Anyway, back the point.  My car is complete.  It took a bit of doing, and a bit of redoing of what I’d already done, but the end result is pretty satisfactory.  If you remember from my previous post, the front suspension was already sagging under the weight of the car, so rather than trying to reduce the weight I opted to increase the strength of the suspension to compensate.  That meant doubling up the springs, using the ones I’d been using for the rear axle and transplanting them into the front subframe.  Of course, that was easier said than done, and I had to make a few modifications to make room for two springs.  But I got there in the end, and the result is a front suspension setup that is twice as strong as it was – still with plenty of movement, but it feels like it’s actually capable of supporting the car now!

It’s not without its downfalls, however.  With the increased weight there is more pressure on the parts, and a couple of times now the custom suspension arms I made have fallen apart under the strain.  If that persists I may have to further strengthen those too.  But for just driving around it seems to be fine.

I also found it useful to make myself a temporary jig for working on the car.  It’s so heavy now that just picking it up or laying it on its side to work on it was becoming more difficult, so I chocked up the rear wheels and propped the front of the car up with a large bit of Lego scenery, and that did the job nicely.  It was like I was working on a real car.  But then, that’s been the experience all along, taking inspiration from real mechanical setups to create a Lego Technic car that functions and looks like a full scale road-going vehicle.  It’s been quite a learning experience, and one that will no doubt be helpful in shaping future projects.

Then of course there’s the rear bodywork, which I started and finished in one evening.  It’s not brilliant, on account of not having nearly enough bricks to do it justice, but I think I’ve got the basics there to give enough shape to the car as a whole.  It doesn’t have a boot, and there is little in the way of interior design, and the doors are merely hinted at.  Still, it looks like a car.  It’s got rear lights in the right place (even if they don’t light up).  It’s even got fake exhaust pipes.

The end result is a Lego model that looks like a car.  It works like a car, in that it has a V6 engine connected to the rear wheels, it has working steering that connects the front wheels to the steering wheel (and the additional steering wheel on the roof), it has independent suspension on the front and live axle suspension at the rear, it has front headlights that work, and it has a bodywork in matching colours that makes it look at least a little like an American muscle car.  Sure, it’s not as complete as I’d like it to be, and the doors don’t open, and the interior steering wheel doesn’t quite line up with the driver’s seat, and the wheels don’t quite match the style of the car.  But hey, I’ve not got as much Lego as some other, more obsessed people out there.  I’m pleased with it.

I mentioned in passing about future projects.  Since the Lego is out on the floor, I figured I’d make a space ship as well while I was at it.  That’s still in progress, not a lot to show at the moment.  It’s got a flight deck with a captain sitting at a range of controls, and a communication/research room behind it with another little man looking at more controls.  Behind that will be the cargo bay, holding an exploration vehicle of some sort.  It’ll be a research craft rather than anything with firepower, and will hopefully have an array of tools for exploring different places, working landing gear, and possibly bunk beds.  Who knows.  I’ll probably post details of that up here too eventually.

With the basic chassis pretty much sorted I started work on the body, taking some inspiration from a Ford Mustang but generally doing what I could with the pieces I have to make something vaguely resembling a muscle car.  First came the front bumper, which incorporated some cool headlights.  Photos don’t do justice to just how cool they look, especially in the dark.  I’m going for a red body, with a white stripe down the middle.  Making convincing curves with Lego has always been a challenge, and the result is usually a somewhat angular version of the intended curves.  Basically, use your imagination and you’ll see a pretty car underneath.

With the front bumper and wheel arches sculpted, I became aware that the front of the car was fast becoming quite heavy, and the suspension was taking a lot more weight than I’d anticipated.  I should have learnt that lesson from when I made my Batman Tumbler, when I had a similar problem with the front suspension (though in all fairness that was a complicated setup, more so than this one).  I don’t think it helped that I moved the engine so that it was directly over the wheels, effectively pushing a lot more of the weight to the front of the car.  The front bumper is also quite dense, and loathe as I am to strip it back I’m beginning to think I might have to.  It’s either that or have the front wheels scraping the top of the wheel arches the whole time and losing all the action in the suspension, which would be a shame.

I also made a start on the rest of the body, tweaking the rear suspension mounts and making the rear subframe more rigid thanks to a sort of roll bar I’ve installed in a bright yellow.  It’s far from being cosmetic though, with the diagonals really stiffening up the rear of the car.  It also meant I had something to attach the roof to.  Creating the front windscreen was a nice challenge too, creating a flexible series of struts that eventually connected together to give a more realistic shape to the top of the car.  While I was at it I also routed the steering both to an interior steering wheel (just in case I inexplicably shrink in size so I can sit inside the car) and to an alternative steering wheel mounted conveniently on the roof so I can actually steer it.

