Any Engineers in the building? Steel Stand question

That's what I meant when I said "tie the legs together". And a 3100lb car with over 600 lb-ft of torque being applied to it, with 1000s of lbs of braking forces when slowing down, can be made with 1/8 inch thick steel 2x3 frame rails. Your 3/16 inch thick rails are overkill (which is never a bad thing). Seriously. People use the same 1/8 inch thick 2x3 steel rails when building off road vehicles that fly (sometimes) over 10 feet in the air, and the frame doesn't break when the vehicles comes back into contact with the ground. Those sheering, and torsional forces, greatly exceed anything your 1800lb tank is ever going to exert on it.

 

Right, but in those cases the frames are made to have some give to them. They're supposed to have some flexibility. If they didn't flex the welds would break, the engines would get torn up, and any deflection would go instead to the wheels and throw them off the track/course. This cannot flex, or the rigid glass above would be stressed....

Still, I am thinking I'm gonna be ok.

 

Nope. The shock absorbers, springs, motor mounts, etc... is what dampens the energies so nothing breaks. The frame rails give it it's rigidity. However, yes the frame rails can flex (very slightly) as ALL steel/iron can. It's called malleability. I was using the above to illustrate the fact that you are NO WHERE NEAR OVERLOADING that frame. You are using a stationary load, not a moving or torsional load, so you are no where near the load limits that a moving vehicle places on the frame rails. The car frames are usually 12-16 foot long by 5 foot wide in dimension. You are 5 foot on 2 foot. WAY LESS FLEX. Again, you are building with 3/16 inch framing which will be overkill. Again, that is good. I don't know how much more clear/reassuring I can be. You are (more than) fine as long as you box in those legs at the bottom. I'm not trying to be a PITA, just trying to let you know: You are more than fine.