Sunday, June 10, 2007

Bridges & towers

For several days I have been working on bridges out of K'nex. First, I built the odd looking thing at right from a 1997 K'nex "educational" bridge set. The bridges of that set seemed to have been designed from sketches of different bridge types, not from real bridges - which may be why K'nex came out with a larger, more accurate, and much more expensive "Real Bridges" set. It surely inspired the name.

After building that bridge "by the book" (or at least "by the card"), I more or less duplicated it using longer K'nex rods, and omitting that truly odd support structure.

I continued to fiddle with it over the next several days, which included an excellent "research" (more accurately "inspiration") trip to a lovely Pratt truss on the Snoqualmie Valley Trail - the former Milwaukee Road Cedar Falls to Monroe railway line, converted in that segment to a hiking and biking trail.

I like the results (top). This version is about five feet long.

Today, I decided I had had enough K'nex, and it was time for some fischertechnik, so I brought out the Universal set again, and built this nice communications tower (left).

I've fiddled with a few short bridge trusses out of fischertechnik, and am just about ready to do something substantial. It may have to be a mixture of yellow and gray - a bridge in the process of being repainted?

Whichever direction I take with it, I am sure it will be Good Block Play.

Just as these projects were all Good Block Play.


Herman said...

I like the bridge. I never knew it was called Pratt truss

Alan said...

"pratt truss" refers to the type of bridge - the pattern of the diagonal members - most of the steel truss railroad bridges we see are pratts