The main problem I foresee for tomorrow is finding enough red pieces.  I’m fast running out of them and I still have a lot of sculpting to do on the rear end.  I think it’s going to end up being somewhat minimal at the back, unless I can justify working in some other colours.  Reducing the weight of the front of the car might help though, freeing up some more red pieces that can be reused elsewhere.  Even so, I doubt I’ll have enough left over to put in working doors, and with the weight issue already surfacing it’s unlikely I’ll be able to do much with the interior either.  Still, I’m really pleased with the progress today – it’s finally looking like a car!

The front subframe also now has a diagonal strut on each side, further strengthening it, which is no bad thing given that’s where a lot of the force is going to be taken, right over the wheels.  I’ve also widened the front subframe to give me more space between the steering shaft and the drive shaft, which has allowed for a far more compact yet satisfactory connection between engine and drive shaft.  It now runs smoothly and efficiently with only the most essential cogs in between (I want to retain a high cog ratio so that the engine spins fast even when the car is moving slowly).  Oh, and the front subframe has been significantly shortened, too.

I haven’t touched the rear end today, and I still haven’t made a start on the bodywork, but that’ll come.  I figured out today a way of having powered lights in the front (thanks to a couple of my old models), which will be fun.  Not particularly bright, but the effect will still be there.  Just about.  Unfortunately I’m coming down with a cold, so staying up late to work on the project just isn’t going to happen.  I also haven’t taken any photos of today’s progress, so I’ll try to do that tomorrow morning when there’s some nice natural light, and update this post with some close-up shots. Photos now included!

Next on my list of things to sort out was the rear axle, which just looked plain ugly.  It would do the job, and would probably be mostly hidden by the bodywork once that was figured out, but I just didn’t like the way it looked or the way it worked – it just wasn’t realistic in any way shape or form.  So that was stripped out too.

In its place is a rear axle that is lighter, uses far fewer pieces, and actually works more realistically too.  I’ve shortened the wheelbase in the process, which should make the car turn a little easier.  It’s still a live axle (which means the axle is a solid fixed horizontal bar connecting the wheels, so movement on one wheel will affect the other), but as it happens there is enough flexibility in the setup that each wheel can actually move on its own to a certain extent, despite the leading arms – technically it shouldn’t work like that, but I think it’s just loose enough to allow it.  The next test will be to see if it still does that once the rear subframe has been further strengthened; I don’t think the independence is being provided by the twisting of the subframe, but increased rigidity may slightly reduce it.  We’ll see.

So, I’ve got the chassis to a stage now where I’m happy with it.  The engine is smoother too, having replaced the elastic bands with proper cogs.  I even took the car for a test drive around the landing to see how it responded.  The engine makes a reasonable noise, given that it’s made of Lego, and the suspension can handle reasonable-sized bumps on any wheel, which is good.  Next time I’ll be routing the steering to somewhere useful and starting on building some bodywork around the chassis.  It’s all coming together nicely!

I’ve made a start on the rear of the car too, building the rear axle.  Rather than tackling the complexities of independent driven suspension at the rear I’ve gone for a live axle with movement in only one direction.  It makes it a lot simpler, though considerably less realistic – movement on one side of the car will affect the other side just as much, which isn’t ideal.  Still, at least it works.  There’s a differential in there too, and the drive shaft has been connected to the engine at the front of the car.  I wanted to have the engine spinning at a good speed when the car is moving, so I’ve geared it all up accordingly.  Unfortunately that does mean that there’s a fair amount of resistance, but I may be able to live with that.  It may be that I’ll be able to connect in an electric motor later on to drive the engine directly and have it drive the car at a manageable speed.

I’ve also been trying to address the problem of the steering.  While the steering/suspension system that I took from the other model does work, it’s proving a little imprecise.  This is largely down to the ultra-compactness of the steering mechanism, compounded by the big heavy wheels I’m using.  I’ve geared it down as I’ve routed the steering shaft past the engine, but now there is so much play in the action that it’s pretty hard to keep in a straight line, especially when one wheel hits a small bump – the front wheels just turn on their own.  I think I might have to re-think the steering mechanism and try to build a little more control into it, otherwise it’s going to be undrivable.

