Assuming a drag coefficient of 1,8 (Cd of the Eiffel tower because there was no Cd for the Abrams), air density 0,683 kg/m3 which is the average of air density between sea level and 17 km (because using density from ISS orbit where air density is negligible gives you double digits mach numbers even with something as un-aerodynamic as an Eiffer tower), and a surface area of 2,44 m x 3,66 m= 8,93m2
SEPv3 Mass: 66.8 tonnes= 66800kg
For acceleration to be equal to zero weight=drag so Drag= 66800x9,81= 655308N.
Using drag's inverse formula V= sqrt((2x655308)/(0,683x8,93x1,8))= 345,513m/s= 1243,84km/h
This entire thing was calculated using highschool math, assumptions and without taking into account deceleration from much higher reentry velocities (so it's as if we dropped an abrams at 17km up in the air instead of orbit) so feel free to go "Uhm akshually 🤓" if you get more accurate numbers
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u/TheirCanadianBoi 9d ago edited 9d ago
I'm not sure if an Abrams could reenter in one piece. The space around the turret and gun would basically act like a plasma cutter.
Does anyone know what the terminal velocity of an Abrams would be? I would assume it would fall front down, but it might also tumble.
It would be fun to try.