Another take on racing trucks. Features fully modular design, return-to-center steering system, full suspension, speedometer and lights.

Datasheet:

Completion date: 20/01/2009
Power: electric (Power Functions)
Dimensions:  length 43 studs / width 18 studs / height 25 studs
Weight: 1.69 kg
Suspension:  front – pendular without shock absorbers/ rear –  dragged axle
Motors: 1 x PF Medium, 2 x PF XL

After a long break, I’ve come back to the subject of the racing trucks. I wanted something faster and better-looking than my two previous trucks, something that I could call ultimate in terms of performance. The only way to achieve the latter goal was, in my opinion, a fully modular design. Therefore, the truck was built out of three basic modules: a cabin, front part of the chassis with the entire steering system, and rear part of the chassis with entire drivetrain and detachable battery box. Thus it was quite easy to make adjustments to the drivetrain and the steering system.

The drivetrain was powered by two PF XL motors connected by a rigid axle (one of them with polarity switched). The rear axle was driven via a small number of double bevel gears, and a chain that transferred the drive to a 4-studs wide differential. The construction of the rear axle was quite uncommon: its structure consisted of several axles and Technic triangles, the differential was moved to the side, and the space gained this way was occupied by a Lego speedometer sensor. The axle was suspended on two stiff shock absorbers, and given a very small travel distance.

The steering system used the mini pendular steered suspension module developed shortly earlier, with the rubber band layout that enabled return-to-center steering. This function lacked some precision, limited steering lock and disabled the proportional steering, but it served its essential purpose.

The modular design involved a single disadvantage – a necessity to locate most of the PF elements behind the cabin, so that they could be easily accessed when e.g. the steering motor had to be disconnected along with the front chassis module. It has significantly degraded the aesthetic impression given by the truck’s cab.

The performance of the truck was way below my expectations. The drivetrain provided excellent speed when the truck’s weight was only a little bit over 1 kilogram, but with the final weight of 1.69 kg the speed was only half as good. After adjusting the gear ratio I was only able to draw close to 4 kmph (compared to the initial 7 kmph of the 1-kilogram heavy chassis). Therefore, despite a number of innovative features and the satisfactory look of the truck, I considered it a major disappointment. It made me think that perhaps the assumed scale of the vehicle and the final weight it imposed were too high for the PF system to provide a decent speed. Certainly a smaller, lighter and suspensionless truck could run much faster.

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Concept of a chopper built out of several interchangeable modules. Features full suspension and V2 piston engine.

Datasheet:

Completion date: 19/10/2008
Power: none
Dimensions:  various
Weight: various
Suspension:  full independent with shock absorbers
Motors: none

Some time ago, I’ve watched the entire process of building a custom chopper from a scratch. I thought it could be mimicked with Lego brick, through a modular system where one universal frame can have a number of compliant modules attached to it. I’ve designed such a system, trying to keep it close to the original one, and in result it consisted of a frame, front and rear wheels, front suspensions, handlebars, engines, seats, exhausts, fuel tanks, rear suspensions and rear fenders. Though I’ve only built few modules of each type, it offered a substantial number of possible combinations, out of which I’ve only assembled five. Each version featured full independent suspension and a V2 piston engine driven by the rear wheel through a chain and a rubber band. Once more, mister Fluffy has been kind enough to honour me with his model’s skills. It is accurate to say that we did a nude session with one of the chopper’s versions

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