Tuesday, January 6, 2009

Load range and other issues

I've gotten some feedback on what we've done so far and I want to quickly touch on a few points, before getting back to working on the measured drawing and more elaborate and prettier versions of this cart.

I had an inquiry about bracing of the rear bolster. The reason you don't see any separate bracing is because; well, there isn't any.

So I guess I ought to address the load range for this puppy--should've done it sooner.

Way long ago we took Caitlin to an event where she slept in her commercial travel crib. We got in late that night, and the following morning when we met our neighbors in the next pavilion they said, "And this must be Caitlin-lie-down!" A deduction based on the litany we'd repeated to her throughout the night. When I built the "John Deere" wagon I thought we'd only be using it to haul Caitlin around Pennsic. Our first night there she said she didn't want to sleep in her travel crib, she wanted to sleep in her wagon, in which she'd played in, on, and around most of the day (needless to say this was very flattering to ol' dad). We packed her in with pillows, stuffies, and blankets, and she was happy as a clam: we never went back to the travel crib.

A year or so later while discussing Viking beds, a friend lamented that he wanted to build a Viking bed for his daughter for their encampment but he couldn't find any plans. I pointed out that rather than build a Viking bed that was only useful for sleeping, it would be better to build a Viking wagon that was multi-purpose.

Thus, the lineage of this wagon is to have a bed 52" x 28" so that it can also serve as a child's bed. It isn't so that it can be overloaded to the point of structural failure! It will handle 3 fifty pound plus kids with ease, but if someone were going to haul extremely heavy loads on rough terrain, I'd suggest adding hounds to the rear bolster and the tongue. I'll cover that modification in a future post.

For the purposes of this wagon, i.e. simple, easy, and quick to build for the skill and toolbox challenged the egg-crate joint of the 2x4 coupling pole with the bolster, combined with the lateral stability of the positioning blocks of the bed is sufficient.

The big wheels make a difference as well. One of the reasons the "Radio Flyer" type of wagon bogs down is those dinky little wheels. Using larger wheels is one of the reasons I moved my designs away from the "John Deere" wagon I built.

In future posts I'll also be showing a completely different undercarriage based on the traditional "double 'A' frame" of heavy draught wagons. Unfortunately, while stronger, this arrangement is more difficult to build because it requires mortise and tenons.

I've been asked about maneuverability. While I mentioned if we had full underlock it would improve maneuverability forward, but I didn't mention backing up. Well, let's be honest--backing up isn't a wagon's strongpoint. You can push the wagon backwards in a nice straight line, but maneuvering in reverse does take a little practice, and again, underlock would improve it.

Oddly enough, dog carts seem to keep cropping up in discussions about my wagons. I've never seen a dog cart at an event, and I'm not sure if it's because dog carting is one of those interesting topics that's easier to study than to do, or if there's a supply problem with dog carts. The last time I looked into dog carts, must be several years ago now, it appeared that the only plans available that are free and easy are for a pvc construction that is jarringly mundane.

I'm not a "dog person" and have no personal experience with pulling dogs beyond watching "Balto" with my daughter once. That being said, I'm not so sure I'd hitch a dog to this particular wagon. Certainly, I'd substitute lighter materials in it's constriction, probably birch plywood, which would necessitate adapting the dimensions. I have no idea what sort of load a properly harnessed dog can pull by himself, but it seems noteworthy to me that dog sleds, which glide on snow, still have eight dogs working. I have to think that with this size wagon you'd be approaching the load limit for a single dog with just the wagon, leaving little left for goods. I could be wrong, though. I also think a wagon for dog pulling would benefit from a completely different running gear from what I've presented so far. I'd want a double "A" frame with two tongues, lighter build, and front and rear hounds, and, for sure, full underlock.

I don't know, it might be intriguing revisit the subject, and maybe build one and blog the process.

TTFN

McK

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