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JennyMo

Capra-Cornone! (aka. Lil'Scamp/Willy's Rocker Mk.3)

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I'll aim to be brief with this particular build, as it's not really Tamiya based at all - but at the same time, I trust a number of the elements (not least the geometry engineering) will be of interest to some of you...

If you trawl back in the Build/Crawler threads and earlier entires in my showroom, you may recall I first got into crawlers a few years ago after buying a cheap RTR vehicle in the US (Messin' in the USA), and subsequently chopped a series of plastic cages around to make more of a Moab style rock-buggy out of the original chassis and running gear (Uncle Willy's Cage Crawler, plus Willy's original Rocker that used a chopped midnight Pumpkin cab as a minimalist body, followed by a Mk2 update which utilised a Vaterra Slickrock cage).

Ultimately, my desire to build more scale appearance vehicles meant that I dropped the box-chassis and canted suspension format (which admittedly offers the best articulation), and built a series of vehicles around a more conventional and realistic ladder chassis using the left-over running gear - including Lisa's Defender 90, and Desmond [the 2.2] which is my performance biased crawler that has been topped off with a narrowed HiLux cab and cage back - in an effort to not restrict any of the available travel.

And it is that ethos of unrestricted crawling performance (while retaining a semblance of realism) which has prompted this latest build, coupled with the fact that I seem to have amassed a stack of unused components that really ought to be utilised for something!

So let me introduce my latest folly - although I can justify it somewhat since a lot of the parts I already had, while the parts required to finish it (or at least get it rolling) are all from Far Eastern eBay manufacturers/sellers, so I hope to bring this whole build in at less than $200.

The heart of this build is the cheap and cheerful 'universal' 2.2 cage chassis from Integy:

i-RbhM2Hq-XL.jpg

I always thought these looked pretty cool - although if you read the reviews on line, a lot of people say that the build quality is not especially good (poor quality welding), and that the fixed/single-location upper mounts for the shocks are in completely the wrong place to offer any meaningful performance... hmmmm, we'll see shall we?

 

i-rKN3g5z-XL.jpg

You can see in the photo above that yes, some of the welds are a bit sparing - although overall the whole chassis is pretty true and nicely powder coated - and hey, it only cost me $23 (reduced from the typical RRP of $35.99) - so I figured it was definitely worth a punt!

The chassis is designed to accept the Axial SCX10 (first generation) skid-plate/gearbox mount, and it does perfectly (note this is the same style of aluminium aftermarket plate that I used for Desmond, although in that application I had to narrow it to fit between the ladder chassis), and is bolted to the cage with four M3 screws through pre-drilled holes.

i-BQL9XfM-XL.jpg

It is then simple to bolt the pattern SCX10 transmission assembly (which I'd originally bought for the currently dormant Mega-Bug build) and a spare 540 motor into the assembly, and ultimately drive will be taken to the front and rear axles with conventional prop-shafts.

cont.

 

 

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Next up, it was time to lay out the other chassis components, and try and figure out the wheelbase and corresponding linkage length (this would be a 4-link coil spring build of course) with the scale axles - the rear one I'd already bought for the Mega-Bug build (but have had second thoughts about), while the front cost me $43 from ebay including all the steering gear.

i-ZfGQ4zD-XL.jpg

I have to say, I actually think these axles are very nice quality - especially when you consider the price. Of course they are nothing like the high-end Vanquish axles (typically $200 each!) you see some builders using, and generally speaking you do indeed get what you pay for - but these appear to be made to just the same standard as the RC4WD 'Yota II' scale axles for example - and are essentially a direct copy, most likely from the very same factory in the Far East I suspect!

 

i-Bz53TF6-XL.jpg

I have literally dozens of 6mm rods, rod-ends, set-screws and other associated hardware these days, so it was easy enough to mix and match some components to make up the four rear linkage arms, and mount the rear axle in the approximate position I wanted - the idea being that rather than stretch this out like a typical 2.2 wheel size performance crawler, I will endeavour to make it a little more of a scale build - like those buggies you see on the slick-rock in Moab - bare bones certainly, but with the electronics hidden as well as I can and as much of a driver figure as I can squeeze in there.

As such, I intend to build this as a 1.9 wheel size class crawler, with a correspondingly shorter wheelbase - even if ultimately that doesn't offer quite the same crawling performance as might be achievable out of this chassis, it's a compromise I'm prepared to make to keep the overall build compact and realistic.

 

i-QLNqZKF-XL.jpg

photo. initially I built the rear end up with relatively short radius arms, and the shocks mounted almost vertically to the designated upper location - and yes, it pretty much sucked!

note. if you were building one of these as essentially a 'rock racer' style buggy, then you could feasibly use shorter shocks (say 80mm) - keeping everything nice and low and just deal with the limited articulation of the axle only travelling the length of the vertical stroke available.

I was aware of course that if you extended the wheelbase and laid the shocks down a little more then the articulation would improve, but I want to retain a compact footprint if at all possible...

i-8rmDqFx-XL.jpg

So instead, I experimented with moving the shock top mounting position dramatically forward (to what are typically alternative upper link mounting holes on the chassis), and in laying the shocks down at closer to 45°, this significantly alters the leverage ratio and allowed masses more articulation to be achieved for the same stroke length - while at the same time, these particular shocks still having enough strength in the springs to support the weight of the vehicle - result!

 note. laying the shocks down like this increases the leverage on the springs, so the suspension ends up much softer - fortunately these spare shocks I am using have adjustable preload, so you can dial-in the ride height while still having really supple suspension - perfect!

In fact, the result of this radical shock location is that the rear end has plenty of sag, so that the centre of gravity remains low, while having huge articulation to cross serious terrain.

i-9X3WSGg-XL.jpg

photo. See what I mean? - that is some impressive articulation from relatively short radius arms, and best of all nothing binds even on full travel!

 

cont.

