[ARCHIVED THREAD] - How does an RPG work? (Page 1 of 2)
Posted: 7/5/2009 5:31:12 PM EDT
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My son asked me and I didn't know what to tell him.
1) Are they accurate? I see no tail fins or stabilizers on the extra rockets I have seen in pics. 2) How does the shaped charge work for penetrating thick steel? |
| The shaped charge is an inverted copper cone, surrounded by explosives and detonated from the rear. The explosive blast shapes the copper into a superheated slug moving at about 75% the detonation velocity of the explosive, which is like 11,000 fps. Huge amount of energy, this is what pierces the armor. But this reaction needs a bit of stand-off distance once it hits its target to form and get the copper slug to that velocity, which is why the RPG war head's top cone is hollow plastic with the contact trigger at the tip. |
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Munroe Effect
Hollow charge or shaped charge. I gather it will turn the copper gaseous so it kind of injects a spray that turns into molten metal as it cools. |
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Disclaimer: I am not an expert in munitions of this type nor do I have any experience dealing with RPGs.
I can't answer about the stability. I know some modern RPGs have some kind of guidance system, but older ones like WWII or some Cold War era are just fire and hope your aim was accurate. As for the penetration factor, what I do know (and hopefully my knowledge here is not inaccurate or outdated) is that once the warhead hits its target, the explosives inside ignite or something inside reacts to create essentially a superheated metal. Think something like liquid steel...pretty hot right? Well that small shaped piece of superheated stuff can go through a lot of armor pretty good since it also has a lot of momentum from the launch to propel it forward. Now add into this mix various additional explosives that might tag along and detonate a short time thereafter. But of course, I could easily be talking out of my ass here so hopefully someone with more knowledge will chime in. |
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Quoted: Disclaimer: I am not an expert in munitions of this type nor do I have any experience dealing with RPGs. I can't answer about the stability. I know some modern RPGs have some kind of guidance system, but older ones like WWII or some Cold War era are just fire and hope your aim was accurate. As for the penetration factor, what I do know (and hopefully my knowledge here is not inaccurate or outdated) is that once the warhead hits its target, the explosives inside ignite or something inside reacts to create essentially a superheated metal. Think something like liquid steel...pretty hot right? Well that small shaped piece of superheated stuff can go through a lot of armor pretty good since it also has a lot of momentum from the launch to propel it forward. Now add into this mix various additional explosives that might tag along and detonate a short time thereafter. But of course, I could easily be talking out of my ass here so hopefully someone with more knowledge will chime in. No RPGs have guidance... Neither do their US counterparts (AT-4 and SMAW).... Shaped charges create a plasma-jet that burns through armor - it requires a precise standoff distance, which is why the RPG has the hollow front cone, and why slat-armor works on them... The 'copper slug' tech described above is an EFP, which although about 1/2 as effective as a same-size shaped charge, is not vulnerable to slat armor. RPGs do not have EFP warheads.... |
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Munroe Effect Hollow charge or shaped charge. I gather it will turn the copper gaseous so it kind of injects a spray that turns into molten metal as it cools. That was what I couldn't remember. |
| A good RPG gunner can hit a moving vehicle from hundreds of meters away, and they will kill any vehicle short of a main battle tank. The inverted-cone shaped-charge warhead will penetrate many inches of armor. Older projectiles explode on impact, while many newer ones explode on impact, or at a certain distance/time (Airburst). When they explode in your face, it sucks. |
| Something like this, http://www.wikihow.com/Play-Dungeons-and-Dragons |
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Nope.
IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... Yep. They can be hell on the shooter. Our CATM guys would wear a face shield and heavy leather gloves when they shot the RPG-7s we had in our Armory. Back blast is pretty impressive, as is the firing and impact of the rounds. It's not like in the movies where you hear this whoosh as the rocket leaves the tube...it is a very loud bang as it ignites, and very shortly afterwords another bang as the rocket impacts. I have seen some RPGs do some crazy stuff after they leave the tube; radical direction changes after the fins have broken off. Our CATM guys would always shoot behind a trench, and would tell us that if we see them chuck it in there to try to keep up as they ran away. Sometimes the motor would not work correctly and the rocket wouldn't leave the tube, and since the rounds they used had a self-destruct they would blow up whether they hit a target or not. |
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Nope.
IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... Dave, on an RPG-7 (ETA: unlike our LAW): The booster motor is gunpowder, and throws the sustainer motor and warhead out of the tube at 350+FPS, where the sustainer motor (the rocket) starts. |
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Nope.
IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... Really? I'm not saying you're wrong but can you explain to me what the tubes in these wax wrappings are? We screwed the to the end of the warheads. I always thought they were charges to get them away from the gunner. Photo is mine of rounds I fired. 
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Nope.
IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... Really? I'm not saying you're wrong but can you explain to me what the tubes in these wax wrappings are? We screwed the to the end of the warheads. I always thought they were charges to get them away from the gunner. Photo is mine of rounds I fired. http://img248.imageshack.us/img248/4337/002z.jpg I've never fired one but I thought those were the booster charges (powder) to get it out of the tube before the rocket motor kicks in. 
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Nope. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... Like this... http://www.youtube.com/watch?v=ZguswO3nFRs |
| The RPG7's nose cone is shaped the way it is because of the detonator, and the standoff distance needed for the shaped charge to work. The pointy tip has a piezo-electric detonator that created an electrical current when it hits the target, and the warhead explodes at the proper distance to focus the blast forces by the position of the detonator in the nose cone. Brilliantly simple if you ask me. |
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Nope.
IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... 
Men Against Tanks, page 107. |
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Nope.
IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... Really? I'm not saying you're wrong but can you explain to me what the tubes in these wax wrappings are? We screwed the to the end of the warheads. I always thought they were charges to get them away from the gunner. Photo is mine of rounds I fired. http://img248.imageshack.us/img248/4337/002z.jpg I've never fired one but I thought those were the booster charges (powder) to get it out of the tube before the rocket motor kicks in. Actually, that is the rocket motor. It is designed to achieve full burn before the exhaust nozzle leaves the front of the launch tube. Otherwise the operator would have to deal with two back blasts, one of which would be in his face. The RPG is not a two stage rocket, it receives a short duration impulse at launch and then follows a balistic trajectory. |
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http://www.defensereview.com/wp-content/uploads/2009/04/airtronic_rpg_7_usa_21.jpg Is this a fucking joke?! 
Tapco has expanded their inventory. |
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It's a rocket propelled grenade. Solid fuel rocket, blows up on impact. Not accurate. Actually, they're quite accurate so long as you aren't an illiterate goat herder who thinks allah will guide the rocket to the infidels so there's no need for you to aim. Also, contrary to what most people would think, RPG's move INTO the wind and not with it like bullets. If you fire a bullet and there's a breeze coming from the right, the bullet will move left. If you fire an RPG and there's a breeze coming from the right, the RPG will move right. I understand it takes some getting use to. |
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http://www.defensereview.com/wp-content/uploads/2009/04/airtronic_rpg_7_usa_21.jpg Is this a fucking joke?!
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It's a rocket propelled grenade. Solid fuel rocket, blows up on impact. Not accurate. Actually, they're quite accurate so long as you aren't an illiterate goat herder who thinks allah will guide the rocket to the infidels so there's no need for you to aim. Also, contrary to what most people would think, RPG's move INTO the wind and not with it like bullets. If you fire a bullet and there's a breeze coming from the right, the bullet will move left. If you fire an RPG and there's a breeze coming from the right, the RPG will move right. I understand it takes some getting use to. I've read this. The wind pushes more on the fins and changes the direction the projectile is pointing (the tail gets pushed away from the direction the wind is coming from than the nose). Because it has propulsion it's pushing into the wind because of the wind. |
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How Rocket-Propelled Grenades Work
I'm a 5th degree black belt in internet-fu. 
