and stagnant - but it makes for a nice photo op.  However I was nervous about letting the truck get too close to it, because it's easy to knock the transmitter and set the cruise control off.

It's been a while since I saw this much light in the woods.

There are some steep climbs, and the truck definitely has less traction with the stiffer tyres installed, but it's still got enough to make the climbs.  The ground being so dry and dusty doesn't help, but it was fun watching something so lumbering and heavy fishtail and scrabble up the slopes.

This section is more for dog walkers and deer, but still makes for some nice scale trails.