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So with the rear end working far more impressively than I had initially hoped, it was easy enough to do something similar at the front - again, custom building a series of linkage arms with threaded rods, rod-ends and set-screws, and dialling in the diff angles using slightly different rod lengths and mounting locations (on the chassis) to try and ensure that the front axle retained it's castor angle throughout the stroke:

i-nWdPBVC-XL.jpg

 

i-mtVC66g-XL.jpg

photo. It's starting to look like a proper rock-buggy already!

I chose to build the front-end initially with the shocks fitted to the dedicated upper mounting points on the cage, as not only is this realistic from a scale/1:1 point of view, but because the front axle is slightly further forward than the rear (not least so the steering servo will hopefully clear the front of the cage on full compression), I felt there would be a little more leverage on the front shocks - bearing in mind that the weight bias will be forward too, with hopefully the battery mounted under the nose rather than in the rear for better climbing ability.

 

However, having the front and rear shocks mounted at such different angles to one-another immediately showed a disparity - the front end being much stiffer, meaning the chassis was more likely to follow the terrain, while conversely the rear axle was far more free to flop around and track the terrain itself...

So I then decided to experiment with a similar laid-down shock set-up at the front too:

i-3h8DQJv-XL.jpg

photo. Fully extended...

 

i-TFfDWvG-XL.jpg

photo. mid-location, wheelbase here is approximately 285mm

 

i-MmW9JnN-XL.jpg

photo. more how I envisaged the vehicle to sit when on it's wheels (ie. offering a huge amount of droop travel) - albeit initially it was very saggy at the front...

 

However, as I mentioned above, the shocks I'm using have adjustable pre-load/ride-height, and with a little tweaking, I could actually get the chassis to self-support midway between the shock stroke front and rear - perfect for crawling and tracking the terrain both up and down:

i-64jjJhX-XL.jpg

photo. Louis was very pleased with himself having finally dialled in the static ride-height...

 

i-8Qj8NQW-XL.jpg

photo. and really impressed with the overall articulation - that is almost 90°!

 

cont.

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Of course this suspension layout is still only theoretical at the moment, since while it is wonderfully supple and smooth, there is every chance that once the wheels are being driven, it has so little resistance that may well suffer from a degree of jacking and torque loading - and that ultimately this layout will have to be revised further...

...however, I didn't realise that revision would actually have to be quite so soon!

i-2m26wXt-XL.jpg

You see once Louis had fitted a set of wheels to the front axle (to check the tyre clearance on full lock and articulation) it was patently clear why you can't use laid-down shocks at the front on a narrow track-width vehicle... while the articulation was awesome with the wheels pointing straight ahead, as soon as you tried to turn the steering, the 115mm diameter tyres immediately hit the shocks of course - doh!

So other that significantly widening the track (something I really don't want to do as I'm trying to get away from the spider-leg look you get with a lot of narrow cage-based crawlers), then then only thing to do was to revert the front shocks to their previous more upright mounting position after all:

i-gKVqSB6-XL.jpg

This time I also mounted them inboard of the axle brackets to maximise steering clearance - and interestingly, this chassis has the top shock mounts spaced at 58mm, while these 'Yota II' pattern axles (also from a Far East supplier) have 72mm between the inside face of the axle mounting brackets - so once you mount these particular shocks with 6mm eyes* at the top and bottom, they mount almost exactly vertical, with the bottoms just slightly further out than the top (1mm each side) - perfect!

*note. with some shocks having 7mm wide eyelets, this would equate to the shocks being absolutely vertical of course - a coincidence, or do the manufacturers actually talk to one another I wonder?!

 

So with the steering sorted, and the shocks re-dialled in, there was nothing for it but to mock-up what it's going to look like with all four 115mm diameter tyres fitted:

i-4qrCD4D-XL.jpg

photo. borrowed spare wheel from the ebaYJeep, and Lisa's original Willy driver from her Cage Crawler - fits perfectly in what will now be his new home!

 

More soon!

Jenny x

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Money money money!

So while I wait for my dedicated wheels and tyres to arrive (and I feel I've scored a bargain by trawling around on eBay this morning), together with the necessary electronics to actually get this buggy moving under it's own power - I thought I'd tot-up what it's cost/costing me so far...

As I hinted at in my introduction, as this is really a pleasant distraction from my main project/s going on at the moment, I wanted to try and keep it as 'affordable' as possible, while at the same time hopefully end up with something that is more unique (both visually and performance wise) than you would get with a typical RTR crawler out of the box...

That said, there are some very capable RTR crawlers available around the $300-350 mark these days (and builders chassis kits starting at around $150-200) - so actually trying to source all the individual components you might/will need to build you own custom project is no longer really the cheapest option - if it ever were of course?

But still, there is a certain satisfaction in not only sourcing and building your own vehicle from a series of otherwise random parts, and not least that the end result is likely to be something far more unique of course. This way, you get to choose exactly what size, style and materials the various components are made from - and certainly most RTR models tend to cut costs with items such as plastic wheels, axle casings, gearbox internals and basic shocks for example - while with this particular build everything is made of metal.

So, as an illustration, my shopping list for this project so far is as follows (note. now I'm living in the US, these prices are in dollars of course) - purchased from a mix of Far East and US eBay/online retailers.

new vehicle components required to complete the build:

front axle - $43

cage/chassis - $23

skid-plate/gearbox mount - $11

wheels & tyres - $50

2x prop-shafts - $13

sub total: $140

 

electronics

waterproof ESC - $18

shorty steering servo - $20

2.4Ghz Tx/Rx - $20

square 6-cell NiMh battery - $13

electronics total: $71

So in total a touch over my $200 budget (but actually only by the cost of the skid-plate) - and that includes a 2600mAh battery pack too of course.

 

And finally a quick tot-up of the other parts I had already purchased/had in my spare stash:

rear axle - $40

SCX10 aluminium gearbox/transmission - $30

70T motor - $10

shocks - $20

So that's essentially another $100 plus the various rods/rod-ends and hardware required to connect everything together.

