6 axles large truck mounted crane.

This was my most impressive crane truck ever. This model was built during the second half of 2000. Here is the bad news: I lost ALL pictures of the finished model (I am so smart). Therefore, I only have about 10 pictures of the construction stages. Needless to say it took me a long time to calm down. I finally decided to go ahead and post these pictures anyway.

Driving/steering is done by hand (this model was so heavy I did not think any kind of motor would move it). Turntable is powered by a geared-down motor. Stabilizer legs are raised/lowered by two regular motors. There are four pairs of stabilizers. Each pair is operated independently (through a gearbox). The boom is a three stage telescopic boom raised/lowered by eight pneumatic pistons. Two motors on the turret power the string spools; one for the hook, and the other to expand/retract the boom.

	The base chassis. Three sets of two axles each. Front and rear axle pairs are countersteered from each other. You can see the mounting points for the stabilizers.
	Other view to show the length of the chassis.The driver's cab will be here in the front.
	Stabilizers are in place, and so is the floor of the driver's cab. The two motors behind the front axles will raise/lower the stabilizers.
	See the air tanks behind the middle set of axles. Above the air tanks is the gearbox (see the yellow lever) to switch between each set of stabilizers.
	On the extreme right of the picture, you can see the motor to power the compressor. The compressor piston is in between the two middle axles. The geared down motor above the second middle axle rotates the turntable which is mounted above the first rear axle.
	The base is now functioning and the cab is done. Notice that the geared down motor to rotate the turntable has been moved to the back of the chassis because of clearance problems.
	You can see the 8 air pistons: 2 rows of three and one row of two. This arrangement can lift a lot of weight and still get a wide angle to raise the boom from horizontal to completely vertical.
	In the back, on the turret, you can see two motors that will work the string spools. The now empty space in front of the turntable hosts the polarity reversers (you can see two of them).
	The three-section boom is mounted (see below for working diagram). The turret operator cab is there, and you can see the counterweight holder at the back of the turret.
	The two motors are mounted above and behind the boom, just left of the operator's cab. Each boom section has a length of about 100 studs. Fully extended and at 80 degrees up from horizontal, the top of the boom was about 2 meters (6 feet) high.

One fixed string (red) pulls section 3 out when section is pulled out. This arrangement makes sections 2 and 3 extend at the same rate. When the motors feed slack to the blue string, the boom's own weight pulls it back in.