Quique Fagoaga retweetledi
The physics of what's happening in that 0.1 seconds of contact should bother you.
Those tires are completely stationary when they hit the ground. The plane is moving at 250 km/h. For the first fraction of a second, the rubber isn't rolling. It's skidding. Pure friction has to accelerate 22 wheels, each weighing 120 kg, from zero to 155 mph in roughly a tenth of a second.
The tread surface goes from -50°C at cruising altitude to over 200°C at the moment of contact. A 250-degree temperature swing in 0.1 seconds. The smoke you see at every commercial landing is rubber vaporizing off the tire surface. Studies at Manchester and Heathrow found that tire smoke at touchdown produces a greater magnitude of particulate emissions than the jet engines themselves.
The tires are inflated to 200 PSI, six times your car's tire pressure, and they're filled with nitrogen instead of air. Regular air contains moisture that would flash to steam and oxygen that could combust at those friction temperatures. Nitrogen eliminates both risks.
Each tire costs $5,500 and lasts about 250 landings before replacement. The A380 carries 22 of them. At max landing weight, those 22 contact patches are distributing 391 metric tons across roughly 15 square feet of rubber. That's 57,000 pounds per square foot.
The reason they don't pre-spin the wheels before landing, which would eliminate the skid and save millions in tire wear, is weight. Adding electric motors to 22 wheels increases fuel burn on every single flight. The math says it's cheaper to vaporize rubber 250 times and buy new tires than to carry the motors.
Chauhan@Platypuss_10
This is the most satisfying video I've ever seen. Slow-motion footage of an A380's weight on wheels during touchdown.
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