pleegwat

Agreed. It makes me want to go looking for an alternative solution.

Is there even a colour-coded 3l pin in LBG? I think there's only the 3l pin with bush (which also exists in several other conflicting colours) and the 3l axle (which isn't a pin).

Only if you mount them parallel to each other. What if you mount them in a trapezium shape - 3u between them at the wheel but 5u between them at the innermost mountpoint. Of course, I have no idea how you would formlock that, and it's going to cost you in ground clearance. I'm trying to think of other pieces with a ball socket, but all other options I can think of offhand are even longer.

Mine arrived today, and I noted something curious when I arrived at phase 2. The list of hoses mentioned at the start of that section included a hose that wasn't in the bag of hoses included in the box. Checking the inventory in the back of the booklet, it lists far more hoses, specifying 3 or 4 copies of hoses for which I only got one in the set. I suspect this to be an error in the manual, but it's not something I've encountered before.

My most common disassembly tools with technic are an 8l axle with stop to push things out, or a pair of pliers (more commonly my teeth) to pull them out. Though the modern brick separator has a 1l axle attached it's generally not long enough for me.

Looks impressive. I agree proportions seem off for a simple cannon. I think it might work as a missile launcher, though I don't think those use closed barrels? Something futuristic could explain a fat barrel (plasma artillery maybe?) but anything which isn't a self-propelled projectile is likely to involve more recoil than this silhouette can handle.

Even when losing the diffs (including everything related to diff locking)?

Is the steering motor on the axle or on the chassis (suspended or unsuspended)?

My first thought seeing this was "Don't I own a set which motor-drives these?" Well yes indeed. 8539. The hubs have pinholes, but can be driven by putting a 16z gear inside them.

That's not quite that simple. The motor has an internal brake and does not backdrive easily, but you do need to take measures to prevent the motor from back-driving the manual input.

You can try the following formula: o = o * (1 - a) + i * a where `i` is the input, `o` is the output, and `a` is a scaling factor between 0 and 1. A higher `a` is more sensitive to input changes. Of course strictly this is not a running average - instead if `a` is 1/3, then the most recent input counts as 1/3, the second most recent is 2/9, the third 4/27, etc.

But they do regularly omit the centre diff in 4x4 vehicles.

According to bricklink, it uses 2742 out of 3696 parts.

I think any kind of suspension is unlikely on a set that has a lifting axle. I do expect a driveline. 2 rearmost axles, simple difs, probably a mini L6. We hardly ever see the large cylinder pieces any more.

@Thirdwigg I did the B model, though likewise not admissible since it was posted before. And I may have taken too many liberties.

True, but those don't always match the position you want to mount the hose in. In some cases a pin perpendicular to the bush direction in that piece would work better.

The mechanism has two pneumatic valves, both of which are actuated automatically. The forward valve is connected to the main arm (in the original using a lever mechanism, in mine using a gear) and controls the pneumatic cylinder in the rear of the cab.. As the arm tips over, this valve switches to the other position. Importantly, this valve is in neutral approximately when the arm is at its topmost position. The pneumatic cylinder in the rear has as its only function to toggle the rear pneumatic valve. This rear pneumatic valve controls all other cylinders - the two cylinders raising the main arm, and the cylinder (one large on in the original, two small ones in my version) which close the jaw. The cycle starts when the arm is in the forward position. Pressure is applied to close the claw and raise the boom. On the original, the claw tends to close first, as it has the lowest load. In my version, this does not work very reliably, as the internal resistance of the two small cylinders is too high. The big cylinders at the sides start raising the boom. Once the boom crosses its topmost position, the forward valve switches. This reduces the pressure on the forward system, as part of the pressure is diverted to the rear cylinder. However, the main boom tips over and falls to its rearmost position before the rear cylinder has much of a chance to move. The rear cylinder takes a second or so to fully switch the rear valve, inverting the direction on the front system This causes the front system to work in reverse. Again, the claw tends to move first (even in my version, if there is a load in the claw the claw will open before the boom starts moving). The boom pulls back forward, and as it crosses the topmost position the forward valve is switched again. After the forward valve switches, the boom falls back into its full forward position, and the rear cylinder moves inverting the front system back to its starting position. The loop repeats.

I don't think you could get them to mesh reliably.

Exactly - the original required a more space-consuming lever mechanism. Between that and the steering axle sitting below the racks instead of above I've freed up quite some space, though most of it ends up sitting unused below the compressor unit.

The 8868 B model has always been a favourite of mine because of the fully automated pneumatic loop included in it. Some time last year I realised that the new pneumatic valves introduced with 42080 might allow a more elegant way to implement this same mechanism, and I decided to try for a 'modern-style' build, in studless style. My first concepts were on power functions, but nothing quite worked for me until I decided to switch to PU and put the battery below the cargo rack. Several months of off-and-on working later this is the result It doesn't work quite as well as I'd like to. Particularly the small cylinders I used on the claw have too much internal resistance (or the arm is not heavy enough) leading it to not always be closed correctly. The front valve is not hooked up to the arm directly but has a gearing mechanism, since the axle holes don't line up. You can also see the rear valve, which similarly required some fiddling to line up. The 'dumb' technic hub would have worked better here. Working steering wheel Detail of the compressor Chassis shot. Unfortunately, while the PU program is trivial, it is still a PU program and I can't run it and record video on the same smartphone at the same time. I may record one when I get a guest over to assist.

I think C+ calibration could detect incorrectly assembled hard-coupled motors turning against each other.

I bought this two months ago; definitely a very impressive model.

Pumps can also leak internally, which is not as easily fixed.

I don't think there's enough thickness for that. Especially since you wouldn't want the shim to work itself into an adjacent axle hole.

I know back in the day I did a motorisation with PF motors and if I remember correctly I used four 5:3 geardowns, definittely no worm gears.