You see it all adds up doesn't it?!

Still, like all these things, the [monetary] bottom line is only part of the equation - for me this hobby is all about the joy of assembly, of the initial choosing and sourcing parts and then the actual build of the vehicle itself; and then of course the hours of enjoyment of actually running the finished article - and in this case, crawlers are huge fun!

More soon, once the postman has been later this week!

Jenny x

 

 

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A quick update while I wait for my bargain-priced alloy wheels and tyres to arrive...

You might have observed from the photos above that my fancy disc brake hex hubs are nicely polished/brushed on the outside faces, but that the black anodising actually completely covers the reverse side of the discs... Now this wouldn't usually be so much of a problem on a traditional [road] car build, as the back of the wheels tend to be hidden inside the wheel arches of course, but on this open-wheel buggy, they do look a bit obvious/unrealistic I thought?

Initially I considered just stripping them completely in oven-cleaner (as I had already done with the anodising on what were the originally blue shock bodies), but then I thought what if I rig up a stub axle in a drill, and see if I can't just sand the black off the inside faces of the discs instead... so I did!

i-jvmWjTm-XL.jpg

photo. hub held onto axle with a regular pin, and secured with an M4 nut on the other side.

 

i-h3g3crB-XL.jpg

photo. sanding with 120 grit sand-paper initially, then finer wet&dry.

 

i-23LqwkJ-XL.jpg

photo. That's not bad at all - certainly good enough for anyone casually peering inside an open wheel I should think.

 

So while I was jigging about with these existing components, I also took the opportunity to refine some of the linkage lengths and locations to eliminate any chance of binding on full travel, and also tidied up the steering linkages with some alternative hardware.

Then earlier today the postman delivered a key component - a shorty servo for the steering (it ought to be clear why I ordered a shorty version in a moment), plus a very nice quality waterproof ESC, which if it works well in this application I might end up changing a couple in my other crawlers for too.

i-BF77n9p-XL.jpg

photo. I do like an online retailer that includes a lollipop in their packaging!

 

i-ftC8mCb-XL.jpg

I mounted the servo in the more forward of the two possible locations - primarily as I hoped the rear edge would clear the nose of the cage on full compression, while an additional benefit (using the supplied plastic servo horn as essentially a ghetto servo-saver) is that the drag link would actually fit behind the horn and completely parallel above the steering tie rod bar - making for a very neat and compact (and I trust well protected) installation.

note. I replaced the original M4 threaded drag link which had the same dimension plastic rod-ends as the tie rod, with an M3 version with much smaller [metal] rod-ends, so that there was enough clearance under the servo when turning fully left and right.

i-G3Ntjz9-XL.jpg

photo. this compact installation ended up working perfectly - offering plenty of clearance with the cage on full compression. You might also notice I've started to experiment with some checker-plate for body panels too.

 

So now I'm just waiting on the wheels and tyres, plus the radio gear, battery, and prop-shafts to arrive - then hopefully this little scamp should be up and running by the weekend!

More soon!

Jenny x

 

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The wheels have arrived, and I have to say they are awesome - even better than I was expecting!

i-ScnGSpb-XL.jpg

I took a punt on these, as the price was really too good not to - four aluminium bead-lock wheels (with an 8 D-hole pattern, which ought to show the brake disc hubs behind well through the gaps), and complete with proper scale M2 hex bolts holding on the outer bead ring (not socket-head screws like most budget, and even some high-end wheels have).

The wheels mount to separate hubs (six bolt 'Toyota' pattern, which are appropriate for my 'Yota' scale axles on this build anyway of course), and have the same bolt PCD as the more expensive SLW pattern Vanquish hubs/wheels, along with SSD and the Axial IFD hubs, so plenty of options if I needed to change the off-set and space the wheels out for example.

As it was, the suppled aluminium hubs mated perfectly with the disc brake hexes I'd already installed (honestly like they were made for them!), and of course having separate hubs, you can even add separate brake discs as spacers between the wheel and hub if desired (I tried this too with my spare SLW discs).

i-Mh9MfsW-XL.jpg

Perhaps most impressive of all is that these particular wheels come with their own machined (again in aluminium, not plastic) centre hub caps to cover the axle bolt, and while they appear to require a special six-pronged tool to tighten them, in actual fact you can just do them up with your fingers as they are actually threaded into the centre of the wheel, complete with an o-ring. I'm impressed!

 

i-ZbRFbdP-XL.jpg

The supplied tyres (the wheels and tyres were a package) were also surprisingly high quality - soft compound with medium to soft foams inside, 115mm diameter and around 45mm wide, while the tread pattern itself looks like a much more expensive 'branded' tyre you get from RC4WD or ProLine for example - and fortunately they didn't come with any nasty sidewall markings like a lot of pattern (I mean 'copy' of course ;o) tyres from the Far East factories can do.

Indeed I'm so taken with this combo that I might end up buying a second set to fit on Ozzy's ebaYJeep, although I do still have a soft spot for the Weller white 8-spokes, which are kind of more appropriate on a beater trail-rig anyway.

The tyres and wheels also went together perfectly, and the inner bead-lock ring does up securely with 8 bolts (one in each spoke), so that tyres can be changed without having to remove the dozens of tiny M2 scale bolts on the outer ring - neat!

 

In fact the only thing that was slightly disappointing was that one of the wheels was missing it's centre hub cap... not the end of the world on a hard-working rock buggy perhaps, but a shame when the other three wheels look so good with them fitted. I've emailed the seller and hopefully they can supply a spare. edit. they did, in double quick time too - excellent service!

 

i-Xqfk7Tc-XL.jpg

photo. So close to being the perfect purchase, unfortunately one wheel was missing it's centre cap... still, they look great with or without them fitted to be honest. note. I will ultimately change the six socket-cap bolts for scale acorn nuts I feel.

 

i-gsVsbHh-XL.jpg

photo. on four matching* wheels at last.

