Weight /dimensions needed for model base?

A good standard (as I have heard) is a ratio of 4 to 1. For every four inches in height, one inch in width at the base. If this thing you are building is not going to be affected by wind loading (blowing wind) then that should be good enough. However, if there IS wind loading then you need to do some wind load calculations. It gets tricky because you need to know the wind speed and the surface area of the, what is essentially a wind screen. Since I don't know those numbers you'll have to do some research. Nevertheless, the area in square inches is 288. With just two pounds per square inch of wind (and I don't know the numbers for figuring that) you're looking at over 500 pounds of force. Since half of the screen is above the average height and the other half below, I'd think (THINK) you'd need to divide that by two to figure the amount of force you need to overcome. So you're back to the 288 (in pounds of force). Your base will need to spread that force over the width of it's footprint. If your base weighs 10 pounds and has a width of 20 inches (that's 10 inches from center out) it should withstand about 100 pounds of force trying to tip it over.

Hopefully wind is not going to be a factor. Just weigh the plexi-glass and calculate the weight and size of the base at that 4 to 1 ratio. If the glass weighs 10 pounds (guessing) and the base weighs 2 pounds (again guessing), AND it's 10 inches wide (five inches from the center out) it should be stable.

Another way to look at it is by torque. How much torque will a 2 foot high object apply over a base that is 1 foot wide? Answer: 2 ft lbs over 1 ft lb. In other words, 2 foot pounds of force. That's WELL WITHIN the 4 to 1 ratio.

My area if expertise is in electrical and electronic power systems design. This is just theory and I could be entirely wrong about my assumptions. However, I KNOW that the 4 to 1 ratio is a good set of numbers. It works for ladders. For every four feet of elevation of a ladder the base needs to be one foot out. That's all that is needed to consider a ladder safe to use.

I know this is a lot to consider, but as spoken from an engineers point of view (and we tend to over engineer EVERYTHING) this may give you some ideas on how to proceed.

ME? I think if it were in door I'd go 2 to 1. For every two feet in elevation I'd go with 1 foot in width. That's six inches from center out. So actually that IS the 4 to 1 ratio. 24 inches high, six inches wide (from center out).

Hope this helps.

'av'a g'day mate.

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