Simple. I could not find anything that gave the measurements of the Chestnut Sparrow's or for Condor's actual body size minus the tail feathers... but the tail feathers of Eagles and Condors appear to be approximately the same proportion of body length as the Chestnut Sparrow from all of the pictures I found of all three. And I did look, seeking the information of the actual featherless body dimensions.
However, if the tails feathers extended the body length by the same proportion on both Condors and C. Sparrows, then I could go ahead and use the overall length for the calculations. I found that the tail feathers of both the C.S. and the Condors were approximately 1/4 to 1/3 of the body length and appeared to be proportionately about the same on both species. Any observational difference errors may account for the slight over-weight of the calculations of the scaled up C. Sparrow although several descriptions for the C. Sparrow mentioned it being a "chunky" bird for its size, so either could be the case.
If, however, the tail feathers were like those of a parakeet (tail feathers equal body length) or Peacocks (tail feathers can be two to three times body length) then obviously I could not have used that figure for the Square Cube Law calculations. The body length is certainly better than using Wing Span.
As to whether teratorns could fly, your calculations of energy requirements are rubbish. Gliding birds may require a significant amount of headwind in order to take off, but once aloft, they seldom flap. Some are not able to take off at all without a headwind.
No, they are not... nor are they MY calculations. They come from a peer-reviewed article by an aeronautical engineer. I have seen California Condors take off from a standing position... and even Gooney Birds can do so... but prefer not to. The calculations show that even the smallest of Teratorns could not have done so.
This leaves unanswered the question of how much time the largest teratorns may have spent flying, and whether flying was a significant component of their hunting.
Of course the lifestyle of extinct animals is only theoretical... but certain things can be learned from their body adaptations... and it is likely that teratorns hunted like Eagles rather than as carrion eaters like Condors. Their body styles are closer to Eagles with talons designed not for walking (or running...) but rather for an attack from the air.
Then they are available and you can show us the numbers.
I gave my example -- admittedly a worst case -- because your articles don't mention anything except length.
You have to understand that science has a feature called consilience. Everything has to be consistent with everything else.
The idea that the earth once rotated every two or three hours is not consistent with known physics.
The question of whether a particular bird may or may not have been able to take off by flapping its wings is a rather minor issue. It's a mystery, but the solution is unlikely to alter our view of cosmology. The large dinosaurs are even less of an issue. It makes no sense to try to invalidate physics based of a projected size and mass of a creature known only by a drawing of one bone that has been lost for over a century.
Your projected weights based on the square cube law are troublesome enough when applied to creatures we can touch and measure and observe. they border on nonsense when they are based on a few bits and pieces that have been mineralized.
If you dispute this, let's see the actual numbers and actual calculations.
Where did you pick up that BS, JS?
I let this go earlier because I was replying on my iPhone... but I have to challenge your totally unscientific absurd assertion.
The Square Cube law is not only for spheres or polyhedrons. It is valid for any 3 dimensional object regardless of how complex it may be.
Let's try it on a cube... a 1 inch by 1 inch by 1 inch cube... double the size...multiply by 2 in every dimension. It's now 2 inches x 2 inches x 2 inches.
The surface area of the 1 inch cube was 6 square inches - six sides, each 1 square inch... The square cube law says that the area should be multiplied by the multiplier squared... 22. So let's do it. 22 = 4, multiply 6 square inches by 4 = 24 square inches. yup, that works.
How about the volume? The Square Cube law says to multiply it by the cube of the multiplier... 23. 23=8, 8 x 13 inches = 8 cubic inches. Yep works there.
This is a mathematical law... it works for everything, js1138.. it's fundamental.
I'm beginning to see why you are failing to grasp the problem.