The scene in Predator where someone holds down the trigger and fires continuously for 45 seconds is actually vaguely possible.
The gun weighs 39 kg or 85 lbs, so it’s possible for a soldier to carry it, especially the soldiers in Predator who are shown to be much, much stronger than the average soldier. The ammo used in 45 seconds would weigh 25 kg, so it’s still vaguely possible that the soldier could carry it along with the weapon. The volume of ammo wouldn’t be that much of an issue. It’s under 1000 rounds for 45 seconds of fire, which would fit in a backpack-sized box.
Another big issue is the recoil. On earth, someone experiences 9.8 newtons per kg of mass. We don’t know how much Bill Duke weighs, because he’s just an actor, but since Jesse Ventura used to be a “wrestler”, we know his billed weight of 111 kg in his wrestling days. So, without any gear on he’d be experiencing 1088 N of force from gravity. Add the weight of the minigun and its ammo that’s 175 kg, or 1715N.
The recoil generated by the gun is based purely on the rounds it fires. An online calculator puts the recoil impulse at 13.4 Ns of impulse per bullet. From that reddit post, they figured out the minigun in that scene had been slightly slowed down from the normal 2000 rounds per minute (33.3 rounds per second) to only about 20 rounds per second. But, even then, that means the gun would be generating 268N of force. So, just to avoid being moved, someone would have to lean atan(268/1715) = 8.8 or about 10 degrees forward. That may not sound like a lot, but when you’re already carrying the equivalent of another person from the weight of the minigun and its ammo, that’s a lot of extra force to deal with.
In many games, you can move normally while carrying a minigun, but as soon as you start firing it you slow to a crawl. They actually got that part right. It would be hard to move freely while this thing is shoving you back with such force.
Their math was wrong. 45 seconds of sustained fire would require a belt far larger than any one man could carry. It wouldn’t even be logical in a vehicle turret.
Nice, I wonder how many rounds per second he was shooting. That looked like the force pushing him backwards was similar to the force of gravity pushing him down.
If the gun runs out of bullets in 45 seconds, you could probably get away with pretty small batteries. The main thing it’s doing is spinning a barrel, which you could probably do with a hand-held drill. The trick is that you don’t want to wait while the barrel spins up, so you want enough power to get it up to full speed very quickly, which means a lot of initial power drawn from the battery, then a lot less to keep the barrels spinning.
Someone on Reddit actually did the math on this 5 years ago.
The scene in Predator where someone holds down the trigger and fires continuously for 45 seconds is actually vaguely possible.
The gun weighs 39 kg or 85 lbs, so it’s possible for a soldier to carry it, especially the soldiers in Predator who are shown to be much, much stronger than the average soldier. The ammo used in 45 seconds would weigh 25 kg, so it’s still vaguely possible that the soldier could carry it along with the weapon. The volume of ammo wouldn’t be that much of an issue. It’s under 1000 rounds for 45 seconds of fire, which would fit in a backpack-sized box.
Another big issue is the recoil. On earth, someone experiences 9.8 newtons per kg of mass. We don’t know how much Bill Duke weighs, because he’s just an actor, but since Jesse Ventura used to be a “wrestler”, we know his billed weight of 111 kg in his wrestling days. So, without any gear on he’d be experiencing 1088 N of force from gravity. Add the weight of the minigun and its ammo that’s 175 kg, or 1715N.
The recoil generated by the gun is based purely on the rounds it fires. An online calculator puts the recoil impulse at 13.4 Ns of impulse per bullet. From that reddit post, they figured out the minigun in that scene had been slightly slowed down from the normal 2000 rounds per minute (33.3 rounds per second) to only about 20 rounds per second. But, even then, that means the gun would be generating 268N of force. So, just to avoid being moved, someone would have to lean atan(268/1715) = 8.8 or about 10 degrees forward. That may not sound like a lot, but when you’re already carrying the equivalent of another person from the weight of the minigun and its ammo, that’s a lot of extra force to deal with.
In many games, you can move normally while carrying a minigun, but as soon as you start firing it you slow to a crawl. They actually got that part right. It would be hard to move freely while this thing is shoving you back with such force.
Their math was wrong. 45 seconds of sustained fire would require a belt far larger than any one man could carry. It wouldn’t even be logical in a vehicle turret.
20 rounds per second, 45 seconds is 900 rounds. Each round is 25g, so 900 rounds is about 25 kg. I don’t see the issue.
yt/zPLfefas7dg
Nice, I wonder how many rounds per second he was shooting. That looked like the force pushing him backwards was similar to the force of gravity pushing him down.
You forgot the weight of the battery for the motor that rotates the barrels. Afaik in the film a wire was run through the actor’s pants.
If the gun runs out of bullets in 45 seconds, you could probably get away with pretty small batteries. The main thing it’s doing is spinning a barrel, which you could probably do with a hand-held drill. The trick is that you don’t want to wait while the barrel spins up, so you want enough power to get it up to full speed very quickly, which means a lot of initial power drawn from the battery, then a lot less to keep the barrels spinning.