rgbrock1
A belly in is hard to envision, the brain wants to take us in many unhelpful directions.
Think of it this way. A 334,000 pound airliner is descending at 2500fpm at a speed of 140 knots. Without being able to arrest descent, or diminish a/s, the airliner contacts the ground (let's say concrete) at the same ROD 2500fpm, and a (now) groundspeed of 140 knots.. The descent in lay terms is roughly 30 miles per hour, Thats a fall from a three story building. No big, right? 334,000 pounds at thirty miles per hour is an unthinkable amount of energy. The a/c hits and the first snapshot shows a two foot section scraped off at the tail rise. roughly 2000 pounds has hit and given its energy to the concrete and to the smithereening of its aluminum. The next snapshot shows a section two feet more deep, a larger section and this time 7,000 pouinds of mass gives it up for friction, disintegration and a very, very minor dissipation of energy of 325,000 pounds of the mass remaining. Third snap, fourth, etc. As the mass is heating itself and the concrete, shredding its metal, the tail has slowed with an energy its mounts cannot survive, it snaps off, and is left behind to tumble and pose for the photographers. The down force it has provided the fuselage to keep the nose up is instantly missing, and the nose starts to drop dramatically. Now the wing box, landing gear, and engines contact the ground. Perhaps 100,000 pounds of mass this time, and it bounces like you cannot believe straight up into the sky, with very little of its energy missing. The trucks of the Main gears have been evaporated, the only piece left is the strut, and it bounces out of its pillow block mount in the wing box like a toothpick. The Nose, having slammed down intensely onto the rock and gravel, disappears into pieces the size of a credit card. The rest of the fuselage has been lifted up behind the nose, and continues along like a plow, as if it was entering the earth itself, except it isn't it is disappearing as the nose did ahead of it. the wings now have the appearance of a boomerang, though undoubtedly the box connecting them is broken. They have a low trajectory, perhaps rolling slowly about the spanwise axis of this 80,000 pound "boomerang". They eventually slow, and drop, roughly in designed for orientation, but the left engine pylon has pierced the upper left wing, and acquired a chord wise rip that at first glance looks like a canoe (Flap fairing). The leading edge is separated full span, yet the ribs, stringers, spars and portions of the center box remain, amazingly robust, considering their experience.
A Ferrari dropped from 30 feet at 140 knots would look the same, substituting component parts. I worked in accident investigation for a time, for attorneys. I quit when they embellished or downplayed my findings before the Court.
jcjeant that's the one.
GarageYears have it your way. I know the story, and without putting a too fine point on it, these two accidents are eerily similar to me. (If indeed the 330 succumbed in this way, so it's really not germane to debate, we don't know the widebody's procuring cause), Jim Graham was the flying pilot. cheers.
bear
Last edited by bearfoil; 21st May 2010 at 22:19.