No idea what sort of car it’s going to be yet, or what it’s going to look like, or even what colour it’s going to be.  I guess that’ll present itself later when the chassis is done.  This project is very evolutionary – it feels like the model is instructing me on how it should be built rather than the other way round!

Today I started work on the front of the car, trying to get a setup capable of steering and suspension in a small space (I want to leave space for the engine in the front too).  In the end I stole an idea from another model, and used the front suspension and steering system almost straight out of the instruction booklet.  The next problem was working out how to connect that solidly to a subframe and not have it get in the way of the drivetrain.

The steering mechanism puts the steering column smack bang in the centre of the subframe, which would be fine were it not for the fact that that’s exactly where I want the drive shaft to be.  I’m going to have to move the steering column to one side eventually so they can sit next to each other.

The engine itself is going to be a V6, connected directly to the rear wheels (no gearbox, no clutch, no electric motor, just keeping things simple for now).

At the moment I’m having real difficulty figuring out how to connect the front axle to the subframe and the engine.  I think I’ll have to sleep on it and see if I can visualise a way through this…

Some of you may remember that a while back I spent a week creating a Lego ‘Tumbler’ (from the film Batman Begins), with working suspension and steering.  That was a technical challenge, but I managed to pull it off eventually.  I even made a couple of videos of the progress.  Since then it’s sat quietly on top of the unit in the lounge, silently gathering dust and being generally forgotten.  Until recently I couldn’t bear it any longer, and just had to start thinking about the next version.  Yes, not satisfied with a Lego Tumbler that has working suspension and steering, now I want to put motors in it too.

This presents several problems, however.  The addition of two chunky motors (one for forward/backward motion, one for steering) will add a significant amount of weight to the model, and the suspension is already struggling to cope with the weight as it is.  So I am having to look into better, more effective ways of setting up the suspension, and generally putting the rest of the model on a diet.

At the front of the car, the setup is especially complicated, because it doesn’t use a conventional steering rack.  Just take a look at the original Tumbler and you’ll see just how odd it is.  Squeezing a comparative mechanism into something much smaller is something of a challenge, and although I managed it last time it was a little crude in places, and I’ve been thinking about alternatives.  From looking at various pictures and the bonus DVD I can see that the actual Tumbler uses a system that would actually be pretty much impossible in Lego, simply because of the amount of space it would take up – it works really well, but the Lego components are just too large relative to the wheel to accommodate that approach.  I’ve done a lot of mental experimentation (which is quite difficult without having the Lego in front of you), and pretty much concluded that my previous method will probably still be the most effective, I’ll just have to refine it.

At the back of the car things are equally complicated, though not because the setup itself is difficult.  People have been making cars with suspension for over a hundred years, so it’s not actually something that’s technically complex.  My problem is that Lego likes to be at right angles, not arbitrary angles to cope with pieces moving in an arc.

The problem derives from the combination of needing each wheel to be sprung, preferably independently, whilst still being connected to the engine so as to be powered.  I have done much research on the various different suspension techniques used in real life, and most of them are actually quite difficult to reproduce faithfully in Lego.  The simplest form of rear suspension is the leaf spring, which works really well in lorries and heavy vehicles.  But Lego doesn’t do leaf springs.  It has coils.  I can’t use a proper independent suspension system because I don’t have enough universal joints to connect the wheels to the differential.  A fixed axle is good and simple, but only reliably works in Lego when both wheels are going up and down at the same time – having the wheels going up and down independently causes alignment problems because Lego doesn’t like odd angles.  Trailing arms are out of the question, as are multi-link, A-arm, and MacPherson struts, for much the same reason.

Don’t get me wrong, suspension is possible with Lego – I’ve done it many times before very successfully.  It’s just a matter of choosing the right setup for this particular application, where space and weight are limited.  I may have to resort to some ‘fudging’ or using a limited style of suspension, which would be a shame, but at the moment I’m struggling to see an alternative.  I’m hoping it will all become clearer once I actually get the Lego out and start fiddling.  Ellie is at back at work starting tomorrow, so I’m planning on taking over the lounge each evening next week and see what I can do.  It’ll be shame to take apart the old model, but it needs to be done, and it’ll no doubt be even more satisfying to get a proper motorised version completed!

As with last time, I’ll put photos up at some point to document the progress.  And since the technical aspect is so important, I’ll try to take some close-up photos of the mechanisms for those as geeky as me who like such details.  I’ll also need a good supply of tea to get me through…