Continuing to ramble on... making no sense. Making of numbers, etc.
Black smoke is generated when things like plaster, drywall, carpet, desks, walls, and the link are BURNING. It has nothing to do with efficiency. You're probably simply thinking about cars, and how they generate black smoke when they start to burn oil.
The planes did partially explode when they hit the building. However, their wings are filled to the brim with jet fuel. Do you honestly think that all the fuel (or even most of it) combused in an instant when the plane hit the building? Gimme a break.
It's also clear that you know nothing of metal working, chemistry, or physics for that matter. As materials heat up, and surpass temperatures specific to their characteristics, they soften. Metal doesn't immediately turn to liquid when heat is applied. Here in the real world, it would continue to soften under the relentless heat of thousands of gallons of burning jet fuel until it succumbed to the force of the floors above. It would take some time. In fact, the steel beams in the WTC were designed to withstand only a few hours of extreme heat. Even still, it clearly didn't live up to it's full potential.
Think... then type. It really does work.