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Nope.
IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... RPG-7 user manual |
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http://www.defensereview.com/wp-content/uploads/2009/04/airtronic_rpg_7_usa_21.jpg Is this a fucking joke?!
That's the Airsoft version. TT |
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Actually, that is the rocket motor. It is designed to achieve full burn before the exhaust nozzle leaves the front of the launch tube. Otherwise the operator would have to deal with two back blasts, one of which would be in his face. The RPG is not a two stage rocket, it receives a short duration impulse at launch and then follows a balistic trajectory. See Page 6 ETA: Beat several times. |
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http://www.defensereview.com/wp-content/uploads/2009/04/airtronic_rpg_7_usa_21.jpg Is this a fucking joke?!
Tapco has expanded their inventory. Some shop called Airtronic is supposedly making them for the US military in one capacity or another, but when I saw the toes at the bottom of the pic... Well, I know one of you is cooking up the world's greatest tapcofuck joke ever.. Complete with NSN. |
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http://www.defensereview.com/wp-content/uploads/2009/04/airtronic_rpg_7_usa_21.jpg Is this a fucking joke?!
Suh-wheat |
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Quoted: Quoted: Nope.IIRC: A blackpowder charge kicks the projectile clear of the tube and then the rocket fires. RPGs do NOT have soft-start capability... The rocket fires in the tube, creating a significant backblast that can injure/kill anyone behind the weapon.... RPGs HAVE a booster which kicks them out of the tube before rocket ignition. The rocket burns from the front, about mid-way up the total length. There are 5 nozzles which angle back about 30 degrees, in front of the fins. Well, the propellent grain is a hollow-type, constant area for a near constant thrust curve, not an end-grain burn. Once the rocket ignites, the warhead is now armed. The nose cone contains the piezo initiator which triggers the detonator at the rear of the warhead. The Munroe Effect causes the cone liner to collapse AND accelerate to a velocity greater than the detonation velocity. During the detonation, the liner is also heated and is sustained by very high pressure, keeping it focused. It is high velocity, high pressure and very high temperature. The combination causes the target to fail. |
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Quoted: http://www.defensereview.com/wp-content/uploads/2009/04/airtronic_rpg_7_usa_21.jpg Is this a fucking joke?! If I buy 12 do I get another one for free? |
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It's a rocket propelled grenade. Solid fuel rocket, blows up on impact. Not accurate. Actually, they're quite accurate so long as you aren't an illiterate goat herder who thinks allah will guide the rocket to the infidels so there's no need for you to aim. . Unfortunitly, some RPG gunners in the Stan are trained well. Before, goat herders. Now they are very deadly gunners. |
| We had about 15 or so that we were supposed to get rid of with EOD. Well we shot off about 10 of them before we decided to stop. A few went about 10m then hit the ground, dud. Another two went almost straight out and up in the air and tumbled the way down and exploded, and the rest went where they were supposed to. The didn't seem reliable or accurate to me.. |
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I read a pamphlet on one, the big warning was dont shoot thru an open window poke yourself or at least the front half of the RPG out the window. guessing its cause the fins would unfold and you'd have a nasty surprise. Um, I'm pretty sure firing from an enclosed space will result in a great deal of pressure inside that space, causing serious injury and or death to all those inside, including the person firing the RPG. |
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I read a pamphlet on one, the big warning was dont shoot thru an open window poke yourself or at least the front half of the RPG out the window. guessing its cause the fins would unfold and you'd have a nasty surprise. It's backblast, my friend. Could screw your world up. |
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This just in. BOTH sides are right. SOME RPG's like the RPG-7 use boosters. SOME RPG's like the M72 LAW or RPG-18 do not use boosters. Right. I just assumed the OP was talking about the RPG-7. Good point. PRG-18 is a copy of the LAW. I've seen and shot the Eat German RPG-18. |
