Rottermannen / tv2mustdie posted this YouTube video of his fully-functional Lego Technic

**Crawler Crane**which can lift 4 kg (8.8 lbs.) at 50 studs distance -- "4 kg (7 x 3.5" Hard disks) at 50 studs radius. Slewing and crawlers working. 5.2 kg ballast + 1.8 kg central ballast." It can lift 7 kg (15.4 lbs.) at a closer distance. His Flickr photoset has 13 pictures with descriptions of how his various load tests developed over time.

He description of his MOC:

"LEGO Technic Lattice Boom Crawler Crane

Lattice boom crawler crane with 9 kg lift capacity made from LEGO Technic.

max. lifting capacity 9 kg at 200 mm (25 studs)

max. load moment 18 Nm

Main boom 432 to 1152 mm (54 to 144 studs)

Lattice jib 420 to 1120 mm (60 to 140 studs)

Crane weight (base + superstructure) 2.7 kg

Central ballast 1.8 kg

Superstructure ballast 6.2 kg

The superstructure is mounted to the base through a turntable powered by 1 small power functions electric motor enabling slewing under full load. The superstructure is equipped with 4 winches and 6.2 kg of counterweight.

The base is equipped with 1.8 kg of ballast and crawlers powered by 2 small power functions electric motors enabling the crane to move with full load.

The lattice boom consists of 2 to 5 sections (54 to 144 studs length) and is connected to an A-frame which is raised and lowered by 2 times 12 falls powered by 2 winches each with 1 large power functions electric motors. The hook is lifted with 2 times 12 falls powered by 2 winches each with large power functions electric motors.

T

he jib is raised and lowered by 1 winch with 1 small power functions electric motor (12 falls) and the jib hook is lifted with 8 falls powered by 1 winch with 1 small power functions electric motor.

Non lego parts:

2 axial steel roller bearings are fitted to the turntable to allow slewing with max load moment. The crane will have similar load capacity without them but slewing will not be possible.

1 mm braided ropes are used on all winches."