amorti

Those long plates are used as leaf springs. They flex, which allows the wheels to rise and fall. I'm nearly there with decoding the front suspension. What do the 9L steering links do?

Wow. Just wow...

No HOG, this is an RC model. The benefit I'd be looking for is helping it to track straight as it gets up to speed. I'll come back when I have pics :)

@astyanax Yebbut, pushrod suspension I don't have any right now. I built a test rig then stripped it for parts. Basically it was the original (it's complete by step 45), but with a 5L wishbone slipped in between the bottom wishbones, and a shorter liftarm inside a 6L wishbone for the top wishbone. There seems to be slightly more space in the front of the wheel housing, so I favoured moving the bottom ball joint forward a little and leaving the top in the same alignment. That might change when all the parts are in, and I can see where any space really is, or isn't. Two main problems came up: building a wheel carrier with the Lego 3 pin hub which would fit inside the wheel and not have bump steer (Land Rover wheels might solve this but they'd only be connected by friction on one axle, which might not be enough to hold. not being able to brace across the ball joints. The model is 1.7kg and will be pretty quick, it needs that part braced for sure. Part of this was I don't have any 5L steering rods, only 6L. Doesn't need to be right on the ball joints I guess, which might make it easier. I will come back with pictures when my bricklink order gets in! Is there any argument that just caster angle is enough and KPI isn't necessary when using the Porsche wheels? The steering centre is pretty close to the middle of the tyre anyway, much more so than with the older wheels.

I just saw it - looks amazing! I guess once I've finished Mantis and played with it a bit, I'll be ordering 11 more wishbones and some buggy motors :D

To be clear: I'm not pointing out any errors here. Only different ways of making the connections. I'm not big on the driveshafts being 2L shorter than the wishbones, but I've played about with it enough now to realise that until Lego gives us wheel hubs without a portal reduction which accept the new CV joints, 1L shorter is as good as it gets and at that point it kind of might as well be 2L shorter, if it works. Same concept for the odd length front wishbones. In theory it should be good as it's like a real car, although without ball joints it'll be binding to a theoretical level. But then, I also don't see any better way to do it because you won't be able to brace across the ball joints of you use them. In the end it's only a plastic toy, you have to pick the compromises you prefer, that's all I'm doing.

Change the wheel axles from 5.5L to 4L with stop. That allows you to change the 2L axles in the tie rods for 4L with stop. Should do it? Edit: oops, forgot it's 4wd. Edit again: But a similar idea should work if you make the lower 4L with stop go in from the other end, and connect the tie rod 1L lower using a 1L liftarm as a spacer. Edit again: Or it might be in harm's way if you go lower, so maybe go higher by flipping the upper perpendicular connector (ball joint) the other way up. That also allows you to flip the other one, slightly improving ground clearance at that point. At that point one of these might be ideal: https://www.brickowl.com/catalog/lego-axle-1-5-with-perpendicular-axle-connector-6553

I guess I wasn't thinking of it as an almost C-model. 90% is really good going, especially since they're quite different vehicles.

Put a 2L axle in the cross hole on the steering rack, go down out the front with one of these , put a 2L axle in the bottom also, and use one of these to get over to the steering knuckle. Stick a 3L sliding pin through that. Now, it will be less likely to pop out because you're relying on the form locking from the 3L connector rather than only the friction locking of the sliding pin.

Looks very sturdy. Front tie rods could be considered a fuse? You could easily enough form lock them in place though.