*well, except for that missing centre cap of course!

So with all four wheels on, it was time to check the stance and clearance, and fit the front and rear prop-shafts which also arrived today:

i-RhFqGqK-XL.jpg

photo. Articulation is impressive, although it remains to be seen how it will actually drive - the rear is significantly softer than the front and while that ought to give it good overall ability, it's possible the rear will squat significantly under power, and possibly torque-twist too.

i-cqZPsTP-XL.jpg

photo. Overall it is tall, but actually quite realistically proportioned when compared to the 2WD Toyota pick up parked next to it. I'd say I've manged to retain a 1/10th scale appearance by using 1.9 wheels and narrower axles than you might with a 2.2 size wheel build?

cont.

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cont.

So it was time to fit the props - and again, these were great quality for the price, and included the grub-screws* (and an allen key) to secure them the gearbox and differential shafts.

*note. while I initially secured the prop-shafts with the suppled grub screws (one either side), I felt the holes in the axle shafts particularly were a little too large for everything to be really secured tightly, so I ended up buzzing a 3mm hole though the output shafts of the gearbox, and securing each end of the props using a single M3 set-screw all the way through each shaft.

i-JXKWnFF-XL.jpg

photo. at the rear the prop clears the gearbox flywheel cage on all but full compression - and all that will need is a slight Dremel to sort out.

 

i-PPkP6vc-XL.jpg

photo. As with the rear, the 4-link suspension means the prop is contained between the upper and lower links and well protected.

 

i-dvbWpss-XL.jpg

photo. Louis is impressed, and so is Willy!

 

i-FHJZPR2-XL.jpg

i-46LHsHz-XL.jpg

So the next stage it to make a start on the body panels (CAD template already cut for the bonnet) - nothing too fancy, just a nose cone/front fender assembly (to hide the eventual battery) and some side panels perhaps for a few stickers...

All being well, the rest of the electronics should be here in the next day or two too!

Jenny x

 

 

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Well Mr Postman didn't let me down - the radio gear arrived on Friday (still waiting on the main battery), and fortunately I had a mini (1100Mah) 7.2v battery lying around, so I thought I'd charge everything up and see if it all works... and it does!

 

i-ZCt5r7f-XL.jpg

photo. Transmitter/Receiver set was less than $20, and comes with a waterproof 3-channel receiver (with a dedicated 3rd channel button on the handset). The Transmitter unit itself is physically smaller than a typical 'full size' handset, but it has electronic trim buttons for the steering and throttle and is essentially the same as you get with some smaller scale RTR models for example.

So with the bench-testing complete, I thought I'd complete the rest of my bodypanels:

 

i-CQNz6dR-XL.jpg

photo. I ended up having to cut each individual template for each panel, as the cage being a cheap and cheerful 'Far-Eastern Fabrication' was not, shall we say, dimensionally a mirror image down each flank. To be fair my example is not that bad, but enough that I had to adjust the sizes from side to side by a couple of millimetres here and there.

 

I had been considering a number of finishes for the bodywork - including cutting all the panels out of either flat sheet aluminium (and I might still do that ultimately), or for speed and simplicity cut from 1mm thick styrene - either painted and/or covered in aluminium checker-plate for example. Following that train of thought, I rummaged around in my stash and found half a sheet of self-adhesive 'carbon fibre' effect vinyl (the same stuff I'd used on the bonnet of Desmond to realistic effect I thought), and felt that would be a quick and easy way to get a neat 'finished' look without having to break out the paint cans.

i-j64pdXT-XL.jpg

photo. 1mm styrene sheet covered in self-adhesive carbon-fibre effect vinyl - far cheaper than the real thing, and far easier to cut too!

 

i-Sq5K9Dm-XL.jpg

photo. the cage doesn't come with any bodywork mounting tabs, so using a trick I'd seen on other similar cage-crawler builds, I simply drilled a series of 3mm holes before covering the styrene with the carbon-fibre, then poked a small hole through the vinyl and inserted the 2.5mm zip-ties through and around the tubes of the cage.

 

i-pdPsN9Q-XL.jpg

photo. the nose-cone/bonnet was also cut from styrene, then heated and bent to follow the profile of the cage, before having the vinyl applied. note I also super-glued a styrene return lip at the base of the 'windscreen' area before covering the whole bonnet assembly with a single piece of vinyl.

 

i-tb2SMBb-XL.jpg

photo. temporary, although possibly quite permanent location for the waterproof ESC on the rear of the gearbox flywheel cage.

 

Despite not having thread-locked any of the bolts yet, I could resist taking it outside for a quick spin in the garden this afternoon (with the tiny battery temporarily installed in the cockpit), and I have to say, I'm impressed with how it drives! It does jack to the right slightly under power on the flat (although it's not really noticeable at all once you're crawling at super-slow speed on the rocks), but the suspension is working well already, and it seems to be very capable - I can't wait to get it out on some more serious terrain!

 

i-RHqQb92-XL.jpg

photo. not a bad looker for a 'budget' crawler I thought?

Once the proper battery arrives, I'll just need to fabricate a secure mounting for that (I'm hoping it will squeeze under the bonnet and out of sight), then a quick buzz with the Dremel and finally Willy ought to be sitting in there snugly too!

More soon!

Jenny x

 

 

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52 minutes ago, speedy_w_beans said:

That's a nice use of leftover and bargain parts.  Good result!

Yes, thank you! - certainly my box(es) of hardware are suitable depleted now - even if I do still have three left over tyres from the ebaYJeep build (I used the forth of a second set for the spare wheel you see, but at $16 for a set of four I couldn't really complain of course ;o)

I'm still debating whether to cut some 1mm thick aluminium sheet for the body panels - in an effort to make more a 'scaler' style rock-buggy, plus rust up the cage a bit and put some worn sponsor stickers on there...

For the time being though, I think I'm going to run this as is just for fun, and get back to my other dormant (or at least stalled) builds... I've still got a rear winch that needs installing on a HiLux for example!

