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Subject: 
Re: Tallest lego crane
Newsgroups: 
lugnet.technic
Date: 
Sun, 2 Jan 2005 01:14:59 GMT
Viewed: 
3926 times
  
In lugnet.general, Ross Crawford wrote:
In lugnet.general, Alvin Brant wrote:
In lugnet.general, Ross Crawford wrote:
In lugnet.general, Alvin Brant wrote:
Good Afternoon All.

I was just curious if anyone could tell me if there is any record for the
tallest lego crane model?  I have just completed the first set up of my own
version of a Liebherr LR-11200 Crawler Crane that is 18 feet tall (almost 6
meters).  There are some pictures posted at the following link.

http://brickshelf.com/cgi-bin/gallery.cgi?f=104438

Check out the Stage 3 pictures for the full setup.  I am currently waiting on an
additional order of parts to add another section to the jib, bringing the total
height to 20 feet.  I think that this will be as tall as I can go.

If anyone has any insight on this matter, please feel let me know.

Man, can I please borrow your nice smooth level driveway?????

But seriously, nice job. I think 20 feet should be possible, it's better to add
the extra length to the luffing jib, because that reduces the weight you need to
raise (1/2 the extra weight is carried by the wheels when raising the boom).

Have you tried a SDBW configuration to see how high you can get? Lifting a
straight boom puts much more stress on everything, it's fun to try!

ROSCO

Ross, I have yet to try the SDBW configuration, however if I add all the
counterweihgts to the Superlift, the crane will hold the boom off the ground at
0 degrees. The only reason i use the wheels is to ease the stress on the motors,
and to speed things up a bit. This puts the same stress on the superstructure as
the SDBW configuration, but does not put as much stress on the boom itself.  I
will have to try it out and let you know what happens.

Yep, that is also the reason real cranes use wheels when raising luffing jibs.
Older cranes often had a special dolly that the tip of the jib rested on for
that purpose, but newer cranes seem to have the axle built into the jib tip, and
just have removable wheels.

My minifig scale LG-1550 can lift a 1.5 metre boom+jib quite easily without the
superlift, with just the standard ballast. But it can only raise about 1 metre
of straight boom before I have to reach for the extra ballast.

Another thing I noticed, the line for your luffing jib seems to go straight up
to the tip of the luffing derrick, I think on the real crane it is actually run
through a pulley at the base of the derrick (top of boom) first? I know most
cranes do it that way, not sure about the 11200.

Yes, it is supposed to go through a pully at the end of the derrick, but this
was the first time it has been put together, so I missed a few things.

Also I'd be interested in how you did the slew ring. Is it just a technic
turntable, or did you do it another way?

It is a technic turntable, and I used hinge plates and bricks along with 2 x 2
tiles to build a 24 stud wide slew ring.  I will add some pictures of it when I
disassemle the base.  My gearing is off, so the crane would not slew under its
own power, which means that i will have to do some additional work on it.  To be
totally honest, i am not all that concerned with the slewing since i dont think
that i am going to be able to make it smooth with the total 50 lbs of
counterweight loaded on the superlift dolly.

By the way, I saw your stage 3, and am very impressed.

Thanks! That was just a test, I can't raise it any higher at my house, but I was
happy with it.

ROSCO

FUT: .technic



Message is in Reply To:
  Re: Tallest lego crane
 
(...) Yep, that is also the reason real cranes use wheels when raising luffing jibs. Older cranes often had a special dolly that the tip of the jib rested on for that purpose, but newer cranes seem to have the axle built into the jib tip, and just (...) (19 years ago, 2-Jan-05, to lugnet.general, lugnet.technic)

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