Waiting for my orders from bricklink and I feel like a dog sitting waiting for the master to come home. So, more time to fiddle and tweak with what I have to hand, then. I have given back the shorter driveshafts. Instead, I've redesigned the transmission frame with some didumos level form locking. You can actually notice the gears spin more freely in this setup. I think it's because 5 liftarms stacked doesn't quite make 5L, but if you lock it like this, the distances between the gears are exactly right. Apologies that the pictures are maybe hard to decipher, it's largely made of darkside bricks and nearly everything is black. Those are black 5x11 frames on their sides, form-locking 5x7 frames sandwiched together. Those sideways frames then give a good solid mount for the wishbones, and somewhere solid to put the ends of all the axles for the 24&8 tooth gears. All with way fewer small connectors and less freeplay. There are 92907 connectors holding the top frame on, they are really solid like that. This also helps give a tighter spacing for the shocks and rear cowl. I'm hoping the crank handles in the bottom won't be necessary once the cockpit is built up, but if so then I'll need to find a neater way to brace that section. The rear bodywork mounts had to be redesigned, but it's all come out nice and sturdy. Bit simpler as I don't need the tilting spoiler. I test fitted the rear cowl, it just needed the lower rear panels swapped for 21/22 panels to clear so as to the top legs of the sideways frames. I used some different pieces for the exhausts, as I didn't like that they were only lodged on there. These ones have a 5.5L axle through, so can't fall off. Really really looking forward to finishing and driving it now!

Those 4 gears are serving to reduce the speed of the M motor just slightly. They also cover the misalignment of half a stud. Is there space to leave that reduction out and go straight into the steering gear instead?

The new large turntables with only gear teeth on the outside are a fair bit tighter than the older type. But there's always going to be an amount of play in Lego. Do you suppose the new 5-gear differentials would have less play?

Bruno's C63 combines one L and one XL motor so it's possible. I can't remember if they were on different ratios unfortunately. Depends what you want the model to do. If you want maximum speed just get the two missing L motors, reason I say that is the motor module is very well braced using pin holes which aren't present in XL motors. If you don't need so much power just use two of your existing motors.

This should solve the #5 connector for the flag. Sorry for linking not pasting the image, bricksafe does weird things when the photo is not square to begin with. (PS: Welcome to the darkside, we have everything in every colour. That sounds fun until you realise you just spent 5 minutes looking for two of a thing in the same colour, ANY FRICKIN' COLOUR) The rest of today's modding was less successful but still fun I mocked up 4x wishbones using a bunch of 5L liftarms and 5L thin beams. First impression was, "hmm this suspension is very soft. No dude, the other type of stiffness was missing from the suspension. With the wishbones in the original position the suspension is all gone by about a 900g loading, but with the wishbones hung 1L higher up, the suspension travel is all gone by about 400g. With a 1.7kg vehicle weight that's biased to the rear where the motors and transmission are, that would probably means it'd scrape its belly the whole time. So the wishbones will have to affix in the original positions. I also gave up trying to get the outer CV joint in line with the suspension pivot. The outer diameter of the joint collides with the only position you can mount the bottoms of the springs. It could be done with the old CV joints, but that's not an option as I've already exploded two of those in Icarus; it can literally shear the end right off the male half. I tested a bunch of possible driveshaft configurations including the original and I'm still pleased that I could get the driveshaft to 1L longer, which is lucky because I've cut them now. In the original configuration there's almost 2mm change in the driveshaft length through the suspension stroke. It's much less after the changes. I've used a 1.9mm o-ring to take up the 1/4L freeplay and it is quite happily not squished through the suspension stroke.

No Lego part number! Literally a rubber O-ring. https://www.amazon.com/1-9mm-4-8mm-Metric-Replacement-ring/dp/B01B3R8U1O?ref_=d6k_applink_bb_marketplace 4.8mm is the equivalent diameter of a Technic axle, this would take up about 1.9mm (~0.25L) of slack across the axle. No idea if the red selector would grip better, but if changing gear doesn't make a real difference to speed, then it doesn't really matter if shifting is reliable as there's no need to shift. However, does it maybe make more difference in absolute terms than you are thinking? When you're talking about 1400rpm, a small percentage change in gear ratio could be a big difference to road speed ?

This would definitely let you put more force on the driving ring to hold it in, but is that the ideal solution? I think you can then end up with the selector fork and driving gear having too much friction to run smoothly. It would also be slower to shift, which could allow the 'splines' on the driving and clutch gears to be ground down. Is there space to put a wave selector on both sides of the driving ring? Would you be willing to use an O-ring to take away any slack between the red and blue clutch gears and the frame they're in?