Jenny x

 

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Sweet! - the new battery just arrived, and it's a lot smaller than I was expecting too!

i-s7vD6b3-XL.jpg

photo. 2600mAh 6-cell NiMh battery - I was expecting it to be six full-size cells in a square formation (the same as I've got fitted in Desmond), but it's actually much smaller...

In fact this is the PERFECT size to fit under the bonnet of the cage without any need for modifying the panels at all - all I need to do is create a base plate/under-tray for it to sit on:

i-jpnStwk-XL.jpg

i-3k43js4-XL.jpg

There is even enough room in the nose to still mount the Receiver there too if I wanted - I'm liking that a lot!

Jx

 

 

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Nosing ahead...

So with all my electrics assembled, it was time to sort out a proper (solid) battery mounting tray, and try and hide the wiring the best I can in this otherwise open chassis/body vehicle.

Initially I'd hope the battery would tuck in neatly under the bonnet, but on closer inspection, it really was a little too wide to fit inside the fender/side panels I'd fabricated to fit between the cage rails, and especially once I'd glued the sides to the [battery] base panel:

i-gxVx9Lf-XL.jpg

However, all was not lost, as actually the small 2600mAh battery didn't weigh all that much more than the ESC and Rx unit together, so I factored I'd just put all the electronics under the bonnet/inside the nose cone, and have the battery in the rear instead!

 

i-sZtHc9v-XL.jpg

photo. I covered the styrene nose cone assembly with self-adhesive carbon-fibre, and also cut a panel of aluminium checker-plate for the underside.

 

i-nHrcQP6-XL.jpg

photo. the electronics compartment - note the side fender panels are the original ones I'd cut, just trimmed slightly and glued to the curved base panel, before being recovered in the vinyl.

 

i-67cmNwN-XL.jpg

photo. ESC held in place with servo-tape. plenty of space in the nose for the Receiver and connector wires.

 

i-dcJHjNV-XL.jpg

photo. all the electronics in place, and the original bonnet panel fits over the top.

 

i-n5gBkJ4-XL.jpg

photo. The bonnet is now held on with two zip-ties around the front cage cross-bar, allowing it to hing forward for access to the wiring if required.

 

cont.

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cont. 

Less is more...

You might have just noticed in the photo above that I'd installed the battery on a flat panel behind the gearbox assembly (high enough so that the rear linkage arms still clear the underside on full compression travel) - and recovered the rear side panels of the now U shaped styrene assembly with self-adhesive aluminium foil...

i-xCK9pPs-XL.jpg

i-rGgmT8S-XL.jpg

photo. I thought the new battery (particularly once held in place with two large zip-ties and some servo tape underneath) actually looked rather like a luggage bundle or trunk?

However, I wasn't entirely happy with this revised look - while I like the industrial nature of the bare aluminium panels (and this effect looks great with a few stickers/decals on too of course), something about the bodywork at the rear seemed a bit clunky compared to the slim carbon-fibre nose perhaps?

 

So I removed the side panels entirely and cut a simple shelf (from slightly thicker styrene) instead:

i-r3B8d75-XL.jpg

photo. again, self-adhesive carbon-fibre was employed as a simple and cost-effective finish.

 

i-nZMrwhT-XL.jpg

photo. now personally, I feel that is 'more better' as the saying goes...

 

i-7rFt7gR-XL.jpg

photo. I also super-glued an M3 nut to the top of the motor, to secure Willy in place (the torso style driver having a screw hole through his left arm) - this will need to be beefed up with some Araldite or similar epoxy.

 

i-hBvJGNj-XL.jpg

photo. Ready to rock!

 

So there we have it - by hiding all the wiring in the nose-cone and under the driver figure, and hiding the battery itself in plain sight as a 'trunk covered with a tarp' on the rear shelf, I feel I've created something that while obviously still an RC rock-crawler, at the same time has a number of scale elements that enhance the overall look towards a real 1:1 Moab style rock-buggy... well, other than Willy's big ol' head perhaps!

In that regard I'm going to run this for a while now, in an effort to obtain some genuine patina, and then consider a degree of weathering and some further scale detailing - perhaps to the extent of stripping the cage itself (it needs some of the welds beefing up with either solder or at least filling with quick-steel anyway) and letting it rust naturally?

Hope you enjoyed this little distraction as much as I have!

Jenny x

 

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I was thinking while reading above that maybe the battery could go in toolbox like one of these diamond-plate models, but I also understand the value of easy battery access and the idea this is more of a casual model...  Anyhow, neat build!

lund-chest-truck-tool-boxes-9447-64_1000

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On 8/13/2019 at 9:35 AM, speedy_w_beans said:

I was thinking while reading above that maybe the battery could go in toolbox like one of these diamond-plate models, but I also understand the value of easy battery access and the idea this is more of a casual model...  Anyhow, neat build!

lund-chest-truck-tool-boxes-9447-64_1000

Hi Speedy - yes, I did consider fabricating a box/chest to contain the battery and covering it in the checker-plate (and I also have a fuel-cell box that would work in a similar way) to hide the battery... the problem is any additional weight on the rear makes the suspension sag too much, and not rebound properly - it's right on the limit as it is with the shocks canted at the angle they are.

Ideally I would rig up some alternative location for the top of the rear shocks to mount to (as I mentioned in the introduction, the stock shock mounts are one of criticisms of this cage chassis with regards to suspension performance), but without actually welding some new tabs onto the frame itself, I'm not sure the rear could support any more weight than it does currently - although at least with this current set-up the rear articulation is immense!

However, over time I'm sure this build will evolve further, just as all my other models seem to do ;o)

Jenny x

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Ch, ch, ch, changes already...

