4 ms·
Let's see. The webm video of the car door shot is 30 fps, with each frame repeated 4 times. This suggests that original was shot at 30 fps and then reduced to 1
by avian 11y ago
Let's see. The webm video of the car door shot is 30 fps, with each frame repeated 4 times. This suggests that original was shot at 30 fps and then reduced to 1/4 speed.
The delay between the first flash from the gun and the entry hole appearing is 4 frames at original fps. At 30 fps, that gives flight time between 100 and 130 ms.
I estimate that the distance from the gun to the car door is around 10 m. That gives speeds on the order of 100 m/s (200 mph).
Energy depends on the mass of the projectile. At these speeds, 27000 joules would require mass in the range of kilograms, which is obviously not true. Still, it seems feasible to me that this gets better than highway speeds.
- danielvf 11y agoPaintball guns are usually limited to 300 feet per second in competition- that's 91 meters per second, which is about what you are measuring. A paintball weight 3grams, whereas the rail gun projectile is 11 grams. Paintball guns can shoot faster than is competition legal, and the much longer barrel could allow it to add more energy than it could with a heavy projectile in an equivalent paintball gun.
- tomcam 11y agoUm, no. A paintball weighs about 3 grams [1]. [1] http://www.dtic.mil/dtic/tr/fulltext/u2/a473706.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/a473706.pdf
- danielvf 11y agoThanks! Corrected. At least I wrote the wrong measure on both, so the ratio was still right.
- simonh 11y agoThey say that the paintball gun doesn't shoot the projectile fast enough for it to overcome friction from the rails, so without the magnetic field it wouldn't exit the gun at all, which seems plausible. So assuming they are trustworthy you can completely discount the energy provided by the painball gun when considering the energy given to the projectile.