Thanks for the tip on the #5 connector, it would definitely have caused me a problem later on! Back to the drawing board for that. I don't have a long career in studless Technic, having only ended my "dark age" this last Christmas, however building and tinkering on @Didumos69's greyhound and rocky MOCs have taught me a lot about form-locking and efficiency of parts usage. This rear module (both the original cut and mine!) really fit D's mantra of a pin hole empty being a waste!

Do you have a phone or camera that can do extreme slow motion videos? Mk ight be helpful to see what's actually happening when it skips; who's bending or moving to allow it to miss? I wonder if using carbon or metal axles may help?

I'm still waiting for a bricklink order which contains most of the big frames and all the wishbones, so I can't build it all yet. But tonight I did start at building the rear module. The way the rear wishbones were off centre to the driveshaft (CV joints 1L too high and 1L too far out from the vehicle's centre line) was driving me crazy. So I redesigned it. I decided to try to channel @Madoca 1977's original instructions for the module: View Building Instructions (Photo Sequence) Yes, I realised right after uploading the pictures that it's a little easier to construct if you use a 3L pin on the bottom 6536 connector like you need to anyway for the panel to clip on. You do have to shorten the new CV joints by 1L for this to work, so if that's not for you then skip ahead :) I've skipped the axle which drives the rear spoiler going up and down. I've had a couple of servos die on me lately, so I want to leave anything unnecessary off the steering. You'd lose some rigidity, but you could put it back in with something based on this picture, if you wanted to keep it. The ride height will be about 1 stud higher since the wishbones will now be angled down a little. I don't yet have any thin wishbones to test it, but I tried a normal lift-arm as a dummy wishbone and it just barely touches where the sloped panel will be so I think where the wishbones are thinner it'll be fine. Once I've got to that point I'll look to see whether it's fine with the extra ground clearance, whether I fit softer springs so it has some sag (like a real car), or whether I look to get that 1 stud back in the hub assembly. I'll need to redesign that anyway so the CV joint sits in the same plane as the suspension pivot. Next thing to try modding will be the front suspension. I think this is going to be fast enough that it'll need all the extra stability it can get, so I'd like to give it some caster angle, maybe even some kingpin inclination too although an experiment on that has shown it's not easy to avoid bump steer, and you can't easily get a brace across the ball joints either :/

I'm sure it would be child's play for @nicjasno, but I've just spent about 3 enjoyable but ultimately fruitless hours trying to design something based on his pictures here. My problem, I think, is trying to use Lego hubs. You have to use that for the Porsche wheels, but then it's very difficult to get everything in the available space (inside the wheel) without getting bump steer. Maybe it would be easier with Land Rover wheels. With the axle hole through them, then I could just replicate the hub in those pictures. A problem for another day, I think.

Well now I am wondering if those unequal length wishbones will be happy without ball joints. I guess it will be fine when the suspension is unloaded as the wishbones sit pretty much parallel to the ground and the frictionless pins are at right angles, but I suspect it will be binding up at least a little bit at the top of its travel. Now it looks like I've got my first "realistic" front suspension setup to build - I'm actually looking forward to that :)

I've never been a fan of artificially-limited steering. You can end up with the servo trying to pull the front of the car apart, which is no good for the chassis or the 30€ motor. I had that problem on Bruno's C63. Virtual pivot steering is definitely a cool idea. I've watched the series of videos from nicjasno with great interest. On the one hand this would be exactly the car to try that on because it doesn't have a lot of bodywork constraints, but on the other hand, it already has unequal length wishbones, and uses the cool F1 wishbone parts. I'm thinking/hoping that with those F1 wishbones triangulating the front wheel, and no upper/lower ball joints, the front wheels should be pretty solidly mounted and it'd be a shame to spoil that, too.

Thank you @astyanax that's really a big help! I think you're right that those swirl tyres will look too skinny, at least on the rear. Also since my Mantis will be white, I think the grey of those wheels won't work. Those Unimog tyres look amazing. It really changes the character of the car from a Le Mans racer, to something from a Batman movie. I wonder if they could steer if they were fitted on Land Rover rims with the new offset?

Clever idea, maybe try fitting it into a basic chassis to see if it works? I think you could maybe use two different rate springs, a soft and a hard, to give it a more defined step between gears.