After a quick run round the garden on the rocks yesterday, I also experimented with relocating the rear shock tops to the pre-set/original mounting locations; and it turns out that while the articulation is significantly reduced, it is still very capable once it's actually being driven under power:

i-N5ftBxz-XL.jpg

photo. more conventional shock location - limits overall articulation [to more of the actual shock stroke length], but still works well... and arguably looks 'right' too?

 

i-9X6rNX8-XL.jpg

photo. it's not completely maxed out here, but it is close...

 

i-S2GnjGV-XL.jpg

photo. and that's still not bad after all...

 

i-Fvgtzj9-XL.jpg

Ultimately, having the rear shocks mounted more conventionally gives a lot more range on the preload adjusters - with them laid down at 45° previously, the preload was maxed out, and only just sufficient to support the weight of the rear end; while now the adjusters are backed off almost all the way in a similar way to the front... Indeed, this way, the front and rear suspension is much more evenly matched, and the overall support from the springs means that the belly is less likely to sag over really rough terrain too.

Time to recharge that battery and get back out there!

Willy is Rockin'!

Jenny x

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An inspired build from (as speedy_w_beans noted) were essentially leftover parts! The carbon-effect vinyl looks quite impressive, and the performance you have gotten out of the rig is even better. Amazing as always :)

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On 8/15/2019 at 11:36 AM, Grastens said:

An inspired build from (as speedy_w_beans noted) were essentially leftover parts! The carbon-effect vinyl looks quite impressive, and the performance you have gotten out of the rig is even better. Amazing as always :)

Thank you Grastens - yes, since the Mega-Bug is currently dormant (hence my new sig. line), I thought it would make sense to try and utilise that motor, gearbox, rear axle and some of the links and other hardware I'd acquired originally for that build...

If I'd been really disciplined, I could have utilised some of the wheels and tyres I already had too (although they wouldn't be bead-locks, which really is essential on a vehicle like this) and it would have meant forfeiting the spare wheel I've now installed on the ebaYJeep of course. I also have a spare FlySky 2.4Ghz Receiver kicking around, although by the time I'd bought a matching Transmitter and paid for postage, the compact TX/RX set I got from eBay was just as cheap, and the new Receiver is waterproof too which ought to be handy on a vehicle like this.

Similarly, I also wanted to try the Hobby Wing waterproof ESC, and I have to say, it's really nicely made and seems to be perfect for a crawler, with a really strong drag-brake on it... for info. if anyone is unfamiliar, it's about the same size as a Tamiya TEU-105BK ESC, but made of metal and waterproof too of course. They also offer a non-crawler version (presumably with a traditional braking function rather than the abrupt stop/lock you get with a crawler ESC), so I think in future that is going to be my go-to brand/model for ESCs in future.

Anyway, I'm hoping that a build like this is a good example of the kind of vehicle you can just leave in the boot of the car perhaps - so that it's always on hand for an impromptu crawling session should I spot any suitable terrain!

Glad you like it!

Jenny x

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Uh oh... seems I can't leave well enough alone...

While the Rock Boogy was a lot of fun, it's been sitting dormant for most of the summer (since I robbed it's electronics for another project), and even though I'd painted and rusted the cage to give it a touch more 'scale' realism, something about it still didn't gel...

So I've spent some more money.

i-ZJ4GBNT-XL.jpg

photo. supersize me - that is an Axial Capra cage and skid plate assembly.

The recently released Axial Capra 'rock buggy' seems to be getting a lot of positive feedback - certainly from a crawling performance point of view - although personally I think the over wide (Wraith width) portal axles make it look a bit gawky, particularly as despite the short[ish] body/cage, the vehicle also has a wheelbase of 318mm. Good for stability, less so for scale looks though perhaps?

Fortunately the majority of Axial's own spare parts are relatively affordable, and sure enough I was impressed that they sell what is essentially the complete cage/chassis for $30 (plastic only, you'll need a bunch of M3 screws too - although I have plenty of those already). It is worth noting however that the skid-plate/transmission mount is not included in the chassis set, and it turns out is not the same as those fitted to the SCX10 II crawler chassis either (which are readily available aftermarket), and indeed what I had fitted to the Lil'Scamp cage already.

So that was another $12 - oh the expenditure!

Otherwise, I factored I'd be able to transfer all the axles/links/shocks/wheels etc. over pretty easily - with perhaps a rod length adjustment here and there to try and retain the current 280mm-ish wheelbase which I really like for this kind of vehicle.

The only other thing it turns out I'd need is an adaptor to mount my existing Axial 3-gear transmission to the Capra skid-plate - as again the pattern/design is different*, so that was another $15...

*note. for anyone not aware - because the stock Capra uses portal axles which have an additional gear reduction in each hub, the dedicated centre transmission is correspondingly much higher geared so the overall speed remains the same. Were I to use that transmission (which in turn would be significantly more money) with the Yota II axles fitted, it would be more of a rock racer than a crawler, hence wishing to retain the traditional lower-geared centre transmission I already have.

i-JhhnnFp-XL.jpg

photo. the key to the conversion - yes, it would be simple enough to make myself, but they have already worked out all the dimensions and laser cut them... plus I like to support the little guys who make parts like this for RC.

 

So I reckon for $57 I've finally got the makings of a proper scale style Moab Rock Buggy... stay tuned as they say!

i-jQDNtqw-XL.jpg

photo. axles, links and wheels transferred over, with new 90mm shocks (with 80mm springs inside for extra sag/droop travel). 

More soon!

Jenny x

 

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It's alive!

While the rolling chassis was easy enough to assemble using all the existing components, unfortunately the installation of the SCX10 style 3-gear transmission was not as straightforward as I'd expected... turns out that Vader adaptor plate is primarily designed for their own flat-bottom skid assembly (which had I been feeling flush might have also sprung for too, despite costing $34.99) - and while the holes line up correctly with the OEM plastic skidplate, the Axial skid is not flat, and also has a moulded lug (for the dig servo mount) which gets in the way initially... although nothing Dr. Dremel can't sort out of course!

i-HXtfV7F-XL.jpg
photo. moulded ribs and lug for the dig servo means alloy adaptor does not fit directly on the stock Axial skid plate.

 
i-mFZQPD9-XL.jpg
photo. thank you Doctor D.

