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I’ve been teaching kids about cranes and bridges since 1997 in Portland Oregon. This is NOT a shop class but an integrated math/engineering program. STEM

The kids learn basic engineering principles, how to apply basic trig etc. They get experience using tools as we build ;

BRIDGES

Using this luffing jib tower crane ( Luffer”)

the kids learn:

-how much load the crane can lift with a boom angle of 60 degrees and no counter-weight

-how to find critical distances using trig

-how to find the Mechanical Advantage of pulleys

i build my bridge and crane models with BRIDGE BEAMS .

Remember Erector sets? They first came out 100 years ago and were even more popular than Legos are today. My BRIDGE BEAMS are made from 1/4 thick plywood pieces that are 2 1/2″ wide. Much stronger than Erector’s thin metal strips.

I use these small brown angle connectors to assemble the different bridges and cranes.

Just like with Erector sets, you can take the “luffer” apart an build something new.

Go to the LUFFER KIT to see what I built.

-20ft pony truss bridge

40ft suspension bridge

and lots of models

CRANES

-working models with an;

8ft long boom-includes a spot for the counter-weight ( that”s kyle as ctwt)

16ft boom- using 1000lbs for ctwt and a load of 3 kids sitting in the “skip”

Most of the bridges and crane on this web-site were built “erector set” style

Erector sets and meccano have been around for over 100 years. Using thin metal strips and small nuts and bolts, kids could build almost anything.

I use 1/4″ plywood, 2 1/2″ wide and small plastic angle connectors for my bridges and cranes.

I call the members BRIDGE BEAMS

Everything goes together with 8-32 machine screws and nuts.

And just like with Erector Sets, you can build abridge/crane, and then take it apart and build something new. Currently I’ve made a dozen new “structures”- see Tranformers.