5 ms·

It's probably 27kJ measured by the stored charge in the capacitor... which probably aren't delivered to the fullest extent. You can see the wires jump--that's

It's probably 27kJ measured by the stored charge in the capacitor... which probably aren't delivered to the fullest extent. You can see the wires jump--that's inductive magic in action. To get any sort of quick magnetic pulse into the railgun, you need high voltage[1] and low transmission line inductance; neither of which are satisfied here. A guy I know works on high power pulse mode lasers and they achieve ridiculous rising edges with thin twisted pair wire. Lots of resistive loss but hey at least the current rising edge is nice and fast. [1]: a few kilovolts.

mangeletti 11y ago
Perhaps it is, but the inefficiency of the machine shouldn't really come into play when describing how powerful it is. Otherwise, I could call my car a 900 horsepower Honda Accord, based on the gas it burns, since the engine probably isn't even close to 30% energy efficient.
- Synaesthesia 11y ago
  I think a lot of the energy is going to heat since the blocks of Aluminum melt and even vaporize.
- hatsunearu 11y ago
  I didn't mean inefficiency, I meant that not all of the energy can be delivered to the projectile because the delivery is rate-limited because of electric properties. Also, there is inefficiencies in play, such as the melting aluminum like the other person suggested.
- iaw 11y ago
  They actually typically report horsepower and torque measurements for cars at the engine and not at the wheels. There's an additional efficiency loss in the drive train not accounted for in marketing numbers.
grecy 11y ago
It's probably 27kJ measured by the stored charge in the capacitor... which probably aren't delivered to the fullest extent. When this was on Reddit yesterday the OP did a mini-AMA in the thread [1], and he confirmed this. 27kJ is the stored charge the capacitor bank. For various reasons, he's vary aware this is not all transferred to the projectile. [1] https://www.reddit.com/r/DIY/comments/3s4o4j/diy_250_lb_giant_mobile_railgun_27000_joules/ https://www.reddit.com/r/DIY/comments/3s4o4j/diy_250_lb_gian...

mangeletti 11y ago

Perhaps it is, but the inefficiency of the machine shouldn't really come into play when describing how powerful it is. Otherwise, I could call my car a 900 horsepower Honda Accord, based on the gas it burns, since the engine probably isn't even close to 30% energy efficient.

Synaesthesia 11y ago
I think a lot of the energy is going to heat since the blocks of Aluminum melt and even vaporize.
hatsunearu 11y ago
I didn't mean inefficiency, I meant that not all of the energy can be delivered to the projectile because the delivery is rate-limited because of electric properties. Also, there is inefficiencies in play, such as the melting aluminum like the other person suggested.
iaw 11y ago
They actually typically report horsepower and torque measurements for cars at the engine and not at the wheels. There's an additional efficiency loss in the drive train not accounted for in marketing numbers.

grecy 11y ago

It's probably 27kJ measured by the stored charge in the capacitor... which probably aren't delivered to the fullest extent. When this was on Reddit yesterday the OP did a mini-AMA in the thread [1], and he confirmed this. 27kJ is the stored charge the capacitor bank. For various reasons, he's vary aware this is not all transferred to the projectile. [1] https://www.reddit.com/r/DIY/comments/3s4o4j/diy_250_lb_giant_mobile_railgun_27000_joules/ https://www.reddit.com/r/DIY/comments/3s4o4j/diy_250_lb_gian...