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Friday, July 25, 2008

g26


One can never build enough towers. This Gernegross tower design has a balcony off the side.

7 comments:

Alan said...

I love the look of this, so looked forward to building it.

I did build it, and with the KG set, but I think it would be better built with large stones - too fussy & wobbly in KG.

At one point the wind caught the far end of the piece of paper I was building it on, and almost knocked it down -- several of the upper stones were knocked akimbo.

But at least I got pictures.

:)

releppes said...

Sometimes, building models with the KG set is a bit like playing operation. It's difficult to place stones "just right". My hands are not that steady.

When it comes to KG models, I mostly build the 2D designs. Of the 3D designs I've created for the KG set, the g7 bridge and the g11 lighthouse are the only models I build over and over again.

BTW: One of the most difficult KG models to build is the g14 monument. Even with the HM set, that design is difficult to keep the stones straight.

Alan said...

Do you build your 2D designs on their backs then?

I build everything standing up and have sorta counted on them being stability tested ;)

The closest I come to building recumbent models is when I am so unsure of how something will go together that I lay out the stones in approximate recumbent vertical layers, side by side -- the Bing design I did yesterday had a bunch of extra lines that turned "#15" stones into pairs of "#19" -- without that laying-out I was afraid I would use the wrong stones in the tile floor and end up short just at the top of the tower as I was finishing.

I think I'll go try your g14 now.

releppes said...

I sometimes create a 2D design by laying the model on it's back. This way I can quickly experiment how I'd like the stones place. But I always build the models vertical.

It's funny you mention stability, because I'm a big stickler for that. I use to avoid 2D models because I was afraid of building something tall only to have it crash down and chip a stone. When it comes to larger models, stability is an even bigger issue. Especially around the roof. I've seen several designs where a 208 roof tile would only have 50% of it's base resting on the structure. Sure, the weight would keep the stone in place, but the slightest bump would cause it to fall. It's far worse when it's a 212 stone and only 25% of it's base is resting on a the structure. There too, if correctly placed, it's weight will hold it in place. I find such an arrangement very unstable, yet I've seen it done in some plans. It's one of the reason I tend to always "trim" my roof lines (not sure of the correct term). As a rule of thumb, I try not to have an over hang of anything over the width of a 69 stone. It's a rule I generally stick to even at the sacrifice of making a better looking model. This is the case to one of my castle designs for set 6 which I hope someday will get up on the blog.

Saying that, yes, I do try to do a fair bit of stability testing. Believe it of not, even this model is very stable.

Alan said...

i've built quite a few of those designs with the rough stones 50% overhanging on the downslope side & they have all been fine as to stability, in spite of my initial concerns

the 208 has 3/4 of its weight on the support and 1/4 overhanging -- the 212 is beyond my calculating prowess at the moment, but seems a little less

that seems to be more than enough to make a safe & sturdy cantilever

do some testing on how far you have to tilt or slide either stone when it's supported in that position, and you will be surprised

i just ran a new set of tests using a #4 as a support, resting on an empty KG box

after my slide & tilt tests, i tried putting each stone in position in turn and tapping the KG box like a table jar -- took quite a lot to destabilize an individual cantilevered stone

adjacent stones can provide enough friction to stabilize things even further

releppes said...

It must just be me then, because when I brought this issue of stability up with George about a year ago, he tends to agree with you.

My peeve wasn't so much a 50% overhang with a 208 stone, but rather the combination of 208 stones overhanging by 50%, then having a 212 stone on a roof corner. I had no problems placing the stones in such a configuration. If the roof didn't line up just so, those corner roof tiles would fall. Or if I got all the stones placed, I'd fat finger something only to have my roof start to fall and crash into something below which would cause a domino effect.

The general conclusion was to be much more careful when placing stones. Because I wanted my structures to be easy to recreate, I opted on the side of clumsiness. I figured the average builder might be off by at lease the width of a 69 stone when putting a roof on.

Do a tilt test by placing a 208 stone with a 50% overhang, then push it another 12.5% (ie: the width of a 69 stone). The 208 stone will still retain it's balance (I think), but it's far less stable.

For that reason, and it's completely my own preference, I try not to have an overhang of anything over the width of a 69 stone. To me, the structure is still pleasing, but much more forgiving to the builder. When I start posting some set 6 designs, you'll see what I mean. Several of my early 6 designs have a large overhand on some roof tiles, but all my later designs have much less of an overhang and almost all the roofs are trimmed.

As far as the initial comment on the g26 structure being wobbly, I observed that with the 29R stone when place on end. The balcony part was stable for me. Because the floor of the balcony is a 69 stone, you can pinch that whole level together to remove any slack. It's the two 72 stones on the next level that give me grief. You need to balance them on end and carefully place the 218 arch on top, then the roof tiles in hopes the 72 stones don't wiggle out of place.

It's a pain, I agree, and it's not one of my favorite designs. I like it because it looks creative for a small set like the KG, however, I don't like it because it's not forgiving to the builder.

Alan said...

ok

you are talking about stability while placing, and i am talking about stability one they are in place

i have vague recollections of early problems with the corner roofs, before i learned better technique, and i admit to a lingering antipathy for them

i dislike putting them on a model, they require special care and maybe special techniques - i try to place them against something, if only a temporary block that will be removed afterward

but i like the effect -- cantilevers are appealing, and that moment before you realize why the block is stable as it sits is fun

i have been tempted to go the opposite direction from you, and explore having an even wider overhang by having the course above slightly overlap the tips of those stones

hmmmm - maybe i should get some 211B stones ...