Yesterday's Lego purchases

15%-off at Kmart, and a bunch of the new 2009 sets have arrived.

I thus felt compelled to pick up some consecutively-numbered Lego construction vehicles:

One #7630 Front-End Loader
Two #7631 Dump Trucks (their 15%-off price is particularly good when compared with the US list price)
One #7632 Crawler Crane...

Lego Crawler Crane

...which is a big almost-Technic set (see also, #744) whose main boom looks distressingly POOP-y. But it's actually not so bad, since the boom is made out of these and these, both new pieces for this set.

The new crane particularly appealed to me, and not just because it's got the nifty new chunky tracks. I've been re-reading J. E. Gordon's classic Structures: Or Why Things Don't Fall Down, and this crane provides a perfect demonstration of how real cranes stay in one piece - it has a strong-in-compression-but-weak-in-tension boom, which is kept in compression by a strong-in-tension-but-useless-in-compression cable. The result is a simple tensegrity structure which, in a sense, gets stronger the more you load it.

If I give the crane to a kid, I may require them to endure a lecture on this subject.

7 Responses to “Yesterday's Lego purchases”

  1. Stuart Says:

    If I give the crane to a kid, I may require them to endure a lecture on this subject.

    Who are you kidding? You aren't about to let some grubby child foul that pristine lego.

  2. FuzzyPlushroom Says:

    I wish I'd had these as a kid. Probably would've spent hours lifting increasingly heavier objects, eventually seeing how successfully I could lift things after reducing the structural integrity of the boom.

  3. Ziggyinc Says:

    For that very reason I try to buy two sets.

  4. TwoHedWlf Says:

    Man, all I ever did with my legos as a kid was make variable sweep wing planes with retractable landing gear...Then run around by room making wooshing noises.

  5. Boran_blok Says:

    Same here, but rather space vehicles

  6. Daniel Rutter Says:

    I believe the word you may be looking for to describe toys well-suited to this activity is "swooshable".

  7. Camping Fag Says:

    My son chose 7630 as his reward for toilet training. I have to say I'm pretty bloody impressed - NZD$16.95 for a set with a lot of non-POOP parts and rather nice minimalist design; I'm particularly fond of the radiator grille on the back. The hydraulic analogue on the front has a tendency to fall off, however.

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