 

To get around the issue of the various moulded ribs in the top of the skid plate, I used these fat cone washers to space the alloy plate high enough to clear the base, the cone helping to centre the screws in the moulded holes too - perfect!

i-x6GC5D5-XL.jpg
photo. spare cone washers repurposed for this noble cause (of avoiding paying out another $35 on this project!)

 

However, the Dremel work was not over yet... once the motor and gearbox assembly was mounted, it turns out there is very little (ie. none) clearance for the prop-shafts against the inner moulded upright for the upper links... again, the proper Vader flat skid [conversion] for the Capra utilises single sided aluminium mounting plates on the outer edge, give valuable space for the prop shafts when using the traditional 3-gear transmission.

i-KQNcQQD-XL.jpg

Still, I was adamant I didn't want to buy the easy way out now (well, not for the moment at least - although maybe as an upgrade somewhere down the line) so took the Dremel to the inner uprights and trimmed them as close as I could, while retaining the lowest hole which is where my upper links connect to with this particular linkage layout. The only other thing required was to flip the whole skid plate round 180° so that the flywheel was now at the front (ie. the output shafts are on the lefthand side of the vehicle) which meant the front prop-shaft now runs at a diagonal angle to the offset [to the right] front pumpkin on these Yota II axles.


So at way past my bedtime last night, there was nothing for it but to hook up some electronics and give the little booger a quick test run - and it works!

i-XJ357nT-XL.jpg
photo. temporary electronics to test everything works and clears...

 

Testing time...

So a few observations after that initial test session... clearly the first thing is that a traditional 6-cell Ni-Mh battery (yes, I'm still old school in that regard) is simply not going to fit inside the cage anywhere  (note. although at a squeeze you could mount it longitudinally along one side perhaps, it then causes the suspension to sag on that side), so it looks like I'm either going to have to run a custom saddle pack or square pack, or finally use this build as the excuse I need to embrace LiPo as a motive force after all (note the Capra battery box is designed specifically to take shorty 2S or 3S LiPo batteries).

The other thing I noticed was that while the steering lock - even on these relatively narrow axles - is really good and the tyres clear the cage return on each side, even at full lock and travel - the rear lugs on the Toya II steering knuckles (which you'd use to mount a drag link behind the pumpkin on a leaf-spring build for example) hit the shocks  once the steering is compressed on full lock - so again, Dr. Dremel was employed there too:

i-DTQJvrV-XL.jpg
photo. the kindest cut.

 
The other thing I've noticed - having run it over the rockery earlier today - is that while the [80mm] droop style suspension is very plush, it does drag it's belly more than I'd like... one option is to refit the 90mm springs inside the shock bodies to raise it slightly, or, as I've hinted but avoided so far, ultimately go for that flat Delrin skid-plate [and aluminium linkage mounts] from Vader Products after all!

But for now that brings us right up to date - it runs, doesn't rub or bind anywhere, and I've temporarily installed the Rx and ESC in the battery footwells while I decide exactly what to do about investing in some LiPo batteries for this, and I imagine in my other 'regularly used' crawlers too - the Defender 90 and Retro Desmond.

I also plan to fabricate some body panels (most likely in aluminium), and fit a driver - because of the limited space inside, I reckon some sort of Wild Willy is going to be right at home in this one!

More soon!

Jenny x

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That Capra just screams feed me LiPo!! They fit so snugly in that battery compartment up front. 

Like you, I have resisted and stuck with NiMH but I had to get a square pack for my JK Jeep and it is just so heavy!

I feel like the LiPo move is inevitable...but maybe not just yet...

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6 minutes ago, Badcrumble said:

That Capra just screams feed me LiPo!! They fit so snugly in that battery compartment up front. 

Like you, I have resisted and stuck with NiMH but I had to get a square pack for my JK Jeep and it is just so heavy!

I feel like the LiPo move is inevitable...but maybe not just yet...

Yes, I know what you mean... they problem I have with LiPo - and I'm sure it's pretty much unfounded these days - is that a number of my models have the batteries 'permanently' installed behind the dash/under the scuttle panel  - my Vanquish 4Runner, the ebaYJeep, and soon the BJ Cruiser too* - and since those are typically charged in situ, I'm worried that it would be a disaster if I were charging the batteries in situ and they caught fire, while having to disassemble them each time just to charge them would be tedious.

*At least with the BJ it is easy enough to access the battery by just undoing the four sill-screws each time.

The Defender 90 is slightly easier, in that I designed the battery compartment to be reasonable easy to access without unscrewing the body (just two wing nuts which hold the sand ladders in place) - so that would be easy enough to run on LiPo too, once I swapped the current ESC for one which was suitable for LiPo I guess.

But then there is the Hopper's HiLux, which really needs the tiny 6xAA cell size batteries (one under each seat), and the Baja Blazer which has a square 6-cell pack due to the limited space in the rear load bed... both of those are more for show that go of course, but it does illustrate how many different batteries I need already!

What I'm trying to avoid is have yet another set of batteries (and a dedicated balance charger), but perhaps now is the time to start investing in LiPo going forward, and start to convert some of my more regularly used older models too... fortunately the $20 ESC I've just fitted to the Capra seems to have a really good drag brake, plus is switchable between NiMh and LiPo, so buying a few more of those isn't really going to break the bank.

Jx

 

 

 

 

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I certainly understand your concern, especially in those models which don't have easy access to the packs.

I had assumed that a LiPo charger would only look after the new batteries but have since  realised that you don't have to pay much for a charger  that would work with the new LiPo packs and take better care of my NiMH. The best of both worlds?

I'm still not sold on something that requires storage charges and more monitoring than my current batteries though.

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On 11/2/2020 at 8:03 PM, Badcrumble said:

I certainly understand your concern, especially in those models which don't have easy access to the packs.

I had assumed that a LiPo charger would only look after the new batteries but have since  realised that you don't have to pay much for a charger  that would work with the new LiPo packs and take better care of my NiMH. The best of both worlds?

I'm still not sold on something that requires storage charges and more monitoring than my current batteries though.

Hee hee - yes, having nerded around on the internet far too long, I actually went to my local hobby shop earlier this week and spoke to a human - who rather refreshingly didn't simply try and sell me the most expensive kit they had, but genuinely answered all my concerns, and fundamentally alleviated [most of] them.

I also had a brainstorm, which I'll explain in a minute - but for anyone else who has yet to make the jump to light speed LiPo, I think it is probably worth doing, certainly going forward... which is what I've done.

Essentially you have two styles of LiPo battery - soft case and hard case. A hard case isn't going to stop the thing catching fire or exploding, but it's more robust so the cells shouldn't get damaged or punctured in general use - significantly reducing the chance of the cells failing in the first place. For an off-road car, and particularly a crawler which is likely to take a tumble from time to time, I'd suggest sticking with a hard case - a little extra weight [of the case] really not being an issue in this kind of vehicle of course.

It's also worth noting that LiPo cells have a narrow voltage range of between 3V (min) and 4.2v (max) - and that should the voltage ever drop below 3V, you're in danger of [irreparably] damaging the cell - hence the requirement for a low voltage cut-off and/or alarm in your ESC. In simple mathematical terms, what this means is that 2S (2 cell) battery has a maximum voltage of 2 x 4.2v - ie. 8.4V, and a 3S battery has 3 x 4.2v - ie. 12.6v (although in practive a 3S more like 11.4v as I understand) - so appreciably more power than a 7.2v NiMh - although as long as your not running them at full speed the whole time, you're unlikely to burn out your existing brushed motors - again, in a crawler, this is unlikely - and what it does offer is a little extra 'boost' as required to get up a steep hill etc.

Essentially LiPos offer higher current for longer - while a NiMh battery slowly discharges and correspondingly reduces power as the voltage drops, the LiPo retains its [maximum] power longer, then drops off more dramatically. According to the guy in the store, in practice you'll know when a LiPo is almost exhausted as the power reduces noticeably... and you can always fit a low-voltage alarm (a little chip which plugs into the charge balance lead on the battery) to help warn you, particularly if the vehicle is being driven a distance away from you.

Charging - as you say Badcrumble, you can get chargers these days which work with both LiPo and NiMh, and a number of other cell types too. The charger I bought ($60) was not the cheapest available - online anyway, where they seem to start around $35  - but was at the cheaper end of those in the store, and the one the guy behind the counter recommended and uses himself.

Basically it would appear that all LiPo chargers us a similar four button system and LCD menus to choose the battery type, capacity and charge rate. It is a common perception that charging at a slower rate (ie. slow charging vs fast charging - less amps vs more amps) is less likely to overheat the battery, although in practice he said it doesn't really matter too much. Still, if you want to be 'safe' perhaps take more time and charge at a lower rate - eg. 3A for a 3000MAh battery, ie. about an hour) than try and force 10 Amps in there as a quick charge. for info. I charged my brand new 2S LiPo which comes with a 'storage' charge of around 3.6v per cell, in about half an hour using a 6A charge rate.

I didn't use/buy a fireproof charging bag, but those are readily available online if you wish, and something I will certainly purchase with my next battery - a good safety precaution.

Regarding 'storage charging' - yes, I agree that all sounds a bit complicated, but in practice - using these modern menu style chargers, you simply select 'storage charge' and charge your battery to that capacity (it cuts off automatically once the voltage - around 3.6v - has been reached), and then you store your batteries somewhere cool - in a cupboard for example. Before you run them again you just top them up (as I did, in about half an hour or less), or if you plan to leave them unused for an extended time, just hook them up to the charger periodically and check/top up they are still holding at 3.6v. note. these menu chargers have a cell voltage checker function too.

Obviously if you plan to run the vehicle again soon, you can just charge the battery completely in the normal way - ie. get in the habit of recharging your batteries soon after a run, rather then leave them empty as you might with a NiMh.

i-qp57NrV-XL.jpg

photo. this is a 2S shorty pack. Apparently there is no capacity/run-time difference between the short and regular length pack at the same mAh, so unless you want the extra weight, go short!

 

The main issue, which I highlighted and you referenced above, is that a number of my models have their NiMh batteries 'built in' under the dash/scuttle panel, and certainly aren't easy to access to remove/replace without undoing a number of screws and [lighting loom] connectors each time, so are typically charged in situ. As you might imagine, with the amount of time and effort I've put into some of these builds, the last thing I want is for any of them to catch fire while being charged.

However, taking stock of my current garage, I realised that both the 4Runner and the Jeep Wrangler which have those main vehicle NiMh batteries squirrelled away under the scuttle, also have a second battery compartment so that I can power their winches independently... Therefore all I need to do is rewire the cables so that the 'main' NiMh batteries (charged in situ) run the winches, while the easier access battery compartments (under the rear load-bay on the Wrangler, and hidden in the load-bay tool chest of the 4Runner) can now house the LiPo to run the motor - bingo!

My other trail-running trail rigs only have single batteries - the Defender 90 already has a quick-change battery compartment behind the truck-cab. and while my latest rebuild of the FJ40 does have the battery mounted under the scuttle, that really only requires 4 screws to be undone to lift the whole body off.

So it looks like I'll be buying a few more LiPo batteries after all - the only other thing required will be swapping the cheapy [but good!] Mad-Gear crawler ESCs currently fitted to my earlier builds with ones which have a dedicated LiPo cut-off circuit - fortunately I've fitted both the Capra and the FJ40 with suitable ESCs already, and those cost around $20 for the crawler [drag brake] specific version.

Looks like I've finally stumbled into the 21st century!

Jenny x

 

 

 

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